A semiconductor light emitting device having a semiconductor stacking structure bonded onto the support member and having excellent characteristics is provided by a preferable electrode structure.
The semiconductor light emitting device comprising; a semiconductor stacking structure having a first semiconductor layer and a second semiconductor layer of conductivity types different from each other, a first electrode connected to the first semiconductor layer, and a second electrode connected to the second semiconductor layer, wherein one principal surface of the first electrode has a portion that makes contact with the first semiconductor layer so as to establish electrical continuity and an external connection section.
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1. A semiconductor light emitting device comprising:
a semiconductor stacking structure having a first semiconductor layer and a second semiconductor layer of conductivity types different from each other,
a first electrode connected to the first semiconductor layer, and
a second electrode connected to the second semiconductor layer,
wherein one principal surface of said first electrode has (1) a portion that makes direct contact with a surface of the first semiconductor layer so as to establish electrical continuity and (2) another portion that is exposed and forms an external connection section,
wherein said semiconductor stacking structure is formed on or above a support member,
wherein said first electrode and said second electrode are provided between said support member and said semiconductor stacking structure, and
wherein a bonding member fills all of a space between confronting surfaces of said support member and said semiconductor stacking structure.
0. 16. A semiconductor light emitting device comprising:
a semiconductor stacking structure having a first semiconductor layer and a second semiconductor layer of conductivity types different from each other,
a first electrode connected to the first semiconductor layer, and a second electrode connected to the second semiconductor layer, wherein
one principal surface of said first electrode has (1) a portion that makes direct contact with a surface of the first semiconductor layer so as to establish electrical continuity and (2) another portion that is exposed and forms an external connection section, and wherein
one of said first electrode and said second electrode is electrically separated into a plurality of electrode segments,
wherein said semiconductor stacking structure is formed on or above a support member,
wherein said first electrode and said second electrode are provided between said support member and said semiconductor stacking structure, and
wherein a bonding member fills all of a space between confronting surfaces of said support member and said semiconductor stacking structure.
11. A semiconductor light emitting device comprising:
a semiconductor stacking structure having a first semiconductor layer and a second semiconductor layer of conductivity types different from each other,
a first electrode connected to the first semiconductor layer, and a second electrode connected to the second semiconductor layer, wherein
one principal surface of said first electrode has (1) a portion that makes direct contact with a surface of the first semiconductor layer so as to establish electrical continuity and (2) another portion that is exposed and forms an external connection section, and wherein
one of said first electrode and said second electrode is electrically separated into a plurality of electrode segments on or above said semiconductor stacking structure,
wherein said semiconductor stacking structure is formed on or above a support member,
wherein said first electrode and said second electrode are provided between said support member and said semiconductor stacking structure, and
wherein a bonding member fills all of a space between confronting surfaces of said support member and said semiconductor stacking structure.
0. 17. A semiconductor light emitting device comprising:
a semiconductor stacking structure having a first semiconductor layer and a second semiconductor layer of conductivity types different from each other,
a first electrode connected to the first semiconductor layer, and
a second electrode connected to the second semiconductor layer,
wherein one principal surface of one of said first and second electrodes has (1) a portion that makes direct contact with a surface of a respective one of said first or second semiconductor layer so as to establish electrical continuity and (2) another portion that is exposed and forms an external connection section,
wherein said semiconductor stacking structure is formed on or above a support member,
wherein said first electrode and said second electrode are each provided between said support member and respective layers of said semiconductor stacking structure, and
wherein said semiconductor light emitting device further comprises a bonding member forming a region that: (1) extends substantially from one side of the semiconductor light emitting device to the other side of the semiconductor light emitting device; (2) is above said support member; and (3) is between confronting surfaces of said support member and said semiconductor stacking structure,
said bonding member thereby providing electrical connectivity between said support member and at least one of said first and second electrodes.
2. The semiconductor light emitting device according to
3. The semiconductor light emitting device according to
one principal surface of the second electrode has a portion that makes contact with the second semiconductor layer so as to establish electrical continuity; and
another principal surface of the second electrode is an external connection section.
4. The semiconductor light emitting device according to
said support member is an electrically conductive substrate,
said bonding member is an electrically conductive member, and wherein
one of said first electrode and said second electrode is bonded with the electrically conductive member so as to establish electrical continuity.
5. The semiconductor light emitting device according to
6. The semiconductor light emitting device according to
7. The semiconductor light emitting device according to
8. The semiconductor light emitting device according to
9. The semiconductor light emitting device according to
10. The semiconductor light emitting device according to
12. The semiconductor light emitting device according to
said bonding member is an electrically conductive bonding member,
said second electrode is composed of said electrode segments being connected to each other by the electrically conductive bonding member, and wherein
said first electrode surrounds said electrode segments.
13. The semiconductor light emitting device according to
14. The semiconductor light emitting device according to
15. The semiconductor light emitting device according to
0. 18. The semiconductor light emitting device according to claim 17, wherein
said first semiconductor layer is an n-type semiconductor layer,
said first electrode is an n electrode, and
said bonding member is electrically connected to said n electrode or said n-type semiconductor layer.
0. 19. The semiconductor light emitting device according to claim 17, wherein
said second semiconductor layer is a p-type semiconductor layer,
said second electrode is a p electrode, and
said bonding member is electrically connected to said p electrode or said p-type semiconductor layer.
0. 20. The semiconductor light emitting device according to claim 17, wherein a pad electrode is provided on said external connection section.
0. 21. The semiconductor light emitting device according to claim 17, wherein
said external connection section is part of said first electrode, and
a pad electrode is provided to said external connection section of said first electrode, for connecting to an external wiring.
0. 22. The semiconductor light emitting device according to claim 17, wherein
said external connection section is part of said first electrode, and
an interconnect electrode connects to said external connection section of said first electrode.
0. 23. The semiconductor light emitting device according to claim 17, wherein said second electrode includes multiple electrodes that are wiring-like electrodes connected with each other on said semiconductor stacking structure.
0. 24. The semiconductor light emitting device according to claim 17, wherein
said one principal surface is included in said first electrode.
0. 25. The semiconductor light emitting device according to claim 17, wherein
said external connection section is part of said second electrode, and
a pad electrode is provided to said external connection section of said second electrode, for connecting to an external wiring.
0. 26. The semiconductor light emitting device according to claim 17, wherein
said external connection section is part of said second electrode, and
an interconnect electrode connects to said external connection section of said second electrode.
0. 27. The semiconductor light emitting device according to claim 17, wherein said first electrode includes multiple electrodes that are wiring-like electrodes connected with each other on said semiconductor stacking structure.
0. 28. The semiconductor light emitting device according to claim 17, wherein
said one principal surface is included in said second electrode.
0. 29. The semiconductor light emitting device according to claim 17, wherein said first electrode is an n electrode.
0. 30. The semiconductor light emitting device according to claim 17, wherein said second electrode is a p electrode, and said second semiconductor layer is p-type.
0. 31. The semiconductor light emitting device according to claim 17, wherein at least one of said first and second electrodes comprises a conductive oxide or nitride.
0. 32. The semiconductor light emitting device according to claim 17, wherein at least one of said first and second electrodes comprises a metal.
0. 33. The semiconductor light emitting device according to claim 32, wherein said at least one of said first and second electrodes has a stacked structure.
0. 34. The semiconductor light emitting device according to claim 32, wherein said metal includes at least one material selected from the group consisting of:
nickel (Ni), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os), iridium (Ir), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), cobalt (Co), iron (Fe), manganese (Mn), molybdenum (Mo), chromium (Cr), tungsten (W), lanthanum (La), copper (Cu), silver (Ag), and yttrium (Y).
0. 35. The semiconductor light emitting device according to claim 32, wherein said metal includes at least one material selected from the group consisting of:
a compound of nickel (Ni), a compound of platinum (Pt), a compound of palladium (Pd), a compound of rhodium (Rh), a compound of ruthenium (Ru), a compound of osmium (Os), a compound of iridium (Ir), a compound of titanium (Ti), a compound of zirconium (Zr), a compound of hafnium (Hf), a compound of vanadium (V), a compound of niobium (Nb), a compound of tantalum (Ta), a compound of cobalt (Co), a compound of iron (Fe), a compound of manganese (Mn), a compound of molybdenum (Mo), a compound of chromium (Cr), a compound of tungsten (W), a compound of lanthanum (La), a compound of copper (Cu), a compound of silver (Ag), and a compound of yttrium (Y).
0. 36. The semiconductor light emitting device according to claim 32, wherein said metal includes at least one material selected from the group consisting of:
ITO, ZnO, In2O3 and SnO2.
0. 37. The semiconductor light emitting device according to claim 36, wherein said ITO has a thickness of 5 nm to 10 μm.
0. 38. The semiconductor light emitting device according to claim 17, wherein at least one of said first and second electrodes comprises an alloy.
0. 39. The semiconductor light emitting device according to claim 38, wherein said at least one of said first and second electrodes has a stacked structure.
0. 40. The semiconductor light emitting device according to claim 38, wherein said alloy includes at least one material selected from the group consisting of:
nickel (Ni), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os), iridium (Ir), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), cobalt (Co), iron (Fe), manganese (Mn), molybdenum (Mo), chromium (Cr), tungsten (W), lanthanum (La), copper (Cu), silver (Ag), and yttrium (Y).
0. 41. The semiconductor light emitting device according to claim 38, wherein said alloy includes at least one material selected from the group consisting of:
a compound of nickel (Ni), a compound of platinum (Pt), a compound of palladium (Pd), a compound of rhodium (Rh), a compound of ruthenium (Ru), a compound of osmium (Os), a compound of iridium (Ir), a compound of titanium (Ti), a compound of zirconium (Zr), a compound of hafnium (Hf), a compound of vanadium (V), a compound of niobium (Nb), a compound of tantalum (Ta), a compound of cobalt (Co), a compound of iron (Fe), a compound of manganese (Mn), a compound of molybdenum (Mo), a compound of chromium (Cr), a compound of tungsten (W), a compound of lanthanum (La), a compound of copper (Cu), a compound of silver (Ag), and a compound of yttrium (Y).
0. 42. The semiconductor light emitting device according to claim 17, wherein at least one of said first and second electrodes is a diffusive conductor.
0. 43. The semiconductor light emitting device according to claim 17, wherein at least one of said first and second electrodes comprises a metal layer including a thin light transmissive film.
0. 44. The semiconductor light emitting device according to claim 17, wherein at least one of said first and second electrodes is a reflective electrode which comprises a metal having a high reflectivity.
0. 45. The semiconductor light emitting device according to claim 44, wherein said metal having high reflectivity is Al, Ag or Rh.
0. 46. The semiconductor light emitting device according to claim 17, wherein at least one of said first and second electrodes comprises Al, Ag or Rh.
0. 47. The semiconductor light emitting device according to claim 17, wherein at least one of said first and second electrodes comprises a first layer, a second layer, and a middle layer which is a barrier layer with a high melting point.
0. 48. The semiconductor light emitting device according to claim 47, wherein the middle layer comprises W, Mo, or a platinum group metal.
0. 49. The semiconductor light emitting device according to claim 17, wherein said first electrode comprises one of gold, Al and a metal of platinum group.
0. 50. The semiconductor light emitting device according to claim 17, wherein said first electrode comprises Ti and Al.
0. 51. The semiconductor light emitting device according to claim 17, wherein at least one of said first and second electrodes comprises W, Mo or Ti.
0. 52. The semiconductor light emitting device according to claim 17, wherein at least one of an end face, a side face, a topmost face, an exposed surface and an interface of said semiconductor stacking structure comprises a concave portion and a convex portion.
0. 53. The semiconductor light emitting device according to claim 52, wherein a transparent insulating film is disposed on said at least one of an end face, side face, topmost face, exposed surface and interface of said semiconductor stacking structure.
0. 54. The semiconductor light emitting device according to claim 53, wherein a concavity and a convexity is formed on the surface of the transparent insulating film.
0. 55. The semiconductor light emitting device according to claim 17, wherein at least one of an end face, a side face, a topmost face, an exposed surface and an interface of said semiconductor stacking structure comprises a plurality of protrusions and recesses.
0. 56. The semiconductor light emitting device according to claim 17, wherein at least one of an end face, a side face, a topmost face, an exposed surface and an interface of said semiconductor stacking structure comprises an irregular surface section.
0. 57. The semiconductor light emitting device according to claim 17, wherein a transparent insulating film is disposed on said semiconductor stacking structure.
0. 58. The semiconductor light emitting device according to claim 17, wherein the topmost surface of said semiconductor stacking structure is covered by a transparent insulating film.
0. 59. The semiconductor light emitting device according to claim 17, wherein a portion of said first electrode and a portion of said second electrode overlap.
0. 60. The semiconductor light emitting device according to claim 59, wherein
said first electrode is an n electrode and said second electrode is a p electrode.
0. 61. The semiconductor light emitting device according to claim 59, wherein said portion of said first electrode and said portion of said second electrode which overlap are separated by an insulating film.
0. 62. The semiconductor light emitting device according to claim 17, wherein said support member comprises a metallic material or a semiconductor material.
0. 63. The semiconductor light emitting device according to claim 62, wherein said metallic material comprises one of Ag, Cu, Au, Pt, W, Mo, Cr, Ni, Cu—W, and Cu—Mo.
0. 64. The semiconductor light emitting device according to claim 17, wherein said support member comprises one of Si, SiC, GaAs, GaP, InP, ZnSe, ZnS, ZnO.
0. 65. The semiconductor light emitting device according to claim 17, wherein said support member comprises a light transmissive material.
0. 66. The semiconductor light emitting device according to claim 17, wherein said bonding member comprises a light transmissive material.
0. 67. The semiconductor light emitting device according to claim 17, wherein a reflecting film is provided on one of said bonding member and said support member.
0. 68. The semiconductor light emitting device according to claim 67, wherein the reflecting film comprises Al or Ag.
0. 69. The semiconductor light emitting device according to claim 17, wherein a reflective electrode is provided on at least one of said bonding member, said support member, and a part of said semiconductor stacking structure.
0. 70. The semiconductor light emitting device according to claim 17, wherein said bonding member comprises a stack structure.
0. 71. The semiconductor light emitting device according to claim 17, wherein said bonding member comprises an alloy structure.
0. 72. The semiconductor light emitting device according to claim 17, wherein said bonding member comprises at least one material selected from the group consisting of a resin, a mixture of Ag paste, carbon paste, ITO paste, a composite material, an organic material, a soldering material, a metal, a stack of metals, and an alloy of metals.
0. 73. The semiconductor light emitting device according to claim 17, wherein said bonding member comprises at least one of Au, Sn, Pd, In, Au—Sn, Sn—Pd, and In—Pd.
0. 74. The semiconductor light emitting device according to claim 17, wherein said bonding member is formed by a metal-to-metal junction.
0. 75. The semiconductor light emitting device according to claim 74, wherein the metal-to-metal junction is an Au-Au junction.
0. 76. The semiconductor light emitting device according to claim 17, wherein a surface of said second electrode is exposed to form an external connection section as an external electrode of said second electrode.
0. 77. The semiconductor light emitting device according to claim 76, wherein said second electrode is a p electrode.
0. 78. The semiconductor light emitting device according to claim 17, wherein a surface of said first electrode is exposed to form said external connection section as an external electrode for said first electrode.
0. 79. The semiconductor light emitting device according to claim 78, wherein said first electrode is an n electrode.
0. 80. The semiconductor light emitting device according to claim 17, wherein a wiring for said semiconductor light emitting device has a 3-dimensional configuration.
0. 81. The semiconductor light emitting device according to claim 17, wherein the semiconductor light emitting device further comprises a base layer for said bonding member.
0. 82. The semiconductor light emitting device according to claim 81, wherein said base layer is also a pad electrode for electrical connection to one of said first and second electrodes.
0. 83. The semiconductor light emitting device according to claim 81, wherein said base layer is a junction layer joining said bonding member to at least one of said first and second electrodes.
0. 84. The semiconductor light emitting device according to claim 81, wherein said base layer is disposed between said support member and said bonding member.
0. 85. The semiconductor light emitting device according to claim 81, wherein said base layer is disposed between said semiconductor stacking structure and said bonding member.
0. 86. The semiconductor light emitting device according to claim 81, wherein said base layer is disposed between an insulating film and said bonding member.
0. 87. The semiconductor light emitting device according to claim 86, wherein said base layer and said insulating film directly contact each other.
0. 88. The semiconductor light emitting device according to claim 87, wherein said base layer and one of said first and second electrodes are electrically connected.
0. 89. The semiconductor light emitting device according to claim 81, wherein said base layer comprises a metal or other conductive material.
0. 90. The semiconductor light emitting device according to claim 89, wherein said base layer comprises Ti, Pt and Au.
0. 91. The semiconductor light emitting device according to claim 81, wherein said base layer comprises a stack structure.
0. 92. The semiconductor light emitting device according to claim 81, wherein said base layer comprises Ti, Pt and Au.
0. 93. The semiconductor light emitting device according to claim 81, wherein said base layer covers substantially the entire surface of said bonding member.
0. 94. The semiconductor light emitting device according to claim 17, wherein the semiconductor light emitting device comprises one light emitting structure section.
0. 95. The semiconductor light emitting device according to claim 17, wherein the semiconductor light emitting device comprises a plurality of light emitting structure sections, each light emitting structure section comprising a portion of said semiconductor stacking structure.
0. 96. The semiconductor light emitting device according to claim 17, wherein the semiconductor light emitting device comprises a plurality of semiconductor stacking structures.
0. 97. The semiconductor light emitting device according to claim 96, wherein said plurality of semiconductor stacking structures, which are separated from each other, are connected by said first electrode.
0. 98. The semiconductor light emitting device according to claim 17, wherein said bonding member has an interface at which two bonding portions of said bonding member are bonded to each other.
0. 99. The semiconductor light emitting device according to claim 17, wherein said bonding member directly contacts said support member.
0. 100. The semiconductor light emitting device according to claim 17, wherein said first electrode is electrically connected to said first semiconductor layer, and said second electrode is electrically connected to said second semiconductor layer.
0. 101. The semiconductor light emitting device according to claim 17, wherein a portion of said first electrode is at a different distance from said support member than a portion of said second electrode.
0. 102. The semiconductor light emitting device according to claim 17, said semiconductor light emitting device further comprising an insulating film disposed between said first electrode and said second electrode.
0. 103. The semiconductor light emitting device according to claim 102, wherein said insulating film comprises a portion located below said second electrode.
0. 104. The semiconductor light emitting device according to claim 102, wherein said insulating film is disposed between said semiconductor stacking structure and said support member.
0. 105. The semiconductor light emitting device according to claim 102, wherein said insulating film is disposed between said bonding member and said at least one of said first and second electrodes having said exposed portion.
0. 106. The semiconductor light emitting device according to claim 17, wherein a top surface of said bonding member includes portions which are at different distances from said support member.
0. 107. The semiconductor light emitting device according to claim 17, wherein said semiconductor stacking structure is formed from a III-V group nitride semiconductor.
0. 108. The semiconductor light emitting device according to claim 107, wherein said III-V group nitride semiconductor is InαAlβGa1-α-βN, wherein 0≦α, 0≦β, and α+β≦1.
0. 109. The semiconductor light emitting device according to claim 17, wherein in a cross-section of said light emitting device, said second semiconductor layer is provided above said support member, and said first semiconductor layer is provided above said second semiconductor layer.
0. 110. The semiconductor light emitting device according to claim 109, wherein an active layer is provided between said first semiconductor layer and said second semiconductor layer.
0. 111. The semiconductor light emitting device according to claim 109, wherein
said first semiconductor layer is a p-type layer and said first electrode is connected to said p-type layer, and
said second semiconductor layer is an n-type layer and said second electrode is connected to said n-type layer.
0. 112. The semiconductor light emitting device according to claim 111, wherein said second electrode is electrically connected to said support member.
0. 113. The semiconductor light emitting device according to claim 109, wherein
said first semiconductor layer is an n-type layer and said first electrode is connected to said n-type layer, and
said second semiconductor layer is a p-type layer and said second electrode is connected to said p-type layer.
0. 114. The semiconductor light emitting device according to claim 113, wherein said first electrode is electrically connected to said support member.
0. 115. The semiconductor light emitting device according to claim 17, wherein an insulating film extends from a bottom side of said second electrode to an area which is higher than a topmost side of said second electrode.
0. 116. The semiconductor light emitting device according to claim 115, wherein said insulating film separates said second electrode from said first electrode.
0. 117. The semiconductor light emitting device according to claim 17, wherein an insulating film isolates said first electrode and said second electrode from each other.
0. 118. The semiconductor light emitting device according to claim 117, wherein said insulating film comprises an oxide of silicon.
0. 119. The semiconductor light emitting device according to claim 17, wherein said semiconductor light emitting device is mounted on a package.
0. 120. The semiconductor light emitting device according to claim 119, wherein
a support member electrode for external connection is electrically connected to said support member, said support member electrode being formed on a mounting surface of said support member on the package, and one lead of said package and said support member electrode are bonded to be electrically connected.
0. 121. The semiconductor light emitting device according to claim 17, wherein said bonding member is larger than a forming surface of at least one of said first and second electrodes.
0. 122. The semiconductor light emitting device according to claim 17, wherein said bonding member covers substantially the entire surface of the device structure.
0. 123. The semiconductor light emitting device according to claim 17, wherein said first and second electrodes are located below a topmost surface of said semiconductor stacking structure.
0. 124. The semiconductor light emitting device according to claim 17, wherein said first and second semiconductor layers form a p-n junction, and a side surface of said p-n junction is covered by an insulating film.
0. 125. The semiconductor light emitting device according to claim 17, wherein said first electrode and said second electrode are both provided on the same surface of said semiconductor stacking structure, on the respective first and second semiconductor layers.
0. 126. The semiconductor light emitting device according to claim 17, wherein
said one principal surface is part of said first electrode and has (1) said portion that makes direct contact with a surface of said first semiconductor layer so as to establish electrical continuity and (2) said another portion that is exposed and forms said external connection section for said first electrode, and
a principal surface of said second electrode has (1) a portion that makes direct contact with a surface of said second semiconductor layer so as to establish electrical continuity and (2) another portion that is exposed and forms an external connection section for said second electrode.
0. 127. The semiconductor light emitting device according to claim 17, wherein at least one of said first and second electrodes comprises a plurality of electrode sections which are physically separated from each other.
0. 128. The semiconductor light emitting device according to claim 127, wherein said plurality of electrode sections are physically separated from each other and are electrically connected to each other.
0. 129. The semiconductor light emitting device according to claim 17, wherein
said second semiconductor layer is provided above said support member,
said first semiconductor layer is provided above said second semiconductor layer,
said first semiconductor layer is n-type,
said second semiconductor layer is p-type,
said first electrode is electrically connected to said n-type first semiconductor layer,
said second electrode is electrically connected to said p-type second semiconductor layer,
said second electrode having said exposed portion and forming said external connection section,
said first electrode is electrically connected to said support member, and
an insulating film is formed between said first and second electrodes.
0. 130. The semiconductor light emitting device according to claim 17, wherein an active layer is provided between said first semiconductor layer and said second semiconductor layer.
0. 131. The semiconductor light emitting device according to claim 130, wherein said semiconductor stacking structure is formed from a III-V group nitride semiconductor.
0. 132. The semiconductor light emitting device according to claim 131, wherein said III-V group nitride semiconductor is InαAlβGa1-α-βN, wherein 0≦α, 0≦β, and α+β≦1.
0. 133. The semiconductor light emitting device according to claim 131, wherein said first and second electrodes overlap, with an insulating film being disposed therebetween.
0. 134. The semiconductor light emitting device according to claim 131, further comprising a base layer.
0. 135. The semiconductor light emitting device according to claim 134,
wherein said base layer is connected to said first electrode.
0. 136. The semiconductor light emitting device according to claim 135, wherein said base layer and said second electrode overlap, with an insulating film being disposed therebetween.
0. 137. The semiconductor light emitting device according to claim 135,
wherein said bonding member, said base layer, an insulating film, said second electrode, and said second semiconductor layer, are stacked in this order from said support member.
0. 138. The semiconductor light emitting device according to claim 137, wherein said insulating film extends from a bottom side of said second electrode to an area which is higher than a topmost side of said second semiconductor layer.
0. 139. The semiconductor light emitting device according to claim 138, wherein said first electrode has a plurality of electrode sections.
0. 140. The semiconductor light emitting device according to claim 139, wherein at least one of an end face, a side face, a topmost face, an exposed surface and an interface of said semiconductor stacking structure comprises a plurality of concave portions or convex portions.
0. 141. The semiconductor light emitting device according to claim 140, wherein said active layer comprises a barrier layer and a well layer.
0. 142. The semiconductor light emitting device according to claim 17, wherein a topmost face of said semiconductor stacking structure comprises a concave portion and a convex portion.
0. 143. The semiconductor light emitting device according to claim 142, wherein a transparent insulating film is disposed on said topmost face of said semiconductor stacking structure.
0. 144. The semiconductor light emitting device according to claim 143, wherein a concavity and a convexity is formed on the surface of the transparent insulating film.
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This is a reissue of U.S. Pat. No. 7,679,097.
The present invention relates a semiconductor light emitting device that has semiconductor stacking structure and, more particularly, to a semiconductor light emitting device that is bonded onto a support member, and a method for manufacturing the same.
A light emitting device based on a semiconductor is made by stacking semiconductor layers such as n-type and/or p-type so as to form a semiconductor stacking structure on a substrate and providing electrodes on the layers of different conductivity types, while electricity is supplied through the electrodes so that the device emits light. There is also such a light emitting device comprising a support member and a semiconductor stacking structure made by bonding a semiconductor device structure formed on a substrate onto the support member (for example, shown in
However, the structure of the light emitting device of the prior art does not allow it to extract sufficient light, and the electrodes of the light emitting device bonded onto the support member cannot be formed so as have sufficient characteristics suitable for a light emitting device due to constraints of the manufacturing process.
Specifically, in the semiconductor stacking structure that is bonded onto the support member, the electrodes provided on the semiconductor stacking structure before bonding can be alloyed by heat treatment or the like after forming the electrodes, so that the properties of the electrodes such as ohmic property, heat resistance, reliability during the operation of the light emitting device, for example heat resistance of the device and bonding property can be improved. However, the electrodes provided on the semiconductor stacking structure after bonding it onto the support member can not be sufficiently heat treated due to restriction resulted from heat resistance of the bonding member. For example, in case denaturing or deformation of the bonding member through heat treatment causes a decrease in the bonding strength, it is necessary to set a lower heat treatment temperature so as to avoid such troubles. As a result, it has been difficult to obtain satisfactory characteristics of the electrodes that are provided on the semiconductor stacking structure after bonding it onto the support member.
There is also such a problem that the structure and the arrangement of the electrodes in the semiconductor stacking structure are such that shade the emitted light depending on the material of the electrodes, and therefore the electrode structure involves advanced design. In case the semiconductor layers of different types of conductivity have different levels of carrier mobility, layout of the electrodes formed on the semiconductor layers different types of conductivity has a great influence on the control of carrier, consequently on the efficiency of light emission. For example, when the surface area of the light emitting device becomes larger, a part of the light emitting structure section may not emit sufficient amount of light due to the structure of the electrode even when the light emitting structure section has a surface area that is proportional to the surface area of the device. Moreover, the light emitting structure section may instead absorb the light propagating in the light emitting device thus making it impossible to increase the optical output in proportion to the increase in the device area. When the area of light emitting devices, area of the light emitting structure and the number of light emitting structure sections are increased, there arise such problems as the uniformity of light emission and loss of light in a portion having low efficiency of light emission. Therefore, design of the structures of the electrodes and the device are very important.
In case the electrode is used for dissipating heat, it must be designed by giving consideration also to the layout of the lead-out portion of the electrode for external connection and the route of dissipating heat from the semiconductor stacking structure. Thus extremely sophisticated design is required to provide the optimum semiconductor stacking structure and electrode structure.
The semiconductor stacking structure bonded onto the support member also has the following problem. When electrodes of the light emitting device are provided between the support member and the semiconductor stacking structure, strength of bonding with the bonding member or with an insulating film that isolates the electrode of the semiconductor stacking structure and the bonding member, layout of these members within a plane and the stacking structure have importance, and it is necessary to give consideration to the heat treatment of the electrodes and heat resistance of the bonding member in the manufacturing process. Also with regard to the stability of the members used in the light emitting device under the influence of the heat generated during operation of the device, design of the route of dissipating heat from the semiconductor stacking structure to the support member is important for ensuring sufficient reliability in terms of bonding strength and the like.
The present invention aims at solving the problems described above, and has an object of providing a preferable electrode structure of a semiconductor light emitting device comprising the semiconductor stacking structure bonded onto the support member, and providing a semiconductor light emitting device having excellent characteristics.
Specifically, the semiconductor light emitting device according to the present invention solves the various problems described above by bringing a part of one principal surface of the electrode provided on the semiconductor stacking structure into electrical continuity with the semiconductor staking structure, and exposing the other portion for the external connection.
The semiconductor light emitting device of the present invention has the semiconductor stacking structure that includes a first semiconductor layer and a second semiconductor layer of conductivity types different from each other, wherein a first electrode is connected to the first semiconductor layer and a second electrode is connected to the second semiconductor layer, while the first electrode has a portion that makes contact with the first semiconductor layer so as to establish electrical continuity and an external connection section provided on one principal surface.
In the semiconductor light emitting device of the present invention constituted as described above, the electrodes provided on the semiconductor layers that constitute the semiconductor stacking structure have semiconductor contact section which makes contact with the semiconductor stacking structure and performs a predetermined function and the external connection section which is connected to an external power source or the like, both provided on the same surface, and achieves the following effects.
The constitution described above increases the degree of freedom in the design of electrode layout. Also reliability of the electrodes can be improved since the external connection section can be exposed after forming the electrodes on the semiconductor stacking structure and applying heat treatment to the electrodes.
As the electrode has a semiconductor contact section that makes contact with an electrode forming section of the semiconductor stacking structure in one portion thereof and the external connection section in the other portion of one principal surface of the electrode, it becomes unnecessary to provide complicated interconnect electrodes for connecting the semiconductor contact section and the external connection section with each other, so that man-hours required to form the electrodes can be reduced and, since the electrode structure is simplified, the electrodes have higher reliability. Also because the external connection section is formed during the semiconductor manufacturing process, it can be formed with a very high precision with minimum surface area.
In the semiconductor light emitting device of the present invention, a pad electrode can be provided on the external connection section for the connection with external wiring members. This enables it to use a material that satisfactorily bonds with the external wiring with high bonding strength as the pad electrode, and therefore highly reliable connection with the external wiring can be established.
In case the semiconductor stacking structure of the present invention includes the first semiconductor layer of the first conductivity type and the second semiconductor layer of the second conductivity type, with the first electrode being formed on the first semiconductor layer and the second electrode formed on the second semiconductor layer, then both the first electrode and the second electrode may be formed to have the semiconductor contact section and the external connection section provided on the same surface, or only the first electrode may be formed to have the semiconductor contact section and the external connection section on the same surface with the second electrode being formed in a different constitution.
In other words, such a constitution may be employed as only the first electrode is formed to have the semiconductor contact section and the external connection section provided on the same surface while the second electrode makes contact, on one of the principal surfaces thereof, with the second semiconductor layer to establish electrical continuity therewith, with the other principal surface of the second electrode being used as the external connection section of the second electrode.
When the second electrode is formed in such a constitution as one of the principal surfaces is used as a semiconductor contact section in one portion thereof and as the external connection section in the other portion similarly to the first electrode, the first electrode and the second electrode can be provided so that the external connection section of the first electrode and the external connection section of the second electrode are disposed in the same direction, thereby enabling it, for example, to connect in the same direction by wire bonding or the like (refer to, for example,
This makes it possible to achieve an advantageous arrangement bounded by an electrode structure layer where the first electrode and the second electrode are formed, in which the support member is arranged on the component mounting side of one side of the electrode structure layer and the light emitting section provided with the semiconductor stacking structure is arranged on the other side.
In case the second electrode is formed so that one of the principal surfaces thereof becomes the semiconductor contact section and the other principal surface becomes the external connection section, unlike the first electrode, for example, the external connection section of the second electrode can be connected so as to oppose the mounting substrate and the external connection section of the first electrode can be connected on the opposite side when mounting the semiconductor light emitting device, and wiring can be made in a 3-dimensional configuration that allows mounting with higher density (refer to, for example,
Also in case the first and second electrode forming surfaces of the device structure are disposed to oppose each other so that the first and second electrodes are formed to sandwich the device structure, the external connection sections of the first and second electrode can be disposed on the same side of the light emitting device, the light emitting device can have the external wirings provided on the same side and the second electrode can have the external connection section of the top surface of the electrode disposed within the semiconductor stacking structure, and therefore a structure of the light emitting device that is advantageous for high mounting density and smaller area can be achieved.
In the case of such an electrode structure as the first electrode and the second electrode are formed on the same surface (on the side of the electrode forming surface) of the semiconductor stacking structure while the first electrode has the semiconductor contact section and the external connection section provided on one of the principal surfaces and the second electrode has the semiconductor contact section on one of the principal surfaces and the external connection section provided on the other principal surface, on the other hand, since the surface of the semiconductor stacking structure other than the electrode forming surface can be left without being covered by the electrode, light emitted by the semiconductor stacking structure can be extracted from the surface of the semiconductor stacking structure other than the electrode forming surface without being shaded by the electrode.
In the light emitting device of the present invention having such as structure as the semiconductor stacking structure is bonded onto the support member as described above, light can be extracted efficiently from the exposed surface of the semiconductor stacking structure other than the bonding surface by disposing the first electrode and the second electrode between the support member and the semiconductor stacking structure as described above.
In case of such an device structure as the semiconductor stacking structure has a plurality of divided electrode segments, electrically conductive members that connect the electrode segments can be provided between the support member and the semiconductor stacking structure. This makes it possible to employ a variety of semiconductor stacking structures and, since the electrode structure that has the semiconductor contact section and the external connection section provided on the same surface allows a high degree of freedom in the design, electrically conductive members for connecting the electrode segments can be easily provided on the semiconductor stacking structure and on the support member. Specifically, in case the first electrode and the second electrode that has the electrode segments are provided on the semiconductor stacking structure, such a constitution may be employed as an insulating film is provided between the first and second electrodes, and the electrically conductive member that connects the electrode segments with each other is formed on the bonding side of the support member in a region larger than the forming surface of the entire electrode segments of the semiconductor stacking structure. Moreover, efficiency of the device structure can be improved further by having the bonding member that bonds the support member and the semiconductor stacking structure serve also as the electrically conductive member that connects the electrode segments with each other.
The present invention also provides a method for manufacturing the light emitting device that solves the problems of the device manufacturing method of the prior art. Specifically, after forming the electrodes to be connected to the semiconductor stacking structure on one surface of the semiconductor stacking structure, a part of the semiconductor stacking structure is removed until a part of the electrode formed on the semiconductor stacking structure is exposed, thereby to use the exposed electrode surface as the electrode for external connection.
Specifically, after forming the semiconductor stacking structure from semiconductor, the electrodes are formed on the electrode forming surface of the semiconductor stacking structure, and then a part of the semiconductor stacking structure is removed in order to expose the surface of the electrode formed on the semiconductor stacking structure for the external connection, thereby making the light emitting device. The problems of the prior art are solved by this method.
With the prior art, it is necessary to form a relatively large interconnect electrode for external connection by giving consideration to the accuracy of alignment during bonding since the electrode for external connection is provided as the interconnect electrode on the support member side. According to the manufacturing method of the present invention, in contrast, the electrode for external connection is formed first in the semiconductor stacking structure by the semiconductor processing technology, and therefore the external connection section and the semiconductor contact section can be disposed in the correct positional relationship without relation to accuracy of alignment during bonding. As a result, since the external connection section can be provided with far higher accuracy than in the prior art, the device structure of higher accuracy and higher density and device mounting with higher density are made possible.
Also because the electrodes are formed on the semiconductor stacking structure before bonding onto the support member, heat treatment can be applied to the electrodes that have been formed without being restricted by the heat resistance of the bonding member used in the bonding process. Other processes of heat treatment of the device such as decreasing the resistance of p-type nitride semiconductor by annealing or turning the semiconductor into p-type can be carried out without being restricted by the heat resistance of the bonding member used in the bonding process. Various processes can be carried out before bonding in this way because, even when the first and second electrodes are provided beforehand in the semiconductor stacking structure, at least one of the electrodes can be connected by means of the external connection section that is provided in the semiconductor processing carried out after bonding onto the support member, and it can undergo manufacturing processes similar to those of the light emitting device that is not bonded onto the support member.
In case a semiconductor growing substrate that allows easy processing such as etching, for example a semiconductor substrate such as GaN substrate, is used, the semiconductor growing substrate can also be removed as well when removing a part of the semiconductor during the process of exposing the electrode. Meanwhile the semiconductor growing substrate may be made of a material that is difficult to etch such as sapphire. In this case, it is preferable to remove the semiconductor growing substrate of the semiconductor stacking structure while having the semiconductor stacking structure bonded onto the support member in the manufacturing method of the present invention.
In case the semiconductor layer is removed in the process of exposing the electrode described above for manufacturing by using a wafer that has a plurality of device regions as shown in
In the method of manufacturing the light emitting device according to the prevent invention, it is also made possible to provide a pad electrode suited to the external wiring to the external connection section of the electrode that is provided after the processing of the device such as electrode exposure process.
Further in the light emitting device of the present invention, the process of bonding the support member can be carried out after forming the insulating film that isolates between the electrodes and forming the member for bonding with the support member on the semiconductor stacking structure as described above, thereby enabling it to form the members accurately. Also because the insulating film has been formed, the bonding member can be provided so as to overlap the two electrode forming surfaces of the device structure, for example to cover substantially the entire surface of the device structure, thereby improving the bonding with the support member.
The present invention utilizes a part of the electrode provided on the semiconductor stacking structure as the electrode for external connection, thereby to achieve a device structure that has high density electrode structure, and various electrode structures and semiconductor stacking structures that can be formed with high accuracy so as to provide various light emitting devices in accordance to the application.
In the case of the light emitting device comprising the semiconductor stacking structure bonded onto the support member, the first and second electrodes of the semiconductor stacking structure can be disposed with high density and high accuracy on the bonding surface, and the light emitting device having high bonding accuracy can be manufactured, thus achieving a high yield of production even for the light emitting device of complicated structure.
Now the light emitting device of the present invention will be described below showing the constitution and components of the present invention by way of embodiments and Examples. It is understood that the present invention is not limited by the Examples and embodiments described later. Constitutions described in some of Examples and embodiments can be employed in other Examples and embodiments. Some of drawings referred to in sonic of Examples and embodiments are partially exaggerated for better understanding.
(Semiconductor Stacking Structure)
The semiconductor stacking structure of the present invention can be constituted by forming layers of predetermined conductivity types from desired semiconductor materials on a semiconductor growing substrate 1 whereon semiconductors are to be grown.
The semiconductor stacking structure of the present invention may be formed from, for example, a nitride semiconductor material. While there is no limitation to the nitride semiconductor material, GaN, AlN, InN, or a mixture of these in the form of III-V group nitride semiconductor (InαAlβGa1-α-βN, 0≦α, 0≦β, α+β≦1) may be used. In addition to these, a mixed crystal may be used where B or the like is used as part or all of the group III elements or a part of N included as a group V element is substituted by P, As, Sb or the like.
GaAs-based material such as AlGaAs and InGaAs, InP-based material such as AlGaInP and other III-V group compounds semiconductors such as InGaAsP that is a mixed crystal of the materials described above may be used as other examples of semiconductor materials that can be used in the light emitting device of the present invention. Nitride semiconductors are used in the Examples and embodiments of the present invention, although the present invention is not limited to these constitutions.
The semiconductor stacking structure can be made by growing n-type and p-type layers such as nitride semiconductor on a substrate by using a vapor phase growing apparatus such as MOVPE (metal organic vapor phase epitaxy), HDVPE (halide vapor phase epitaxy), MBE (molecular beam vapor phase epitaxy) or MOMBE (metal organic molecular beam vapor phase epitaxy). The semiconductor stacking structure can be formed by employing such various materials and growing methods.
Specifically, the semiconductor stacking structure may be formed, for example, by stacking, on a semiconductor growing substrate such as sapphire substrate:
a low temperature-grown buffer layer of non-dope-GaN to a thickness of 20 nm, a first underlying layer of non-dope-GaN to a thickness of 5 μm, composition and concentration gradient layer of AlGaN used as a second underlying layer to a thickness of 0.4 μm with Al moler fraction graded from 0 to 0.07 and Si concentration graded from 0 to 1×1019/cm3, so as to constitute a underlying layer of the device structure from these layers;
an n-type layer formed by stacking a first n-type layer of n-type Al0.07Ga0.93N doped with Si with a concentration of 1×1019/cm3 to a thickness of 1.7 μm and a second n-type layer of n-type Al0.07Ga0.93N doped with Si with a concentration of 2×1017/cm3 to a thickness of 0.8 μm;
an active layer formed by stacking barrier layers (B) of Al0.09Ga0.91N doped with Si with a concentration of 1×1019/cm3 having thickness of 20 nm and well layers (W) of non-dope-In0.01Ga0.99N having thickness of 15 nm in the order of B/W/B/W/B/W/B/W/B/W/B; and
a p-type layer formed by stacking a first p-type layer (p-type cladding layer) of Al0.38Ga0.62N doped with Mg with a concentration of 1×1020/cm3 to a thickness of 20 nm, a second p-type layer of Al0.07Ga0.93N doped with Mg with a concentration of 4×1018/cm3 to a thickness of 0.1 μm, and a third p-type layer (p-type contact layer) of Al0.07Ga0.93N doped with Mg with a concentration of 1×1020/cm3 to a thickness of 0.02 μm.
The semiconductor stacking structure described above is a device structure formed for the purpose of making a UV light emitting device to be bonded onto a support member, where the underlying layer is removed together with the semiconductor growing substrate after being bonded.
Electrodes formed on the device structure described above may be constituted, for example, by partially etching the semiconductor stacking structure shown in
(Electrodes of Device Structure)
In the light emitting device of the present invention, the electrodes that are characteristic to the present invention that constitutes the device functions, in a part thereof, as a portion that makes ohmic contact on the electrode surface which makes contact with the semiconductor stacking structure, with other part thereof being led to the outside of the semiconductor stacking structure and is exposed for external connection. In the light emitting device of this embodiment, at least one of the electrodes connected to the semiconductor stacking structure has such a characteristic constitution as described above.
As described above, the electrodes characteristic to the present invention have a part of one of the principal surfaces (first principal surface) being semiconductor contact surfaces that make surface contact with the semiconductor stacking structure, with the rest of the one of the principal surfaces being external connection surface for connecting with the outside.
There has been such a structure that has external connection wiring provided with a wiring section formed on the support member side, mounting side when bonding onto the support member and mounting the components on the mounting surface, with a method that utilizes via holes drilled from the bottom of the semiconductor stacking structure to one conductivity type of the layers so as to form the electrodes. In any of these constitutions, one of the opposing surfaces of the electrode is used as the surface connected to the semiconductor and the other surface is used as the electrode surface for connecting to an external circuit.
In case one of the opposing electrode surfaces is used as the electrode surface for connection with the device (contact surface with the semiconductor layer) and the other surface is used a surface for external connection, constraint related to manufacture (manufacturing process, restriction of the order thereof) and constraint related to the design of device structure become problems. According to the present invention, however, since at least one of the electrodes provided in the semiconductor stacking structure has the semiconductor contact section provided so as to make direct contact with the device and the external connection section exposed to the outside that are formed on the same side, higher degree of freedom in the design is provided so that electrodes having high reliability, for example high bonding property with the device structure, electric characteristic and high adhesibility with the external interconnection can be easily obtained.
In the light emitting device of the present invention, while one (first electrode) of the electrodes provided in the semiconductor stacking structure has the electrode structure described above, the other electrode may have either such a constitution that has the semiconductor contact section and the external connection section on the same side similarly to the first electrode, or such a constitution as one of the opposing electrode surfaces is used as the semiconductor contact section and the other surface is used as the external connection section. This depends on the degree of freedom in the design of the device structure, and may be selected according to which mounting method and electrode arrangement are required for the light emitting device as a whole.
For example, as shown in the example described hereinafter, the semiconductor stacking structure is such that has the light emitting layer between the first and second conductivity type layers having the first electrode on the layer of one conductivity type and the second electrode on the layer of the other conductivity type. However, the semiconductor stacking structure may have either such a structure that includes a plurality of light emitting structure sections as shown in
The light emitting structure section is formed, for example in the semiconductor stacking structure comprising the layer of first conductivity type, the light emitting layer and the layer of the second conductivity type, by etching until the layer of first conductivity type is exposed, and separating the light emitting layer and the layer of the second conductivity type in the form of islands or stripes. When the light emitting structure sections are separated in this way, it is necessary to connect the second electrodes provided on the separate light emitting stricture sections with each other.
The light emitting device of the present invention may have a plurality of semiconductor stacking structures as shown in
(Structure of Light Emitting Device)
The structure of light emitting device may be such that since at least one of the electrodes provided in the semiconductor stacking structure has the semiconductor contact section and the external connection section that are formed on the same side as described above, and specific constitution thereof will be described below with reference to the accompanying drawings. The following description deals with an example in which the semiconductor stacking structure has p-type and n-type layers each having electrode formed thereon.
The second electrodes 31 are separated from each other by the sectional plane and are separated from each other on the semiconductor stacking structure. Alternatively, the second electrodes 31 may also be a continuous electrode connected with each other on the semiconductor stacking structure. In this embodiment, as described above, the bonding member 5 is made of an electrically conductive material and the support member 7 is made of an electrically conductive substrate, thereby to bring one of the principal surfaces of the second electrode 31 into contact with the p-type layer 3 so as to make it possible to make external connection from the other principal surface side of the second electrode 31. In other words, one of the principal surfaces of the second electrode 31 is the surface for making contact with the semiconductor, and the other principal surface of the second electrode 31 functions as the surface for external connection. With the support member 7 to be bonded made of an electrically conductive material, it is made possible to electrically connect the support member 7 to the second electrode 31, thereby to bring the back side opposite to the surface on the semiconductor stacking structure side into external connection of the second electrode, so that connection with an external circuit can be made via the electrode provided on the back surface of the support member 7. This makes it possible to make such an electrode structure that has an electrode connected to the second electrode on the back surface of the support member 7 and the external connection section 21a of the first electrode 21 on the semiconductor stacking structure side. In case the support member is made of an insulating material, the electrodes can be lead out from the back surface of the support member also by connecting the electrode of the support member formed on the semiconductor stacking structure side and the electrode formed on the opposite back surface by means of interconnect electrode.
The light emitting device shown in
The light emitting device shown in
The light emitting device shown in
The light emitting device shown in
The light emitting device shown in
In the light emitting device shown in
In the light emitting device shown in
The two semiconductor stacking structures are a plurality of semiconductor stacking structures that are separated from each other. The light emitting device of the present invention allows it to provide a plurality of semiconductor stacking structures in a single light emitting device as in this example. By providing a plurality of stacked structures that are separated from each other as described above, it is made possible to suppress the absorption loss due to propagation of light within each stacked structure 10 make a light emitting structure section having high efficiency of extracting light to the outside.
(Electrode)
For the material to form the first and second electrodes 21, 31, particularly the electrodes for p-type nitride semiconductor, a metal or alloy, stacked structure, which include at least one kind selected from among a group consisting of nickel (Ni), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os), iridium (Ir), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), cobalt (Co), iron (Fe), manganese (Mn), molybdenum (Mo), chromium (Cr), tungsten (W), lanthanum (La), copper (Cu), silver (Ag) and yttrium (Y), or a compound thereof such as conductive oxide or nitride, including an electrically conductive metal oxide (oxide semiconductor), indium oxide doped with tin (Indium Tin Oxide; ITO) having thickness of 5 nm to 10 μm, ZnO, In2O3, SnO2 or the same doped with a group III element of nitride semiconductor such as Ga, which can be preferably used as a translucent electrode. In the case of an oxide semiconductor material, an intermediate function between the layers 2, 3 of respective conductivity types and the electrodes 21, 31 thereof is performed, while the layers 2, 3 and the metal oxide may have the same conductivity type. In case oxide semiconductor layers of different conductivity types are used as the electrodes, an interposed layer (opposite conductivity type layer, oxide semiconductor, metal layer) may be provided between the semiconductor stacking structure 10. Alternatively, such a semiconductor layer and electrode material may be used as a diffusive conductor on the first conductivity type layer 2 side, because of the function as a diffusive conductor. In case the electrode 21 is made of a metal layer, it may be formed from a thin film that ensures light transmission in order to be transmissive. In order to form a reflective electrode, a metal having high reflectivity may be used such as Al, Ag or Rh.
The first electrode may be formed from a Ti layer (first layer) for ohmic contact with the first conductivity type layer and bonding with the nitride semiconductor, and an Al layer (second layer) for bonding with the insulating film 4 and the bonding member 5 preferably gold, Al or a metal of platinum group, such as Ti/Al. Such a structure is also employed as a layer made of a metal having a high melting point (W, Mo, platinum group) is provided as a barrier layer between the first layer for ohmic contact (for example, W, Mo or Ti is preferable for ohmic contact with the first conductivity type layer) and the second layer provided for bonding or pad, for example, W/Pt/Al, Ti/Rh (barrier layer 1)/Pt (barrier layer 2)/Al, Ti/Al/Ti/Pt (barrier layer)/Al is used particularly for the first electrode (for ohmic contact). For the ohmic electrode 23 of the second conductivity type layer 3, in addition to the two-layer structures of Ni/Au and Co/Au which are stacked in order from p-type layer, one that uses an electrically conductive oxide such as ITO, metal such as platinum group element or stacked structure or alloy thereof, for example two-layer structures of Rh/Ir, Pt/Pd is preferably used.
In the light emitting device structure of the present invention, in case the electrode forming surface in the semiconductor stacking structure, the surface that opposes the support member is used as the light extracting surface as shown in
(Support Member and Bonding Structure Thereof)
The structure that bonds the support member and the semiconductor stacking structure may be formed in various forms as shown in
The semiconductor growing substrate whereon the semiconductor stacking structure 10 is grown may be, in the case of a nitride semiconductor device, an insulation material such as spinel (MgAl2O4) or sapphire that has principal surface in C plane, R plane or A plane, silicon carbide (6H, 4H, 3C), silicon, ZnS, ZnO, Si, GaAs, diamond, or an oxide that makes lattice bonding with the nitride semiconductor such as lithium niobate or neodymium gallate. A substrate made of a nitride semiconductor such as GaN or AlN may also be used provided that the thickness is large enough for device processing (several tens of micrometers or more). The substrate of different material may be prepared with an offset angle. In case that C plane of sapphire is used, the offset angle is in a range from 0.01 to 3.0°, preferably 0.05 to 0.5°.
The support member 7 may be formed from various materials in accordance to the purpose, such as a metallic material or a semiconductor material for an electrically conductive substrate to increase the heat dissipation, or an insulating substrate made of a ceramic material or sintered material. Specifically, a semiconductor substrate made of a semiconductor material such as Si, SiC, GaAs, GaP, InP, ZnSe, ZnS, ZnO, a substrate made of a single metal, a metallic substrate made of a composite of two or more metals that do not form a solid solution with each other or have a low limit of solid solution, in which case the metallic materials may be at least one kind of metal selected from among a group of high conductivity metals such as Ag, Cu, Au, Pt, etc., and at least one kind of metal selected from among a group of high hardness metals such as W, Mo, Cr, Ni, etc. In case the support member 7 made of a semiconductor material is used as shown in
For the material and structure of the bonding member, in addition to a mixture such as Ag paste, carbon paste or ITO paste, a composite material (organic material), soldering material, metals such as Au, Sn, Pd, In or the like, stack or alloy thereof is preferably used for the reason of heat resistance in consideration of heat dissipation from the light emitting device 120, which is effective for the device of the present invention having a large area and generates a large amount of heat through operation with a large current. For the combination of eutectic forming layers, Au—Sn, Sn—Pd or In—Pd is preferably used. In addition, metal bump or metal-to-metal junction such as Au—Au junction may be used.
When the bonding member is formed and bonded onto the support member, it can be bonded without forming void between the semiconductor stacking structure and the support member in the bonding portion. This makes it possible to achieve efficient light emission from the semiconductor stacking structure without being lost in void between the semiconductor stacking structure and the support member. Also when an electrically conductive material is used for the bonding member, it is made possible to electrically connect a plurality of electrode segments that are separated on the semiconductor stacking structure, or electrically connect to the support member side via the bonding member. In case the electrode on the semiconductor stacking structure and the support member are electrically connected, it is made possible to form a wiring section for connecting the support member and the external circuit, and therefore excellent light emission characteristic can be ensured without being affected by the positional accuracy during bonding with the support member even when the positional accuracy is low, thereby improving the yield of production, advantageously.
In
(Light Emitting Apparatus)
Now an example of light emitting apparatus constituted from the light emitting device of the embodiment will be described.
The light emitting device shown in
In
In another example, as shown in
In the example shown in
(Method for Manufacturing a Light Emitting Device)
The method for manufacturing the light emitting device will now be described by way of Examples 1 through 3.
Example 1 shows by way of
In Example 1, the semiconductor stacking structure 10 is constituted by forming n-type layer and p-type layer from nitride semiconductor on the semiconductor growing substrate 1, and forming the electrode forming section 11 (the exposed portion of the surface of the n-type layer 2) for forming the first electrode (11 electrode) (
Then as shown in
Then as shown in
The light emitting device 101 obtained as described above has a structure shown in
The light emitting device of Example 1 described above has an optical output of 74.64 mW, about 7% higher than the optical output of 69.59 mW in comparative example 1.
In Example 2, first the n-type layer 2 and the p-type layer 3 made of nitride semiconductor are grown on the semiconductor growing substrate 1 (
Then etching operation is carried out so as to expose the electrode forming surface (surface of the n-type layer 2) for the formation of the first electrode (n electrode) and separate into a plurality of light emitting structure sections 12, thereby to form the first electrode 21 on the electrode forming surface of the n-type layer 2, and form the second electrode 31 on the p-type layer 3 of the light emitting structure section 12 (
Then the insulating film 4 that isolates between the first electrode 21 and the second electrode 31 (
The support member 7 that has the bonding member 5b provided on one surface thereof is prepared and, with the bonding member 5b and the bonding member 5a disposed to oppose each other, the support member 7 and the stacked structure of the semiconductor growing substrate 1 are bonded by thermocompressive bonding so as to interpose the semiconductor stacking structure wherein the first electrode 21 and the second electrode 31 are formed (
After bonding, the semiconductor growing substrate 1 and the underlying layer are removed (
Then the semiconductor stacking structure outside of the light emitting device structure is removed in order to expose the surface of the first electrode 21 that becomes the external connection section 21a on the same surface with the semiconductor contact section of the first electrode 21 (
In Example 2, a protective film is formed on the surface of the semiconductor stacking structure and a pad electrode is formed on the external connection section 21a, although not shown in the drawing.
Also in Example 2, a process may be provided for processing the device to add an optical function that improves the efficiency of extracting light on the light extracting side of the semiconductor stacking structure as shown in
Also after the process of forming the electrodes described above, processes may also be provided for heat treatment of the electrodes and heat treatment of the device structure, so as to improve the characteristics of the electrodes and the device.
The light emitting device shown in
In Example 3, a light emitting device that has the first electrode and the second electrode having the external connection section formed on the same surface with the semiconductor contact section is manufactured.
In Example 3, the n-type layer 2 and the p-type layer 3 are grown on the semiconductor growing substrate 1, etching operation is carried out so as to expose the electrode forming surface for the formation of the first electrode and separate into a plurality of light emitting structure sections 12, thereby to form the first electrode 21 on the electrode forming surface of the n-type layer 2, and form the second electrode 32 on the p-type layer 3 of the light emitting structure section 12 (
Then the bonding member 5a for bonding with the support member 7 is applied between the first electrode 21 and the second electrode 31, and bonded onto the support member 7 that has the bonding member 5b applied onto one of the surfaces thereof (
After bonding, the semiconductor growing substrate 1 and the underlying layer are removed (
In this case, an insulating substrate is used as the support member and an insulating member is used as the bonding member in the bonding operation.
Then the semiconductor stacking structure outside of the light emitting device structure is removed in order to expose the surface of the first electrode 21 that becomes the external connection section 21a on the same surface with the semiconductor contact section 21b of the first electrode 21, and expose the surface of the second electrode 32 that becomes the external connection section 32a on the same surface with the semiconductor contact section 32b of the second electrode 32 (
Thus the light emitting device of the present invention can be manufactured, wherein the first electrode 22 has the semiconductor contact section 21b and the external connection section 21a on the same surface and the second electrode 32 also has a similar electrode structure.
Manufacturing process is similar to that of Example 1, except for the following points. Before bonding onto the support member, only the second electrode (p electrode) is formed without forming the electrode forming section where the n-type layer is exposed. The first electrode (n electrode) is formed on the exposed n-type layer after bonding onto the support member and removing the semiconductor growing substrate and the underlying layer and a part of the n-type layer. In this process, removal of the semiconductor stacking structure for providing the external connection section in Example 1 is not carried out, and the pad electrode is not formed. That is, the light emitting device of comparative example 1 has such a structure as neither the first electrode nor the second electrode have the external connection section, and the first and second electrodes are disposed opposing each other to interpose the semiconductor stacking structure.
Since the first electrode is formed on the light extracting side in comparative example 1, optical output tends to be lower than that in Example 1 because light is shaded by the electrode and is absorbed by the electrode material. Also because the first electrode is formed after bonding, it is necessary to give consideration to the heat resistance of the bonding member during the heat treatment, and sufficient heat treatment cannot be carried out. As a result, it is difficult to obtain the light emitting device having the first electrode of sufficient characteristics (heat resistance, bonding property, etc.).
The present invention is applicable mainly to the structure of electrodes provided in a semiconductor stacking structure formed by stacking semiconductor layers, and the device structure can be used, in addition to the light emitting device, LED and LD, in a light emitting apparatus wherein the light emitting device is mounted on a substrate or a package, a light emitting apparatus that utilizes a light conversion member such as phosphor material that converts a part of light from the light emitting device.
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