JPH11266056A - Optical semiconductor device and manufacture thereof - Google Patents

Abstract

(57) [Abstract] [Problem] To use a bonding technique such as a solid-phase bonding technique to obtain a wavelength,
An optical semiconductor device such as a semiconductor laser having a high degree of freedom in structure and a low threshold value with high yield and high productivity, and a method of manufacturing the same. An optical semiconductor device includes first semiconductor units (1, 2, 3).
3 and 4 and the second semiconductor portions 5 and 6 are joined so that electrical coupling can be obtained in the minute region 13. The junction occurs when at least the minute region 13 formed in one of the first and second semiconductor portions to constrict the current is joined. The minute region 13 is formed by a surface treatment such as partial etching or oxidation, and the bonding is solid-phase bonding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor device such as a surface-emitting semiconductor light emitting device having a low yield and a high yield, which is easy to manufacture, and a method for manufacturing the same.

[0002]

2. Description of the Related Art For applications such as large-capacity parallel optical information processing, high-speed optical connection, and a thin display cable, the development of a two-dimensional array type surface-type solid state light emitting device is desired. For these applications, low cost, low power consumption, high productivity, high reliability and the like are necessary conditions. Various materials have been researched and developed.Semiconductor single crystals are very suitable to ensure the reliability of devices.In particular, the development of surface light-emitting devices using compound semiconductors has been actively pursued. Have been done. In a compound semiconductor, light can be used in a wide wavelength range from ultraviolet to infrared by changing the substrate and the material, and is promising as a display element. Also, among the light emitting elements,
Laser diode (LD) with reflection mirrors on both ends
In this case, the luminous efficiency is much higher than that of natural light emission, and power consumption can be reduced even when a two-dimensional array is used. From such a viewpoint, a surface type semiconductor laser (Vertic
al Cavity Surface Emitting Laser (VCSEL) has been actively developed in recent years.

At present, VCSELs are also being developed from a wavelength of about 400 nm blue to a communication wavelength band of 1.55 μm, and AlGaN / InGaN on a sapphire substrate is being developed.
System, InGaAlP / InAlP system on GaAs substrate,
InGaAs / AlGaAs, InG on InP substrate
Research has been conducted on material systems such as the aAs / InGaAsP system.

FIG. 8 shows a basic structure of a conventional VCSEL. A laser beam is emitted vertically from the substrate 1001 and several μm is emitted.
The structure is such that a highly reflective film 1009 of 99% or more is provided on both surfaces of the epitaxial growth layer having a thickness of about m. In FIG. 8, reference numeral 1002 denotes an etching stop layer;
005 is a spacer layer, 1004 is an active layer, 1006 is a contact layer, 1007 is an insulating layer, 1008 is an electrode, 10
Reference numeral 10 denotes a polyimide embedding layer. As the reflective film 1009, a multilayer film having a λ / 4 film having a different refractive index is mainly used, and the material is dielectric glass (this is the case in FIG. 8) or an epitaxially grown semiconductor. Is common. An example of an epi-grown mirror is ELECTR
As described in ONICS LETTERS, 31 , p.560 (1995), GaAs
AlAs / GaAs multi-layer mirror and active layer on s substrate in one growth, APPLIED PHYSICS LE
As described in TTERS, 66 , p.1030 (1995), G is applied to an InGaAsP / InP laser structure grown on an InP substrate.
For example, a GaAs / AlAs mirror on an aAs substrate is bonded by direct bonding.

[0007] As an approach for lowering the threshold value of a VCSEL, as shown in FIG.
Selective etching of As layer (1012 is a selective etching layer of AlAs layer) (OSA, SEMICONDUCTOR, LASERS '95, Techni
cal Digest, p.106 (1995)) to form a current constriction structure. In FIG. 9, 1008 is an electrode, 10
Reference numerals 11 and 1014 are semiconductor multilayer mirrors and 1015 is a semiconductor substrate.

Further, as shown in FIG. 10, AlAs constituting the DBR mirror is selectively oxidized (ELECTRONICS LETTERS, 31,
p.560 (1995)) to form a current confinement structure. In FIG. 10, 1011 and 1014 are semiconductor multilayer mirrors, 1013 is an active layer, 1015 is a semiconductor substrate, 1016 is AlO _{x obtained} by selectively oxidizing AlAs,
1017 is a GaAs layer and 1018 is a polyimide buried layer.

In the example of the current confinement structure shown in FIGS. 9 and 10, a threshold value of 100 μA or less has been achieved.

[0008]

However, when a semiconductor epitaxial layer is used as a multilayer mirror, depending on the material system, for example, InGaAsP / InP, etc.
Because the difference in refractive index cannot be made very large, the number of layers increases, the growth time is long, the film thickness is thick, productivity is low,
Processing and flattening are difficult. The practical material of the semiconductor mirror is GaAs / AlAs at present, and the oscillation wavelength band is limited in consideration of the lattice constant. GaAs / AlA
When the s-mirror is attached by direct bonding, it can be applied to other wavelength bands, but is effective only in a small area.

Further, the conventional proposals for the current confinement structure shown in FIGS. 9 and 10 are all side processes, in which a cylindrical structure or the like serving as a light emitting region is etched, and the surface that appears after etching is used as a base point. The process, ie, etching or oxidation, is performed in the lateral direction. In this case, since the surface that appears after etching is rough, if a confined structure is manufactured, the front surface of the etching or oxidation may not be rough, and the threshold value may be further reduced due to the influence of light scattering and absorption. Had become difficult. Further, the diameter of the constricted portion is determined by conditions of selective etching or selective oxidation, but has a large in-plane or lot-to-lot variation, which is a factor that limits the yield.

In view of these problems, an object of the present invention is to
An object of the present invention is to provide an optical semiconductor device such as a semiconductor laser or the like having a high degree of freedom in wavelength, structure, etc., a high yield, a low productivity and a low threshold value by using a bonding technology such as a solid phase bonding technology. .

[0011]

In order to achieve the above object, an optical semiconductor device such as a semiconductor laser according to the present invention provides an electric coupling between a first semiconductor portion and a second semiconductor portion in a minute area. The junction is characterized in that the junction is formed by at least joining the minute region that narrows the current formed in either the first or second semiconductor portion.

Here, the minute region is formed by a surface treatment such as partial etching or oxidation. The bonding may be a solid phase bonding. As a result, a current confinement structure is established at the junction of the minute regions, so that it is joined even between different types of semiconductor materials and has a high degree of freedom in wavelength, structure, etc., and has a high yield, high productivity, and a low threshold value. Is realized.

More specifically, the following embodiment is also possible.
The first semiconductor portion is a semiconductor portion having an active layer formed thereon, the second semiconductor portion is a semiconductor portion having no active layer, and the minute region is formed near the active layer. Is configured as Several μm
When a small region of about the same size is formed and solid phase bonding is performed in this region, a current confinement structure is formed only by the surface process, and the bonding area of one laser is small, so that a large area such as a large array is formed. In this case, since the bonding can be performed by alleviating the distortion, a semiconductor laser having a low threshold value, a high yield, and high productivity can be provided.

The minute region has a two-stage structure, and in the minute region, only the small region formed in the upper stage is joined. Thus, a structure can be provided in which solid phase bonding can be performed over a wide area and low threshold oscillation can be achieved.
Further, when the above-mentioned minute region is formed in a two-stage structure, the junction portion is small and the current is sufficiently confined, and the other region can be made larger in size than the current path region, so that etching damage to the side wall and increase in resistance can be avoided. .

The metal thin films are simultaneously bonded in regions other than the bonded micro regions. Thereby, the joining force can be increased. If the metal films are formed in a gear shape so as to mesh with each other and are simultaneously bonded, the bonding strength can be further increased.

The minute region is formed by forming a current blocking layer by oxidizing a region other than the current-carrying region on the surface. Thus, a structure that can be easily manufactured and achieve low threshold oscillation can be provided. By selectively oxidizing the surface of the region other than the current path, which is a minute region, to form a current blocking layer, low threshold oscillation can be achieved by a simple process.

The minute area is a closed figure such as a circle, an ellipse, and a polygon, and is formed near the active layer and closer to the first substrate forming the first semiconductor portion than the active layer. The active layer is sandwiched by a reflection mirror and a reflection mirror formed closer to the second substrate forming the second semiconductor portion than the active layer in the vicinity of the active layer and the first or second substrate Are formed as surface emitting lasers capable of emitting light vertically from at least one of the surfaces. Thus, a surface-emitting laser can be provided with the optical semiconductor device as described above. That is, by providing reflection mirrors above and below the active layer, a surface emitting laser can be obtained.

The reflecting mirror near the first substrate forming the first semiconductor portion is formed by a dielectric multilayer mirror formed on an epitaxial growth layer forming a laser structure which is formed by removing the first substrate. Become. Thereby, it is possible to provide a structure of a reflection mirror which is important in the above-described surface emitting laser. That is, by removing the substrate on which the active layer is formed and forming a mirror made of a dielectric multilayer film, a surface emitting laser as described above can be obtained.

The reflection mirror formed near the first substrate forming the first semiconductor portion comprises a semiconductor multilayer mirror which is epitaxially grown between the active layer and the first substrate. By forming the semiconductor multilayer mirror before growing the active layer on the substrate on which the active layer is formed, a surface emitting laser as described above can be obtained.

The reflection mirror near the second substrate forming the second semiconductor portion is a semiconductor multilayer mirror that is epitaxially grown on the second substrate. Thus, by growing and joining a semiconductor multilayer mirror to a substrate having no active layer, a surface emitting laser as described above can be obtained.

The reflecting mirror near the second substrate forming the second semiconductor portion is a semiconductor multilayer film continuously and epitaxially grown on the active layer of the first substrate forming the first semiconductor portion. Consists of a mirror. Thus, by continuously growing the semiconductor multilayer mirror on the active layer, the above-described surface emitting laser can be obtained.

The reflection mirror near the second substrate forming the second semiconductor portion is a semiconductor multilayer film continuously and epitaxially grown on the active layer of the first substrate forming the first semiconductor portion. And a semiconductor multilayer film epitaxially grown on the second substrate. Thereby, the semiconductor multilayer film continuously grown on the active layer and the semiconductor multilayer film grown on another substrate are joined to form one mirror, thereby obtaining the above-described surface emitting laser. be able to.

Further, in order to achieve the above object, a method of manufacturing an optical semiconductor device such as a semiconductor laser according to the present invention comprises preparing a first semiconductor portion and a second semiconductor portion, and preparing the first or second semiconductor portion.
A micro-region for confining current is formed in one of the semiconductor portions by surface treatment, and the first semiconductor portion and the second semiconductor portion are connected by a solid phase so that electrical coupling can be obtained in the micro-region. It is characterized by joining by joining or the like.

More specifically, it can be performed as follows. In the surface treatment, a micro region having a two-stage structure is formed by etching, and in the micro region, bonding is performed only in the small region formed in the upper stage. At this time, the bonding of the metal thin films may be performed simultaneously in a region other than the bonded minute region.

In the surface treatment, a current blocking layer is formed by oxidizing a region other than the current-carrying region on the surface, which is the minute region.

The first semiconductor portion is prepared by forming an active layer on a first substrate, and the minute region is a closed figure such as a circle, an ellipse, and a polygon. A reflection mirror formed closer to the first substrate forming the first semiconductor portion than the active layer, and closer to the second substrate forming the second semiconductor portion than the active layer near the active layer; The active layer is sandwiched by the reflection mirror formed in the first and second planes, and is formed as a surface-emitting laser capable of emitting light vertically from at least one of the surfaces of the first and second substrates. In this case, a reflection mirror near the first substrate forming the first semiconductor portion is formed by forming a dielectric multilayer mirror on an epitaxial growth layer forming a laser structure appearing after removing the first substrate. May be formed. In addition, a reflection mirror formed near a first substrate forming the first semiconductor portion is formed by the active layer and the first semiconductor substrate.
A semiconductor multi-layer mirror that is epitaxially grown may be formed between the substrates. Further, the reflection mirror near the second substrate forming the second semiconductor portion may be formed by forming a semiconductor multilayer film mirror epitaxially grown on the second substrate. In addition, a reflecting mirror near the second substrate forming the second semiconductor portion may be a semiconductor multilayer mirror continuously epitaxially grown on the active layer of the first substrate forming the first semiconductor portion. May be formed by film formation. Further, a reflection mirror close to a second substrate forming the second semiconductor portion may be formed as a semiconductor multilayer film continuously and epitaxially grown on the active layer of the first substrate forming the first semiconductor portion. A semiconductor multilayer film epitaxially grown may be formed on the second substrate by bonding.

According to the present invention, the area to be joined is made very small to the extent that electrical coupling can be obtained, so that a large area can be joined at a plurality of locations, and a portion (small area) having a small area to be joined is provided. In the vicinity of the active layer of the light emitting device, the current injection constriction structure is also constituted by this minute region. If the junction of one micro area is as small as about several μmΦ, stress due to the difference in lattice constant is hardly applied, so there is no problem in bonding between different types of substrates, and this micro area is arrayed on the same substrate. In this case, the bonding can be performed over a wide area, so that the productivity is improved.

Further, if the minute region is formed by a surface process, the size and shape can be freely designed, and the yield is good. Therefore, when this minute region is used as a current confinement structure, the in-plane distribution and the variation between lots are extremely reduced, and the productivity is improved.

The principle of the present invention will be described with a specific example. FIG. 1 is a cross-sectional view of a surface emitting laser using a small area junction. I
A laser structure is grown on an nP substrate, and a two-step projection shape as shown in FIG. 1 is formed on the nP substrate by a surface process. The minute area was a circle having a diameter of 3 μmΦ. On the other hand, a current confinement structure can be easily manufactured by joining a reflection mirror composed of a multilayer film of AlAs / AlGaAs grown on a GaAs substrate to the above-mentioned substrate in a small area. On the other hand, since the bonding area is small and the strength cannot be maintained, the metal 11 such as Al
Are formed on both substrates, and the strength is increased by the adhesive force between the metals.

Next, this manufacturing method will be briefly described with reference to FIG. 1A, a laser structure is epitaxially grown on an n-InP substrate 31. 3 in (b)
Etch only 0.2 μm with a diameter of μmφ, and further 25
Etching is performed at about 0.8 μm with a diameter of μmφ. Next, SiN
Is formed, and Al11 is formed in a gear shape. The thickness of this Al is about 0.8 μm. (C)
In the above, p-AlAs / AlG is formed on a p-GaAs substrate.
A multilayer film made of aAs is grown, and the insulating film 1 is formed in the same manner as in FIG.
0 is formed, and Al11 is formed in a gear shape. This Al gear shape may be either the substrate 31 side or the substrate 6 side. At this time, the Al gear is formed so as to have a pattern which is shifted by a half cycle from that formed on the InP substrate, and is formed so that the irregularities are exactly meshed. Then, the two substrates are bonded together in a hydrogen atmosphere while applying a load.
Joining by heating to ° C. At this time, the air gap 12
Contains hydrogen at the time of bonding. If the atmosphere gas is changed, gases such as nitrogen and argon can be contained. Further, if the pressure is set to a negative pressure, it becomes easier to maintain the bonding state. After the bonding, the InP substrate 31 is removed. 2D, the etch stop layer 4 and the spacer layer 3 are removed in a region outside 24 in FIG. 2 in order to separate from the adjacent surface emitting laser. The steps may be filled with polyimide (not shown) or the like so that the subsequent electrode wiring pattern can be easily formed. Further, electrodes 8 and 9 are formed so as to make holes in a region of 25 μmφ. Finally, if a dielectric mirror is formed, a surface emitting laser as shown in FIG. 1 is completed.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a cross-sectional view of a surface emitting laser using solid-state bonding of a small area according to Embodiment 1 of the present invention, and FIG. As shown in FIG.

In the present embodiment, I oscillating in the 1.3 μm band
It is applied to an nP-based surface emitting laser. The laser structure is first formed by epitaxially growing p-type on an InP substrate (which is eventually removed and not shown).
InP spacer layer 1, undoped InGaAs / InG
A multiple quantum well active layer 2 made of aAsP, an n-InP spacer layer 3, and an n-InGaAsP etch stop layer / contact layer 4 are formed. This is processed into a two-step projection shape as shown in FIG. 1, and a minute projection 13 is formed on another p-GaAs substrate 6 by a p-AlAs / AlGaAs multilayer mirror (25 pairs for each layer λ / 4 thickness) 5. Is solid-phase bonded to the surface on which epitaxial growth has been performed. Projection 1 to be joined
3 has a cylindrical shape with a height of 0.2 μm and a diameter of 3 μmφ.
On the other hand, the second-stage projection has a cylindrical shape of 25 μmφ, and the distance from the junction to the active layer 2 is 0.5 μm (spacer layer 1).
Is determined by the thickness).

The solid phase junction is very small as described above,
Because of the current confinement effect, the threshold can be lowered, and at the same time, since the junction area is small and the air gap portion 12 is provided, InP on the InP substrate side and GaAs on the GaAs substrate 6 side
Stress caused by a difference in lattice constant of s is reduced, and a surface emitting laser can be arrayed in a relatively wide range. Since the bonding area is small and the strength cannot be maintained by itself, bumps made of metal 11 such as Al are formed on both substrates around the bonding portion, and the strength is increased by the adhesive force between the metals 11. I have. After the bonding, the InP substrate is removed, and the periphery of the etch stop layer 4 and the spacer layer 3 is removed in order to avoid current interference with an adjacent laser. Also, the spacer layer 3
On top of this is formed a dielectric multilayer mirror 7 made of Si / Al ₂ O ₃ .

FIG. 2 shows how the surface emitting laser is formed into a two-dimensional array. This is written in a perspective view on the side of the dielectric mirror 7, where 21 is a minute joint of the minute protrusion 13, 22 is the outer diameter of the spacer layer 7, 23 is the air gap, and 24 is the spacer for electrode separation. A spacer region remaining after removing the layer 3; 25, an adhesion region of Al11;
Reference numeral 26 denotes a surface of the lower AlAs / AlGaAs mirror 5. Therefore, the region where the spacer layer remains is smaller than the Al bonding region.

Next, the manufacturing method of this embodiment will be described with reference to FIG. In (a), on an n-InP substrate 31,
n-InGaAsP etch stop layer 4 (thickness 0.3 μm)
m), n-InP spacer layer (thickness: 32 μm), 5-well active layer 2 made of undoped InGaAs / InGaAsP, p-InP spacer layer (thickness: 10.5 μm)
m) is epitaxially grown.

In (b), when the diameter of 3 μmφ is 0.2 μm,
m, and a diameter of 25 μmφ
Etch μm. Next, an insulating film 10 such as SiN is formed, and Al11 is formed in a concentric gear shape. This A
The thickness of 111 is about 0.8 μm.

In (c), a multilayer film 5 made of p-AlAs / AlGaAs is grown on a p-GaAs substrate 6, an insulating film 10 is formed in the same manner as in (b), and Al11 is formed in a concentric gear shape. I do. At this time, the gear of Al11 is I
The pattern formed on the nP substrate 31 is shifted from the pattern formed on the nP substrate 31 by a half cycle, and is formed so that the unevenness just meshes.
However, it is not always necessary to form a gear, and one or both may be a plane layer of Al.

Then, the two substrates 6 and 31 are bonded to each other, and heated to 300 ° C. in a hydrogen atmosphere while applying a load to perform bonding. At this time, hydrogen at the time of joining is sealed in the air gap 12. If you change the atmosphere gas,
Gases such as nitrogen and argon can be contained.
If such a gas is contained, the device is hardly deteriorated, and the life is extended. Further, if the pressure is set to a negative pressure, it becomes easier to maintain the bonding state. After the bonding, the InP substrate 31 is removed by using both lapping and wet etching. co
If nc-HCl is used, only the InP substrate 31 is etched, and the etching can be completely stopped by the etch stop layer 4.

In (d), the etch stop layer 4 and the spacer layer 3 are removed in the region as shown in FIG. 2 in order to separate the adjacent surface emitting laser. The steps may be filled with polyimide (not shown) or the like so that the subsequent electrode wiring pattern can be easily formed. Furthermore, 25 μm
The electrodes 8 and 9 are formed up and down so as to make holes in the area of φ. Finally, when the dielectric mirror 7 is formed, the surface emitting laser as shown in FIG. 1 is completed.

The electrode 8 may be connected to a power source by directly bonding the electrode region to the electrode region by wire bonding or a clip chip.
Wire bonding or clip chip mounting (not shown) may be provided outside the SEL region. In this case, since the anode common configuration is used, high-speed driving is facilitated.

In a surface emitting laser manufactured by utilizing solid-state bonding in a small region at a relatively low temperature as described above, a suitable current confinement structure is formed. it can. The active layer 2 is made of undoped InG
Since it is a multiple quantum well composed of aAs / InGaAsP and the substrate 6 is a GaAs substrate, light can be extracted from both directions, as shown in FIG.

By changing the size and shape of the micro-joining region only by a simple planar process, the desired spot diameter and
Control of threshold, optical power (smaller if the area of the junction region is smaller), polarization (for example, if the shape of the junction region is made rectangular, linear polarization is stabilized in a longer extending direction), etc. Can be. Conventionally, in the case of solid phase bonding, the substrate area is limited to about 1 cm square, but in this embodiment, bonding can be performed in a region of about 2 ″ φ, and bonding between semiconductors having different lattice constants can be performed. However, since no distortion is accumulated, a large-area array can be realized.

In the present embodiment, a circular shape is used as the minute joining region. However, other shapes such as a square, a rectangle, and an ellipse may be used. In this embodiment, the air gap portion 11 is formed, but polyimide or the like may be buried therein.

Embodiment 2 In Embodiment 2 according to the present invention, as shown in FIG. 4, a projection is provided on the side of the semiconductor multilayer mirror 5 grown on the GaAs substrate 6. The layer configurations of the laser and the multilayer mirror are the same as those in the first embodiment, and the same functional units are denoted by the same reference numerals.

In this embodiment, p-In on the laser wafer side is used.
The P spacer layer 1 is thin and has a thickness of 0.2 μm. Since no projection is provided here, the thickness can be reduced. Semiconductor multilayer mirror 5
Is 3 μm at a depth of 0.5 μm at the joint portion 13.
The shape is a square with corners, and polarization can be stabilized. The second-stage projection has a thickness of 25 μmφ and a thickness of 0.5 μm so that the overall depth is 1 μm. In the present embodiment, the processing on the laser substrate side is not performed, so that process damage to the active layer 2 can be reduced. In addition, since the current constriction portion due to the protrusion 13 can be made closer to the active layer 2 (in the first embodiment, the constriction was created by etching on the laser side, so the distance from the active layer at the junction changes due to an etching error). The threshold can be further reduced. Other points are the same as the first embodiment.

Embodiment 3 In Embodiment 3 of the present invention, as shown in FIG. 5, instead of forming a projection, an AlAs oxide layer 51 is formed on a bonding surface to form a current confinement structure.

AlAs grown on p-GaAs substrate 6
/ AlGaAs The top layer of the mirror 5 is made of AlAs, and a region corresponding to the light emitting portion is patterned in a circular shape of 3 μmφ with a resist or the like.
The surface is selectively oxidized by heating to ° C. to form an AlO _x layer 51. Thereafter, the inner diameter is 25 μm and the outer diameter is 40 μm
After forming a projection by etching into a donut shape, bonding is performed. Thereby, it is possible to conduct electricity only in the minute region 52. In this case, since the bonding surface of the minute region 52 and the outer peripheral region are surely the same in height, the mechanical strength is maintained by the bonding of the outer peripheral portion without forming the Al bump unlike the above embodiment. , Making it easier.

In this embodiment, the air gap portion 11 may be omitted, but if it is provided, the distortion of the joint portion can be suitably alleviated, and a large area array can be realized. The other points are the same as those in the first embodiment, and the same reference numerals are given to the same functional units.

Embodiment 4 Embodiment 4 according to the present invention is directed to a GaAs device oscillating at 980 nm.
It is applied to an s-based surface emitting laser. This is shown in FIG.
Shown in In the GaAs system, the upper and lower semiconductor mirrors (made of AlAs / AlGaAs) and the active layer can be manufactured by one growth.

On an n-GaAs substrate (not shown), n-A
Multi-layer mirror 61 composed of 30 AsIR / AlGaAs, active layer 62 having 1λ cavity composed of GaAs / AlGaAs multiple quantum wells and AlGaAs spacer layer, p-AlAs / AlGaAs 25 Pa
A multilayer mirror 63 made of ir is grown. Since the holes are harder to move, in order to reduce the resistance, the number of layers of the p-side multilayer mirror 63 is smaller than that of the n-side multilayer mirror 6.
The number of layers is less than one. As in the above embodiment,
The structure is such that a minute region 13 having a depth of 1.5 μm and a square of 3 μm and a two-stage projection having a diameter of 25 μm are formed on the multilayer mirror 63 and bonded to a p-GaAs substrate 64. In this case, since the thickness of the p-side mirror 63 is about 2 μm, the distance from the minute region 13 to the active layer 62 is about 0.5 μm (2 μm−1.5 μm). In the present apparatus, it is not necessary to form the dielectric mirror later because the mirror has already been formed.

Conventionally, when the mirror diameter is reduced as shown by reference numeral 13, the electrode contact area is reduced, so that the resistance is increased, and heat generation and power consumption are increased.
In the present embodiment, since the p-GaAs substrate 64 is bonded here to form the p-side electrode 9 on the substrate 64, this can be solved. As shown in FIG. 6, light is extracted from below. The other points are the same as those in the first embodiment, and the same reference numerals are given to the same functional units.

Fifth Embodiment A fifth embodiment according to the present invention is directed to a Ga oscillating in the 830 nm band.
This is applied to an As-based surface emitting laser. Example 4
The upper and lower semiconductor mirrors were manufactured by a single growth in the same manner as described above, but the p-side mirror 71 was joined as shown in FIG.
pair only, and the uppermost layer was AlAs. Next, in the same manner as in Example 3, the surface of the AlAs layer is patterned into a 3 μmφ circular shape with a resist or the like at a portion corresponding to the light emitting portion, and the surface is selectively oxidized by heating to 400 ° C. in a steam atmosphere. Thus, an AlO _x layer 72 is formed. Thus, it is possible to conduct electricity only in the minute region 75.

On the other hand, p-Al
The substrate on which the As / AlGaAs multilayer mirror 74 has been grown is etched into a donut shape having an inner diameter of 25 μmΦ and an outer diameter of 40 μmΦ to form a projection shape, and the two substrates are joined. Also in this case, the Al bump may not be provided. The light removes the substrate on which the active layer 62 has been grown and removes the n-side mirror 6.
You just need to take it out of 1. Substrate removal can be performed by performing selective etching of GaAs and AlAs with a mixed solution of ammonia and hydrogen peroxide water. 7, the same reference numerals are given to the same functional units as those in FIG.

Conventionally, since the substrate is an absorber, a ring electrode is formed on the uppermost layer of the growth, and light is extracted from the window of the central electrode. Therefore, the pattern matching process is difficult. Since only a part of the oscillating light can be extracted, there is a problem that a large amount of light is lost and a resistance is increased. In the present embodiment, current constriction becomes possible while lowering the problematic p-side (substrate 73 side) resistance, and a ring electrode is not required on the substrate side. Become.

In the case where the current confinement structure is formed by selective oxidation as in the present embodiment, similarly to the third embodiment, when it is not necessary to perform a large-area junction, the projection is not formed. The planes may be joined together. In the present embodiment in which the current confinement structure is formed in the middle of one of the semiconductor mirrors, the current confinement portion 75 can be made closer to the active layer 62 as in the third embodiment. Further, a structure in which minute projections are provided as in the first and second embodiments may be adopted.

In the above embodiment, an example of a surface emitting laser is shown, but a similar structure can be applied to an edge emitting laser. In this case, referring to the example of FIG. 1, considering FIG. 1 as a cross section perpendicular to the resonator direction, the multilayer mirrors 5 and 7 are omitted, and the electrodes 8 and 9 are not ring-shaped but stripe-shaped in the resonator direction. The structure may be extended. Further, the minute junction region 13 is elongated in the resonator direction.

[0057]

As described above, the following effects can be obtained by the present invention. Since different semiconductor materials can be bonded using bonding technology such as solid-phase bonding technology, optical semiconductor devices such as low-threshold semiconductor lasers with high flexibility in wavelength, structure, etc., and high yield and productivity are realized. can do. Further, if selective etching is used as a surface process to form a minute region, it is possible to provide a structure capable of performing solid-state bonding over a large area and achieving low threshold oscillation. In addition, the mechanical bonding force can be enhanced by using the bonding of the metal films. Also,
If a technique of selectively oxidizing as a surface process is used to form a minute region, it is possible to provide a structure that can be easily manufactured and achieve low threshold oscillation. Also, the wavelength,
It is possible to provide a low threshold surface emitting laser with a high degree of freedom in structure, a high yield and a high productivity.
The structure of the reflection mirror which is important in the surface emitting laser can also be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of Example 1 of a surface emitting laser using a small area junction according to the present invention.

FIG. 2 is a plan view when the surface emitting laser according to the present invention is formed into a two-dimensional array.

FIG. 3 is a first embodiment of a surface-emitting laser according to the present invention;
FIG. 3 is a view for explaining a manufacturing process of FIG.

FIG. 4 is a cross-sectional view of a surface emitting laser using a small area junction according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of a surface-emitting laser using selective oxidation and small area junction according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a surface emitting laser using a small area junction according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view of a surface emitting laser using selective oxidation and small area junction according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view showing a conventional example of a surface emitting laser.

FIG. 9 is a cross-sectional view of a conventional surface emitting laser using selective etching of AlAs.

FIG. 10 is a cross-sectional view of a conventional surface emitting laser using selective oxidation of AlAs.

[Explanation of symbols]

1, 3, 1003, 1005 Spacer layer 2, 62, 1004, 1013 Active layer 4, 1002 Etching stop layer 5, 61, 63, 71, 74, 1011, 1014
Semiconductor multilayer mirror 6, 31, 64, 73, 1001, 1015 Semiconductor substrate 7, 1009 Dielectric multilayer mirror 8, 9, 1008 Electrode 10, 1007 Insulating film 11 Metal film 12, 23 Air gap 13, 21 Micro junction (Small projections) 22 Second-stage projections 24 Boundary for removing semiconductor layer for electrode separation 25 Metal film area for bonding 26 Substrate with semiconductor multilayer mirror 51, 72, 1016 AlAs selected Oxidized Al
O _x 52,75,1019 AlAs fine opening (micro conducting portion) 1006 contact layers 1010,1018 polyimide burying layer 1012 AlAs selective etch layer 1017 GaAs layer

Claims (25)

[Claims] In an optical semiconductor device, a first semiconductor portion and a second semiconductor portion are joined to each other so as to obtain an electrical connection, and the junction is formed by the first or second semiconductor portion. An optical semiconductor device characterized in that at least a minute region for constricting a current formed in any one of them is joined. 2. The optical semiconductor device according to claim 1, wherein said minute region is formed by surface treatment. 3. The optical semiconductor device according to claim 1, wherein said bonding includes a solid phase bonding. 4. The semiconductor device according to claim 1, wherein the first semiconductor portion is a semiconductor portion having an active layer formed thereon, the second semiconductor portion is a semiconductor portion having no active layer, and the minute region is formed near the active layer. 4. The optical semiconductor device according to claim 1, wherein the optical semiconductor device is configured as a semiconductor laser device. 5. The optical semiconductor according to claim 1, wherein the minute region has a two-stage structure, and in the minute region, only the small region formed in the upper stage is joined. apparatus. 6. The optical semiconductor device according to claim 5, wherein the metal thin films are joined together in a region other than the joined minute region. 7. The optical semiconductor device according to claim 1, wherein said minute region is formed by oxidizing a portion other than a current-carrying region on the surface to form a current blocking layer. 8. The minute area is a closed figure such as a circle, an ellipse, and a polygon, and is formed near the active layer and closer to a first substrate on which the first semiconductor portion is formed than the active layer. The active layer is sandwiched by the reflection mirror formed and a reflection mirror formed closer to the second substrate forming the second semiconductor portion than the active layer in the vicinity of the active layer, and the first or second active layer is sandwiched. 8. The optical semiconductor device according to claim 1, wherein the optical semiconductor device is formed as a surface emitting laser capable of emitting light vertically from at least one of the surfaces of the substrate. 9. A dielectric multilayer film formed on an epitaxial growth layer forming a laser structure which is formed by removing the first substrate, wherein the reflection mirror near the first substrate forming the first semiconductor portion is formed. 9. The optical semiconductor device according to claim 8, comprising a mirror. 10. The semiconductor device according to claim 1, wherein the reflection mirror formed near the first substrate forming the first semiconductor portion comprises a semiconductor multilayer film mirror epitaxially grown between the active layer and the first substrate. The optical semiconductor device according to claim 8, wherein 11. The light according to claim 8, wherein the reflection mirror near the second substrate forming the second semiconductor portion is a semiconductor multilayer mirror epitaxially grown on the second substrate. Semiconductor device. 12. A reflection mirror near a second substrate forming the second semiconductor portion, the semiconductor being continuously epitaxially grown on the active layer of the first substrate forming the first semiconductor portion. 9. The optical semiconductor device according to claim 8, comprising a multilayer mirror. 13. The semiconductor device according to claim 1, wherein the reflection mirror near the second substrate forming the second semiconductor portion is a semiconductor continuously and epitaxially grown on the active layer of the first substrate forming the first semiconductor portion. 9. The optical semiconductor device according to claim 8, wherein the multilayer film and a semiconductor multilayer film epitaxially grown on the second substrate are joined. 14. The optical semiconductor device according to claim 1, wherein the optical semiconductor device is configured as an edge emitting semiconductor laser. 15. A method for manufacturing an optical semiconductor device according to claim 1, wherein a first semiconductor section and a second semiconductor section are provided, and wherein the first semiconductor section and the second semiconductor section are provided. A small area that narrows the crab current is formed by surface treatment,
A method for manufacturing an optical semiconductor device, comprising: joining the first semiconductor portion and the second semiconductor portion so that electrical coupling can be obtained in the minute region. 16. The method according to claim 15, wherein said bonding is a solid phase bonding. 17. The surface treatment according to claim 15, wherein a minute region having a two-stage structure is formed by etching, and in said minute region, bonding is performed only in a small region formed in an upper stage. A method for manufacturing an optical semiconductor device. 18. The method of manufacturing an optical semiconductor device according to claim 17, wherein bonding of the metal thin films is performed simultaneously in a region other than the bonded minute region. 19. The method for manufacturing an optical semiconductor device according to claim 15, wherein in said surface treatment, a current blocking layer is formed by oxidizing a portion other than the current-carrying region on the surface which is said minute region. 20. The first semiconductor part is prepared by forming an active layer on a first substrate, and the minute region is a closed figure such as a circle, an ellipse, a polygon, and the like. A reflection mirror formed closer to the first substrate forming the first semiconductor portion than the active layer; and a second mirror forming the second semiconductor portion more than the active layer near the active layer. The active layer is sandwiched by a reflection mirror formed near the substrate, and is formed as a surface-emitting laser capable of emitting light vertically from at least one of the surfaces of the first or second substrate. Claims 15 to 19
The method for manufacturing an optical semiconductor device according to any one of the above. 21. A reflection mirror near the first substrate forming the first semiconductor portion, and a dielectric multilayer mirror formed on an epitaxial growth layer forming a laser structure appearing by removing the first substrate. 21. The method for manufacturing an optical semiconductor device according to claim 20, wherein the optical semiconductor device is formed as a film. 22. A reflection mirror formed near a first substrate forming the first semiconductor portion, the reflection mirror being formed by the active layer and the first substrate.
21. The optical semiconductor device according to claim 20, wherein a semiconductor multilayer mirror formed by epitaxial growth is formed between the substrates. 23. A reflection mirror near a second substrate forming the second semiconductor portion, wherein a reflection mirror formed by epitaxially growing a semiconductor multilayer film mirror is formed on the second substrate. Item 21. An optical semiconductor device according to item 20. 24. A semiconductor wherein a reflecting mirror near a second substrate forming the second semiconductor portion is epitaxially grown continuously on the active layer of the first substrate forming the first semiconductor portion. 21. The optical semiconductor device according to claim 20, wherein the optical semiconductor device is formed by forming a multilayer mirror. 25. A semiconductor wherein a reflection mirror close to a second substrate forming the second semiconductor portion is epitaxially grown continuously on the active layer of the first substrate forming the first semiconductor portion. 21. The optical semiconductor device according to claim 20, wherein the multilayer film is formed by joining a semiconductor multilayer film epitaxially grown on the second substrate.