JP2007116065A - Light emitting element and process for fabrication thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting element which is stuck easily and firmly and, moreover, in which a manufacturing cost is held down, in the light emitting element in which a compound substrate having at least a light emitting layer and a reflective layer for reflecting a light from the light emitting layer is stuck to a silicon substrate and it comes to unite, and to provide a process for fabrication. <P>SOLUTION: The light emitting element is formed by sticking, at least, a compound semiconductor substrate having a light emitting layer and a reflective layer for reflecting a light from the light emitting layer and a silicon substrate. The sticking surface is stuck by solid solving an Au film formed on one substrate and an Ag film formed on the other substrate. In the process for fabrication thereof, the Au film is formed on either one of the sticking surface of the compound semiconductor substrate and the sticking surface of the silicon substrate, the Ag film is formed on the other, the Au film and the Ag film are superposed, subjected to solid solution, and stuck. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting element manufactured by bonding a light emitting layer and a compound semiconductor substrate into which a light reflecting layer that reflects light with high efficiency without depending on an incident angle and a silicon substrate, and a method for manufacturing the same.

  As a result of many years of progress in materials and element structures used in light-emitting elements such as light-emitting diodes and semiconductor lasers, the photoelectric conversion efficiency inside the elements is gradually approaching the theoretical limit. Accordingly, when an element with higher luminance is to be obtained, the light extraction efficiency from the light emitting element is extremely important.

  For example, in a light emitting device having a light emitting layer portion formed of AlGaInP mixed crystal, a thin AlGaInP (or GaInP) active layer is sandwiched between an n-type AlGaInP clad layer and a p-type AlGaInP clad layer having a larger band gap. By adopting a sandwiched double hetero structure, a high-luminance element can be realized. Such an AlGaInP double heterostructure can be formed by epitaxially growing each layer of an AlGaInP mixed crystal on a GaAs single crystal substrate by utilizing the lattice matching of the AlGaInP mixed crystal with GaAs. When this is used as a light emitting element, a GaAs single crystal substrate is usually used as an element substrate as it is.

  However, since the AlGaInP mixed crystal constituting the light emitting layer has a larger band gap than GaAs, the emitted light is absorbed by the GaAs substrate, and it is difficult to obtain sufficient light extraction efficiency. In order to solve this problem, a method (for example, Patent Document 1) in which a reflective layer made of a semiconductor multilayer film is inserted between a substrate and a light emitting element has also been proposed. Therefore, only light incident at a limited angle is reflected, and a significant improvement in light extraction efficiency cannot be expected in principle.

On the other hand, in Non-Patent Document 1, a metal layer mainly composed of Au is used as a reflective layer between the light emitting layer portion and the silicon substrate. Specifically, a silicon substrate is oxidized to form an AuBe layer and an Au layer on SiO ₂ , and light generated in the light emitting layer is reflected by the Au layer. With this structure, a high reflectance independent of the incident angle can be obtained, and the light extraction efficiency can be greatly increased. The structure is in the order of AlGaInP double heterostructure light emitting layer / GaAs cap layer + (bonding interface) metal reflective layer / oxide film / silicon substrate.
However, in this manufacturing method, no current flows in the vertical direction to the light emitting layer, the reflective layer, and the silicon substrate. This complicates the structure and increases the manufacturing process and cost.

  Further, for example, as disclosed in Patent Document 2 and Patent Document 3, the light emitting layer is peeled off from the grown light emitting layer, and the light emitting layer is reflected on a semiconductor substrate such as silicon having a metal layer formed on the surface. A technique is disclosed in which bonding is performed on the release surface via an Au layer that also serves as a layer. Further, Patent Document 4 discloses a light-emitting element in which an Ag layer instead of an Au layer is formed as a reflective layer and bonded together.

  However, in the above bonding, in the case of bonding Au and Au, the amount of Au used increases, resulting in a costly light emitting element. In addition, prioritizing cost reduction, when an Ag layer is formed as a reflective layer and bonded with Ag and Ag, bonding is less likely than with bonding between Au and Au, resulting in poor bonding. easy.

JP-A-7-66455 JP 2002-217450 A JP 2003-243699 A JP 2004-207508 A Applied Physics Letters, 75 (1999) 3054

  The present invention has been made in view of such problems, and is formed by laminating a compound semiconductor substrate having at least a light emitting layer and a reflective layer for reflecting light from the light emitting layer, and a silicon substrate. An object of the present invention is to provide a light-emitting element that is easily and firmly attached to the light-emitting element and has a low manufacturing cost, and a method for manufacturing the light-emitting element.

  In order to solve the above-described problems, the present invention provides a light-emitting element in which a compound semiconductor substrate having at least a light-emitting layer and a reflective layer for reflecting light from the light-emitting layer and a silicon substrate are bonded together. The bonding surface of the compound semiconductor substrate and the silicon substrate is formed by bonding the Au film formed on one substrate and the Ag film formed on the other substrate into a solid solution. A light emitting device characterized by the above is provided.

  In this way, the compound semiconductor substrate and the bonding surface of the silicon substrate may be a light-emitting element in which the Au film formed on one substrate and the Ag film formed on the other substrate are bonded together by solid solution. For example, the amount of Au on the bonding surface can be reduced to less than half that of the bonding between Au and Au, and a light emitting device with reduced manufacturing cost can be obtained. Further, since Au and Ag are formed into a solid solution and bonded together, both substrates can be bonded easily and firmly as compared with the case of bonding Ag and Ag. In addition, it is possible to obtain a bonding strength equivalent to the bonding of Au and Au.

At this time, the reflective layer is preferably made of any one of Au, Ag, and AgPdCu (claim 2).
Thus, the reflective layer can be made of any one of Au, Ag, and AgPdCu. The reflection layer made of such a material can efficiently extract light.

  The compound semiconductor substrate has a diffusion prevention metal layer between the reflection layer and the Au film or Ag film formed on the bonding surface, and the diffusion prevention metal layer is formed of the reflection layer. It is preferable that Au or Ag is prevented from being mixed in (claim 3).

  As described above, if a diffusion preventing metal layer is provided between the reflective layer and the Au film or Ag film formed on the bonded surface, Au or Ag is prevented from being mixed into the reflective layer. be able to. For this reason, in the reflective layer, it is possible to prevent a decrease in reflectivity due to the mixing, and the light extraction efficiency can be increased.

At this time, it is preferable that the diffusion preventing metal layer is made of any one of Ti, W, Cr, and Ni.
In this way, the diffusion preventing metal layer can be made of any one of Ti, W, Cr, and Ni, and Au or Ag can be effectively prevented from being mixed into the reflective layer.

The light emitting layer is preferably composed of a double hetero structure in which an n-type cladding layer, an active layer, and a p-type cladding layer are laminated in this order.
Thus, if the light-emitting layer has a double hetero structure in which an n-type cladding layer, an active layer, and a p-type cladding layer are stacked in this order, a light-emitting element with higher luminance can be obtained. it can.

  Further, the present invention is a method for manufacturing a light emitting element by bonding a compound semiconductor substrate having at least a light emitting layer and a reflective layer for reflecting light from the light emitting layer, and a silicon substrate, An Au film is formed on one of the bonding surface of the compound semiconductor substrate and the bonding surface of the silicon substrate, an Ag film is formed on the other, and the Au film and the Ag film are superposed and solidified. A method for manufacturing a light-emitting element, characterized by being bonded together, is provided.

  In this way, an Au film is formed on one of the bonding surface of the compound semiconductor substrate and the bonding surface of the silicon substrate, an Ag film is formed on the other, and the Au film and the Ag film are overlaid and fixed. If it is melted and bonded, the Au film is formed only on one substrate, so the amount of Au used is reduced compared to the case of bonding Au and Au, and a light emitting device is manufactured without cost. can do. In addition, since the Ag film and the Au film are solidified and bonded, it is possible to bond them more easily than in the case of bonding Ag and Ag. In addition, a bonding strength equivalent to the bonding of Au and Au is obtained, and poor bonding is less likely to occur.

At this time, it is preferable that the reflective layer is formed of any one of Au, Ag, and AgPdCu.
Thus, the reflective layer can be made of any one of Au, Ag, and AgPdCu. By using such a material for the reflective layer, it is possible to extract light more efficiently.

Preferably, the Au film or the Ag film is formed on the bonding surface of the compound semiconductor substrate after forming a diffusion preventing metal layer for preventing Au or Ag from being mixed into the reflective layer. Claim 8).
Thus, if an Au film or an Ag film is formed after forming a diffusion preventing metal layer on the bonding surface of the compound semiconductor substrate, it is possible to prevent Au or Ag from being mixed into the reflective layer. . For this reason, in the reflective layer, it is possible to prevent a decrease in reflectivity due to the mixing, and it is possible to increase the light extraction efficiency.

At this time, the diffusion preventing metal layer is preferably formed of any one of Ti, W, Cr, and Ni.
As described above, the diffusion preventing metal layer can be formed of any one of Ti, W, Cr, and Ni, and Au or Ag can be effectively prevented from being mixed into the reflective layer.

Preferably, the light emitting layer is formed of a double hetero structure in which an n-type cladding layer, an active layer, and a p-type cladding layer are stacked in this order.
Thus, if the light-emitting layer has a double hetero structure in which an n-type cladding layer, an active layer, and a p-type cladding layer are stacked in this order, a light-emitting element with higher luminance can be obtained. it can.

  A compound semiconductor substrate having at least a light emitting layer and a reflective layer for reflecting light from the light emitting layer and a silicon substrate are bonded to Ag and Ag by the light emitting element and the method for manufacturing the light emitting element of the present invention. Thus, it is possible to obtain a light-emitting element that is easily and firmly bonded as compared with the above case, and is bonded at a lower cost than the bonding of Au and Au.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.
As described above, in order to obtain a high-luminance element, the light extraction efficiency from the light-emitting element is regarded as important. In order to improve the light extraction efficiency, a reflective layer is provided inside the device. In the method for manufacturing a light emitting element, the GaAs substrate for growing the light emitting layer is peeled off from the light emitting layer, while a semiconductor substrate such as silicon having a metal layer formed on the surface is used as an Au layer or an Ag layer that also serves as a reflective layer. And a technique for manufacturing by bonding to the release surface of the light emitting layer.
However, in this bonding, if the metal layer on the surface of the silicon substrate is Au and bonding with Au and Au is costly, the bonding with Ag and Ag is a case of bonding with Au-Au. There was a problem that it was difficult to stick in comparison.

  Therefore, the present inventor has conducted earnest research on a bonded light emitting element having a reflective layer between a light emitting layer and a silicon substrate and a manufacturing method thereof in order to improve light extraction efficiency. A compound semiconductor substrate having a reflective layer and a silicon substrate are bonded to each other. The bonding surfaces of both substrates are an Au film formed on one substrate and an Ag film formed on the other substrate. In the case of a light-emitting element bonded in a solid solution, the cost is lower than that of bonding with Au and Au, and bonding is easier and stronger than bonding with Ag and Ag, and is the same as bonding of Au and Au. The present invention has been completed by finding that a certain degree of bonding strength can be obtained and bonding defects can be reduced.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a schematic view showing an example of the structure of a light emitting device according to the present invention.
A light-emitting element 1 of the present invention includes a compound semiconductor substrate having at least a light-emitting layer and a reflective layer for reflecting light from the light-emitting layer, and a silicon substrate, and at least the above-described The light-emitting layer 21, the reflective layer 13, the Au / Ag solid solution layer 30, and the silicon substrate portion 19 are included.

  As described above, the compound semiconductor substrate has at least the light emitting layer 21 and the reflective layer 13. First, as the light emitting layer 21, for example, an n-type cladding layer, an active layer, and a p-type cladding layer are arranged in this order. It is preferable that the layer is composed of a double heterostructure laminated with a layer. An AlGaInP mixed crystal in which an active layer 8 made of AlGaInP is sandwiched between an n-type AlGaInP cladding layer 9 and a p-type AlGaInP cladding layer 7 is an example of such a double hetero structure. Moreover, GaInP mixed crystal etc. are mentioned. By adopting such a structure, holes and electrons injected from both clad layers are efficiently recombined in a form confined in the narrow space of the active layer, so that a high-luminance light emitting device can be obtained. .

  Moreover, as the reflection layer 13, what consists of either Au, Ag, AgPdCu etc. is mentioned. By effectively reflecting the light from the light emitting layer by the reflective layer composed of these, light can be extracted efficiently. Note that the material of the reflective layer 13 may be appropriately selected depending on the wavelength of light to be extracted.

As described above, the present invention is obtained by bonding a compound semiconductor substrate and a silicon substrate. Therefore, there is a bonding surface between the compound semiconductor substrate portion and the silicon substrate portion, and the bonding surface is It is made of a solid solution layer 30 of Au and Ag.
This is a layer formed by solidifying the Au film formed on one substrate and the Ag film formed on the other substrate when the compound semiconductor substrate and the silicon substrate are bonded to each other. The fine particles of Au and Ag are combined by force. Au and Ag are completely solidified, and have a bonding strength comparable to that of Au and Au.
Note that by bonding to the silicon substrate, the element itself can be used as a part of a conduction path for driving the light emitting element, and the element structure can be simplified. By using a particularly inexpensive silicon substrate, a light-emitting element manufactured at a reduced cost can be obtained.

  Further, a diffusion preventing metal layer 14 is provided between the solid solution layer 30 and the reflective layer 13. The diffusion preventing metal layer 14 can be composed of, for example, any one of Ti, W, Cr, and Ni. By providing such a diffusion preventing metal layer 14, it is possible to prevent Au or Ag from being mixed into the reflective layer from the solid solution layer when the Ag film and the Au film are bonded together by solid solution. For example, when the reflective layer 13 is made of Au, the reflectance decreases if Ag is mixed in the reflective layer, but by providing the diffusion preventing metal layer 14 as described above, the above mixing is prevented, It is possible to reflect light efficiently without deteriorating the reflectance.

  Further, as shown in FIG. 1, a current diffusion layer 6 (p-AlGaAs), a contact layer and an antioxidant cap layer 5 (p-GaAs), and an electrode 22 are formed on the light emitting layer 21 having a double hetero structure. Has been. Since the electrode 22 is formed so as to cover only a part of the surface of the light emitting layer 21, the current diffusion layer 6 is formed so as to be uniform in the in-plane direction with respect to the double hetero structure. A current can be diffused, and a light emission state with high luminance can be obtained even in a region not covered with the electrode 22.

  A current diffusion layer 10 (n-GaAs), an etching stop layer 11 (n + GaAs), and an ohmic electrode 12 (AuGeNi) are formed between the light emitting layer 21 and the reflective layer 13. The etching stop layer 11 is formed for the step of removing a growth substrate, which will be described later, when the light emitting element 1 is manufactured. Moreover, by forming the ohmic electrode 12, it is possible to contribute to reduction of the series resistance of the element.

Further, on the opposite silicon substrate side through the solid solution layer 30, a silicon diffusion prevention layer 17 for preventing silicon from mixing from the silicon substrate portion 19, a bonding layer between the silicon substrate and the silicon diffusion prevention layer 17. 18 are provided. The silicon diffusion preventing layer 17 can be made of any of Ti, W, Cr, Ni, AuSn, AuIn, AuGa, and AuPb, for example. Examples of the bonding layer 18 include AuSb and AgSb.
Further, the silicon substrate portion 19, the bonding layer 18, the silicon diffusion preventing layer 17, and the electrode 20 (Au) are further formed.

  With such a light-emitting element 1, it is possible to bond the compound semiconductor substrate and the silicon substrate more easily and firmly than the bonding of Ag and Ag, and hardly cause bonding failure. Moreover, it is possible to obtain a bonding strength equivalent to the bonding of Au and Au. Further, it is possible to obtain a light emitting element in which the amount of Au used is suppressed and the cost is reduced as compared with the case of bonding Au and Au.

Next, the manufacturing method of the light emitting device of the present invention will be specifically described. FIG. 2 is a schematic explanatory view showing an example of a manufacturing process of the light emitting device of FIG.
First, a process of preparing a GaAs single crystal substrate 25, which is a semiconductor crystal substrate, as a light emitting layer growth substrate and forming a light emitting layer on the GaAs substrate will be described (FIG. 2A). First, GaAs buffer layer 24 is formed on the surface, for example, 0.5 μm, AlInP layer 23 for etching stop, GaAs layer 11 is each 5 nm, and current diffusion layer 10 made of n-type AlGaAs layer is, for example, 2 μm. Let

Further, a 1 μm n-type AlGaInP cladding layer 9, a 0.6 μm non-doped AlGaInP active layer 8, and a 1 μm p-type AlGaInP cladding layer 7 are sequentially epitaxially grown on the light emitting layer so that a double heterostructure is formed thereon. 21 is formed.
Thus, if the light emitting layer 21 is comprised by the said double hetero structure, a high-intensity light emitting element can be manufactured and light can be taken out effectively.

  Thereafter, an AlGaAs layer 6 (or GaP layer) as a current diffusion layer is epitaxially grown to 1 μm, and a GaAs layer 5 as a contact layer and an antioxidant cap layer is epitaxially grown to 5 nm. Thereafter, an AuZn or AuBe layer 4 is vapor-deposited as a P electrode 22. A Ti layer 3 and an Au layer 2 are deposited.

Next, a process for manufacturing the compound semiconductor substrate 28 to be bonded to the silicon substrate 29 in a later process will be described. First, a support substrate 26 that serves as a support portion of the compound semiconductor substrate is prepared. The support substrate and the substrate on which the light emitting layer is formed are overlapped with each other through a spin-coated wax 27, and both substrates are bonded together by applying thermocompression bonding (FIG. 2B).
Thereafter, the GaAs substrate portion 25, the GaAs layer 24, and the AlInP layer 23 of the light emitting layer growth substrate are removed by selective etching in this order. As an etchant having selective etching properties with respect to GaAs, for example, an ammonia / hydrogen peroxide mixed solution is used to etch and remove both the GaAs substrate 25 and the GaAs buffer layer 24, and then the AlInP layer 23 is etched using, for example, hydrochloric acid. It is removed (FIG. 2C).

  Next, a dot electrode of AuGeNi or AgGeNi is formed on the surface of the GaAs layer 11 as the etching stop layer by vapor deposition or sputtering, and heat treatment is performed at a temperature of 450 ° C. for 5 minutes so as to become the ohmic electrode 12. The sintering process of the p-electrode 22 is performed simultaneously (FIG. 2D).

  Thereafter, the reflective layer 13 is formed. As described above, the reflective layer 13 can be formed of, for example, any one of Au, Ag, and AgPdCu. By forming such a reflective layer, light can be efficiently reflected and light extraction can be realized. In this way, the compound semiconductor substrate 28 can be manufactured.

Then, a diffusion preventing metal layer 14 is provided on the surface of the reflective layer 13, and an Au film or an Ag film (here, referred to as an Au film 15) is formed for bonding to the silicon substrate (FIG. 2E). ). Thus, by forming the Au film or the Ag film after forming the diffusion preventing metal layer 14, it is possible to prevent Au or Ag from being mixed into the reflective layer 13 when it is dissolved. The diffusion preventing metal layer 14 can be formed of any of Ti, W, Cr, and Ni, for example. Such a diffusion preventing metal layer 14 prevents a decrease in reflectance due to mixing of Au and Ag, and enables effective extraction of light.
The reflective layer 13, the diffusion preventing metal layer 14, and the Au film 15 (or Ag film) can be formed by, for example, vapor deposition or sputtering.

  Here, a silicon substrate 29 to be bonded to the compound semiconductor substrate 28 is prepared (bottom of FIG. 2E). After the silicon substrate is washed with HF, an AuSb layer or an AgSb layer 18 is formed on the silicon substrate, and Ti, W, Any one of Cr, Ni, AuSn, AuIn, AuGa, and AuPb is deposited. Then, an Ag film or an Au film (here, referred to as Ag film 16) is formed on the bonding surface. On the opposite surface, Au to be the electrode 20 is formed. Thereafter, an ohmic electrode is formed at 200 to 364 ° C. The AuSb layer 18, the silicon diffusion preventing layer 17, the Ag film 16, Au serving as the electrode 20, etc. can be formed by vapor deposition or sputtering.

  At this time, if the film formed on the bonding surface of the compound semiconductor substrate 28 is an Au film as in this example, the Ag film is formed on the bonding surface of the silicon substrate 29. The Au film or Ag film formed on the bonding surfaces of both substrates may be reversed. An Au film or an Ag film is formed on the bonding surface of both substrates so that the Au film and the Ag film are superposed and solid-solved and bonded together.

Next, the compound semiconductor substrate 28 and the silicon substrate 29 are attached to each other (FIG. 2F). As described above, the Au film 15 (or Ag film) formed on the bonding surface of the compound semiconductor substrate 28 and the Ag film 16 (or Au film) formed on the bonding surface of the silicon substrate 29 are overlaid and compressed. Then, heat treatment is performed for 20 minutes at a temperature of 180 to 360 ° C. and a pressure of 1 kPa to 5000 kPa.
At this time, in the Au film 15 and the Ag film 16 formed on both substrates, the Au fine particles and the Ag fine particles are bonded to each other at a low temperature and a low pressure due to the binding force at the nano level, and the solid solution of Au and Ag occurs. The solid solution layer 30 is formed and both substrates can be bonded together. In this case, both metals are solid-solved and can be bonded together to the same extent as Au and Au.
In addition, this bonding process can be performed using the wafer bonding machine (HPF-75) by a Fujikoshi machine industry company, for example.

  Thereafter, the support substrate 26 and the wax 27 are removed, diced by a normal method to form a semiconductor chip, placed on a pedestal, wire bonding of the lead wire, etc., and then resin-sealed with epoxy resin or silicone resin Thus, the light-emitting element 1 can be obtained (FIG. 2G). When a GaP layer is formed as the current diffusion layer 6 on the p-electrode 22 side with respect to the light emitting layer 21, it is preferable to perform a frost treatment after dicing in order to extract a large amount of light from the light emitting layer 21.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to this.
Example 1
First, a GaAs single crystal substrate is prepared as a light emitting layer growth substrate, and a buffer layer (GaAs layer), an etching stop layer (AlInP layer and GaAs layer), a current diffusion layer (AlGaAs layer), and a light emitting layer are provided on each substrate. (N-type AlGaInP cladding layer, AlGaInP active layer, p-type AlGaInP cladding layer), current diffusion layer (AlGaAs layer), contact layer and antioxidant cap layer (GaAs layer) are epitaxially grown. Thereafter, AuBe is vapor-deposited as a P electrode, and Ti and Au are vapor-deposited on the AuBe layer.

Then, the support substrate and the substrate on which the light emitting layer is formed are overlapped with each other through wax, and bonded by thermocompression bonding, and an ammonia / hydrogen peroxide mixture solution or hydrochloric acid is added in the order of the GaAs substrate, the GaAs layer, and the AlInP layer. And selective etching to remove these substrates and layers.
Next, a dot electrode of AuGeNi is vapor-deposited on the GaAs layer of the etching stop layer, and heat treatment is performed at 450 ° C. for 5 minutes so as to become an ohmic electrode, and at the same time, sintering of the P electrode is also performed.
Thereafter, Au as a reflective layer is deposited thereon, and Ti is deposited as a metal diffusion prevention layer. Further, an Au film is formed on the bonding surface.
In this way, a compound semiconductor substrate having an Au film formed on the bonding surface was produced.

  Meanwhile, a silicon substrate to be bonded to the compound semiconductor substrate was prepared. First, after cleaning the substrate with hydrofluoric acid, AuSb was vapor-deposited on the front and back surfaces as a bonding layer, and Ti was vapor-deposited as a silicon diffusion prevention layer. Further, an Ag film was formed on the bonding surface, and Au was vapor-deposited on the opposite surface to form an ohmic electrode at 200 ° C.

  As described above, a compound semiconductor substrate having an Au film formed on the bonding surface and a silicon substrate having an Ag film formed on the bonding surface are prepared, and a wafer bonding machine (HPF-75 manufactured by Fujikoshi Machinery Co., Ltd.) is prepared. The two substrates were bonded together at a temperature of 260 ° C. and a pressure of 200 kPa. Thereafter, dicing was performed to obtain a semiconductor chip.

  In the semiconductor chip thus obtained, the Au film and the Ag film formed on the bonded surface were solidified to form an Au / Ag solid solution layer. Further, when the bonding failure rate of these semiconductor chips was investigated, it was only 2%.

(Example 2)
A semiconductor chip was fabricated by the same procedure as in Example 1 except that an Ag film was formed on the bonding surface of the compound semiconductor substrate and an Au film was formed on the bonding surface of the silicon substrate.
The obtained semiconductor chip was formed with a solid solution layer of an Ag film and an Au film, and the bonding failure rate was 2%.

(Comparative Example 1)
An Au film was formed on the bonding surface of the compound semiconductor substrate, an Au film was formed on the bonding surface of the silicon substrate, and a semiconductor chip was fabricated by the same procedure as in Example 1 except that.
The obtained semiconductor chip had an Au layer formed on the bonded surface, and the bonding failure rate was 2%.

(Comparative Example 2)
A semiconductor chip was manufactured in the same procedure as in Example 1 except that an Ag film was formed on the bonding surface of the compound semiconductor substrate and an Ag film was formed on the bonding surface of the silicon substrate.
The obtained semiconductor chip had an Ag layer formed on the bonding surface, and the bonding failure rate was 8%.

As can be seen from Examples 1 and 2 and Comparative Examples 1 and 2, it can be seen that the method for producing a light emitting device of the present invention can be easily and firmly attached as compared with the case of bonding Ag and Ag. In addition, a bonding strength equivalent to the bonding of Au and Au can be obtained.
Further, since the amount of Au used can be suppressed as compared with the case of bonding Au and Au, the cost can be reduced.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

It is the schematic which shows an example of the structure of the light emitting element according to this invention. It is a schematic explanatory drawing which shows an example of the process of manufacturing the light emitting element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light emitting element, 2 ... Au layer, 3 ... Ti layer, 4 ... AuBe (AuZn) layer,
5 ... contact layer and antioxidation cap layer, 6, 10 ... current spreading layer,
7, 9 ... cladding layer, 8 ... active layer, 11, 23 ... etching stop layer,
12, 20, 22 ... electrode, 13 ... reflective layer, 14 ... diffusion prevention metal layer,
15 ... Au film, 16 ... Ag film, 17 ... Silicon diffusion prevention layer, 18 ... Bonding layer,
19 ... Silicon substrate part, 21 ... Light emitting layer, 24 ... GaAs buffer layer,
25 ... GaAs single crystal substrate, 26 ... support substrate, 27 ... wax,
28 ... Compound semiconductor substrate, 29 ... Silicon substrate, 30 ... Au / Ag solid solution layer.

Claims (10)

  A light-emitting element in which a compound semiconductor substrate having at least a light-emitting layer and a reflective layer for reflecting light from the light-emitting layer and a silicon substrate are bonded to each other, and the compound semiconductor substrate and the silicon substrate The light-emitting element, wherein the bonding surface is obtained by solidifying and bonding an Au film formed on one substrate and an Ag film formed on the other substrate.   The light emitting device according to claim 1, wherein the reflective layer is made of any one of Au, Ag, and AgPdCu.   The compound semiconductor substrate has a diffusion prevention metal layer between the reflection layer and an Au film or an Ag film formed on the bonding surface, and the diffusion prevention metal layer is formed on the reflection layer with an Au film. 3. The light emitting device according to claim 1, wherein the light emitting device prevents contamination of Ag. 4.   4. The light emitting device according to claim 3, wherein the diffusion preventing metal layer is made of any one of Ti, W, Cr, and Ni.   5. The light emitting layer according to claim 1, wherein the light emitting layer has a double hetero structure in which an n-type cladding layer, an active layer, and a p-type cladding layer are laminated in this order. The light emitting element according to one item.   A method of manufacturing a light emitting element by bonding a compound semiconductor substrate having at least a light emitting layer and a reflective layer for reflecting light from the light emitting layer, and a silicon substrate, wherein the compound semiconductor substrate is bonded An Au film is formed on one of the surface and the bonding surface of the silicon substrate, an Ag film is formed on the other, and the Au film and the Ag film are superposed, solidified, and bonded together. A method for manufacturing a light emitting device.   The method for manufacturing a light-emitting element according to claim 6, wherein the reflective layer is formed of any one of Au, Ag, and AgPdCu.   The diffusion film is formed on the bonding surface of the compound semiconductor substrate to prevent Au or Ag from being mixed into the reflective layer, and then the Au film or Ag film is formed. Item 8. The method for manufacturing a light-emitting element according to Item 6 or 7.   The method of manufacturing a light emitting element according to claim 8, wherein the diffusion preventing metal layer is formed of any one of Ti, W, Cr, and Ni.   10. The light emitting layer is formed of a double hetero structure in which an n-type cladding layer, an active layer, and a p-type cladding layer are stacked in this order. 10. Of manufacturing the light-emitting device.

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