JPH11340570A - Photoelectric conversion element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion element and its manufacturing method, by which an effect of heat generation can be suppressed through the promotion of heat radiation. SOLUTION: A plurality of laser oscillation parts 20 are provided on the same substrate 11. A heat radiating layer 15 is provided between the laser oscillation parts 20 with an insulation layer 14 in between, thereby flattening a clearance therebetween. The heat radiation layer 15 is lattice-matched with the substrate 11, they are formed of semiconductor added with no impurities, and then they are formed on the surface of the substrate 11 by making it through grown epitaxialy. An insulation layer 16 is formed on the surface of the heat radiating layer 15. Therefore, a heat generating in the laser oscillation part 20 can be radiated actively through the heat radiation layer 15, and an increase in threshold voltage or a decrease in emission output due to thermal interferance can be thereby suppressed. Furthermore, the surface on the side of laser oscillation part can be flattened by the heat radiating layer 15, and a multilayer wiring can be made easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion element provided with a photoelectric conversion portion composed of a plurality of stacked semiconductor layers and a method of manufacturing the same, and more particularly to a photoelectric conversion device provided with a plurality of photoelectric conversion portions on the same substrate. The present invention relates to a conversion element and a method for manufacturing the conversion element.

[0002]

2. Description of the Related Art At present, various devices using a semiconductor laser (laser diode; LD) as a photoelectric conversion element, such as an optical disk device, a laser beam printer, and a copying machine, have been developed. In recent years, these devices have been required to operate at higher speeds and have higher performance, and it is conceivable to use a plurality of laser beams as one method of achieving them. For example, in an optical disk device, the reading speed can be easily increased by simultaneously reading a plurality of tracks using a plurality of laser beams. Therefore, development of a semiconductor laser capable of simultaneously emitting a plurality of laser beams (that is, a multi-beam laser) is required.

FIG. 10 shows a configuration example of a conventional multi-beam laser. This multi-beam laser has two laser oscillators 120 formed on the same substrate 111.
have. In addition, between each laser oscillation unit 120,
A flattening layer 117 made of polyimide or the like is embedded. This is because by flattening the space between the laser oscillating units 120, it is possible to form multiple layers of wirings respectively connected to the laser oscillating units 120 on the surface thereof.

[0004]

However, in such a multi-beam laser, since the respective laser oscillating sections 120 are formed close to each other, thermal interference occurs in each of the laser oscillating sections 120 due to heat generated during driving. Had been lost. As a result, in each of the laser oscillators 120, there have been problems such as an increase in threshold voltage and a decrease in light emission output. In order to suppress such thermal interference, the area of the laser oscillating unit 120 may be increased to promote heat radiation. The interval between the parts 120 becomes narrow, and extremely high precision is required in manufacturing. Therefore, it is difficult to increase the area of the laser oscillation unit 120 in manufacturing. In particular, these problems become more remarkable as the beam interval becomes narrower due to the recent increase in density.

Further, since the flattening layer 117 formed between the laser oscillating portions 120 is made of polyimide or the like having a low thermal conductivity, the heat generated in each laser oscillating portion 120 is transferred to the flattening layer. At 117, it is difficult to radiate heat, which is one of the causes that thermal interference cannot be suppressed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a photoelectric conversion element capable of suppressing the influence of heat generation by promoting heat radiation and a method of manufacturing the same. .

[0007]

According to the present invention, there is provided a photoelectric conversion element comprising a plurality of stacked semiconductor layers, the photoelectric conversion section having a side surface at an end in a direction perpendicular to the stacking direction, and a photoelectric conversion section. And a heat radiation layer having a heat radiation function formed on at least a part of the side surface of the light emitting element.

[0008] The method for manufacturing a photoelectric conversion element according to the present invention comprises:
A step of forming a photoelectric conversion unit having a side surface at an end in a direction perpendicular to the stacking direction, which is made of a plurality of stacked semiconductor layers, and a step of forming a heat radiation layer on at least a part of the side surface of the photoelectric conversion unit Is included.

In the photoelectric conversion device according to the present invention, light energy and electric energy are exchanged in the photoelectric conversion unit. At this time, heat is generated in the photoelectric conversion unit, but the generated heat is positively radiated by the heat radiation layer. Therefore, the influence of heat generation is eliminated, and a decrease in performance of the photoelectric conversion unit is suppressed.

In the method for manufacturing a photoelectric conversion element according to the present invention, a photoelectric conversion portion including a plurality of semiconductor layers stacked is formed, and a heat radiation layer is formed on at least a part of a side surface of the photoelectric conversion portion.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 shows a configuration of a semiconductor laser which is a photoelectric conversion element according to the embodiment. FIG. 2 shows a cross-sectional structure along the line II shown in FIG. Here, the photoelectric conversion element is an element that converts light energy and electric energy, and is a concept that includes both an element that converts light energy to electric energy and an element that converts electric energy to light energy. It is.

As shown in FIG. 1, this semiconductor laser is a laser as a photoelectric conversion unit arranged on one surface (100 surface) of the same substrate 11 in a direction perpendicular to the resonator direction A. A plurality of (here, two) oscillation units 20 are provided. Each laser oscillation unit 20 has a substantially rectangular parallelepiped shape in which two pairs of side surfaces are formed at ends in a direction parallel to one surface of the substrate 11. One of the side surfaces is located at an end in the resonator direction A, and the other pair is located at an end in a direction perpendicular to the resonator direction A. As for the size of each laser oscillation section 20, for example, the length in the resonator direction A is 200 μm, and the width in the direction perpendicular to the resonator direction A is 100 μm. The interval between the laser oscillators 10 is, for example, 50 μm.

Each of these laser oscillating units 20 has the same structure as each other, and as shown in FIG. 2, each of the laser oscillating units 20 as semiconductor layers from the substrate 11 side in a direction perpendicular to one surface of the substrate 11. The n-type cladding layer 21, each active layer 22, each p-type cladding layer 23, and each cap layer 24 are sequentially laminated. That is, two pairs of side surfaces of each laser oscillation unit 20 are located at ends in a direction perpendicular to the laminating direction of each semiconductor layer. In FIG. 1, illustration of each semiconductor layer is omitted.

Each n-type cladding layer 21 is formed, for example, on the substrate 1
1 has a thickness of 2 μm in a direction perpendicular to one surface (hereinafter simply referred to as a thickness), and silicon (S) as an n-type impurity.
i) or n-type AlGaAs doped with selenium (Se)
Each is composed of mixed crystals. This n-type AlGa
The composition ratio of the As mixed crystal in the group III element is, for example, aluminum (Al) 45% (mol%; the same applies hereinafter) and gallium (Ga) 55%. Each active layer 22 has, for example, a thickness of 80 μm and an i-A
Each is composed of an lGaAs mixed crystal (i- represents that no impurity is added). This AlGaAs
The composition ratio of the group III element of the s mixed crystal is, for example, 14% for aluminum and 86% for gallium.

Each p-type cladding layer 23 has a thickness of, for example, 0.5 μm, and is made of a p-type AlGaAs mixed crystal to which zinc (Zn) is added as a p-type impurity. The composition ratio of the p-type AlGaAs mixed crystal in the group III element is, for example, 45% for aluminum and 55% for gallium. Each cap layer 24 has a thickness of, for example, 0.1 μm, and is formed by adding p-type impurity to zinc.
GaAs mixed crystals.

In each of the p-type cladding layers 23, a current blocking layer 25 is inserted on both sides along the resonator direction A in a part in the laminating direction. That is, the width of each of the p-type cladding layers 23 in the direction perpendicular to the resonator direction A is reduced in a part of the laminating direction, thereby constituting the current confinement portion 23a. The width of the current constriction portion 23a is, for example, 4 μm. Each current block layer 25 has a thickness of, for example, 1 μm, and is made of n-type GaAs to which silicon or selenium is added as an n-type impurity.

The substrate 11 has, for example, a thickness of 350
μm, and is made of n-type GaAs to which silicon or selenium is added as an n-type impurity.

As shown in FIG. 1, each laser oscillating unit 20 has a pair of continuous end films 26 and 27 on a pair of side surfaces located at the ends in the cavity direction A, respectively. One end face film 26 is made of, for example, aluminum oxide (Al
₂ O ₃ ) and has a low reflectance. The other end face film 27 is formed by alternately stacking, for example, an aluminum oxide layer and an amorphous silicon (amorphous silicon) layer, and has a high reflectance. That is, the light generated in each active layer 22 is applied to the pair of end face films 2.
The laser beam is amplified by reciprocating between 6, 27 and emitted from the end face film 26 as a laser beam.

Each of the laser oscillation sections 20 has a corresponding one of the p-side electrodes 12 provided for each of the cap layers 24.
And an n-side electrode 13 provided on the other surface of the substrate 11 opposite to the one surface thereof are electrically connected to each other. Each p-side electrode 12 has a structure in which, for example, a titanium (Ti) layer, a platinum (Pt) layer, and a gold (Au) layer are sequentially stacked from the cap layer 24 side and alloyed by a heat treatment. The n-side electrode 13 has a structure in which, for example, an alloy layer of gold and germanium (Ge), a nickel (Ni) layer, and a gold layer are laminated in order from the substrate 11 side and alloyed by heat treatment.

A heat radiation layer 15 is formed between the respective laser oscillators 20 via respective insulating layers 14 provided adjacent to each other.
Is flattened. That is, on each side surface 20 a between the laser oscillation units 20 located at the end in the direction perpendicular to the cavity direction A, the heat radiation layer 1
5 are formed. The heat radiation layer 15 is for dissipating the heat generated in each laser oscillation unit 20 and is made of a material having a high thermal conductivity that is equal to or higher than the semiconductor constituting each laser oscillation unit 20. Is preferred. Specifically, for example, it is constituted by a semiconductor. It is preferable that the semiconductor constituting the heat radiation layer 15 has a lattice constant matching that of the semiconductor constituting the substrate 11. Each laser oscillating section 20 is distorted by a lattice mismatch or dangling bond generated at the interface.
This is so as not to adversely affect the performance. Further, a semiconductor to which no impurity is added in order to ensure insulation between the laser oscillation units 20 is preferable. For example, here, substrate 1
1 is made of GaAs, i-GaAs
It is preferred to be constituted by

On the side of the heat radiation layer 15 opposite to the substrate 11,
An insulating layer 16 is formed. Each of the insulating layers 14 and 16
It is intended to secure insulation between the laser oscillation section 20, respectively composed of an insulating material such as silicon nitride (Si ₃ N _4). It is preferable that each side surface 20a of each laser oscillation unit 20 has a plane shape perpendicular to one surface of the substrate 11 (that is, a plane shape parallel to the lamination direction). This is because when the heat radiation layer 15 is grown on one surface side of the substrate 11, the growth surface can be made parallel to one surface of the substrate 11, and the surface of the heat radiation layer 15 can be flat.

The photoelectric conversion element having such a configuration is
It can be manufactured as follows.

FIGS. 3 to 7 show the respective manufacturing steps by a cross-sectional structure along the line II shown in FIG.
First, as shown in FIG. 3A, for example, n-type GaAs
s is prepared, and MOCVD (Metal Orga
nic Chemical Vapor Deposition (metal organic chemical vapor deposition)
According to the method, an n-type AlGaAs is
n-type cladding layer 21 made of s mixed crystal, i-AlGaAs
An active layer 22 composed of a mixed crystal and a part of a p-type cladding layer 23 composed of a p-type AlGaAs mixed crystal are sequentially grown.

Next, as shown in FIG. 3B, an n-type layer is formed on the p-type cladding layer 23 by MOCVD, for example.
A current blocking layer 25 of type GaAs is grown.
Subsequently, for example, reactive ion etching (Reactive Ion
This current blocking layer 25 is formed by an etching (RIE) method.
Is selectively removed according to the laser oscillation portion forming region 31,
Shape into a predetermined shape. Although there are a plurality of semiconductor laser formation regions on one surface side of the substrate 11, only each region corresponding to one semiconductor laser is represented in each process drawing.

After shaping the current block layer 25, FIG.
As shown in (C), for example, by the MOCVD method,
On the current blocking layer 25 and the p-type cladding layer 23, p
A part of the p-type cladding layer 23 made of the type AlGaAs mixed crystal and the cap layer 24 made of the p-type GaAs are sequentially grown. After that, zinc is diffused into the cap layer 24 so as to make ohmic contact between the cap layer 24 and the p-side electrode 12 formed thereon.

After the zinc is diffused, as shown in FIG. 4A, each auxiliary film 32 is formed on the cap layer 24 so as to correspond to each laser oscillation portion forming region 31.
In addition, each auxiliary film 32 has a role as a mask when etching each semiconductor layer in a process described later, and also has a role to cover the surface of each cap layer 24 when growing the heat radiation layer 15. Things. Each of the auxiliary films 32 is preferably made of, for example, an insulating material such as silicon nitride.

Thereafter, the cap layer 24, the p-type cladding layer 23, the current blocking layer 25, the active layer 22, and the n-type cladding layer 21 are selectively removed by, for example, RIE using the respective auxiliary films 32 as masks. These are separated from each other so as to correspond to the respective laser oscillation portion forming regions 31. Note that it is preferable to use dry etching for this etching. Each side surface that separates each semiconductor layer, that is, each side surface 20a between each laser oscillation unit 20 is attached to the substrate 1
This is because a plane perpendicular to one surface is formed. This etching is performed in a region between the laser oscillation portion forming regions 31 (hereinafter, referred to as an isolation region 33).
It is more preferable to go until 1 is exposed. It is sufficient to selectively remove the cap layer 24 to a part of the n-type cladding layer 21 only for separating the respective laser oscillation units 20, but here, for example, i-GaAs
This is because the heat radiation layer 15 made of s is grown in the isolation region 33.

After separating each semiconductor layer, FIG.
As shown in (B), an insulating layer 14 made of silicon nitride is formed on the entire surface on the side of each auxiliary film 32 by, for example, a CVD (Chemical Vapor Deposition) method. Thereby, each surface of each auxiliary film 32 and each side surface 20 of each semiconductor layer are formed.
The insulating layer 14 is formed on the surface of the substrate 11 in the area a and the isolation region 33, respectively.

After forming the insulating layer 14, as shown in FIG. 5A, for example, RIE using oxygen gas (O ₂ )
The insulating layer 14 is selectively removed by the method, and the substrate 11 is exposed in the separation region 33. By this etching, a portion of the insulating layer 14 corresponding to the surface of each auxiliary film 32 is simultaneously removed, and each auxiliary film 32 is also exposed. However, a portion of the insulating layer 14 corresponding to each side surface 20a is not removed. After exposing the surface of the substrate 11, as shown in FIG. 5B, the heat radiation layer 15 made of i-GaAs is selectively grown on the exposed surface of the substrate 11 by, for example, MOCVD. At this time, since the surface of each cap layer 24 in each laser oscillation portion forming region 31 is covered with each auxiliary film 32 and each side surface 20a of each semiconductor layer is covered with each insulating layer 14, Layer 15 is the substrate 1 in isolation region 33
1 only epitaxially grows on the surface.

After the heat radiation layer 15 is formed, as shown in FIG. 6A, for example, RIE using oxygen gas (O ₂ )
According to the method, the entire surface on the side of each auxiliary film 32 is etched to remove each auxiliary film 32, and each cap layer 24 is exposed. After exposing each cap layer 24, as shown in FIG.
An insulating layer 16 made of silicon nitride is formed on the entire surface on the side by, for example, a CVD method. After that, the separation region 33
The photoresist film 34 on the surface of the insulating layer 16
Is selectively formed, and the insulating layer 16 is selectively removed using the photoresist film 34 as a mask. Thereby, the insulating layer 16 is shaped.

After shaping the insulating layer 16, as shown in FIG. 7A, for example, a titanium layer, a platinum layer, and a gold layer are sequentially deposited on the surface of the photoresist film 34 and the cap layers 24, respectively. The p-side electrodes 12 are respectively formed. After that, the p-side electrode 12 formed on the surface of the photoresist film 34 is removed (lifted off) together with the photoresist film 34. As a result, each p-side electrode 12 is left corresponding to each cap layer 24. After removing the photoresist film 34, as shown in FIG. 7B, for example, an alloy layer of gold and germanium, a nickel layer and a gold layer are sequentially deposited on the other surface side of the substrate 11 to form an n-side layer. An electrode 13 is formed. After that, a heat treatment is performed so that the p-side electrode 12 and n
The side electrodes 13 are alloyed.

After the heat treatment, although not shown here, the substrate 11 is cleaved in the resonator direction A and in a direction perpendicular to the resonator direction A so as to correspond to the formation region of each semiconductor laser. Thereafter, end films 26 and 27 are formed on a pair of side surfaces located at ends in the resonator direction A by, for example, a CVD method. Thus, the semiconductor laser shown in FIG. 1 is formed.

The semiconductor laser manufactured as described above operates as follows.

In this semiconductor laser, when a predetermined voltage is applied between each p-side electrode 12 and each n-side electrode 13, a current is injected into each active layer 22 in each laser oscillating section 20, and the electron- Light emission due to hole recombination occurs. These lights are amplified by reciprocating between the pair of end films 26 and 27 and are emitted from the end films 26 to the outside. At this time, heat is generated in each of the laser oscillating units 20. Here, since the heat radiating layer 15 having a heat radiating function is provided between the laser oscillating units 20, the heat radiating layer 15 is provided.
Also, the generated heat is positively dissipated. Therefore,
In each laser oscillation unit 20, an increase in threshold current and a decrease in luminous efficiency are suppressed.

As described above, according to the semiconductor laser of the present embodiment, since the heat radiation layer 15 is provided, the heat generated in each laser oscillation section 20 can be actively radiated by the heat radiation layer 15. it can. Therefore, an increase in the threshold voltage and a decrease in the luminous efficiency of each laser oscillation unit 20 can be suppressed, and high quality can be maintained for a long time.

Further, since the heat radiation layer 15 is formed on the side surface 20a of each laser oscillation unit 20 via each insulating layer 14, even if the heat radiation layer 15 is formed of a semiconductor, the heat radiation layer 15 is formed between the laser oscillation units 20. Insulation can be ensured, and independent driving of each laser oscillation unit 20 can be ensured. Therefore, the heat radiation layer 15 can be made of a semiconductor having a high thermal conductivity, and a higher heat radiation effect can be obtained.

Further, a heat radiation layer 1 is provided between each laser oscillation section 20.
5 so that each laser oscillation unit 2
A multilayer wiring can be easily formed on the zero side, and each wiring connected to each laser oscillation unit 20 can be easily formed.

In addition, the side surface 2 between each laser oscillation section 20
0a is formed in a plane substantially perpendicular to one surface of the substrate 11, so that when the heat radiation layer 15 made of a semiconductor is grown, the growth surface can be made parallel to one surface of the substrate 11, and The surface of the layer 15 can be flat.
Therefore, the space between the laser oscillation sections 20 can be flattened, and multilayer wiring can be facilitated.

Further, according to the method of manufacturing a semiconductor laser according to the present embodiment, after laminating a plurality of semiconductor layers on one surface side of the substrate 11, the respective semiconductor layers are selectively removed and separated. Since the heat radiation layer 15 is formed between the separated semiconductor layers, the semiconductor laser according to the present embodiment can be easily formed, and the semiconductor laser according to the present embodiment can be easily realized. Can be.

Further, each semiconductor layer is selectively removed using each auxiliary film 32 formed on the cap layer 24 so as to correspond to each laser oscillation portion forming region 31 as a mask. Since the heat dissipation layer 15 made of a semiconductor is grown in the isolation region 33 while covering the surface of the layer 24, the heat dissipation layer 15 can be easily and accurately formed with a small number of manufacturing steps.

In addition, since each semiconductor layer is selectively removed by dry etching, each side surface 20a between each laser oscillation unit 20 is formed to be a plane perpendicular to one surface of the substrate 11. it can. Therefore, the heat radiation layer 1 can be easily formed.
5 can be made flat.

(Second Embodiment) FIG. 8 shows a second embodiment of the present invention.
13 shows a cross-sectional structure in a direction perpendicular to a resonator direction A of the semiconductor laser according to the embodiment. This semiconductor laser has the same configuration, operation and effect as the first embodiment except that the configuration of the heat radiation layer 15 is different and the insulating layer 16 is removed. This semiconductor laser can be formed in the same manner as in the first embodiment. Therefore, here, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

The heat radiation layer 15 is formed of a p-type layer 15a made of a p-type semiconductor doped with p-type impurities from the substrate 11 side.
And one or more n-type layers 15b made of an n-type semiconductor to which n-type impurities are added. The semiconductors forming the p-type layer 15a and the n-type layer 15b are preferably those that lattice-match with the semiconductor forming the substrate 11, as in the first embodiment. For example, the p-type layer 15a is preferably made of p-type GaAs to which zinc is added, and the n-type layer 15b is preferably made of n-type GaAs to which silicon or selenium is added.

As described above, according to the present embodiment, the p-type layers 15a and the n-type layers 15b are alternately laminated, so that the insulating layer 16 can be formed on the surface of the heat radiation layer 15. In addition, it is possible to completely cut off the current flow between the heat radiation layer 15 and the substrate 11, and to ensure insulation between the laser oscillation units 20. Therefore, the configuration can be simplified, and the manufacturing process can be simplified.

(Third Embodiment) The semiconductor laser according to the third embodiment has the same configuration, operation and effect as the first embodiment except that the heat radiation layer 15 is made of metal. doing. Therefore, here, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

The metal constituting the heat radiation layer 15 is preferably, for example, gold (Au).

Note that, unlike the first embodiment, this semiconductor laser may include an insulating layer between the heat radiation layer 15 and the substrate 11. Further, the respective n-type cladding layers 21 of the respective laser oscillation units 20 may not be completely separated and may be partially continuous. That is, the heat radiation layer 15 may be formed on one surface side of the substrate 11 via a part of the n-type cladding layer 21 and the insulating layer. Further, each side surface 20a between the laser oscillation units 20 does not need to be a plane perpendicular to one surface of the substrate 11. This is because, unlike the case where the heat radiation layer 15 is formed of a semiconductor, the heat radiation layer 15 is not formed by epitaxial growth.

This semiconductor laser can be manufactured as follows.

First, in the same manner as in the first embodiment, an n-type cladding layer 21, an active layer 22, and a part of the p-type cladding layer 23 are sequentially grown on one side of the substrate 11 (FIG. 3).
(A)). Next, similarly to the first embodiment, after forming the current blocking layer 25 on the p-type cladding layer 23 (see FIG. 3B), a part of the p-type cladding layer 23 and the cap layer 24 are formed. Are sequentially grown to diffuse zinc into the cap layer 24 (see FIG. 3C).

Subsequently, although not shown here, for example,
Using a lithography process, the cap layer 24, the p-type cladding layer 23, the current blocking layer 25, the active layer 22, and the n-type cladding layer 21 are selectively removed by etching.
Each semiconductor layer is separated according to each laser oscillation portion forming region 31. At this time, it is sufficient to etch only a part of the n-type cladding layer 21, and it is not necessary to expose the substrate 11. In addition, wet etching or dry etching may be used for this etching.

After separating each semiconductor layer, an insulating layer 14 made of silicon nitride is formed on the entire surface on the side of each semiconductor layer by, for example, a CVD method. After that, the insulating layer 14 is selectively removed by, for example, RIE to leave the insulating layer 14 only on each side surface 20a of each semiconductor layer. At this time, the insulating layer 14 may be left on the side surface 20 a of each semiconductor layer and the surface of the substrate 11 in the isolation region 33 by using a lithography process.

After the insulating layer 14 is selectively formed, a photoresist film (not shown) is formed in each of the laser oscillation portion forming regions 31.
Are formed selectively in correspondence with. After that, a metal layer made of gold or the like is vapor-deposited on the entire surface, and the metal layer formed on the photoresist film is removed (lifted off) together with the photoresist film, and the heat radiation layer 15 is selectively made to correspond to the isolation region 33. Formed.

After the heat radiation layer 15 is formed, the insulating layer 16 is selectively formed corresponding to the isolation region 33 as in the first embodiment (see FIG. 6B). after that,
Similarly to the first embodiment, each p-side electrode 12 is selectively formed on each cap layer 24 (see FIG. 7A), and an n-side electrode is formed on the other surface of the substrate 11. 13
(See FIG. 7B), and the p-side electrode and the n-side electrode are alloyed by heat treatment.

After the heat treatment, the substrate 11 is cleaved in a manner corresponding to the formation region of each semiconductor laser in the same manner as in the first embodiment, and a pair of side surfaces located at the ends in the cavity direction A are formed. Then, end face films 26 and 27 are respectively formed. Thereby, the semiconductor laser according to the present embodiment is formed.

As described above, according to the present embodiment, since the heat radiation layer 15 is made of metal, a higher heat radiation effect can be obtained, and the threshold current of each laser oscillation unit 20 rises and the light emission. A decrease in efficiency can be suppressed more effectively.

(Fourth Embodiment) FIG. 9 shows a fourth embodiment of the present invention.
13 shows a cross-sectional structure in a direction perpendicular to a resonator direction A of the semiconductor laser according to the embodiment. The semiconductor laser includes four laser oscillation units 20 on one surface side of the same substrate 11 and a pair of support units 30 formed on the substrate 11 so as to sandwich each laser oscillation unit 20 in the arrangement direction B. In addition, each insulating layer 1 is also provided between each of the laser oscillation sections 20 and each of the support sections 30 located on the side of each of the support sections 30.
Except that the heat radiation layers 15 are formed via the respective layers 4, they have the same configuration, operation and effect as those of the first embodiment. This semiconductor laser can be formed in the same manner as in the first embodiment. Therefore, here, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

Each support section 30 is for forming each heat radiation layer 15 well between each laser oscillation section 20 and each support section 30 located at both ends in the arrangement direction B. Incidentally, the arrangement direction B here is a direction perpendicular to the resonator direction A. Each support portion 30 has substantially the same structure as each laser oscillation portion 20, and is formed in the same step as each laser oscillation portion 20. Further, the surface of each support portion 30 is covered with an insulating layer 16 similarly to each heat radiation layer 15. In addition, even if each support part 30 is not formed, each heat radiation layer 1 is provided on each side surface 20b outside each laser oscillation part 20 located at both ends in the arrangement direction B.
5 can be formed individually, and each support 30
It is not always necessary to provide.

As described above, according to the present embodiment, each heat radiation layer 1 is disposed outside each laser oscillator 20 in the arrangement direction B.
5 are formed, so that the laser oscillation unit 2
Even when the number of zeros increases and the interval between the laser oscillation units 20 becomes narrow, heat radiation can be promoted by the heat radiation layers 15 provided on the outside. Further, if the width of each heat radiation layer 15 provided on the outside in the arrangement direction B is increased, the heat radiation effect can be further promoted. Therefore, even if the number of the laser oscillation units 20 increases, the increase in the threshold voltage and the decrease in the luminous efficiency can be effectively suppressed.

Although not described in detail here, the second
This embodiment can be similarly applied to the third embodiment and the third embodiment.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to these embodiments, and can be variously modified. For example, in the first to third embodiments, a semiconductor laser including two laser oscillation units 20 on the same substrate 11 will be specifically described, and in the fourth embodiment,
Although the semiconductor laser including the four laser oscillation units 20 on the same substrate 11 has been specifically described, the present invention can be widely applied regardless of the number of the laser oscillation units 20. That is, the present invention can be widely applied to a photoelectric conversion element including one or more photoelectric conversion units.

In each of the above embodiments, at least one side surface of each of the laser oscillation sections 20 located at the end in the direction perpendicular to the resonator direction A is provided on the entire surface via the insulating layer 14. Although the heat radiation layer 15 is formed, it may be formed on at least a part thereof.

Further, in the fourth embodiment,
The heat radiation layers 15 are provided between the respective laser oscillation units 20 and also provided outside the respective laser oscillation units 20 located at both ends in the arrangement direction B. The heat radiation layer 15 may be provided only between the laser oscillation units 20 between the laser oscillation units 20 and between the laser oscillation units 20 without being provided between the laser oscillation units 20. The laser oscillators 20 may be provided only on at least one of the outsides.

In addition, in each of the above embodiments, the heat radiation layer 1 is provided on the side surface of each laser oscillation section 20 via the insulating layer 14.
5 is formed, but when the heat radiation layer 15 is made of an insulating material, the insulating layer 14 may not be provided. For example, the heat radiation layer 15 may be made of an intrinsic semiconductor, aluminum nitride (AlN), diamond, or the like.

Further, in each of the above embodiments,
Although the material constituting each laser oscillation unit 20 has been specifically described with reference to specific examples, the present invention can be applied to the case where the laser oscillation unit 20 is made of another material. For example, the substrate 11 and the cladding layers 21 and 23 are each composed of InP, and the active layer 22 is composed of InGaAsP. Alternatively, the substrate 11 is composed of GaAs and the cladding layers 21 and 23 are each composed of AlGaInP. 22 can also be applied to the one made of GaInP.

In these cases, too, the heat radiation layer 1
When forming 5 from a semiconductor, it is preferable to use a material that lattice-matches with the semiconductor forming the substrate. For example, the cladding layers 21 and 23 are made of InP, and the active layer 22 is made of InP.
When each is made of GaAsP, the substrate 11
Is composed of InP, the heat radiation layer 15 is also preferably composed of InP.
When the 1GaInP and the active layer 22 are each made of GaInP, the substrate 11 is made of GaAs, so that the heat radiation layer 15 is also preferably made of GaAs.

In addition, in each of the above embodiments, the structure of each laser oscillation section 20 has been described by way of example, but the present invention can be similarly applied to those having other structures. it can. For example, one having a guide layer, a p-type cladding layer, an active layer,
The present invention can also be applied to a structure in which mold clad layers are sequentially laminated.

Further, in the second embodiment, the heat radiation layer 15 is formed by alternately laminating one or more p-type layers 15a and n-type layers 15b in order from the substrate 11 side. However, especially when the substrate 11 is made of a p-type semiconductor, the n-type layers 15b may be alternately stacked first.

In addition, in each of the above embodiments, the semiconductor laser provided with the laser oscillation section 20 as the photoelectric conversion section has been specifically described. However, the present invention converts the light energy to the electric energy. The present invention can be widely applied to a photoelectric conversion element including another photoelectric conversion unit that converts electric energy into light energy. For example, a light emitting diode (light emitting diod)
e; LED) and semiconductor light receiving elements such as photodetectors.

[0070]

As described above, according to the photoelectric conversion element of any one of the first to tenth aspects, the heat radiation layer is provided, so that the heat generated in the photoelectric conversion portion is dissipated by the heat radiation layer. The heat can be actively dissipated. Therefore, it is possible to prevent the performance of the photoelectric conversion unit from being reduced due to the influence of heat generation, and it is possible to maintain high quality for a long period of time.

In particular, according to the photoelectric conversion element of the second aspect, since the insulating layer is provided between the photoelectric conversion portion and the heat radiation layer, the photoelectric conversion portion can be formed even if the heat radiation layer is made of a conductive material. Can ensure the insulation properties of the substrate. Therefore, the range of selection of the material forming the heat dissipation layer is widened, and the heat dissipation layer can be made of a material having high thermal conductivity. Therefore, there is an effect that a higher heat radiation effect can be obtained.

Further, according to the photoelectric conversion element of the fifth aspect, the heat radiation layer has a configuration in which the p-type layer and the n-type layer are alternately provided, respectively. This has the effect that insulation can be ensured and the manufacturing process can be simplified.

Further, according to the photoelectric conversion element of the present invention, since the side surface of the photoelectric conversion portion on which the heat radiation layer is formed is formed in a plane parallel to the laminating direction, for example, the heat radiation layer is formed of a semiconductor. Even in the case where the heat radiation layer is constituted by the above, the surface of the heat radiation layer can be made flat. Therefore, there is an effect that the wiring can be easily formed on the photoelectric conversion unit.

Further, according to the photoelectric conversion element of the ninth aspect, since the heat radiation layer is provided between the two adjacent photoelectric conversion parts, the space between each photoelectric conversion part can be flattened. Multilayer wiring can be facilitated. Therefore, even if the number of photoelectric conversion units formed on the same substrate increases, each wiring connected to each photoelectric conversion unit can be easily formed.

In addition, according to the photoelectric conversion element of the tenth aspect, since the heat radiation layer is provided on at least one of the outer sides of the photoelectric conversion portions located at both ends in the arrangement direction, they are formed on the same substrate. Even when the number of photoelectric conversion units is increased and the interval between the photoelectric conversion units is reduced, heat radiation can be promoted by the heat radiation layer provided on the outside. Further, if the width of the heat radiation layer in the arrangement direction is increased, the heat radiation effect can be further promoted. Therefore, even if the number of photoelectric conversion units increases, the effect of effectively eliminating the influence of heat generation can be achieved.

Further, according to the method for manufacturing a photoelectric conversion element according to any one of claims 11 to 15, a step of forming a photoelectric conversion portion composed of a plurality of stacked semiconductor layers, and a step of forming a side surface of the photoelectric conversion portion And a step of forming a heat radiation layer on at least a part of the device. Therefore, the photoelectric conversion device of the present invention can be easily formed, and the photoelectric conversion device of the present invention can be easily realized. To play.

In particular, according to the method for manufacturing a photoelectric conversion element of the present invention, the semiconductor layer is selectively removed by dry etching, so that the side surfaces of the photoelectric conversion portion are parallel to the stacking direction. Shape. Therefore, for example, even when the heat dissipation layer is made of a semiconductor, the surface of the heat dissipation layer can be flattened.

According to the method of manufacturing a photoelectric conversion device of the present invention, the semiconductor layer is selectively removed by using the auxiliary film as a mask, and the heat radiation layer is formed while the semiconductor surface is covered by the auxiliary film. Therefore, there is an effect that the heat radiation layer can be easily and accurately formed with a small number of manufacturing steps.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of a semiconductor laser according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the semiconductor laser shown in FIG. 1 taken along the line II.

FIG. 3 is a cross-sectional view illustrating each manufacturing process of the semiconductor laser illustrated in FIG.

FIG. 4 is a sectional view illustrating each manufacturing step following FIG. 3;

FIG. 5 is a sectional view illustrating each manufacturing step following FIG. 4;

FIG. 6 is a sectional view illustrating each manufacturing step following FIG. 5;

FIG. 7 is a sectional view illustrating each manufacturing step following FIG. 6;

FIG. 8 is a sectional view illustrating a configuration of a semiconductor laser according to a second embodiment of the present invention.

FIG. 9 is a sectional view illustrating a configuration of a semiconductor laser according to a fourth embodiment of the present invention.

FIG. 10 is a cross-sectional view illustrating a configuration of a conventional multi-beam laser.

[Explanation of symbols]

11, 111: substrate, 12: p-side electrode, 13: n-side electrode, 14, 16: insulating layer, 15: heat dissipation layer, 20, 120
... Laser oscillation part (photoelectric conversion part), 21 ... n-type cladding layer, 22 ... active layer, 23 ... p-type cladding layer, 23a ... current confinement part, 24 ... cap layer, 25 ... current blocking layer,
31: laser oscillation part forming region, 32: auxiliary film, 33: separation region, 34: photoresist film, 117: flattening layer,
A: Resonator direction, B: Array direction

Claims (15)

[Claims] 1. A photoelectric conversion unit comprising a plurality of stacked semiconductor layers and having a side surface at an end in a direction perpendicular to the stacking direction, and forming at least a part of the side surface of the photoelectric conversion unit. And a heat radiation layer having a heat radiation function. 2. The photoelectric conversion device according to claim 1, further comprising an insulating layer between the side surface of the photoelectric conversion unit and the heat radiation layer. 3. The photoelectric conversion element according to claim 1, wherein said heat radiation layer is made of a semiconductor. 4. The semiconductor device according to claim 3, wherein the photoelectric conversion section is formed on a substrate made of a semiconductor, and the heat radiation layer is made of a semiconductor whose lattice constant matches that of a semiconductor forming the substrate. The photoelectric conversion device according to any one of the preceding claims. 5. The photoelectric conversion element according to claim 3, wherein the heat radiation layer has at least one p-type layer made of a p-type semiconductor and one or more n-type layers made of an n-type semiconductor alternately. 6. The photoelectric conversion element according to claim 1, wherein the heat radiation layer is made of a metal. 7. The photoelectric conversion element according to claim 1, wherein a side surface of the photoelectric conversion portion on which the heat radiation layer is formed has a plane shape parallel to a stacking direction. 8. The photoelectric conversion device according to claim 1, wherein a plurality of said photoelectric conversion units are provided on the same substrate. 9. The photoelectric conversion element according to claim 8, wherein the heat radiation layer is provided between two adjacent photoelectric conversion units. 10. The plurality of photoelectric conversion units are arranged in one direction, and the heat radiation layer is provided outside at least one of the photoelectric conversion units located at both ends in the arrangement direction. Item 8. The photoelectric conversion element according to Item 8. 11. A step of forming a photoelectric conversion unit comprising a plurality of stacked semiconductor layers and having a side surface at an end in a direction perpendicular to the stacking direction, and a heat radiation layer on at least a part of the side surface of the photoelectric conversion unit. Forming a photoelectric conversion element. 12. The method according to claim 1, further comprising a step of forming an insulating layer on at least a part of a side surface of the photoelectric conversion unit before forming the heat radiating layer, and forming the heat radiating layer via the insulating layer. The method for manufacturing a photoelectric conversion element according to claim 11. 13. The step of forming the photoelectric conversion portion includes the steps of: stacking a plurality of semiconductor layers on one surface side of a substrate; selectively removing at least a part of the stacked plurality of semiconductor layers; 12. The method for manufacturing a photoelectric conversion element according to claim 11, comprising a step of forming. 14. The method according to claim 13, wherein the semiconductor layer is selectively removed by dry etching. 15. The semiconductor device according to claim 1, wherein the semiconductor layer is selectively removed by using the auxiliary film formed on the semiconductor layer as a mask, and the heat radiation layer is formed in a state where the surface of the semiconductor layer is covered by the auxiliary film. 14. The method for producing a photoelectric conversion element according to 13 above.