JPH10135563A - Method of manufacturing photo-semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make feasible of manufacturing a photo-semiconductor device having semiconductor layer made of a plurality of regions in different layer thickness and excellent production efficiency. SOLUTION: Insulating film masks 2 with striped aperture parts 20 made of a plurality of regions in different widths exposing a substrate 1 on the bottoms thereof are formed on a substrate 1. Next, after wet etching the substrate 1 using the insulating masks 2, an n type InP lower clad layer 3, an undoped InGaAsP active layer 4 and a p type upper clad layer 5 are successively led to crystal growth on the substrate 1 also using the insulating masks 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical semiconductor device, and more particularly to a method for manufacturing an optical semiconductor device having a continuous region that generates, guides, or absorbs light with different thicknesses in space. It is.

[0002]

2. Description of the Related Art In recent years, as an example of improving the performance of an optical semiconductor device, a modulator-integrated laser diode in which a light emitting region and a region for modulating the amount of light absorbed by an electric field are integrated, In an integrated laser or the like in which the divergence angle of an emitted laser beam is narrowed by integrating a tapered waveguide region in which the width continuously changes, an active layer such as a waveguide, an active layer, and an absorption layer is formed by one epitaxial layer. Along with
A technique of changing the thickness of these layers in the direction in which light travels is used. An example of this is a report on a tapered waveguide, which was published in the 1995 IEICE General Conference SC-4-4, p.4
63.

An important technique for manufacturing these devices is a crystal growth technique for forming a semiconductor crystal having a different layer thickness depending on a place, instead of growing a flat semiconductor crystal on a semiconductor substrate. At present, a method of forming a semiconductor having such a layer thickness distribution is described by Kenichi Iga. Semiconductor laser. The selective growth technology using an insulating film mask as shown in Ohmsha, p.364 is the mainstream.

FIG. 6 is a view showing main steps of a conventional method for manufacturing an optical semiconductor device. FIG. 6 (a) is a plan view and FIG. 6 (b) is a view taken along the line VI-VI of FIG. 6 (a). A cross-sectional view, that is, a cross-sectional view along the direction in which the waveguide extends, and FIG. 6C is a plan view. In the figure, reference numeral 105 denotes one element forming region of a semiconductor device, 100 denotes an n-type InP substrate, 100a denotes a wafer made of n-type InP, 101 denotes an n-type InP lower cladding layer, 102 denotes an active layer made of an undoped InGaAsP layer, and 103 denotes an active layer. p-type InP upper cladding layer, 110 is 20 μm
An insulating film mask composed of two insulating films arranged so as to be parallel and line-symmetrical to each other at a constant interval of about m, each insulating film comprising a plurality of regions having different widths. 110a is the widest region of each insulating film, 110b is the narrowest portion of the insulating film, 110c is an insulating film provided between the wide region 110a and the narrow portion 110b. Is an area where the width of the changes continuously. The width of each insulating film of the insulating film mask 110 is about 200 μm at the widest point. Further, the length of each of the insulating films in the wide region 110a in the direction in which the insulating films extend in parallel to each other is about 400 μm,
The length of the region 110c where the width changes is about 150 μm. This method for manufacturing an optical semiconductor device particularly shows a method for manufacturing an optical semiconductor device in which a semiconductor laser and a tapered waveguide are integrated, and has a stripe shape sandwiched between two insulating films of an insulating film mask 110. A waveguide and an active layer are formed as active layers in the region.

Next, a manufacturing method will be described. First, I
An insulating film (not shown) is formed on the nP substrate 100, and this is selectively etched using a resist or the like to form an insulating film mask 110 as shown in FIG. 7A.

Then, using this insulating film mask 110 as a selective growth mask, the n-type InP lower cladding layer 10 is formed.
1. An undoped InGaAsP active layer 102 and a p-type InP upper cladding layer 103 are sequentially grown selectively by MOCVD or the like.

At the time of this selective growth, on the substrate 110,
Although the source gas is supplied uniformly, crystal growth does not occur on the insulating film mask 110, so that the growth species in the source gas are not consumed in this portion, and the source gas is present in the portion where the insulating film mask 110 is present. The concentration of growing species inside increases.
For this reason, a distribution of the growth species concentration occurs on the substrate 110, and particularly in a region where the growth species concentration is high, that is, in a region on the substrate 110 adjacent to the wide insulating film, a large amount of growth species is supplied. become. As a result, the growth rate of the portion sandwiched between the wide insulating films is accelerated, and as shown in FIG. 6B, the thickness of each layer grown on the narrow portion 110b is reduced to the wide portion 110a. In the region 110c where the width is continuously changed while the thickness is smaller than the thickness, the thickness is gradually reduced as the width is reduced. As a result, a crystal growth layer having a different layer thickness, in particular, the active layer 102 can be obtained by a single crystal growth.

Subsequently, a diffraction grating (not shown), a current narrowing structure (not shown), an electrode (not shown), and the like are formed as necessary, and the substrate is cut out in one element formation region 105. Thus, an optical semiconductor device including the active layer 102 including a plurality of regions having different layer thicknesses, that is, an optical semiconductor device in which a plurality of elements are integrated is obtained.

[0009]

Here, in this method of manufacturing an optical semiconductor device, in practice, as shown in FIG. 6C, a plurality of insulating film masks are formed on a wafer 100a having a sufficient size. By using 110, a plurality of optical semiconductor devices are simultaneously formed.

However, in the selective growth step of the method for manufacturing an optical semiconductor device, in particular, when selective growth is performed with a large layer thickness ratio, that is, a ratio of a thick part to a thin part, the adjacent insulating film mask 110 is used. Since it is easily affected by the concentration distribution of the generated growth species, in order to obtain an optical semiconductor device having a desired layer thickness distribution, the interval between adjacent insulating film masks 110 is sufficiently wide, for example, 600
In this case, a plurality of insulating film masks 110 must be discretely arranged, and a substrate area required for forming one element is increased. Therefore, the number of elements obtained from one wafer is reduced. However, there is a problem that the production efficiency is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an optical semiconductor device having a semiconductor layer comprising a plurality of regions having different thicknesses can be obtained with high production efficiency. An object of the present invention is to provide a method for manufacturing a device.

[0012]

According to the present invention, there is provided a method of manufacturing an optical semiconductor device, comprising the steps of: preparing a semiconductor substrate; and forming, on the substrate, a plurality of regions having different widths on the bottom surface of which the substrate is exposed. Forming a mask made of an insulating film having a stripe-shaped opening, etching the substrate using the insulating film mask, and exposing the substrate by the etching step using the insulating film mask. And a step of growing a semiconductor crystal on a substrate.

In the method for manufacturing an optical semiconductor device, the etching step may be performed by etching capable of side etching.

In the method for manufacturing an optical semiconductor device, the insulating film mask may be formed by forming a groove provided along the stripe-shaped opening comprising the plurality of regions and exposing the surface of the substrate at the bottom surface. At least, the opening is provided at a position close to a region whose width is narrower than other regions.

In the method for manufacturing an optical semiconductor device, the groove is provided only at a position close to a region of the opening having a width smaller than other regions.

Further, in the method of manufacturing an optical semiconductor device according to the present invention, the etching step is performed by using the supply-controlled etching, and the height position of the semiconductor crystal layer formed in a step subsequent to the etching step is adjusted. Is performed so as to be the same as the height position of the substrate before being etched in the etching step.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a plan view (FIG. 1) for explaining a method of manufacturing an optical semiconductor device according to Embodiment 1 of the present invention.
(a)) and a cross-sectional view taken along line Ib-Ib in FIG. 1 (a) (FIG. 1 (b))
In the figure, reference numeral 10 denotes one element forming region of the optical semiconductor device, 1 denotes an n-type InP substrate, 3 denotes an n-type InP lower cladding layer, 4 denotes an active layer made of an undoped InGaAsP layer,
Reference numeral 5 denotes a p-type InP upper cladding layer, and reference numeral 2 denotes an insulating film mask made of an insulating film such as SiN or SiO ₂ provided with a stripe-shaped opening 20 formed of a plurality of regions having different widths on a center line passing through the center. The opening 20 of this insulating film mask 2
The substrate 1 is exposed inside. The opening 20 of the insulating film mask 2 includes a region 2a having the widest opening width, a portion 2b having the smallest opening width, and a wide region 2a and a narrowing portion 2a.
b, a region 2c whose opening width continuously changes from a wide region 2a to a narrow portion 2b, and the opening width in one element forming region 10 is increased. The length of the wide region 2a and the region 2c where the opening width is continuously changed in the direction along the direction in which the stripe of the opening 20 extends is about 400 μm and about 1 μm, respectively.
50 μm. Here, the planar shape on the opening 20 side of the region 2c where the opening width is changed is curved, but this is for forming a crystal growth layer with a layer thickness distribution suitable as a tapered waveguide. The shape may be another shape, for example, a linear shape, if necessary. The method for manufacturing an optical semiconductor device according to the first embodiment particularly shows a method for manufacturing an optical semiconductor device in which a semiconductor laser and a tapered waveguide are integrated, and the stripe shape of the insulating film mask 2 shown in FIG. In the opening 20 of
An active layer, which is an active layer of the optical semiconductor device, and a waveguide are formed.

FIG. 2 is a view for explaining main steps of a method for manufacturing a semiconductor device according to the first embodiment of the present invention.
FIGS. 2A and 2C are cross-sectional views taken along line IIa-IIa in FIG. 1A, and FIGS. 2B and 2D are cross-sectional views taken along line IIb-IIb in FIG. 1A. In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

Next, the manufacturing method will be described. First, I
An insulating film (not shown) such as SiO _{2 having a} thickness of about 100 nm is formed on the nP substrate 1, a resist (not shown) is formed on the insulating film, and the resist is patterned. As a mask, an insulating film mask 2 as shown in FIG. 1A is formed by selective etching using hydrofluoric acid or the like.

Subsequently, using the insulating film mask 2 as a selective etching mask, the substrate 1 is wet-etched using, for example, a sulfuric acid-based etchant or the like. At this time, the orientation in which the stripe-shaped openings 20 of the insulating film mask 2 extend is previously set to the reverse mesa direction, so that the cross-sectional shape of the etching is the reverse mesa shape as shown in FIGS. 2 (a) and 2 (b). Becomes During this etching, side etching is performed not only in the depth direction of the substrate 1 but also in the lateral direction. Therefore, the width of the opening 20 in the line IIa-IIa vicinity of the insulating film mask 2 and LG _1, LG ₂ the width of the etched bottom surface of this portion
When, with respect to the opening width LG _1, the width of the etched bottom surface L
G ₂ is increased by the amount of side etching. Similarly, the opening 2 near the IIb-IIb line of the insulating film mask 2
0 opening width 'and _1, the width of the etched bottom surface of this portion LG' LG When ₂ 'to _1, the width LG of etching the bottom surface' opening width LG ₂ is increased by the amount of side etching. Although the sulfuric acid-based wet etching is performed here, any etching may be performed as long as the side etching sufficiently occurs.

Subsequently, using the insulating film mask 2 as a selective growth mask, a vapor phase growth method, for example, MOCVD (Me
A semiconductor crystal layer, that is, an n-type InP lower cladding layer 101, an undoped InGaAsP active layer 102, and a p-type InP upper cladding layer 103 are sequentially and selectively grown by a tal-Organic Chemical Vapor Deposition method. At this time, since no semiconductor crystal nucleus is formed on the insulating film, the crystal is epitaxially grown selectively on the surface of the opening 20 of the insulating film mask 2 where the semiconductor substrate 1 is exposed.

Here, the crystal growth on the etched bottom surface having the width of LG ₂ is mainly performed by diffusing the growth gas species from the gas phase through the opening 20 of the insulating film mask 2 having the width of LG ₁ . Occurs. The thickness of the grown layer at the center of the etched bottom surface of this portion is d. Similarly, in the IIb-IIb section of the insulating film mask 2 where the opening width is narrow, crystal growth occurs on the semiconductor surface having the bottom surface of the width LG ′ ₂ through the gap of the width LG ′ ₁ . The thickness of the growth layer at the center of the etching bottom surface in this portion is d '.

In both cases, the crystal growth rate is considered to be dominated by the diffusion of the growth gas species in the gas phase due to the concentration gradient. Therefore, the supply amount of the gas species in the IIa-IIa line section and IIb-IIb line section is considered. Is proportional to the gap widths LG ₁ and LG ′ ₁ .
On the other hand, the growing area is LG ₂ , L
Since the growth rate is proportional to G ′ ₂ , the growth rate is inversely proportional to the growth area when the growth gas species is the same supply amount. Therefore grown layer thickness d, d 'are each LG ₁ / LG _2, LG' is proportional to ₁ / LG _'2. At this time, since the amount of side etching by wet etching is substantially constant regardless of the opening width of the insulating film mask, if LG ₁ is set to be sufficiently larger than LG ′ ₁ , 1 ≒ LG ₁ / LG ₂ > LG ′ ₁ / LG ′ ₂ , and the relationship between the layer thicknesses is d> d ′ (FIGS. 2C and 2D). Therefore, in the region 2a having a wide opening width, the thickness of each layer of the growth layer is smaller than the thickness of each layer of the growth layer in the region 2b having a small width, and in the region 2c whose width is continuously changing, As the width becomes smaller, the thickness of each layer of the growth layer is formed so that the thickness becomes smaller sequentially. As shown in FIG. 1 (b), the crystal growth layers having different thicknesses are formed by one crystal growth. In particular, an active layer 4 can be obtained. At the time of etching, as the ratio of the side etching width to the opening width increases, the ratio of the width of the etching bottom to the opening width of the insulating film mask increases, so that the effect of reducing the crystal growth rate increases. Is larger, the growth rate hardly changes even if the value of the opening width is changed, so that the crystal growth layer grown in the region with the smaller opening width and the crystal growth layer grown in the region with the larger opening width have in order to increase the layer thickness ratio is sufficiently wide opening width LG ₁ of a wide region, for example with an approximately 20μm approximately, less than a few μm about the opening width LG _'1 a narrow area width, preferably It is necessary that the thickness be 1 μm or less.

Subsequently, a diffraction grating (not shown), a current narrowing structure (not shown), an electrode (not shown), and the like are formed as necessary. By cutting out, an optical semiconductor device including an active layer including a plurality of regions having different layer thicknesses, that is, an optical semiconductor device in which a plurality of elements are integrated is obtained.

In this method for manufacturing an optical semiconductor device,
As in the conventional method of manufacturing an optical semiconductor device, it is possible to perform selective growth having a layer thickness distribution by a single crystal growth step, and to provide an optical semiconductor device having an active layer including a plurality of regions having different layer thicknesses. In order to obtain the layer thickness distribution, it is only necessary to change the opening width of the insulating film mask 2. As in the method of manufacturing an optical semiconductor device described in the related art, the growth gas in the gas phase is used. Since the kind of concentration distribution on the wafer surface is not required and is not easily affected by such a distribution, the width of the insulating film mask 2 itself can be made smaller than that of the conventional insulating film mask, and the width of the insulating film mask 2 can be reduced. By narrowing the arrangement interval between the insulating film masks 2, the insulating film masks 2 can be densely arranged on the wafer. For example, when one width separated by the opening of the insulating film mask 2 is set to about 200 μm which is almost the same as the conventional one,
The distance between the adjacent insulating film masks 2 may be twice as long as that, that is, about 400 μm or less. As a result, the degree of integration of the optical semiconductor device on the wafer in the manufacturing process can be improved, and the productivity can be improved.

As described above, according to the first embodiment of the present invention, the substrate 1 is provided with the stripe-shaped openings 20 formed of a plurality of regions having different widths at which the substrate 1 is exposed on the bottom surface. An insulating film mask 2 is formed, and using this,
After the substrate is wet-etched, the n-type InP lower cladding layer 3, the undoped InGaAsP active layer 4, and the p-type In
Since the P upper cladding layer 5 is sequentially crystal-grown, the thickness of the insulating layer mask 2 in the region where the opening width is wide can be made larger than the thickness of the growth layer in the region where the opening width is small. As a result, an optical semiconductor device having a layer thickness distribution can be obtained by one-time selective growth, the insulating film mask 2 can be arranged on the wafer at a high density, and the substrate area required for forming one element can be reduced. By reducing the size, the number of elements obtained from one wafer can be increased, and the production efficiency can be improved.

Embodiment 2 FIG. FIG. 3 is a plan view (FIG. 3 (a)) for explaining a method of manufacturing an optical semiconductor device according to the second embodiment of the present invention, and a cross-sectional view taken along line III-III of FIG. 3 (a). 3 (b) and (c)), in which the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and 6 denotes a surface provided on the insulating film mask 2 and the surface of the substrate 1 is exposed on the bottom surface. The width is about 1 μm, and the gap between the groove 6 and the opening 20 is about 1 μm. 5 μm.

In the steps shown in FIGS. 2C and 2D of the method for manufacturing an optical semiconductor device according to the first embodiment, the substrate 1 exposed by etching in the opening 20 of the insulating film mask 2 is formed. The supply of the growth gas species to the bottom surface is mainly by diffusion from the gas phase.
It is supplied by adsorbing on the surface and moving on the surface of the insulating film by surface migration. As described above, the amount of the growth gas species supplied by the migration depends on the insulating film mask 2.
Since the amount does not depend on the opening width of the insulating film mask 2, depending on the setting of the width of the insulating film mask 2 and the like, the layer thickness distribution between the regions having different opening widths of the opening 20 of the insulating film mask 2 due to such migration, that is, In some cases, the ratio between the maximum layer thickness and the minimum layer thickness is reduced.

On the other hand, in the method for manufacturing an optical semiconductor device according to the second embodiment, as shown in FIG.
An insulating film mask 2 having an opening 20 composed of a plurality of regions having different opening widths is provided, and minute portions along the sides of the opening 20 are formed in portions of the insulating film mask 2 close to the opening 20. Since the groove having the width is provided, after the etching is performed using the insulating film mask 2 (FIG. 3B), the insulating layer is formed when the semiconductor layer, for example, the n-type InP lower cladding layer 3 is selectively grown. Growing species diffused by surface migration on the film mask 2 can be trapped in the groove 6, thereby reducing the influence of the migration on the selective growth. In comparison with this, there is an effect that selective growth having a better layer thickness distribution can be performed.

Embodiment 3 FIG. 4 is a plan view showing main steps of a method for manufacturing an optical semiconductor device according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIG. A groove provided in the film mask 2 and exposing the surface of the substrate 1 on the bottom surface, and is parallel to the opening 20 side only in a region where the opening width of the insulating film mask 2 is smaller than other regions. The width and the distance from the opening 20 are the same as those of the groove 6 shown in FIG.

In the method of manufacturing an optical semiconductor device according to the third embodiment, an insulating film mask provided with a groove so as to be parallel along the entire side of the opening 20 as used in the second embodiment is used. Instead, selective etching and selective growth are performed using the insulating film mask 2 provided with the groove 7 only in a portion close to a region narrower than the other region of the width of the opening 20. The insulating film mask 2
In the selective growth using GaN, the supply of growth species by surface migration is limited only in a region narrower than the other region of the opening width. Is slowed down by the effect of the migration as compared with the region where the opening width is supplied, and as a result, there is an effect that the selective growth having a larger layer thickness distribution can be performed.

Embodiment 4 FIG. FIG. 5 is a plan view (FIG. 5A) for explaining a method of manufacturing a semiconductor device according to a fourth embodiment of the present invention, and a cross-sectional view taken along line VV of FIG.
(b), (c)), and in the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

In the fourth embodiment, in the step of etching the substrate using the insulating film mask of the first embodiment, the etching in the depth direction such as HCl gas etching is a rate-limiting etching, that is, an etchant. The etching is performed such that the reaction speed between the substrate 1 and the substrate 1 is sufficiently high, and the etching speed changes mainly depending on the rate of supply of the etchant. By performing etching using the same insulating film mask 2 as in Embodiment 1, the etching depth can be increased where the opening width is large and the etching depth can be decreased where the opening width is small.
The distribution of the etching depth can be obtained (FIG. 5B).
Therefore, when the distribution of the etching depth is made to substantially match the distribution of the growth layer thickness in the next step, the selective growth, the height position of the growth layer surface after the selective growth is adjusted to the original surface of the substrate 1. It is possible to match the height position (FIG. 5 (c)). Accordingly, the surface of the growth layer becomes flat, so that mask formation and the like can be easily performed in a subsequent processing step, high-precision processing can be easily performed, and an optical semiconductor device having excellent characteristics can be obtained at a high yield. There is an effect that can be obtained.

In the first to fourth embodiments, a method of manufacturing an optical semiconductor device in which a tapered waveguide and a semiconductor laser are integrated has been described. However, the present invention relates to, for example, an optical modulator and a semiconductor laser. The present invention can also be applied to an optical semiconductor device in which another optical semiconductor element such as an integrated optical semiconductor device is integrated. In such a case, the same effects as those of the first to fourth embodiments can be obtained.

In the first to fourth embodiments,
Although the present invention has been described using an InP-based optical semiconductor device, the present invention is also applicable to other material-based optical semiconductor devices. In such a case, the first to fourth embodiments are also applicable.
It has the same effect as.

[0036]

As described above, according to the present invention, a step of preparing a semiconductor substrate and a step of forming a stripe-shaped opening formed on the substrate at a bottom surface thereof by exposing the substrate to a plurality of regions having different widths. Forming a mask made of an insulating film having a portion, etching the substrate using the insulating film mask, and forming a semiconductor crystal on the substrate exposed by the etching step using the insulating film mask. And a step of growing a crystal of the insulating film mask, the thickness of the growth layer in the region where the opening width of the insulating film mask is wide can be made larger than the thickness of the growth layer in the region where the opening width is small, and An optical semiconductor device having a layer thickness distribution can be obtained by one-time selective growth, an insulating film mask can be arranged on a wafer at a high density, and a substrate area required for forming one element can be reduced. To, increasing the number of elements obtained from one wafer, there is an advantage that it is possible to improve production efficiency.

Further, according to the present invention, since the above-mentioned etching step is performed by etching capable of side etching, the substrate area required for forming one element is reduced, and the production efficiency is improved. The effect that it can be obtained is obtained.

Further, according to the present invention, the insulating film mask is formed by forming at least the groove portion provided along the stripe-shaped opening formed of the plurality of regions and exposing the surface of the substrate at the bottom surface. Since the opening is provided at a position closer to a region whose width is narrower than other regions, the supply of growth species by migration during selective growth is restricted, and a better layer thickness distribution is obtained. There is an effect that selective growth can be performed.

Further, according to the present invention, the groove is provided only at a position close to a region of the opening having a width smaller than that of the other region. There is an effect that it is possible to restrict the supply of the growth species by migration to the region where the width of the portion is small, and to perform selective growth having a large layer thickness distribution.

Further, according to the present invention, the etching step is performed by using the supply-limiting etching, and the height position of the semiconductor crystal layer formed in the subsequent step of the etching step is changed by the etching step. Since the height of the substrate before the etching is set to be the same as that of the substrate, the height of the crystal growth layer after the selective growth and the substrate can be aligned and the substrate surface can be flattened. Has the effect that the manufacturing process can be performed accurately.

[Brief description of the drawings]

FIG. 1 is a process chart showing a method for manufacturing an optical semiconductor device according to Embodiment 1 of the present invention.

FIG. 2 is a process chart showing main steps of a method for manufacturing the optical semiconductor device according to the first embodiment of the present invention.

FIG. 3 is a process chart showing a method for manufacturing an optical semiconductor device according to a second embodiment of the present invention.

FIG. 4 is a process chart showing main steps of a method for manufacturing an optical semiconductor device according to Embodiment 3 of the present invention.

FIG. 5 is a process chart showing a method for manufacturing an optical semiconductor device according to Embodiment 4 of the present invention.

FIG. 6 is a process chart showing a conventional method for manufacturing an optical semiconductor device.

[Explanation of symbols]

1,100 n-type InP substrate, 2,110 insulating film mask, 2a, 110a wide area, 2b, 110b narrow area, 2c, 110c continuously changing area, 3,101 n-type InP lower cladding layer, 4,1
02 InGaAsP active layer, 5,103 p-type InP
Upper cladding layer, 6,7 groove, 10,105 1 element formation region, 20 opening, 100a wafer.

Claims (5)

[Claims] 1. A step of preparing a semiconductor substrate, and forming a mask made of an insulating film having a stripe-shaped opening composed of a plurality of regions having different widths on the bottom surface of the substrate, the substrate being exposed on the substrate. Performing the step of: etching the substrate using the insulating film mask; and growing a semiconductor crystal on the substrate exposed by the etching step using the insulating film mask. A method for manufacturing an optical semiconductor device. 2. The method for manufacturing an optical semiconductor device according to claim 1, wherein the etching step is performed by etching capable of side etching. 3. The method of manufacturing an optical semiconductor device according to claim 1, wherein the insulating film mask is provided along a stripe-shaped opening made up of the plurality of regions, and a bottom surface of the substrate is exposed. A method of manufacturing an optical semiconductor device, comprising: forming a groove at a position close to at least a region of the opening having a width smaller than that of another region. 4. The method of manufacturing an optical semiconductor device according to claim 3, wherein the groove is provided only at a position in the opening close to a region where the width of the opening is smaller than another region. Of manufacturing an optical semiconductor device. 5. The method for manufacturing an optical semiconductor device according to claim 1, wherein the etching step is performed using a supply-limited etching, and the semiconductor crystal layer formed in a step subsequent to the etching step is formed. A method of manufacturing an optical semiconductor device, wherein the height position is set to be the same as the height position of a substrate before being etched in the etching step.