Source: https://patents.google.com/patent/JP5024247B2/en
Timestamp: 2019-10-15 12:18:59
Document Index: 488034943

Matched Legal Cases: ['art 110', 'art 110', 'art 120', 'art 130', 'art 130', 'art 110', 'art 144', 'art 110', 'art 120', 'art 120', 'art 120', 'art 110', 'art 110', 'art 130', 'art 120', 'art 110', 'art 110', 'art 110', 'art 120', 'art 120', 'art 112', 'art 110', 'art 114', 'art 116', 'art 117', 'art 130', 'art 132']

JP5024247B2 - Light emitting element - Google Patents
Light emitting element Download PDF
JP5024247B2
JP5024247B2 JP2008234748A JP2008234748A JP5024247B2 JP 5024247 B2 JP5024247 B2 JP 5024247B2 JP 2008234748 A JP2008234748 A JP 2008234748A JP 2008234748 A JP2008234748 A JP 2008234748A JP 5024247 B2 JP5024247 B2 JP 5024247B2
JP2008234748A
JP2010067891A (en
恒弘 海野
2008-09-12 Application filed by 日立電線株式会社 filed Critical 日立電線株式会社
2008-09-12 Priority to JP2008234748A priority Critical patent/JP5024247B2/en
2010-03-25 Publication of JP2010067891A publication Critical patent/JP2010067891A/en
2012-09-12 Publication of JP5024247B2 publication Critical patent/JP5024247B2/en
The present invention relates to a light emitting element. In particular, the present invention relates to a light emitting device capable of high luminance and large current.
In order to realize a high-intensity light emitting diode (LED), it is required to realize not only an improvement in luminous efficiency but also a structure capable of supplying a large current. An LED to which a large current of an ampere order is supplied has a large chip size, and a thin wire electrode may be formed on the surface of the LED for the purpose of supplying current uniformly to the entire chip.
Conventionally, a substrate, a light emitting layer provided on the substrate, an electrode provided on the light emitting layer, and a contact layer selectively provided between the light emitting layer and the electrode, A light emitting element in which a thin wire electrode is connected to an electrode provided on the top is known (for example, see Patent Document 1).
JP 2006-66449 A
However, when a conventional light emitting device such as the light emitting device described in Patent Document 1 supplies a large current, the thin wire electrode may be burned by heat generated due to the small cross-sectional area of the thin wire electrode. In addition, when the width of the fine wire electrode is increased for the purpose of preventing the fine wire electrode from being burned out, the light is absorbed by the ohmic junction between the fine wire electrode and the semiconductor, and the light emission efficiency may be lowered.
Accordingly, an object of the present invention is to provide a light emitting element capable of high luminance and large current.
In order to achieve the above object, the present invention provides a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type different from the first conductivity type, a first semiconductor layer, a second semiconductor layer, A semiconductor multilayer structure having an active layer sandwiched between the first semiconductor layer, a current supply unit for supplying a current from the outside to the semiconductor multilayer structure, and adjacent to the current supply unit. A thin wire electrode having a light reflecting portion for reflecting light emitted from the active layer, and electrically connected to the thin wire electrode, and is provided above the first semiconductor layer via a transmission layer that transmits light. There is provided a light emitting device including a surface center electrode portion provided.
In the light emitting element, the surface center electrode portion may reflect light at an interface between the transmission layer and the surface center electrode portion. Further, the current supply unit may be provided including a metal layer that is in ohmic contact with a part of the semiconductor multilayer structure, and a metal layer for a thin wire electrode that is provided on the opposite side of a part of the semiconductor multilayer structure of the metal layer. . The light reflecting portion includes a transmissive portion that transmits light of the active layer and has a resistivity higher than the resistivity of the current supply portion, and a fine wire electrode metal layer. The transmissive portion and the fine wire electrode metal layer The light may be reflected at the interface.
The light-emitting element fills a support substrate having a reflective layer that reflects light emitted from the active layer, a transparent layer provided between the reflective layer and the semiconductor multilayer structure, and a region penetrating a part of the transparent layer. The semiconductor laminated structure may be supported by a support substrate via a transparent layer, and the contact part may electrically connect the semiconductor laminated structure and the reflective layer.
The light-emitting element includes a surface center electrode portion including a pad portion to which a wire is connected, and a linear electrode connected to the pad portion and extending along the horizontal direction of the active layer. It may be formed with a width wider than that of the electrode.
In the light-emitting element, the transmissive layer and the transmissive portion may be formed of an insulating material that transmits light. Alternatively, the transmissive layer and the transmissive portion may be formed of a conductive material that transmits light. Alternatively, the transmissive layer and the transmissive portion may be formed from a semiconductor material that transmits light.
The light emitting device according to the present invention can provide a light emitting device capable of high luminance and large current.
FIG. 1A shows a schematic top view of a light emitting device according to a first embodiment of the present invention. 1B shows a schematic longitudinal section of the light emitting device according to the first embodiment of the present invention, and FIG. 1C shows a partially enlarged longitudinal section of the light emitting device. Specifically, FIG. 1B is a longitudinal sectional view of the light emitting element 1 in the AA section of FIG. 1A, and FIG. 1C is a partial longitudinal sectional view of the light emitting element 1 in the BB section of FIG. 1A. .
(Outline of structure of light-emitting element 1)
Referring to FIG. 1A, the light emitting device 1 according to the first embodiment is formed in a substantially square shape in a top view. As an example, the light-emitting element 1 has a thickness of about 200 μm and a light-emitting diode (Light Emitting Diode: LED) for supplying a large current (corresponding to a large current) formed in a chip size of 2 mm × 2 mm square in a top view. It is. The light emitting element 1 is supplied with a large current of an amperage class such as 1 A (ampere), for example. The light emitting element 1 is connected to the light extraction surface 103a from which the light emitted from the light emitting element 1 is extracted to the outside of the light emitting element 1, and the pad portion 112 to which the wire is connected and the pad portion 112 to the outer edge of the light emitting element 1. The surface center electrode part 110 which has the linear electrode 114 extended toward the surface, and the some thin wire electrode 116 provided in electrical connection with the surface center electrode part 110 are provided.
First, an outline of the structure of the light-emitting element 1 will be described with reference to FIGS. 1B and 1C. The light-emitting element 1 includes a semiconductor multilayer structure 10 having an active layer 105 that emits light of a predetermined wavelength, a thin wire electrode 116 that is electrically connected to a partial region on one surface of the semiconductor multilayer structure 10, and a semiconductor multilayer structure. A contact portion 120 in ohmic contact with a part of the other surface of the semiconductor layer 10; a transparent layer 140 provided in contact with the other surface of the semiconductor stacked structure 10 excluding a region where the contact portion 120 is provided; And a reflective portion 130 provided on the surface of the transparent layer 140 opposite to the surface in contact with the semiconductor multilayer structure 10.
Referring to FIG. 1B, the pad portion 112 and the linear electrode 114 are provided in the semiconductor multilayer structure 10 via a transmissive layer 142 that transmits light emitted from the active layer 105. Note that the transmissive layer 142 is formed of a material having a higher resistivity than the material constituting the pad portion 112 and the linear electrode 114 provided on the transmissive layer 142. As an example, the transmissive layer 142 is formed from a substantially electrically insulating material. 1C, the thin wire electrode 116 is provided in the semiconductor multilayer structure 10 via a metal layer 117 that is in ohmic contact with a partial region of one surface of the semiconductor multilayer structure 10.
Further, referring to FIG. 1B, the light emitting element 1 includes an adhesion layer 200 having electrical conductivity provided on the opposite side of the surface in contact with the contact part 120 and the transparent layer 140 of the reflection part 130, and the reflection part 130 of the adhesion layer 200. And an electrically conductive support substrate 20 provided on the opposite side of the surface in contact with the substrate. The support substrate 20 has a back electrode 210 on the surface opposite to the surface in contact with the adhesion layer 20 (that is, the back surface of the support substrate 20).
In addition, the semiconductor multilayer structure 10 of the light-emitting element 1 according to this embodiment includes a p-type contact layer 109 provided in contact with the contact portion 120 and the transparent layer 140, and a surface in contact with the transparent layer 140 of the p-type contact layer 109. A p-type cladding layer 107 as a second conductivity type second semiconductor layer provided on the opposite side of the active layer 105, and an active layer 105 provided on the opposite side of the surface of the p-type cladding layer 107 in contact with the p-type contact layer 109; The n-type cladding layer 103 as the first conductivity type first semiconductor layer provided on the opposite side of the surface of the active layer 105 in contact with the p-type cladding layer 107 and the active layer 105 of the n-type cladding layer 103 are in contact with each other. And an n-type contact layer 101 provided in a partial region on the opposite side of the surface. The n-type contact layer 101 is provided in a part of the region immediately below the thin wire electrode 116.
The surface of the semiconductor multilayer structure 10 opposite to the side in contact with the transparent layer 140 is the light extraction surface 103a of the light emitting element 1 according to this embodiment. Specifically, a part of the surface of the n-type cladding layer 103 opposite to the surface in contact with the active layer 105 (that is, a portion excluding the region directly below the surface center electrode portion 110 and the fine wire electrode 116) is the light extraction surface. 103a. The light extraction surface 103a can also be formed with a concavo-convex portion on the order of microns for the purpose of improving the light extraction efficiency. The uneven portions can be provided on the light extraction surface 103a in an array having regularity such as a matrix shape or a honeycomb shape. Further, the uneven portions can be provided on the light extraction surface 103a in an irregular arrangement. Note that part of the light reflected by the light extraction surface 103a changes to heat in the process of returning to the active layer 105 side. Therefore, by providing the concavo-convex portion, heat generated by part of the light reflected on the active layer 105 side can be reduced.
Further, the reflective portion 130 is provided in contact with the reflective layer 132 on the opposite side of the reflective layer 132 provided in contact with the contact portion 120 and the transparent layer 140 and the surface of the reflective layer 132 in contact with the contact portion 120 and the transparent layer 140. The barrier layer 134 includes a bonding layer 136 provided in contact with the barrier layer 134 on the side opposite to the surface of the barrier layer 134 in contact with the reflective layer 132. The adhesion layer 200 includes a bonding layer 202 that is electrically and mechanically bonded to the bonding layer 136 of the reflective portion 130, and a contact electrode 204 that is provided on the opposite side of the surface of the bonding layer 202 that contacts the reflective portion 130. Have The back electrode 210 is provided in ohmic contact with the back surface of the support substrate 20.
(Detailed structure of the thin wire electrode 116)
Reference is now made to FIG. 1C. The thin wire electrode 116 according to the present embodiment is provided with a current supply unit 116a that supplies an external current to the semiconductor multilayer structure 10 and a light reflection unit 116b that is provided adjacent to the current supply unit 116a. . The current supply unit 116 a includes a metal layer 117 provided in ohmic contact with the surface of the n-type contact layer 101 provided in a partial region above the n-type cladding layer 103, and the n-type contact layer 101 of the metal layer 117. And a thin wire electrode metal layer 118 provided in electrical contact with the surface opposite to the surface in contact with the electrode.
The light reflecting portion 116b is provided adjacent to the n-type cladding layer 103 in the normal direction of the surface of the n-type cladding layer 103, and transmits the light emitted from the active layer 105. and a thin wire electrode metal layer 118 provided in contact with the surface opposite to the surface in contact with the n-type cladding layer 103. The thin wire electrode metal layer 118 is in contact with the respective surfaces of the metal layer 117 and the transmission portion 144, and the portion in contact with the metal layer 117 and the portion in contact with the transmission portion 144 are provided integrally. .
In the present embodiment, the n-type contact layer 101 and the metal layer 117 are provided in a thin line shape when viewed from above. One thin wire electrode 116 includes two current supply portions 116a, and the two current supply portions 116a are provided to face each other with the light reflection portion 116b interposed therebetween. Each of the current supply portions 116a is formed of a metal layer 117 and a thin wire electrode metal layer 118 that is in electrical contact with the metal layer 117. The light reflecting portion 116b is formed of the transmissive portion 144 and the thin wire electrode metal layer 118 in contact with the transmissive portion 144.
For example, referring to FIG. 1A, the plurality of thin wire electrodes 116 are provided substantially parallel to each other when the light emitting element 1 is viewed from above. Further, the width of the plurality of thin wire electrodes 116 in the top view is formed to be narrower than the width of the linear electrodes 114 in the top view. As an example, the width of the linear electrode 114 in the top view is formed to be 50 μm, and the width of each of the plurality of thin wire electrodes 116 in the top view is formed to be 10 μm. In addition, the width of the n-type contact layer 101 and the metal layer 117 in the top view (that is, the width of one current supply unit 116a) is, for example, about 1.5 μm, and the width of the light reflection unit 116b in the top view. As an example, the film is formed to have a thickness of about 7 μm.
(Details of functions of the surface center electrode portion 110 and the fine wire electrode 116)
In the present embodiment, the surface center electrode portion 110 is formed, for example, having a cross-sectional area that does not burn even when a large current of ampere class is supplied. Referring to FIG. 1A, the current supplied to the pad portion 112 is conducted through the linear electrode 114 connected to the pad portion 112. Since the substantially insulating transmissive layer 142 is provided immediately below the pad portion 112 and the linear electrode 114, the current is not directly supplied from the surface center electrode portion 110 to the semiconductor multilayer structure 10. The current is conducted to the fine wire electrode 116 that is electrically connected to the linear electrode 114, specifically, to the fine wire electrode metal layer 118 that is electrically connected to the fine wire electrode 116 as shown in FIG. 1C. . Subsequently, the current is conducted to the metal layer 118 that is electrically connected to the metal layer 118 for thin wire electrodes. The current is supplied from the metal layer 118 to the semiconductor multilayer structure 10 including the active layer 105 via the n-type contact layer 101.
Further, as shown in FIG. 1B, the pad portion 112 and the linear electrode 114 of the surface center electrode portion 110 are provided on the n-type cladding layer 103 via the transmission layer 142. The surface center electrode portion 110 can be formed to have a layer made of a metal material such as Ti, Al, Pt, Au, or Ag, or a stacked structure in which a plurality of these layers are stacked. For example, the surface center electrode portion 110 is formed on the side in contact with the transmission layer 142 via a thin film adhesion layer that improves the adhesion between the transmission layer 142 and the surface center electrode portion 110. The thin film adhesion layer is formed to have a thickness that does not substantially absorb the light emitted from the active layer 105. For example, the thin film adhesion layer can be formed of a metal material such as Ni or Al. And the surface center electrode part 110 is formed from the metal material which has a high reflectance with respect to the said light. In the present embodiment, since the active layer 105 emits red light, the surface center electrode portion 110 can be formed of Au having a high reflectance with respect to light in the red region, for example.
The transmissive layer 142 transmits light emitted from the active layer 105 and is formed of an electrically insulating material. That is, the transmissive layer 142 is substantially transparent to the light and is formed of a substantially electrically insulating material. As an example, the transmissive layer 142 can be formed of silicon dioxide (SiO 2 ). The interface 110a between the transmissive layer 142, the pad portion 112, and the linear electrode 114 reflects the light emitted from the active layer 105 incident on the interface 110a to the active layer 105 side. Further, the transmission part 144 of the thin wire electrode 116 can also be formed from silicon dioxide (SiO 2 ) that transmits light emitted from the active layer 105 and has electrical insulation.
Reference is now made to FIG. 1C. The metal layer 117 of the thin wire electrode 116 is formed of a metal material that is in ohmic contact with the n-type contact layer 101. For example, the metal layer 117 can be formed of an alloy material containing a metal material such as Au or Ge, or a stacked structure of layers made of these alloy materials and a metal material such as Au or Ni. As an example, the metal layer 117 is formed in the order of AuGe / Ni / Au from the n-type contact layer 101 side. The thin wire electrode metal layer 118 can be formed to have a layer made of a metal material such as Ti, Al, Pt, Au, or Ag, or a stacked structure in which a plurality of these layers are stacked. For example, the thin wire electrode metal layer 118 can be formed of Au having a high reflectance with respect to light in the red region. The interface 144a between the thin wire electrode metal layer 118 and the transmission portion 144 reflects the light emitted from the active layer 105 incident on the interface 144a to the active layer 105 side.
Each of the surface center electrode portion 110 and the fine wire electrode metal layer 118 can be made of the same material. In this case, the surface center electrode portion 110 and the fine wire electrode metal layer 118 can be integrally formed. In addition, a thin film adhesion layer can be provided between the fine wire electrode metal layer 118 and the transmission portion 144 for the purpose of improving the adhesion of the fine wire electrode metal layer 118 to the transmission portion 144. This thin film adhesion layer is formed from the same material as the thin film adhesion layer that can be provided between the surface center electrode portion 110 and the transmission layer 142 and having the same function.
That is, in the present embodiment, the surface center electrode portion 110 has a function of mainly supplying a current supplied to the light emitting element 1 to the thin wire electrode 116 and a function of reflecting light emitted from the active layer 105. . On the other hand, the fine line electrode 116 has both a function of supplying the current supplied from the surface center electrode part 110 to the fine line electrode 116 to the semiconductor multilayer structure 10 and a function of reflecting light emitted from the active layer 105. Specifically, the thin wire electrode 116 has a function in which the current supply unit 116a supplies the current supplied from the surface center electrode unit 110 to the thin wire electrode 116 to the semiconductor multilayer structure 10, and the light reflection unit 116b includes: It has a function of reflecting light emitted from the active layer 105.
(Arrangement of surface center electrode portion 110 and thin wire electrode 116)
Referring to FIG. 1A, in the present embodiment, pad portion 112 of surface center electrode portion 110 is provided at substantially the center of light emitting element 1 in a top view. As an example, the pad portion 112 is formed in a substantially circular shape. The linear electrode 114 is formed to extend from the outer edge of the pad portion 112 toward the outer edge of the light emitting element 1 along the horizontal direction of the surface of the semiconductor multilayer structure 10 (for example, the active layer 105). For example, the linear electrode 114 is a linear electrode extending with a substantially constant width from the pad portion 112 side toward the outer edge of the light emitting element 1.
Each of the plurality of fine wire electrodes 116 extends along the horizontal direction of the surface of the semiconductor multilayer structure 10 and extends in a direction substantially perpendicular to the direction in which the linear electrode 114 extends. Each of the plurality of thin wire electrodes 116 is provided to be electrically connected to the outer edge of the linear electrode 114 or the outer edge of the pad portion 112. In addition, the plurality of fine line electrodes 116 are provided with a substantially constant distance between one fine line electrode 116 and another fine line electrode 116 adjacent to the one fine line electrode 116.
The pad portion 112 has an upper surface as long as it has a size that allows a ball formed at the end of the wire to be connected when a wire made of Au or the like connected to the pad portion 112 is wire-bonded. The shape in view is not limited to a circle. For example, the pad portion 112 can be formed in a polygonal shape such as a square shape, an elliptical shape, or the like when viewed from above. In the present embodiment, the linear electrode 114 is formed to have substantially the same width, but the linear electrode 114 is formed to have a shape that gradually decreases in width as the distance from the vicinity of the pad portion 112 increases. You can also. Furthermore, although the thin wire electrode 116 is formed to have substantially the same width in this embodiment, the thin wire electrode 116 is formed to have a shape that gradually narrows as the distance from the vicinity of the linear electrode 114 increases. You can also.
(Semiconductor laminated structure 10)
Referring to FIG. 1B, the semiconductor multilayer structure 10 according to this embodiment is formed by including an AlGaInP-based compound semiconductor that is a III-V group compound semiconductor. For example, the semiconductor stacked structure 10 includes an active layer 105 formed including an AlGaInP-based compound semiconductor quantum well structure, an n-type cladding layer 103 formed including n-type AlGaInP, and a p-type AlGaInP. The p-type clad layer 107 is formed to be sandwiched between the layers.
The active layer 105 emits light of a predetermined wavelength when a current is supplied from the outside. For example, the active layer 105 is formed to have a quantum well structure that emits red light having a wavelength of around 630 nm. The quantum well structure can be formed from any of a single quantum well structure, a multiple quantum well structure, or a strained multiple quantum well structure. The n-type cladding layer 103 includes an n-type dopant such as Si or Se at a predetermined concentration. As an example, the n-type cladding layer 103 is formed of an n-type AlGaInP layer doped with Si. Furthermore, the p-type cladding layer 107 contains a p-type dopant such as Zn or Mg at a predetermined concentration. As an example, the p-type cladding layer 107 is formed of a p-type AlGaInP layer doped with Mg.
Furthermore, the p-type contact layer 109 included in the semiconductor multilayer structure 10 is formed, for example, from a p-type GaP layer doped with high-concentration Mg. For example, the n-type contact layer 101 is formed from a GaAs layer doped with high-concentration Si. Here, the n-type contact layer 101 is provided in a region where the metal layer 117 is formed on the upper surface of the n-type cladding layer 103.
(Contact part 120)
The contact part 120 is provided on a part of the surface of the p-type contact layer 109. The contact portion 120 is formed from a material that is in ohmic contact with the p-type contact layer 109, and as an example, is formed from a metal alloy material containing Au and Be, or Au and Zn. The shape of the contact portion 120 in a top view is formed to have a shape in which a current supplied from the surface center electrode portion 110 via the thin wire electrode 116 is supplied to substantially the entire surface of the active layer 105, for example, a comb shape. . In addition, although the contact part 120 which concerns on this Embodiment is also formed directly under the surface center electrode part 110 and the fine wire electrode 116, in the modification of this Embodiment, the surface center electrode part 110 and the fine wire electrode 116 are used. It is also possible to form the contact portion 120 in a region other than directly below.
(Transparent layer 140)
The transparent layer 140 is provided on the surface of the reflecting portion 132 (or the surface of the p-type contact layer 109) and the region where the contact portion 120 is not provided. Transparent layer 140 is formed of a material that transmits light of a wavelength emitted from the active layer 105, as an example, is formed of a transparent dielectric layer such as SiO 2, TiO 2, SiN x . Further, the transparent layer 140 has a function as a current blocking layer that does not propagate current in a portion where the transparent layer 140 is provided. The current supplied to the light emitting element 1 does not propagate through the transparent layer 140 as a current element layer, but propagates to the semiconductor multilayer structure 10 and the support substrate 20 through the contact portion 120.
(Reflecting part 130)
The reflective layer 132 of the reflective unit 130 is formed of a conductive material having a high reflectance with respect to light emitted from the active layer 105. As an example, the reflective layer 132 is formed of a conductive material having a reflectance of 80% or more with respect to the light. The reflection layer 132 reflects the light reaching the reflection layer 132 out of the light emitted from the active layer 105 toward the active layer 105 side. That is, the reflective layer 132 reflects light at the interface between the reflective layer 132 and the transparent layer 140. The reflective layer 132 is formed of, for example, a metal material such as Al, Au, or Ag, or an alloy containing at least one metal material selected from these metal materials. As an example, the reflective layer 132 is formed of Au having a predetermined thickness. Further, the reflective layer 130 is electrically connected to the contact part 120.
Further, the barrier layer 134 of the reflecting portion 130 is formed of a metal material such as Ti or Pt, and as an example, is formed of Ti having a predetermined thickness. The barrier layer 134 suppresses propagation of the material forming the bonding layer 136 to the reflective layer 132. The bonding layer 136 is formed of a material that is electrically and mechanically bonded to the bonding layer 202 of the adhesion layer 200, and is formed of Au having a predetermined thickness as an example.
(Supporting substrate 20)
The support substrate 20 is formed from a conductive material. For example, the support substrate 20 can be formed from a p-type or n-type conductive Si substrate, a Ge substrate, a GaAs substrate, a semiconductor substrate such as a GaP substrate, or a metal substrate made of a metal material such as Cu. As an example, in this embodiment, a conductive Si substrate that exhibits a low resistance by having a high carrier concentration is used as the support substrate 20.
Then, the bonding layer 202 of the adhesion layer 200 can be formed of Au having a predetermined thickness, similarly to the bonding layer 136 of the reflecting portion 130. Further, the contact electrode 204 is formed from a metal material such as Ti that is in ohmic contact with the support substrate 20. The back electrode provided on the back surface of the support substrate 20 is formed of a metal material such as Al or Ti that is in ohmic contact with the support substrate 20.
The light-emitting element 1 is made of Cu or the like using a conductive bonding material such as Ag paste or a eutectic material such as AuSn with the back surface of the support substrate 20 (that is, the exposed surface of the back electrode 210) facing down. It is mounted at a predetermined position of a stem formed from the metal. In the light emitting element 1 mounted on the stem, the pad portion 112 and a predetermined region of the stem are connected by a wire such as Au, and the light emitting element 1 and the whole wire are covered with a transparent resin such as an epoxy resin or a silicone resin. Can be provided as a light emitting device.
The light emitting element 1 according to the present embodiment emits light including red having a wavelength of 630 nm, but the wavelength of light emitted from the light emitting element 1 is not limited to this wavelength. The light emitting element 1 that emits light in a predetermined wavelength range can also be formed by controlling the structure of the active layer 105 of the semiconductor multilayer structure 10. Examples of light emitted from the active layer 105 include light in a wavelength range such as orange light, yellow light, or green light. The semiconductor multilayer structure 10 included in the light emitting element 1 can also be formed from a GaN-based compound semiconductor including an active layer 105 that emits light in an ultraviolet region, a violet region, or a blue region. Furthermore, the semiconductor multilayer structure 10 can also be formed from an AlGaAs compound semiconductor including an active layer 105 that emits light in the infrared region.
Moreover, the surface center electrode part 110 and the thin wire electrode metal layer 118 included in the light emitting element 1 can be formed of a material having a high reflectance with respect to light having the wavelength according to the wavelength of light emitted from the active layer 105. For example, when the light emitted from the active layer 105 is light in a blue region, the surface center electrode portion 110 and the fine wire electrode metal layer 118 can be formed of Al or Ag. Further, a region for electrically connecting the surface center electrode part 110 and the semiconductor multilayer structure 10 (for example, the n-type cladding layer 103) may be formed in a part of the transmission layer 142 immediately below the surface center electrode part 110. it can.
The transmissive layer 142 and the transmissive portion 144 can each be formed from a material other than SiO 2 . For example, the transmissive layer 142 and the transmissive portion 144 transmit titanium light (TiO 2 ), silicon nitride (SiN x ), magnesium fluoride (MgF), phosphorous doped spin that transmit light emitted from the active layer 105 and have electrical insulation. It can be formed from a transparent material such as -on glass (PSG). Further, the transmissive layer 142 and the transmissive portion 144 can be formed from a transparent conductive material having a resistivity higher than the resistivity of the material constituting the surface center electrode portion 110, the fine wire electrode metal layer 118, and the metal layer 118. . As the transparent conductive material, for example, ITO, tin oxide, ZnO or the like can be used.
Even when the transmissive layer 142 is made of a transparent conductive material, the resistance of the transmissive layer 142 is higher than the resistance of the surface center electrode portion 110, so that the current supplied to the surface center electrode portion 110 is mainly a linear electrode. The thin wire electrode 116 is supplied via 114. Therefore, no current is supplied to the semiconductor multilayer structure 10 from the transmissive layer 142 formed of a transparent conductive material. When the transmissive layer 142 and the transmissive portion 144 are formed from a transparent conductive material, the current supplied to the surface center electrode portion 110 is dispersed in the transmissive layer 142 and the transmissive portion 144.
Further, the transmissive layer 142 and the transmissive portion 144 can be formed of a semiconductor material that transmits light emitted from the active layer 105. For example, when the light emitted from the active layer 105 is light in the red region, the transmissive layer 142 and the transmissive portion 144 can be formed from a wide band gap semiconductor material such as ZnSe or ZnS that is transparent to the light in the red region. . Here, when the transmissive layer 142 and the transmissive portion 144 are formed from a semiconductor, the semiconductor can be formed from either a single crystal or a polycrystal as long as it is substantially transparent to light emitted from the active layer 105. Note that in the case where ZnS is used as the semiconductor, the transmissive layer 142 and the transmissive portion 144 can be formed by a solution method.
The thin wire electrode 116 can also be formed having a plurality of current supply portions 116a. For example, three current supply portions 116a and two light reflection portions 116b provided in a region sandwiched between the current supply portions 116a can be formed. Further, the plurality of current supply portions 116a can be formed by being partially connected. For example, in the thin wire electrode 116 having two current supply portions 116a, a region electrically connected between one current supply portion 116a and the other current supply portion 116a facing the one current supply portion 116a is partially It is also possible to provide a ladder-shaped current supply portion as viewed from above.
Although the light emitting element 1 according to the present embodiment is formed in a substantially square shape when viewed from above, the vertical dimension and the horizontal dimension when viewed from above can be made different. In this case, the shape of the light emitting element 1 in a top view is a rectangle. Moreover, the dimension in the top view of the light emitting element 1 can also be made into a chip size larger than 2 mm x 2 mm.
Furthermore, in the semiconductor multilayer structure 10 included in the light emitting element 1, the conductivity type of the compound semiconductor layer constituting the semiconductor multilayer structure 10 can be made opposite to that of the first embodiment. For example, the conductivity type of the n-type contact layer 101 and the n-type cladding layer 103 can be p-type, and the conductivity type of the p-type cladding layer 107 and the p-type contact layer 109 can be n-type.
2A to 2R show the flow of the manufacturing process of the light emitting device according to the first embodiment of the present invention.
First, as shown in FIG. 2A (a), an AlGaInP-based material including a plurality of compound semiconductor layers on an n-type GaAs substrate 100 by, for example, metal organic chemical vapor deposition (MOCVD). A semiconductor multilayer structure 11 is formed. In the present embodiment, a semiconductor multilayer structure 11 including at least an etching stop layer 102, an n-type cladding layer 103, an active layer 105, and a P-type cladding layer 107 is formed on an n-type GaAs substrate 100. .
As an example, an etching stop layer 102 having GaInP, an n-type contact layer 101 having n-type GaAs, an n-type cladding layer 103 having n-type AlGaInP, and AlGaInP are formed on an n-type GaAs substrate 100. A quantum well type active layer 105, a p-type cladding layer 107 having p-type AlGaInP, and a p-type contact layer 109 having p-type GaP are formed in this order by MOCVD. As a result, an epitaxial wafer in which the semiconductor multilayer structure 11 is formed on the n-type GaAs substrate 100 is formed. In addition, by providing the n-type contact layer 101 and the p-type contact layer 109, good electrical junction between the metal layer 117 and the n-type contact layer 101 and between the p-type contact layer 109 and the contact part 120 is achieved. Is easier to take.
Note that raw materials used in the MOCVD method are organometallic compounds such as trimethylgallium (TMGa), triethylgallium (TEGa), trimethylaluminum (TMAl), and trimethylindium (TMIn), arsine (AsH 3 ), and phosphine (PH 3 ). A hydride gas such as can be used. Furthermore, disilane (Si 2 H 6 ) can be used as a raw material for the n-type dopant. Then, the raw material of p-type dopant can be used biscyclopentadienyl magnesium (Cp 2 Mg).
Alternatively, hydrogen selenide (H 2 Se), monosilane (SiH 4 ), diethyl tellurium (DETe), or dimethyl tellurium (DMTe) can be used as a raw material for the n-type dopant. And dimethyl zinc (DMZn) or diethyl zinc (DEZn) can also be used as a raw material of a p-type dopant.
The semiconductor multilayer structure 11 on the n-type GaAs substrate 100 can be formed using a molecular beam epitaxy (Molecular Beam Epitaxy: MBE). Further, when the GaN-based semiconductor multilayer structure 11 is formed, it can also be formed using a halide vapor phase epitaxy (HVPE).
Next, as shown in FIG. 2A (b), after the epitaxial wafer formed in FIG. 2A (a) is unloaded from the MOCVD apparatus, a transparent layer 140 is formed on the surface of the p-type contact layer 109. Specifically, a SiO 2 film as the transparent layer 140 is formed on the surface of the p-type contact layer 109 using a plasma CVD (Chemical Vapor Deposition) apparatus. The transparent layer 140 can also be formed by a vacuum deposition method.
Next, as shown in FIG. 2B (c), an opening 140a is formed in the transparent layer 140 by using a photolithography method and an etching method. For example, a photoresist pattern having a groove in a region where the opening 140 a is to be formed is formed on the transparent layer 140. The opening 140 a is formed to penetrate from the surface of the transparent layer 140 to the interface between the p-type contact layer 109 and the transparent layer 140. Specifically, an opening 140a is formed in the transparent layer 140 by removing the transparent layer 140 in a region where the photoresist pattern is not formed using a hydrofluoric acid-based etchant diluted with pure water. The opening 140a is formed in a region where the contact portion 120 is provided.
Subsequently, as shown in FIG. 2B (d), an AuZn alloy which is a material constituting the contact portion 120 is formed in the opening 140a by using a vacuum deposition method and a lift-off method. For example, the contact portion 120 is formed by vacuum-depositing AuZn in the opening 140a using a photoresist pattern used for forming the opening 140a as a mask.
Next, as shown in FIG. 2C (e), an Au layer as the reflective layer 132, a Ti layer as the barrier layer 134, and an Au layer as the bonding layer 136 are formed by vacuum deposition or sputtering. It is formed on the transparent layer 140 and the contact part 120. Thereby, the semiconductor laminated structure 1a is formed. Note that the barrier layer 134 is formed by stacking layers made of a high melting point material such as a Ti layer or a Pt layer as long as the material constituting the bonding layer 136 can be prevented from propagating to the reflective layer 132. You can also. An adhesive thin film that improves the adhesion of the reflective layer 132 to the transparent layer 140 may be further provided between the transparent layer 140 and the reflective layer 132. The adhesion thin film is formed to have a thickness that does not substantially absorb the light emitted from the active layer 105. For the reflective layer 132, a material having a high reflectance is selected in accordance with the wavelength of light emitted from the active layer 105.
Then, as shown in FIG. 2D (f), Ti as the contact electrode 204 and Au as the bonding layer 202 are formed in this order on the Si substrate as the support substrate 20 in this order. Thereby, the support structure 20a is formed. Subsequently, the bonding surface 136a, which is the surface of the bonding layer 136 of the semiconductor multilayer structure 1a, and the bonding surface 202a, which is the surface of the bonding layer 202 of the support structure 20a, are overlapped to form this state from carbon or the like. Hold with a jig to be done.
Subsequently, a jig that holds the semiconductor laminated structure 1a and the support structure 20a in an overlapped state is introduced into a wafer bonding apparatus (for example, a wafer bonding apparatus for a micromachine). Then, the inside of the wafer bonding apparatus is depressurized to a predetermined pressure. Subsequently, pressure is applied substantially uniformly to the stacked semiconductor stacked structure 1a and the support structure 20a through a jig. Next, the jig is heated to a predetermined temperature at a predetermined temperature increase rate.
Specifically, the temperature of the jig is heated to 350 ° C. And after the temperature of a jig reaches about 350 degreeC, a jig is hold | maintained at the said temperature for about 1 hour. Thereafter, the jig is slowly cooled. The temperature of the jig is sufficiently lowered to, for example, room temperature. After the temperature of the jig has dropped, the pressure applied to the jig is released. And the pressure in a wafer bonding apparatus is made into atmospheric pressure, and a jig is taken out. As a result, as shown in FIG. 2D (g), a bonded structure 1b in which the semiconductor multilayer structure 1a and the support structure 20a are mechanically bonded between the bonding layer 136 and the bonding layer 202 is formed.
In the present embodiment, the semiconductor multilayer structure 1 a includes the barrier layer 134. Therefore, even when the semiconductor multilayer structure 1a and the support structure 20a are bonded to each other at the bonding surface 136a and the bonding surface 202a, the material forming the bonding layer 136 and the bonding layer 202 diffuses into the reflective layer 132. This can be suppressed and deterioration of the reflection characteristics of the reflective layer 132 can be suppressed.
Next, the bonding structure 1b is affixed to the jig of the polishing apparatus with affixing wax. Specifically, the support substrate 20 side is attached to the jig. Then, the n-type GaAs substrate 100 of the bonded structure 1b is polished until it reaches a predetermined thickness. As an example, the n-type GaAs substrate 100 is polished until the remaining thickness of the n-type GaAs substrate 100 is about 30 μm. Subsequently, the polished bonded structure 1b is removed from the jig of the polishing apparatus, and the wax adhering to the surface of the support substrate 20 is removed by washing. Then, as shown in FIG. 2E (h), the n-type GaAs substrate 100 is selectively and completely removed from the bonded structure 1b after polishing by using an etchant for GaAs etching to expose the etching stop layer 102. The joined structure 1c is formed. As an etchant for GaAs etching, for example, a mixed solution of ammonia water and hydrogen peroxide water can be used. Note that the entire n-type GaAs substrate 100 may be removed by etching without polishing the n-type GaAs substrate 100.
Subsequently, as shown in FIG. 2E (i), the etching stop layer 102 is removed from the bonded structure 1c by etching using a predetermined etchant. Thereby, the bonded structure 1d from which the etching stop layer 102 has been removed is formed. When the etching stop layer 102 is formed of GaInP, an etchant containing hydrochloric acid can be used as the predetermined etchant. As a result, the surface of the n-type contact layer 101 is exposed to the outside.
Next, as shown in FIG. 2F, a mask pattern 30 is formed on the surface of the n-type contact layer 101 by using a photolithography method. The mask pattern 30 is formed on the region where the metal layer 117 is to be formed. Specifically, the mask pattern 30 is formed in a region corresponding to the region where the thin wire electrode 116 shown in FIG. 1A is formed and the metal layer 117 shown in FIG. 1C is formed. Thereby, the laminated structure 1e in which the mask pattern 30 is formed in each of the element regions 50, which are regions where the light emitting elements 1 are formed, is formed. 2G shows a cross-sectional view taken along the line CC in FIG. 2F. As shown in FIG. 2G, each of the plurality of mask patterns 30 of the laminated structure 1e includes a plurality of fine wire-shaped n-type cladding layers to be formed on the n-type cladding layer 103 included in the light-emitting element 1 of the present embodiment. It is formed in a region corresponding to 101. That is, as shown in FIG. 1C, the mask pattern 30 is formed in correspondence with the current supply portion 116a that the light emitting element 1 will have.
Subsequently, using the mask pattern 30 as a mask, the n-type contact layer 101 is etched using a mixed solution of sulfuric acid, hydrogen peroxide solution, and water. Thereby, the n-type contact layer 101 in the region where the mask pattern 30 is not formed is removed. After the etching of the n-type contact layer 101 is completed, the mask pattern 30 is removed. As a result, as shown in FIG. 2H, a laminated structure 1f in which the n-type contact layer 101 remains is formed in a region on the n-type cladding layer 103 where a metal layer 117 to be described later is to be formed. By using the mixed liquid, the n-type contact layer 101 formed from GaAs can be selectively etched with respect to the n-type cladding layer 103 formed from n-type AlGaInP. Therefore, in the junction structure 1f, the surface of the n-type cladding layer 103 is exposed to the outside.
Next, the transmissive material film 40 is formed on the entire surface of the multilayer structure 1f. Thereby, the laminated structure 1g as shown in FIG. 2I is formed. Specifically, a transmissive material film 40 having a thickness that covers the n-type contact layer 101 included in the multilayer structure 1f and made of a material that transmits light emitted from the active layer 105 is formed into a film formation method such as a CVD method. To form. For example, the transmissive material film 40 is a SiO 2 film formed by a CVD method. 2J shows a DD cross section of FIG. 2I. As shown in FIG. 2J, the n-type contact layer 101 included in the laminated structure 1g is covered with a transmissive material film 40.
Subsequently, a mask pattern is formed on the region where the transmissive material film 40 is to be left using a photolithography method. The mask pattern is formed in a region where the surface center electrode portion 110 shown in FIG. 1A and the light reflecting portion 116b shown in FIG. 1C are to be formed. As a result, the region excluding the region where the mask pattern is formed is exposed to the outside. Next, the permeable material film 40 exposed to the outside is removed by etching. After removing the transparent material film 40 in the region excluding the region where the surface center electrode portion 110 and the light reflecting portion 116b are to be formed, the mask pattern is removed. Thereby, the laminated structure 1h as shown in FIG. 2K is formed.
FIG. 2L shows an EE cross section of FIG. 2K. In the laminated structure 1 h, between one n-type contact layer 101 corresponding to a region immediately below the region where the thin wire electrode 116 is to be formed and the other n-type contact layer 101 facing one n-type contact layer 101. The permeable material film 40 remains. The transmissive material film 40 is formed to be thicker than the n-type contact layer 101. Moreover, FIG. 2M shows the FF cross section of FIG. 2K. In the laminated structure 1h, the transmissive material film 40 is formed on the n-type cladding layer 103 corresponding to the region immediately below the region where the surface center electrode portion 110 is to be formed.
Next, a mask pattern that exposes the surface of the n-type contact layer 101 is formed by photolithography. That is, a mask pattern is formed in a region excluding the surface of the n-type contact layer 101. Then, a metal material is deposited on the n-type contact layer 101 using a vacuum deposition method. The metal material is formed, for example, by vapor-depositing an AuGe alloy, Ni, and Au on the n-type contact layer 101 in this order. Subsequently, after removing the mask pattern, an alloy process (alloy process) is performed on the laminated structure 1h on which the metal material is formed. As an example, the alloy structure 1h is subjected to an alloy process at a temperature of about 400 ° C. in a nitrogen atmosphere as an inert atmosphere. By this alloy process, the metal material is ohmic-bonded to the n-type contact layer 101 to form the metal layer 117. As a result, a laminated structure 1 i in which the metal layer 117 as shown in FIG. 2N is formed on the n-type contact layer 101 is formed.
Subsequently, a mask pattern having an opening in a region where the surface center electrode portion 110 and the fine wire electrode metal layer 118 are to be formed is formed by using a photolithography method. That is, the surface of the transmissive material film 40 provided in the region where the surface center electrode portion 110 is to be formed, and the surfaces of the transmissive material film 40 and the metal layer 117 provided in the region where the thin wire electrode 116 is to be formed. A mask pattern having an opening through which is exposed is formed. Next, the surface center electrode portion 110 (that is, the pad portion 112 and the linear electrode 114) and the thin wire electrode metal layer 118 are formed by using a vacuum deposition method or a sputtering method. As an example, the surface center electrode portion 110 and the fine wire electrode metal layer 118 are formed of a lower metal layer (for example, Al) and an outermost surface metal layer (for example, Au). The outermost metal layer can be formed thicker than the lower metal layer. Thereby, the laminated structure 1j as shown in FIG. 2O is formed.
Next, the back surface electrode 210 is formed on the back surface of the support substrate 20 by using a vacuum evaporation method or a sputtering method. Then, for the purpose of ohmic bonding between the back electrode 210 and the support substrate 20, for example, an alloy treatment at a predetermined temperature is performed in an inert atmosphere. Thereby, the laminated structure 1k including the back electrode 210 as shown in FIG. 2P is formed.
In addition, before or after this alloy treatment, an uneven portion may be formed on the surface of the n-type cladding layer 103 exposed to the outside for the purpose of improving the light extraction efficiency. The uneven portion is formed as follows, for example. First, a mask pattern in which micron-order openings are regularly or irregularly arranged is formed on the n-type cladding layer 103 using a photolithography method. Then, by using this mask pattern as a mask, the surface of the n-type cladding layer 103 is subjected to an etching process, whereby fine irregularities can be formed on the surface of the n-type cladding layer 103.
Subsequently, a mask pattern for separating the light emitting elements is formed on the surface of the bonding structure 1k by using a photolithography method. That is, a mask pattern for separating light emitting elements is formed on the surface of the n-type cladding layer 103 of the bonded structure 1k. Then, using the mask pattern as a mask, the light emitting elements are separated from each other by removing from the surface side of the n-type cladding layer 103 to the p-type contact layer 109 by a wet etching method. As a result, as shown in FIG. 2Q, a bonded structure 1l in which a plurality of light emitting elements are separated is formed.
Then, using a dicing apparatus having a dicing blade, the junction structure 1l is separated. Thereby, as shown to FIG. 2R, the several light emitting element 1 which concerns on this Embodiment is formed. In this case, since the semiconductor structure including the active layer 105 in the bonding structure 1l is element-isolated by wet etching, a mechanical defect enters the semiconductor layer including the active layer 105 by element isolation using a dicing apparatus. This can be suppressed.
(Effects of the first embodiment)
The light emitting element 1 according to the present embodiment has a structure in which the light emitted from the active layer 105 is reflected by the surface center electrode portion 110 and the light reflection portion 116b of the thin wire electrode 116, thereby allowing the surface center electrode portion 110 and the light. Since the light can be reflected by the reflecting portion 116b, the light absorption loss by the surface center electrode portion 110 and the thin wire electrode 116 can be reduced, and the light extraction efficiency can be greatly improved.
The light-emitting element 1 also has a surface center electrode portion 110 having a cross-sectional area that does not burn even when a large ampere class current is supplied, and a current supply that supplies the current supplied to the surface center electrode portion 110 to the semiconductor multilayer structure 10. Since the electrode is configured by the thin wire electrode 116 having the portion 116a, it is possible to suppress the thin wire electrode 116 from being burned out by a large current. Thereby, since it is not necessary to increase the width of the thin wire electrode 116 in preparation for supplying a large current, light absorption by the current supply portion 116a of the thin wire electrode 116 can be minimized.
Further, in the light emitting element 1, the surface center electrode portion 110 to which a large current is supplied mainly exhibits a function of reflecting light except for a function of supplying a current to the thin wire electrode 116. Therefore, even if the width of the linear electrode 114 of the surface center electrode portion 110 is increased in preparation for supplying a large current, light absorption by the surface center electrode portion 110 can be substantially ignored, so that the light extraction efficiency can be improved. It can be greatly improved.
In addition, since the light emitting element 1 according to the present embodiment has a large chip size and emits high brightness with only one light emitting element 1, in the lighting device configured by arranging a plurality of light emitting elements in parallel, By configuring the light emitting element with the light emitting element 1 according to the present embodiment, the power consumption of the lighting device can be significantly reduced. The light emitting element 1 according to the present embodiment can also be applied to traffic signals, building lighting, and the like.
FIG. 3 shows an outline of a partial cross section of a light emitting device according to the second embodiment of the present invention.
The light emitting device according to the second embodiment of the present invention is substantially the same as the light emitting device 1 except that the structure of the thin wire electrode 116 is different from that of the light emitting device 1 according to the first embodiment of the present invention. It has a configuration. Therefore, detailed description is omitted except for the differences.
The thin wire electrode 116 of the light emitting device according to the second embodiment has a configuration in which a current supply unit 116a is sandwiched between two light reflecting units 116b. In the light emitting element according to the second embodiment, the light emitted from the active layer 105 can be reflected by the two light reflecting portions 116b of the one thin wire electrode 116.
Based on the structure of the light emitting device 1 according to the first embodiment of the present invention, the light emitting device according to the example was manufactured. Specifically, a light emitting device having the following configuration was manufactured.
First, the semiconductor multilayer structure was formed of an n-type cladding layer 103 made of n-type AlGaInP, an active layer 105 made of a quantum well structure, and a p-type cladding layer 107 made of p-type AlGaInP. The transparent layer 140 was formed from a SiO 2 layer. An Au layer was used as the reflective layer 132 of the reflective unit 130, and an Au layer was used as the bonding layer 136. Further, an Au layer was used as the bonding layer 202. In addition, a low resistance conductive Si substrate was used as the support substrate 20. The transmissive layer 142 and the transmissive portion 144 were each formed from SiO 2 having a thickness of 300 nm.
The metal layer 117 was formed of AuGe / Ni / Au, and the surface center electrode portion 110 and the fine wire electrode metal layer 118 were formed of 50 nm thick Al and 2 μm thick Au. The pad portion 112 was formed in a circular shape when viewed from above, and its diameter was formed to 200 μm. In addition, the width of the linear electrode 114 was formed to 50 μm, and the width of the thin wire electrode 116 was formed to 10 μm. Further, the number of fine wire electrodes 116 is 16 in total (the 16 fine wire electrodes 116 are opposed to each other with the linear electrode 114 as the axis of symmetry). Further, the width of the light reflecting portion 116b in the top view is 7 μm. The chip size of the light emitting element 1 is 2 mm × 2 mm. The light extraction surface 103a was subjected to fine uneven processing on the order of microns.
The light emitting device according to this example was mounted on a TO-46 stem using a eutectic alloy. And the pad part 112 and the current injection part of TO-46 stem were connected by the wire. Subsequently, resin molding was performed with silicone. And the TO-46 stem carrying the light emitting element was fixed to the heat radiating jig. When the characteristics of this light emitting device were evaluated, the following results were obtained.
That is, a current of 2 A (ampere) was supplied to the light emitting device according to the example, and the light emission wavelength, the light output, and the forward voltage were measured. As a result, the emission wavelength was 630 nm, the emission output was 2.1 W, and the forward voltage was 2.5V.
In addition, as a comparison with the light-emitting element according to the example, a light-emitting element including a surface center electrode portion and a thin wire electrode that does not have a function of reflecting light was formed.
FIG. 4 shows a schematic longitudinal section of a light emitting device according to a comparative example.
In the light emitting device according to the comparative example, an ohmic electrode 190 that is in ohmic contact with the n-type cladding layer 103 is provided instead of the transmission layer 142 immediately below the surface center electrode portion 110. Further, the light reflecting portion was not provided immediately below the thin wire electrode, and the entire surface was used as a current supply portion. Other configurations are the same as those of the light emitting device according to the example.
Similarly to the example, the light emitting device according to the comparative example was mounted on the TO-46 stem and sealed with resin. And the characteristic of the light emitting element which concerns on a comparative example was evaluated. When a current of 2 A was supplied to the light emitting device according to the comparative example, the forward voltage was 2.4 V, which was lower than that of the light emitting device according to the example, but the light emission output was 1.4 mW. That is, the light emission output of the light emitting element according to the comparative example was about two thirds of the light emission output of the light emitting element according to the example. This is considered to be due to the large light absorption loss at the surface center electrode portion and the thin line portion in the light emitting device according to the comparative example, and the superiority of the light emitting device according to this example was shown.
While the embodiments and examples of the present invention have been described above, the embodiments and examples described above do not limit the invention according to the claims. It should be noted that not all combinations of features described in the embodiments and examples are necessarily essential to the means for solving the problems of the invention.
It is a typical top view of the light emitting element concerning a 1st embodiment. It is a typical longitudinal cross-sectional view of the light emitting element in the AA cross section of FIG. 1A. It is a partial longitudinal cross-sectional view of the light emitting element in the BB cross section of FIG. 1A. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is CC sectional drawing of FIG. 2F. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is DD sectional drawing of FIG. 2I. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is EE sectional drawing of FIG. 2K. It is FF sectional drawing of FIG. 2K. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a fragmentary sectional view of the light emitting element concerning a 2nd embodiment. It is a typical longitudinal cross-sectional view of the light emitting element which concerns on a comparative example.
DESCRIPTION OF SYMBOLS 1, 2 Light emitting element 1a Semiconductor laminated structure 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l Junction structure 10, 10a Semiconductor laminated structure 11 Semiconductor laminated structure 20 Support substrate 20a Support structure Body 30 mask pattern 40 transparent material film 50 element region 100 n-type GaAs substrate 101 n-type contact layer 102 etching stop layer 103 n-type cladding layer 103a light extraction surface 105 active layer 107 p-type cladding layer 109 p-type contact layer 110 surface center Electrode part 110a Interface 112 Pad part 114 Linear electrode 116 Thin wire electrode 116a Current supply part 116b Light reflection part 117 Metal layer 118 Metal layer for fine line electrode 120 Contact part 130 Reflection part 132 Reflection layer 134 Alloying inhibition layer 136, 202 Bonding layer 136a, 20 2a Bonding surface 140 Transparent layer 140a Opening 142 Transmission layer 144 Transmission portion 144a Interface 200 Adhesion layer 204 Contact electrode 210 Back electrode
A first conductivity type first semiconductor layer; a second conductivity type second semiconductor layer different from the first conductivity type; and an active layer sandwiched between the first semiconductor layer and the second semiconductor layer. A semiconductor laminated structure;
A current supply unit provided in a partial region above the first semiconductor layer and supplying an external current to the semiconductor multilayer structure, and a light provided adjacent to the current supply unit and emitted from the active layer A thin wire electrode having a light reflecting portion for reflecting
A light emitting device comprising: a surface center electrode portion provided electrically connected to the thin wire electrode and provided above the first semiconductor layer through a transmission layer that transmits the light.
The light emitting device according to claim 1, wherein the surface center electrode portion reflects the light at an interface between the transmission layer and the surface center electrode portion.
The current supply unit is provided including a metal layer that is in ohmic contact with a part of the semiconductor multilayer structure, and a metal layer for a thin wire electrode that is provided on the opposite side of the metal layer to a part of the semiconductor multilayer structure. Item 3. A light emitting device according to Item 2.
The light reflecting portion includes a transmissive portion that transmits light of the active layer and has a resistivity higher than a resistivity of the current supply portion, and the metal layer for the fine wire electrode, and the transmissive portion and the fine wire The light emitting element according to claim 3, wherein the light is reflected at an interface with the electrode metal layer.
A support substrate having a reflective layer for reflecting the light emitted by the active layer;
A transparent layer provided between the reflective layer and the semiconductor multilayer structure;
A contact portion provided by filling a region penetrating a part of the transparent layer,
The semiconductor laminated structure is supported on the support substrate through the transparent layer,
The light emitting element according to claim 4, wherein the contact portion electrically connects the semiconductor multilayer structure and the reflective layer.
The surface center electrode portion includes a pad portion to which a wire is connected, and a linear electrode connected to the pad portion and extending along a horizontal direction of the active layer,
The light emitting device according to claim 5, wherein the linear electrode is formed to have a width wider than that of the thin wire electrode.
The light-emitting element according to claim 6, wherein the transmissive layer and the transmissive portion are made of an insulating material that transmits the light.
The light-emitting element according to claim 6, wherein the transmissive layer and the transmissive portion are made of a conductive material that transmits the light.
The light-emitting element according to claim 6, wherein the transmissive layer and the transmissive portion are made of a semiconductor material that transmits the light.
JP2008234748A 2008-09-12 2008-09-12 Light emitting element Active JP5024247B2 (en)
JP2008234748A JP5024247B2 (en) 2008-09-12 2008-09-12 Light emitting element
US12/382,598 US7968903B2 (en) 2008-09-12 2009-03-19 Light emitting device
CN 200910151713 CN101673794B (en) 2008-09-12 2009-07-06 Light emitting device
JP2010067891A JP2010067891A (en) 2010-03-25
JP5024247B2 true JP5024247B2 (en) 2012-09-12
ID=42006420
JP2008234748A Active JP5024247B2 (en) 2008-09-12 2008-09-12 Light emitting element
US (1) US7968903B2 (en)
JP (1) JP5024247B2 (en)
CN (1) CN101673794B (en)
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