JP4164689B2 - Semiconductor light emitting device - Google Patents

Description

  The present invention relates to a semiconductor light emitting device including a light emitting layer made of a semiconductor such as AlGaAs, AlGaInP, or GaN, and a method for manufacturing the same.

  A conventional typical semiconductor light emitting device in which a light emitting layer, that is, an active layer is formed of an AlGaInP compound semiconductor, includes a support substrate made of GaAs and a plurality of AlGaInP systems necessary for light emission disposed on the support substrate. A main semiconductor region including a compound semiconductor layer. The AlGaInP-based compound semiconductor can be epitaxially grown relatively well on the GaAs support substrate.

  However, the GaAs support substrate has a very high light absorption coefficient in the wavelength band of the light emitted from the light emitting layer included in the main semiconductor region. For this reason, most of the light emitted from the light emitting layer to the support substrate side is absorbed by the GaAs support substrate, and a light emitting element having high light emission efficiency cannot be obtained.

  As a method for preventing light absorption by the GaAs support substrate and increasing the light emission efficiency, the main semiconductor region including the light emitting layer is epitaxially grown on the support substrate such as GaAs in the semiconductor light emitting device having the basic structure described above, and then the GaAs support substrate is formed. A method is known in which a light-transmitting substrate made of, for example, GaP is attached to the main semiconductor region including the light-emitting layer, and an electrode having light reflectivity is formed on the lower surface of the light-transmitting substrate. However, the structure in which the light-transmitting substrate and the light-reflecting electrode are provided is such that the forward voltage between the anode electrode and the cathode electrode is compared by the resistance at the interface between the main semiconductor region including the light emitting layer and the light-transmitting substrate. Has the disadvantage of becoming larger.

Japanese Laid-Open Patent Publication No. 2002-217450 (hereinafter referred to as Patent Document 1) discloses a method for solving the above drawbacks. That is, in Patent Document 1, an ohmic property is excellent on the lower surface side of the main semiconductor region including the light emitting layer, but an AuGeGa alloy layer having low reflectivity is formed in a dispersed manner. Both the lower surface of the main semiconductor region including the uncovered light emitting layer is covered with a metal reflective film such as Al having excellent reflectivity, and the conductive support substrate made of, for example, conductive silicon is used for the metal reflective film. Is disclosed. The ohmic contact with the semiconductor region of the metal reflective film made of Al is poor. However, the AuGeGa alloy layer has a relatively good ohmic contact with a semiconductor region such as AlGaInP and the light reflecting film. Therefore, according to this structure, the forward voltage between the anode electrode and the cathode electrode can be reduced.
Further, the light emitted from the light emitting layer to the conductive support substrate side can be favorably reflected by the metal reflective film made of Al.

However, in the light emitting device described in Patent Document 1, a reaction occurs between the metal reflective film and the AuGeGa alloy layer and the main semiconductor region adjacent thereto in the course of various heat treatment steps in the manufacturing process. The reflectivity at the interface may decrease. For this reason, a semiconductor light emitting device having a high luminous efficiency could not be produced with a high yield as expected. Further, since AuGeGa alloy for ohmic contact is formed dispersively with respect to the lower surface of the main semiconductor region, it was not possible to sufficiently satisfy both the light emission efficiency and the forward voltage. That is, when the ratio of the AuGeGa for ohmic contact to the lower surface of the semiconductor region is increased, the forward voltage is reduced, but the reflection amount is reduced due to the reduction of the area of the Al reflection film, and the light emission efficiency is lowered. Therefore, in the prior art, it is difficult to improve both the luminous efficiency and the forward voltage at the same time.
JP 2002-217450 A

Accordingly, an object of the present invention is that a semiconductor light emitting device having high light emission efficiency cannot be obtained.

The present invention for solving the above problems is as follows.
A contact layer having a plurality of semiconductor layers for light emission and having one main surface for extracting light and the other main surface opposite to the one main surface and exposed to the other main surface A semiconductor region having
A first electrode electrically connected to a semiconductor layer disposed on one main surface side of the semiconductor region;
A light-transmitting film that is in ohmic contact with the other main surface of the semiconductor region, has conductivity, and is transmissive to light generated in the semiconductor region;
A metal light reflection film disposed so as to cover the light transmission film and having a function of reflecting light generated in the semiconductor region;
Comprising a second electrode electrically connected to the light-transmitting film or the metal light-reflecting film, the thickness T and refractive index of the contact layer n ₁ is
T = (2m + 1) × (λ / 4n ₁ ) ± λ / 8n ₁
n ₁ = (n ₂ × n ₃ ) ^1/2 × 0.8 to (n ₂ × n ₃ ) ^1/2 × 1.2
Here, m is a value of 0, 1 or 2,
n ₂ is the refractive index of the light transmission film,
n ₃ is the refractive index of the layer in contact with the contact layer in the semiconductor region,
λ is the wavelength of light generated from the semiconductor region,
The present invention relates to a semiconductor light emitting device characterized by the above.
The semiconductor light emitting device in the present invention may be not only a completed light emitting device but also a light emitting chip as an intermediate product.

The semiconductor region is preferably made of a Group 3-5 compound semiconductor.
The semiconductor layer exposed on the other main surface of the semiconductor region is preferably made of a compound semiconductor containing arsenic (As). A compound semiconductor containing As such as gallium arsenide (GaAs) or aluminum gallium arsenide (AlGaAs) is in good low-resistance contact with the light-transmitting film. As a result, a low operating voltage can be obtained more reliably.
The light transmissive film is preferably made of a light transmissive metal oxide.
The light transmitting film is made of In ₂ O _3, indium oxide or a mixture of indium trioxide and SnO _2, ie, tin oxide or stannic oxide (hereinafter referred to as ITO), aluminum-doped zinc oxide (ZnO ) (Hereinafter referred to as AZO), fluorine-doped tin oxide (SnO ₂ ) (hereinafter referred to as FTO), ZnO or zinc oxide, SnO or tin oxide or stannous oxide, ZnSe or zinc selenium, And at least one selected from GaO or gallium oxide. The light-transmitting film made of these materials has good low-resistance contact with the metal reflecting film and the semiconductor region, and also has excellent light transmittance, suppresses light attenuation, and emits light generated in the semiconductor region to the metal light reflecting film side. In addition, it has a function that can be favorably guided in the opposite direction, and that suppresses the diffusion of the metal light reflection film to the semiconductor region side of the metal satisfactorily.
The light transmission film preferably has a thickness of 10 nm to 1 μm. The light transmission film having a thickness of 10 nm or more has a function of suppressing the reaction between the metal light reflection film and the semiconductor region, that is, the mutual diffusion between the semiconductor and the metal, and an alloy layer having a large light absorption is formed at the interface between them. To prevent it. Moreover, when the thickness of the light transmission film is limited to 1 μm or less, the attenuation of light in the light transmission film is reduced, and the external quantum efficiency can be improved.
The metal light reflecting film is preferably a layer including at least one selected from aluminum (Al), silver (Ag), gold (Au), and copper (Cu). A metal light reflection film formed of these metal films forms a good light reflection surface at the interface with the light transmission film. That is, the metal light reflection film composed of the Al film and the Ag film has good reflection characteristics with respect to visible light in a relatively wide wavelength region from a short wavelength to a long wavelength. Further, the metal light reflection film made of the Cu film and the Au film has good reflection characteristics with respect to visible light having a relatively long wavelength.
The semiconductor light emitting device preferably further includes a conductive support substrate bonded to the metal light reflecting film. When the semiconductor light emitting element has a conductive support substrate, stable mechanical support of the semiconductor region, the light transmission film, and the metal light reflection film is achieved.
Preferably, the second electrode is coupled to the conductive support substrate and electrically connected to the light transmission film via the conductive support substrate and the metal light reflection film. Thus, formation of the second electrode is facilitated.

In the semiconductor light emitting device according to the present invention, the conductive light transmissive film disposed between the semiconductor region and the metal light reflective film is in ohmic contact with both the semiconductor region and the metal light reflective film, and Since the alloying between the semiconductor region and the metal light reflecting film is suppressed, a light reflecting surface superior to the case where the conventional metal light reflecting film is brought into direct contact with the semiconductor region can be configured. Further, the light transmission film absorbs less light than the conventional AuGeGa alloy. For this reason, the light radiated | emitted from the semiconductor region to the metal light reflection film side can be satisfactorily returned to one main surface side of the semiconductor region, and the external light emission efficiency can be increased.
Further, compared to the semiconductor light emitting device of Patent Document 1, the area of the region where the metal light reflecting film is in ohmic contact can be increased. When the area of the ohmic contact region is increased in this way, the resistance of the current path during light emission is reduced, the forward voltage is reduced, the power loss is reduced, and the light emission efficiency is improved.
Further, when the thickness T and the refractive index n _{1 of} the contact layer are set as in the present invention, the light reflected between the light transmission film and the metal light reflection film is totally reflected at the interface between the contact layer and the light transmission film. Can be prevented. As a result, the light reflected at the interface between the light transmission film and the metal light reflection film can be favorably guided to one main surface side of the semiconductor region .

  Next, a semiconductor light emitting device, that is, a light emitting diode, and a method for manufacturing the same according to an embodiment of the present invention will be described with reference to FIGS.

  As shown schematically in FIG. 1, a double heterojunction semiconductor light emitting device 1 according to Example 1 of the present invention includes a semiconductor region 2 necessary for light emission, a light transmission film 3 according to the present invention, and a metal light reflection. The film 4, the first and second bonding metal layers 5 and 6, the conductive silicon support substrate 7, the cathode electrode 8 as the first electrode, and the anode electrode 9 as the second electrode.

The semiconductor region 2 is selected from a group 5 element such as P (phosphorus), N (nitrogen), or As (arsenic), and Al (aluminum), Ga (gallium), In (indium), B (boron), or the like. Further, it is composed of a compound semiconductor with one or a plurality of Group 3 elements, and can also be called a main semiconductor region or a light emitting semiconductor substrate. The semiconductor region 2 in the embodiment of FIG. 1 has one main surface 11 and the other main surface 12, and is sequentially arranged from one main surface 11 toward the other main surface 12 (n-type (first)). (1 conductivity type) first auxiliary layer 13, n type second auxiliary layer 14, n type semiconductor layer 15, which can also be called an n type cladding layer or a first conductivity type semiconductor layer, a light emitting layer, An active layer 16 that can also be called, a p-type semiconductor layer 17 that can also be called a p-type (second conductivity type) cladding layer or a second conductivity type semiconductor layer, a p-type third auxiliary layer 18, and p And a mold contact layer 19.
The most important parts for light emission in the semiconductor region 2 for the double heterojunction light emitting diode are the n-type semiconductor layer 15, the active layer 16, and the p-type semiconductor layer 17. Accordingly, all or part of the n-type first auxiliary layer 13, the n-type second auxiliary layer 14, the p-type third auxiliary layer 18, and the p-type contact layer 19 in the semiconductor region 2 are omitted. be able to. Further, when the double heterojunction type is not used, the active layer 16 can be omitted. Therefore, the semiconductor region 2 only needs to include at least the n-type semiconductor layer 15 and the p-type semiconductor layer 17.
The light emitting element 1 is configured to extract light emitted from the active layer 16 from one main surface 11 side of the semiconductor region 2.
Next, each part of the light emitting element 1 will be described in detail.

The active layer 16 disposed between the n-type semiconductor layer 15 and the p-type semiconductor layer 17 is made of a group 3-5 compound semiconductor. This group 3-5 compound semiconductor has the chemical formula Al _x Ga _y In _1-xy P
Here, x and y are 0 ≦ x ≦ 1,
0 ≦ y ≦ 1,
A numerical value satisfying 0 ≦ x + y ≦ 1,
It is desirable that the material can be represented by. However, the active layer 16 can also be composed of another Group 3-5 compound semiconductor such as Al _x Ga _y In _1-xy N.
In this embodiment, the conductivity determining impurity is not added to the active layer 16. However, it is possible to add a p-type impurity to the active layer 16 at a concentration lower than that of the p-type cladding layer 17, or to add an n-type impurity at a concentration lower than that of the n-type semiconductor layer 15. Further, in FIG. 1, the active layer 16 is shown as a single layer for the sake of simplicity, but in practice, a well-known multi-quantum well (MQW) structure or a single layer is used. It has a quantum well (SQW: Single-Quantum-Well) structure.

The n-type semiconductor layer 15 disposed on one side of the active layer 16 is made of a Group 3-5 compound semiconductor to which an n-type impurity (for example, Si) is added. This group 3-5 compound semiconductor is, for example, the chemical formula Al _x Ga _y In _1-xy P
Here, x and y are 0 ≦ x <1,
0 ≦ y ≦ 1,
A numerical value satisfying 0 ≦ x + y ≦ 1,
It is desirable that the material can be represented by. In order to satisfactorily extract the light generated in the active layer 16 to the outside, the Al ratio x of the n-type semiconductor layer 15 has a larger value than the Al ratio x of the active layer 16, and preferably 0.15 to. 45, more preferably 0.2 to 0.4. The Ga ratio y is preferably 0.05 to 0.35, more preferably 0.1 to 0.3. The n-type impurity concentration of the n-type semiconductor layer 15 is desirably 5 × 10 ¹⁷ cm ⁻³ or more. The band gap of the n-type semiconductor layer 15 is larger than the band gap of the active layer 16.
Note that the n-type semiconductor layer 15 may be formed of another group 3-5 compound semiconductor such as Al _x Ga _y In _1-xy N.

The p-type semiconductor layer 17 disposed on the other side of the active layer 12 is made of a Group 3-5 compound semiconductor to which a p-type impurity (for example, Zn) is added. This group 3-5 compound semiconductor is, for example, the chemical formula Al _x Ga _y In _1-xy P
Where x and y are 0 ≦ x ≦ 1,
0 ≦ y ≦ 1,
A numerical value satisfying 0 ≦ x + y ≦ 1,
It is desirable that the material can be represented by. In order to satisfactorily extract the light generated in the active layer 16 to the outside, the Al ratio x of the p-type semiconductor layer 17 has a larger value than the Al ratio x of the active layer 16, and preferably 0.15 to 0.00. A range of 5 is set. The concentration of the p-type impurity in the p-type semiconductor layer 17 is determined to be 5 × 10 ¹⁷ cm ⁻³ or more, for example. The band gap of the p-type semiconductor layer 17 is larger than the band gap of the active layer 16.
Note that the p-type semiconductor layer 17 may be composed of another group 3-5 compound semiconductor such as Al _x Ga _y In _1-xy N.

The second auxiliary layer 14 disposed on the n-type semiconductor layer 15 can also be called a current diffusion layer or a buffer layer, and mainly has a function of improving the uniformity of the forward current distribution. That is, the second auxiliary layer 14 has a function of spreading a current to the outer peripheral side of the cathode electrode 8 when viewed from a direction perpendicular to the one main surface 11 of the semiconductor region 2. The second auxiliary layer 14 has a function of spreading out the light generated in the active layer 16 to the outer peripheral side of the device. The second auxiliary layer 14 of Example 1 is made of n-type GaAs. However, the second auxiliary layer 14 is made of, for example, GaP other than GaAs, such as GaP, Ga _x In _1-x P, Al _x Ga _1-x As, or GaN, or Ga _x In _1-x N, or Al _x Ga. It can be composed of another n-type group 3-5 compound semiconductor such as _1-xN .

The n-type first auxiliary layer 13 disposed on the second auxiliary layer 14 can also be called an n-type contact layer, and mainly has a function of improving the ohmic contact of the cathode electrode 8. Furthermore, it also has a function as an etching stopper in the manufacturing process of the light emitting element described later. The first auxiliary layer 13 is formed of, for example, the chemical formula Al _x Ga _y In _1-xy P
Here, x and y are 0 ≦ x ≦ 1,
0 ≦ y ≦ 1,
A numerical value satisfying 0 ≦ x + y ≦ 1,
It consists of what added the n-type impurity to the group 3-5 compound semiconductor which can be shown by these.
The first auxiliary layer 13 can also be composed of another group 3-5 compound semiconductor such as Al _x Ga _y In _{1 -xy} N.

  The third auxiliary layer 18 disposed adjacent to the p-type semiconductor layer 17 can also be called a current diffusion layer or a buffer layer, and has a function of mainly improving the uniformity of the forward current distribution. That is, the third auxiliary layer 18 has a function of spreading a current to the outer peripheral side of the cathode electrode 8 when viewed from a direction perpendicular to the one main surface 11 of the semiconductor region 2. The third auxiliary layer 18 is composed of another group 3-5 compound semiconductor such as p-type GaP (gallium phosphorus) or p-type GaN.

The p-type contact layer 19 disposed adjacent to the third auxiliary layer 18 is a semiconductor layer exposed on the other main surface 12 of the semiconductor region 2, in order to obtain good ohmic contact of the light transmission film 3 according to the present invention. Is provided. The p-type contact layer 19 is preferably made of a Group 3-5 compound semiconductor containing As. In this embodiment, p-type GaAs (gallium arsenide) is used, but not limited to this, other group 3-5 compound semiconductors such as p-type AlGaAs, p-type GaN, and p-type AlGaN can be used.
The thickness of the contact layer 19 is T, the refractive index is n ₁ , the refractive index of the light transmission film 3 is n ₂ , the refractive index of the third auxiliary layer 18 is n ₃ , and the wavelength of light generated from the active layer 16 is λ. In this case, it is desirable to determine the thickness T and refractive index of the contact layer 19 so that n ₁ satisfies the following conditions.
T = (2m + 1) × (λ / 4n ₁ ) ± λ / 8n ₁
Here, m is 0 or any value of 1 or 2.
n ₁ = (n ₂ × n ₃ ) ^1/2 × 0.8 to (n ₂ × n ₃ ) ^1/2 × 1.2
When the thickness T and the refractive index n _{1 of the} contact layer 19 are set in this way, the light reflected between the light transmission film 3 and the metal light reflection film 4 is totally reflected at the interface between the contact layer 19 and the light transmission film 3. Reflection can be prevented. As a result, the light reflected at the interface between the light transmission film 3 and the metal light reflection film 4 can be guided well to the one main surface 11 side of the semiconductor region 2.

The light transmissive film 3 has conductivity and is transmissive to light generated in the semiconductor region 2, and is in ohmic contact with the other main surface 12 of the semiconductor region 2, that is, the entire p-type contact layer 19. . The light transmission film 3 is formed of a material that has a greater transmittance for light generated in the semiconductor region 2 than the transmittance of the semiconductor region 2. The transmittance of the light transmissive film 3 is desirably 60% or more. The light transmission film 3 is formed of a material and a method in which an alloying part or an interdiffusion part is not generated or only slightly generated between the semiconductor region 2 and the metal light reflection film 4. A preferable material of the light transmission film 3 is a metal oxide or a metal compound, and a more preferable material is, for example, at least one selected from ITO, AZO, FTO, ZnO, SnO, ZnSe, and GaO, and the most preferable material. Is ITO. Moreover, the preferable formation method of the light transmissive film | membrane 3 is sputtering, CVD (Chemical Vapor Deposition), or vapor deposition.
The thickness of the light transmission film 3 is desirably 10 nm to 1 μm. When the thickness of the light transmission film 3 is 10 nm or more, alloying between the metal light reflection film 4 and the semiconductor region 2 can be satisfactorily suppressed. Moreover, when the thickness of the light transmission film 3 is limited to 1 μm or less, the attenuation of light in the light transmission film 3 is reduced, and the external quantum efficiency can be improved. The light transmission film 3 is most preferably formed on the entire surface of the other main surface 12 of the semiconductor region 2, but can also be formed in a range of 50 to 100% of the other main surface 12.

The metal light reflection film 4 has a function of reflecting light generated in the semiconductor region 2 and is disposed so as to cover the entire surface of the light transmission film 3. The metal light reflecting film 4 is made of at least one metal selected from aluminum (Al), silver (Ag), gold (Au), and copper (Cu), or aluminum (Al), silver (Ag), gold ( It is desirable to form an alloy containing at least one metal selected from Au) and copper (Cu). In this embodiment, the metal light reflection film 4 is formed of aluminum (Al) which is advantageous in terms of cost. The metal light reflection film 4 is most preferably formed on the entire surface of the light transmission film 3, but can also be formed in a range of 50 to 100% of the light transmission film 3 or the other main surface 12. In order to obtain a sufficient light reflection function, the metal light reflection film 4 is preferably formed to a thickness of 0.05 μm to 1 μm.

In order to mechanically protect and support the semiconductor region 2, the light transmission film 3, and the metal light reflection film 4, the conductive support substrate 7 reflects the metal light through the first and second bonding metal layers 5 and 6. Bonded to the membrane 4. The first bonding metal layer 5 is made of, for example, gold (Au) and is formed so as to cover the metal light reflection film 4. The second bonding metal layer 6 is made of, for example, gold (Au) and is formed so as to cover the conductive support substrate 7. The first and second bonding metal layers 5 and 6 are bonded to each other by a thermocompression bonding method. In this embodiment, a silicon substrate to which a conductivity determining impurity is added and has a thickness of 300 μm is used as the conductive support substrate 7. Silicon substrates have the advantage of being inexpensive and easy to process.

  The cathode electrode 8 as the first electrode is made of a metal layer and is in ohmic contact with one main surface 11 of the semiconductor region 2, that is, the center of the first auxiliary layer 13. Accordingly, a portion of the one main surface 11 of the semiconductor region 2 where the cathode electrode 8 is not formed becomes a light extraction surface. The cathode electrode 8 can also be configured by a combination of a light transmissive electrode such as ITO and a bonding pad electrode. Further, the cathode electrode 8 can be connected to one arbitrary position selected from the n-type first auxiliary layer 13, the second auxiliary layer 14, and the n-type semiconductor layer 15.

  The anode electrode 9 as the second electrode is formed on the entire lower surface of the silicon support substrate 7. When a metal support substrate is provided instead of the silicon support substrate 7, this serves as a cathode electrode, so that the cathode electrode 9 of FIG. 1 can be omitted.

When manufacturing the semiconductor light emitting device 1 of FIG. 1, the semiconductor region 2 is first formed. That is, the semiconductor substrate 10 made of, for example, GaAs shown in FIG. 2 is prepared, and the n-type first auxiliary layer 13 and the GaAs semiconductor substrate 10 are formed on the GaAs semiconductor substrate 10 using a known metal organic chemical vapor deposition (MOCVD) apparatus. The n-type second auxiliary layer 14, the n-type semiconductor layer 15, the active layer 16, the p-type semiconductor layer 17, the p-type third auxiliary layer 18, and the p-type contact layer 19 are sequentially formed. The semiconductor region 2 is obtained by epitaxial growth.

Next, ITO is deposited on the entire exposed main surface of the p-type contact layer 19 by sputtering, CVD, vapor deposition, or the like to form the light transmissive film 3. Next, a metal made of Al is formed on the light transmissive film 3. A light reflecting film 4 is formed, and a first bonding metal layer 5 made of Au is further formed.

  Next, a material obtained by vacuum-depositing a second bonding metal layer 6 made of Au on one main surface of a support substrate 7 made of an Si substrate containing impurities shown in FIG. 2 is prepared. The first and second metal bonding layers 5 and 6 are bonded to each other by subjecting the layers 5 and 6 to pressure contact, performing a heat treatment at a temperature of 300 ° C. or less, and diffusing Au to each other. The semiconductor region 2 with the metal light reflection film 4 and the first bonding metal layer 5 and the support substrate 7 with the second bonding metal layer 6 are integrated.

Next, the semiconductor substrate 10 made of GaAs is removed by etching. Thereby, the semiconductor region 2 with the light transmission film 3, the metal light reflection film 4, and the first bonding metal layer 5 is obtained. The semiconductor substrate 10 made of GaAs can be removed before the support substrate 7 with the second bonding metal layer 6 is bonded to the first bonding metal layer 5.

  Thereafter, the cathode electrode 8 and the anode electrode 9 shown in FIG. 1 are formed to complete the semiconductor light emitting device.

This embodiment has the following effects.
(1) Since the light transmission film 3 having conductivity is formed between the metal light reflection film 4 and the semiconductor region 2, the metal reflection film 4 and the semiconductor region 2 are not subjected to various heat treatment steps during the manufacturing process. The alloying reaction that occurs in the meantime can be prevented or suppressed. If an alloyed portion is generated, the reflectance is lowered, but such a problem does not occur in this embodiment. For this reason, a light-emitting element having high light emission efficiency can be easily produced with a high yield.
(2) Since the light transmission film 3 is formed by depositing a metal oxide by sputtering, CVD, vapor deposition, or the like, the alloying reaction is suppressed or prevented with respect to the metal light reflection film 4 and the semiconductor region 2. Make ohmic contact. Therefore, the light absorption at the ohmic contact portion of the light transmission film 3 is reduced and the resistance is reduced, so that it is possible to suppress the reduction in light emission efficiency and the increase in operating voltage.
(3) Since the light transmission film 3 and the metal light reflection film 4 are opposed to substantially all of the other main surface 12 of the semiconductor region 2, the ohmic contact area is increased, and a forward voltage is applied to the semiconductor light emitting device 1. The resistance between the anode electrode 9 and the cathode electrode 8 when applied can be reduced.
(4) Since the contact layer 19 is provided on substantially the whole of the other main surface 12 of the semiconductor region 2, the other of the semiconductor regions 2 is compared with the semiconductor light emitting device of Patent Document 1 in which the contact layer 19 is partially provided. The flatness of the main surface 12 is improved and the bonding of the silicon support substrate 7 can be satisfactorily achieved.
(5) Since it is not necessary to partially provide the contact layer 19, patterning for partially providing the contact layer 19 is not required, and the manufacturing process is simplified.

  Next, the semiconductor light emitting device 1a according to the second embodiment will be described with reference to FIG. 3 that are the same as those in FIGS. 1 and 2 are given the same reference numerals, and descriptions thereof are omitted.

  The semiconductor light emitting device 1a of FIG. 3 is formed in the same manner as in FIG. 1 except that a deformed semiconductor region 2a and a deformed support substrate 7a are provided and the connection position of the anode electrode 9 is changed. The modified semiconductor region 2a in FIG. 3 corresponds to the semiconductor region 1 in FIG. 1 in which the first and third auxiliary layers 13 and 18 and the p-type contact layer 19 are omitted. Therefore, the cathode electrode 8 as the first electrode is connected to the main surface of the current diffusion layer 14 having the same configuration as that of the second auxiliary layer 14 in FIG. The support substrate 7a, the light transmission film 3, and the metal light reflection film 4 are formed so as to have a portion protruding laterally from the semiconductor region 2a. The anode electrode 9 is directly connected to the light transmission film 3. Further, the metal light reflecting film 4 is directly coupled to the support substrate 7a. The support substrate 7a is formed of a metal material having good thermal conductivity in order to improve heat dissipation.

  Also in the semiconductor light emitting device 1a of FIG. 3, since the metal light reflection film 4 is coupled to the other main surface 12 of the semiconductor region 2a through the light transmission film 3, the same effect as that of the first embodiment of FIG. Can be obtained.

The present invention is not limited to the above-described embodiments, and for example, the following modifications are possible.
(1) When the mechanical strength of the semiconductor region 2 or 2a is sufficient, the support substrate 7 or 7a of FIGS. 1 and 3 can be omitted. In this case, the metal light reflection layer 4 functions as a cathode electrode.
(2) The conductivity type of each layer 13, 14, 15, 17, 18, 19 of the semiconductor region 2 or 2a can be reversed from that of the embodiment.

It is sectional drawing which shows the semiconductor light-emitting device according to Example 1 of this invention. It is sectional drawing which shows the state in the manufacture stage of the semiconductor light-emitting device of FIG. It is sectional drawing which shows the semiconductor light-emitting device according to Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Semiconductor light-emitting device 2, 2a Semiconductor area | region 3 Light transmission film | membrane 4 Metal light reflection layer 5,6 1st and 2nd joining metal layer 7 Silicon support substrate 8 Cathode electrode 9 Anode electrode 15 N-type semiconductor layer 16 Active layer 17 p-type semiconductor layers 13, 14, 18 First, second and third auxiliary layers 19 Ohmic contact layer

Claims (8)

A contact layer having a plurality of semiconductor layers for light emission and having one main surface for extracting light and the other main surface opposite to the one main surface and exposed to the other main surface A semiconductor region having
A first electrode electrically connected to a semiconductor layer disposed on one main surface side of the semiconductor region;
A light-transmitting film that is in ohmic contact with the other main surface of the semiconductor region, has conductivity, and is transmissive to light generated in the semiconductor region;
A metal light reflection film disposed so as to cover the light transmission film and having a function of reflecting light generated in the semiconductor region;
Comprising a second electrode electrically connected to the light-transmitting film or the metal light-reflecting film, the thickness T and refractive index of the contact layer n ₁ is
T = (2m + 1) × (λ / 4n ₁ ) ± λ / 8n ₁
n ₁ = (n ₂ × n ₃ ) ^1/2 × 0.8 to (n ₂ × n ₃ ) ^1/2 × 1.2
Here, m is a value of 0, 1 or 2,
n ₂ is the refractive index of the light transmission film,
n ₃ is the refractive index of the layer in contact with the contact layer in the semiconductor region,
λ is the wavelength of light generated from the semiconductor region,
The semiconductor light emitting element characterized by being determined . 2. The semiconductor light emitting device according to claim 1, wherein the semiconductor layer exposed on the other main surface of the semiconductor region is made of a compound semiconductor containing As.   3. The semiconductor light-emitting element according to claim 1, wherein the light-transmitting film is made of a light-transmitting metal oxide.   The light transmission film is selected from a mixture of indium oxide and tin oxide (ITO), zinc oxide doped with aluminum (AZO), tin oxide doped with fluorine (FTO), ZnO, SnO, ZnSe, and GaO. 3. The semiconductor light emitting device according to claim 1, comprising at least one of the above.   The semiconductor light emitting element according to claim 1, 2, 3, or 4, wherein the light transmission film has a thickness of 10 nm to 1 μm. The semiconductor light emitting element according to claim 1, 2, 3, 4, or 5, wherein the metal light reflection film is a layer containing at least one selected from Al, Ag, Au, and Cu.   The semiconductor light emitting device according to claim 1, further comprising a conductive support substrate bonded to the metal light reflection film. 8. The second electrode is coupled to the conductive support substrate, and is electrically connected to the light transmission film through the conductive support substrate and the metal light reflection film. The semiconductor light emitting element as described.

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