JP2010098070A - Edge light emitting semiconductor laser element and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an edge light emitting semiconductor laser element having a configuration and a structure capable of surely suppressing the generation of ripples in a laser beam. <P>SOLUTION: The edge light emitting semiconductor laser element includes: (A) a base layer 112 comprising a compound semiconductor layer including In (indium); and (B) a light emitting part 20 comprising a laminated structure formed by successively laminating an n-type compound semiconductor layer 21, an active layer 23 and a p-type compound semiconductor layer 22 on the base layer 112. In the base layer 112, In is segregated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an edge-emitting semiconductor laser device and a method for manufacturing the same.

For example,
(A) substrate,
(B) an underlayer composed of a compound semiconductor layer formed on the substrate, and
(C) a light-emitting unit composed of a stacked structure in which an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on a base layer;
An edge-emitting semiconductor laser device including the above is well known. Incidentally, in the edge-emitting semiconductor laser element having such a structure, ripples are often observed in the laser light emitted from the end face. That is, in the light intensity distribution of the laser light emitted from the end face, a small peak is often recognized in the vicinity of the maximum light intensity peak. The occurrence of ripple in such laser light is generated in the active layer, and the laser light that has reached the interface (in the mirror surface state) between the n-type compound semiconductor layer and the underlayer via the n-type compound semiconductor layer. This is caused by being reflected at the interface or totally reflected, returned to the active layer through the n-type compound semiconductor layer, and interfering with the laser beam generated in the active layer. The occurrence of such ripple adversely affects, for example, FFP (Far Field Pattern) characteristics.

JP 2001-267245 A JP 2002-280611 A JP 2001-094216 A

  As measures for suppressing the occurrence of such ripples, it is conceivable to increase the thickness of the n-type compound semiconductor layer and to lower the refractive index of the n-type compound semiconductor layer. However, these measures reduce the design freedom of the edge emitting semiconductor laser element. Further, the n-type compound semiconductor layer has a problem that crystal defects such as cracks and dislocations are likely to occur.

  Techniques for providing uneven portions on the surface of the underlayer are well known from, for example, Japanese Patent Application Laid-Open Nos. 2001-267245, 2002-280611, and 2001-094216. However, the technique disclosed in Japanese Patent Laid-Open No. 2001-267245 exclusively improves the crystallinity of an n-type compound semiconductor layer grown on a base layer. In addition, the technique disclosed in Japanese Patent Laid-Open No. 2002-280611 exclusively aims at light extraction efficiency from the light emitting element. The technique disclosed in Japanese Patent Laid-Open No. 2001-094216 is also intended to select an appropriate orientation from among a plurality of crystal orientations and arrange an element region. And the technique disclosed in any patent publication is not a technique for suppressing the occurrence of ripples.

  Accordingly, it is an object of the present invention to provide an edge-emitting semiconductor laser device having a configuration and structure that can reliably suppress the occurrence of ripples in laser light, and a method for manufacturing such an edge-emitting semiconductor laser device. .

In order to achieve the above object, an edge-emitting semiconductor laser device according to the first aspect of the present invention includes:
(A) an underlayer composed of a compound semiconductor layer containing In (indium), and
(B) a light-emitting unit composed of a stacked structure in which an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on a base layer;
With
In (indium) is segregated in the underlayer.

  In the edge-emitting semiconductor laser device according to the first aspect of the present invention, the laser light generated in the active layer and incident on the underlayer via the n-type compound semiconductor layer is scattered in the underlayer, Or it can be made into the form by which interference between the laser beam which is absorbed or is scattered and absorbed, and is radiate | emitted from an end surface is suppressed.

In order to achieve the above object, an edge-emitting semiconductor laser device according to the second aspect of the present invention includes:
(A) An underlayer comprising a compound semiconductor layer, having a recess, or a protrusion, or a combination of a recess and a protrusion, and
(B) a light-emitting unit composed of a stacked structure in which an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on a base layer;
With
The laser light generated in the active layer and having reached the interface between the n-type compound semiconductor layer and the base layer via the n-type compound semiconductor layer is a concave portion of the base layer, or a convex portion, or a concave portion and a convex portion. Scattered or absorbed in the combination, or scattered and absorbed, so that interference with the laser light emitted from the end face is suppressed.

In order to achieve the above object, an edge-emitting semiconductor laser device according to the third aspect of the present invention includes:
(A) A substrate provided with a concave portion or a convex portion, or a combination of a concave portion and a convex portion on the surface, and
(B) a light-emitting unit composed of a stacked structure in which an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on a substrate;
With
The laser light generated in the active layer and reaching the substrate surface via the n-type compound semiconductor layer is scattered in the concave portion of the substrate surface, or the convex portion, or the combination of the concave portion and the convex portion. Interference with the laser beam emitted from is suppressed.

In order to achieve the above object, an edge-emitting semiconductor laser device according to the fourth aspect of the present invention includes:
(A) a base layer composed of a compound semiconductor layer containing In (indium), a base layer composed of an n-type compound semiconductor layer, and
(B) a light-emitting unit composed of a stacked structure in which an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on a base layer;
With
A cavity is formed inside the underlayer,
The laser light generated in the active layer and incident on the underlayer through the n-type compound semiconductor layer and the base layer is scattered in the cavity inside the underlayer, and thus interferes with the laser light emitted from the end surface. Is suppressed.

The method for manufacturing an edge-emitting semiconductor laser device according to the first aspect of the present invention for achieving the above object is a method for manufacturing the edge-emitting semiconductor laser device according to the first aspect of the present invention,
(A) forming a base layer made of a compound semiconductor layer containing In (indium) on a substrate;
(B) An n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on the base layer to obtain a light-emitting portion configured from a stacked structure.
With each process,
A step of applying energy to the underlayer to segregate In (indium) is provided.

  In the method for manufacturing an edge-emitting semiconductor laser device according to the first aspect of the present invention, energy is applied to the underlayer by irradiating an electron beam between the step (a) and the step (b). Or, alternatively, the base layer (or the whole) is heated between the steps (a) and (b) to give energy to the base layer, Or after the said process (b), it can be set as the form which gives energy to a base layer by heating a base layer (or the whole).

The method for manufacturing an edge-emitting semiconductor laser device according to the second aspect of the present invention for achieving the above object is a method for manufacturing the edge-emitting semiconductor laser device according to the second aspect of the present invention,
(A) On the substrate, a base layer made of a compound semiconductor layer having a concave portion, a convex portion, or a combination of the concave portion and the convex portion is formed;
(B) An n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on the base layer to obtain a light-emitting portion configured from a stacked structure.
It has each process,
The laser light generated in the active layer and having reached the interface between the n-type compound semiconductor layer and the base layer via the n-type compound semiconductor layer is a concave portion of the base layer, or a convex portion, or a concave portion and a convex portion. Scattered or absorbed in the combination, or scattered and absorbed, so that interference with the laser light emitted from the end face is suppressed.

  In the manufacturing method of the edge-emitting type semiconductor laser device according to the second aspect of the present invention, in the step (a), after forming the base layer on the substrate, the surface of the base layer is etched to form the concave portion. Alternatively, a base layer having a convex portion or a combination of a concave portion and a convex portion (hereinafter, these may be collectively referred to as “a concave portion and / or a convex portion”) may be obtained. Alternatively, in the step (a), by forming a mask layer for selective growth on the substrate and then forming a foundation layer, a foundation layer having recesses and / or projections (specifically, recesses, Or it can be set as the form which obtains a convex part or a foundation layer which has a combination of a crevice and a convex part. In some cases, it is also possible to obtain an underlayer having a convex portion simply by crystal growth of the underlayer on the substrate. Alternatively, in the step (a), after the first underlayer is formed on the substrate, the selective growth mask layer is formed on the first underlayer, and then the second underlayer is formed. A base layer having a two-layer structure of a first base layer and a second base layer and having a concave portion and / or a convex portion (specifically, a lower portion having a concave portion or a convex portion, or a combination of a concave portion and a convex portion. Formation).

The method for manufacturing an edge-emitting semiconductor laser device according to the third aspect of the present invention for achieving the above object is a method for manufacturing the edge-emitting semiconductor laser device according to the third aspect of the present invention,
(A) After providing a concave portion, a convex portion, or a combination of a concave portion and a convex portion on the surface of the substrate,
(B) On the substrate, an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked to obtain a light emitting unit configured from a stacked structure.
It has each process,
The laser light generated in the active layer and reaching the substrate surface via the n-type compound semiconductor layer is scattered in the concave portion of the substrate surface, or the convex portion, or the combination of the concave portion and the convex portion. Interference with the laser beam emitted from is suppressed.

  In the method for manufacturing an edge-emitting semiconductor laser device according to the third aspect of the present invention, in the step (a), the substrate surface is etched to provide a recess and / or a protrusion on the surface of the substrate. It is possible to adopt a form (specifically, a form in which a concave part, a convex part, or a combination of a concave part and a convex part is provided).

The method for manufacturing an edge-emitting semiconductor laser device according to the fourth aspect of the present invention for achieving the above object is a method for manufacturing the edge-emitting semiconductor laser device according to the fourth aspect of the present invention,
(A) After forming a base layer made of a compound semiconductor layer containing In (indium) and a base layer made of an n-type compound semiconductor layer on a substrate,
(B) A cavity is formed inside the underlayer by heating in a hydrogen gas atmosphere, an ammonia gas atmosphere, or a hydrogen gas and ammonia gas atmosphere,
(C) On the base layer, an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked to obtain a light-emitting portion configured from a stacked structure.
It has each process,
The laser light generated in the active layer and incident on the underlayer through the n-type compound semiconductor layer and the base layer is scattered in the cavity inside the underlayer, and thus interferes with the laser light emitted from the end surface. Is suppressed.

  The edge-emitting semiconductor laser device according to the first aspect of the present invention including the above preferred embodiment or a method for manufacturing the same, the edge-emitting semiconductor laser device according to the second aspect of the present invention or the method for manufacturing the same, In the edge-emitting semiconductor laser device or the manufacturing method thereof according to the third aspect, or the edge-emitting semiconductor laser device or the manufacturing method thereof according to the fourth aspect of the present invention, the maximum in the light intensity distribution of the laser light emitted from the end surface It is desirable that the light intensity peak (the center of the light field at the end face) be located in the n-type compound semiconductor layer. In order to realize such a configuration, for example, the thickness of the n-type compound semiconductor layer and the thickness of the p-type compound semiconductor layer are optimized (specifically, the thickness of the p-type compound semiconductor layer is set to n It is only necessary to optimize the composition of the n-type compound semiconductor layer and the composition of the p-type compound semiconductor layer. In general, the loss of light is greater in the p-type compound semiconductor layer than in the n-type compound semiconductor layer. Moreover, it is large in the active layer containing In. Therefore, by setting the maximum light intensity peak in the light intensity distribution of the laser light emitted from the end face at the end face of the n-type compound semiconductor layer, the loss of the laser light generated in the active layer in the compound semiconductor layer is reduced. It is possible to improve resistance to instantaneous optical damage (COD: Catastrophic Optical Damage). In addition, since the p-type compound semiconductor layer usually has higher resistance than the n-type compound semiconductor layer, the p-type compound semiconductor layer can be formed by reducing the thickness of the p-type compound semiconductor layer to be smaller than the thickness of the n-type compound semiconductor layer. Heat generation in the semiconductor layer can be suppressed, and low voltage driving and low heat generation of the edge-emitting semiconductor laser element can be achieved. As a result of the above, it becomes possible to provide a high-power edge-emitting semiconductor laser device. In addition, for example, it becomes possible to reduce the content of Al (aluminum) in the n-type compound semiconductor layer, and the distortion of the entire light emitting portion can be reduced. As a result, the lifetime of the edge-emitting semiconductor laser device can be extended. Can be achieved.

  The edge-emitting semiconductor laser device according to the first aspect of the present invention including the above-described preferred embodiment or the method for manufacturing the same may be hereinafter simply referred to as “first aspect of the present invention”. In addition, the edge-emitting semiconductor laser device according to the second aspect of the present invention including the above-described preferred embodiment or the manufacturing method thereof may be simply referred to simply as “the second aspect of the present invention” hereinafter. is there. Further, the edge-emitting semiconductor laser device according to the third aspect of the present invention including the above-described preferred embodiment or the method for manufacturing the same will hereinafter be collectively referred to simply as “the third aspect of the present invention”. There is. In addition, the edge-emitting semiconductor laser device according to the fourth aspect of the present invention including the preferred embodiment or the method for manufacturing the same may be simply referred to simply as “fourth aspect of the present invention” hereinafter. is there. Furthermore, a combination of a concave portion and a convex portion may be referred to as an “uneven portion”.

  The first aspect of the present invention including the above preferred forms and configurations, the second aspect of the present invention, the third aspect of the present invention, or the fourth aspect of the present invention (hereinafter collectively referred to as " The structure and structure of the light emitting portion and the laminated structure can be a known structure and structure, and there is no particular limitation or limitation.

  In the present invention, the edge-emitting semiconductor laser device is first provided on a substrate, but as a final form of the edge-emitting semiconductor laser device, a form formed on the substrate and a form in which the substrate is removed. Can be mentioned. The edge-emitting semiconductor laser element may be mounted (mounted) by a junction-up method or may be mounted (mounted) by a junction-down method. As a method for removing the substrate, a method of removing the substrate by etching after supporting the light emitting portion of the edge-emitting semiconductor laser element with an appropriate support member, a method of removing by polishing, and a combination of etching and polishing are used. And a method of peeling the underlayer from the substrate by causing laser abrasion by irradiating the substrate with laser light from the back surface.

As a substrate in the first aspect of the present invention, the second aspect of the present invention, or the fourth aspect of the present invention, a GaAs substrate, GaP substrate, AlN substrate, AlP substrate, InN substrate, InP substrate, GaN substrate, AlGaInN substrate , AlGaN substrate, AlInN substrate, GaInN substrate, AlGaInP substrate, AlGaP substrate, AlInP substrate, GaInP substrate, ZnS substrate, sapphire substrate, SiC substrate, alumina substrate, ZnO substrate, LiMgO substrate, LiGaO ₂ substrate, MgAl ₂ O ₄ substrate, Examples thereof include a Si substrate, a Ge substrate, and a substrate in which a buffer layer is formed on the surface (main surface) of these substrates.

In the third aspect of the present invention, as a substrate, a GaAs substrate, a GaP substrate, an AlN substrate, an AlP substrate, an InN substrate, an InP substrate, a GaN substrate, an AlGaInN substrate, an AlGaN substrate, an AlInN substrate, a GaInN substrate, an AlGaInP substrate, AlGaP substrate, AlInP substrate, GaInP substrate, ZnS substrate, sapphire substrate, SiC substrate, alumina substrate, ZnO substrate, LiMgO substrate, LiGaO ₂ substrate, MgAl ₂ O ₄ substrate, Si substrate, Ge substrate, surfaces of these substrates (mainly And a surface having a buffer layer formed thereon.

  In the present invention, the compound semiconductor constituting the n-type compound semiconductor layer, the active layer, and the p-type compound semiconductor layer is a BAlGaInN-based compound semiconductor (any combination of binary, ternary, quaternary, and quinary mixed crystals. May also be exemplified. Examples of n-type impurities added to the compound semiconductor layer include silicon (Si), selenium (Se), germanium (Ge), tin (Sn), carbon (C), titanium (Ti), and oxygen (O). Examples of the p-type impurity include zinc (Zn), magnesium (Mg), beryllium (Be), cadmium (Cd), calcium (Ca), and barium (Ba). The active layer may be composed of a single compound semiconductor layer, or may have a single quantum well structure [QW structure] or a multiple quantum well structure [MQW structure]. As a method for forming various compound semiconductor layers including an underlayer and an active layer (crystal growth method, film formation method), metal organic chemical vapor deposition (MOCVD method, MOVPE method) or metal organic molecular beam epitaxy method (MOMBE method) ), Molecular beam epitaxy (MBE), and hydride vapor phase epitaxy (HVPE) in which halogen contributes to transport or reaction.

  The type of compound semiconductor to be used as the compound semiconductor constituting the underlayer is determined as appropriate based on the material constituting the substrate, the compound semiconductor constituting the n-type compound semiconductor layer, the active layer, and the p-type compound semiconductor layer. do it. Specifically, in the first aspect of the present invention, examples of the compound semiconductor layer containing In constituting the base layer include BInN, BAlInN, BGaInN, BAlGaInN, AlInN, AlGaInN, and GaInN. In the second aspect of the present invention, BN, BAlN, BGaN, BInN, BAlGaN, BAlInN, BGaInN, BAlGaInN, AlN, AlGaN, AlInN, AlGaInN, GaN, GaInN, and InN are used as the compound semiconductor layers constituting the base layer. Can be mentioned. Furthermore, examples of the compound semiconductor layer constituting the first underlayer include BN, BAlN, BGaN, BInN, BAlGaN, BAlInN, BGaInN, BAlGaInN, AlN, AlGaN, AlInN, AlGaInN, GaN, GaInN, and InN. Similarly, examples of the compound semiconductor layer constituting the second underlayer include BN, BAlN, BGaN, BInN, BAlGaN, BAlInN, BGaInN, BAlGaInN, AlN, AlGaN, AlInN, AlGaInN, GaN, GaInN, and InN. Furthermore, in the fourth aspect of the present invention, BInN, BAlInN, BGaInN, BAlGaInN, AlInN, AlGaInN, and GaInN can be given as examples of the compound semiconductor layer containing In constituting the base layer.

In the first embodiment of the present invention, In is segregated by applying energy to the underlayer. For example, an electron beam having an energy of 1 × 10 ⁵ eV to 4 × 10 ⁵ eV is irradiated at 35 A / cm ² or more. The underlayer may be irradiated in an amount. Alternatively, for example, heating may be performed at 750 ° C. to 1000 ° C. for 5 minutes to 1 hour in a nitrogen gas atmosphere of 1 atm.

In the third aspect of the present invention, the material constituting the selective growth mask layer is a semiconductor oxide layer or semiconductor nitride layer such as SiO ₂ , SiN, or SiON, a refractory metal layer, a refractory metal oxide layer, a high A melting point metal nitride layer can be exemplified. In addition, as a method for forming the mask layer for selective growth, a combination of physical vapor deposition (PVD) such as sputtering, chemical vapor deposition (CVD), and patterning by lithography and etching techniques is used. Can be mentioned. The selective growth mask layer may be left as it is or may be removed. The removal of the selective growth mask layer may employ a wet etching method or a dry etching method depending on the material constituting the selective growth mask layer.

  In the fourth aspect of the present invention, the underlayer is heated to form a cavity. For example, in a hydrogen gas atmosphere of 1 atm or lower pressure, or in an ammonia gas atmosphere, or in hydrogen gas and ammonia gas Heating may be performed at 750 ° C. to 1200 ° C. for 5 minutes to 1 hour in an atmosphere.

  As the shape and form of the concave portion and / or convex portion provided in the base layer in the second aspect of the present invention, specifically, a convex portion protruding from the surface of the base layer, a concave portion recessed from the surface of the base layer, The uneven | corrugated | grooved part provided in the surface of the base layer can be mentioned. Here, when the concavo-convex portion is provided, the concave portion and the convex portion may be continuous or discontinuous. As a cross-sectional shape of a continuous convex part or concave part when the base layer is cut in a virtual plane perpendicular to the base layer, a triangle; an arbitrary quadrangle including a square, a rectangle, a trapezoid; an arbitrary polygon; an arbitrary including a circle, etc. A smooth curve can be illustrated. Alternatively, when the structure is a discontinuous convex portion and / or a concave portion, as a discontinuous convex shape or concave shape, a pyramid, a cone, a truncated pyramid, a truncated cone, a cylinder, a triangular prism, or a quadrangular prism is used. Examples include various smooth curved surfaces such as a polygonal column and a part of a sphere. The height, depth, pitch, and shape of the recesses and / or projections may be constant or may vary, but the arrangement, arrangement, depth, pitch, shape, etc. of the recesses and / or projections The absence of regularity is desirable from the viewpoint of laser light scattering. In addition, there is no essential limitation on the depth, pitch, shape, etc. of the recesses and / or projections, but from the standpoint of laser light scattering, when the wavelength of the laser beam is λ, the recesses and / or projections It is desirable that the depth, pitch, or shape of each is λ / 2 or more.

  As the shape and form of the recesses and / or protrusions provided on the substrate surface in the third aspect of the present invention, specifically, the protrusions protruding from the substrate surface, the recesses recessed from the substrate surface, provided on the substrate surface The uneven | corrugated | grooved part produced can be mentioned. Here, when the concavo-convex portion is provided, the concave portion and the convex portion may be continuous or discontinuous. As a cross-sectional shape of continuous convex portions or concave portions when the substrate is cut in a virtual plane perpendicular to the substrate, any quadrangle including a triangle, square, rectangle, trapezoid; any polygon; any smooth including a circle, etc. A curve can be illustrated. Alternatively, when the structure is a discontinuous convex portion and / or a concave portion, as a discontinuous convex shape or concave shape, a pyramid, a cone, a truncated pyramid, a truncated cone, a cylinder, a triangular prism, or a quadrangular prism is used. Examples include various smooth curved surfaces such as a polygonal column and a part of a sphere. The height, depth, pitch, and shape of the recesses and / or projections may be constant or may vary, but the arrangement, arrangement, depth, pitch, shape, etc. of the recesses and / or projections The absence of regularity is desirable from the viewpoint of laser light scattering. Further, although there is no essential limitation on the depth, pitch, shape, etc. of the concave and / or convex portions, from the viewpoint of scattering of laser light, the depth, pitch, or shape of the concave and / or convex portions is λ / 2 or more is desirable.

  In the present invention, the light emitting part is provided on the main surface side of the substrate. The first electrode (n-side electrode) is provided on the back surface of the substrate opposite to the main surface, and the second electrode (p-side electrode) is provided on the top surface of the light emitting part. Can do. Alternatively, a part of the n-type compound semiconductor layer and the n-side contact layer is exposed, and a first electrode (n-side electrode) is provided on the exposed portion of the n-type compound semiconductor layer and the n-side contact layer, and light emission It can be set as the structure by which the 2nd electrode (p side electrode) is provided in the top surface of the part.

  Here, examples of the material constituting the second electrode (p-side electrode) include Pd, but are not limited thereto. Moreover, as a 1st electrode (n side electrode), the laminated structure of Ti layer / Pt layer / Au layer can be mentioned, for example. The thicknesses of the Ti layer, the Pt layer, and the Au layer are, for example, 15 nm, 50 nm, and 300 nm, respectively, but are not limited thereto.

  In addition, for the extended portions of the first electrode and the second electrode, for example, [adhesive layer (Ti layer, Cr layer, etc.)] / [Barrier metal] such as Ti layer / Pt layer / Au layer, etc. Layer (Pt layer, Ni layer, TiW layer, Mo layer, etc.) / [Contact part (pad) composed of a multilayer metal layer having a laminated structure such as a metal layer (for example, Au layer) that is compatible with mounting. Part) may be provided. The first electrode including the extended portion, the second electrode including the extended portion, and the contact portion (pad portion) are, for example, various PVD methods such as vacuum deposition and sputtering, and various chemical vapor deposition methods ( (CVD method) and plating method.

  Most of the laser light generated in the active layer is emitted from the end face of the light emitting portion to the outside, but part of the laser light is incident on the base layer or the substrate via the n-type compound semiconductor layer. In the present invention, In is segregated in the underlayer, or the underlayer has a recess and / or a protrusion, or the substrate surface is provided with a recess and / or a protrusion. Alternatively, a cavity is formed inside the underlayer. Therefore, the laser light that reaches the base layer or the substrate is not totally reflected, but is scattered or absorbed in the base layer in which In is segregated, or is scattered (or irregularly reflected) at the concave portion and / or the convex portion. Alternatively, it is scattered in the cavity inside the underlayer, and the traveling direction becomes random. Therefore, the amount of laser light returning to the active layer is reduced, and interference with the laser light emitted from the end face is suppressed. As a result, ripples in the FFP can be reliably prevented, and a high performance edge-emitting semiconductor laser device can be provided. In addition, the design freedom of the edge-emitting semiconductor laser element does not decrease, and there is no problem that crystal defects such as cracks and dislocations are likely to occur in the n-type compound semiconductor layer.

  Here, in the first aspect of the present invention, the portion of the underlayer in which In is segregated has a higher absorption coefficient than other portions and absorbs a lot of laser light. Therefore, in the laser light generated in the active layer and incident on the underlayer through the n-type compound semiconductor layer, the reflection state in the portion of the underlayer where In is segregated and the reflection in the other portion. Due to the different state, it is scattered in the underlayer.

  In the fourth aspect of the present invention, the underlayer is made of a compound semiconductor layer containing In. A cavity is formed inside the base layer, and the cavity can be formed by evaporating In by heating the base layer. The cavity portion has a lower refractive index than other underlying layer portions. Therefore, the laser light generated in the active layer and incident on the base layer via the n-type compound semiconductor layer and the base layer is scattered in a cavity having a lower refractive index than other portions.

  Hereinafter, the present invention will be described based on examples with reference to the drawings.

  Example 1 is an edge-emitting semiconductor laser device according to the first aspect of the present invention (hereinafter abbreviated as “semiconductor laser element”), and a method for manufacturing the semiconductor laser element according to the first aspect of the present invention. About. A schematic partial cross-sectional view of the semiconductor laser device of Example 1 is shown in FIG.

The semiconductor laser device of Example 1 is
(A) an underlayer 112 made of a compound semiconductor layer containing In (indium), and
(B) The light emitting unit 20 configured by a stacked structure in which the n-type compound semiconductor layer 21, the active layer 23, and the p-type compound semiconductor layer 22 are sequentially stacked on the base layer 112,
It has.

In Example 1, specifically, the substrate 110 is made of an n-type GaN substrate, and the compound semiconductor layer containing In constituting the base layer 112 is made of In _x Ga _(1-x) N (however, x ≦ 1), the n-type compound semiconductor layer 21 is composed of an n-type cladding layer 21A and an n-type guide layer 21B from the bottom, the active layer 23 has a multiple quantum well structure [MQW structure], and a p-type compound semiconductor The layer 22 includes a p-type guide layer 22B and a p-type cladding layer 22A from the bottom. The underlayer 112 is formed on the substrate 110.

  In the indium layer 112, In (indium) is segregated at random. In the semiconductor laser device of Example 1, laser light generated in the active layer 23 and incident on the base layer 112 via the n-type compound semiconductor layer 21 is randomly scattered and / or absorbed in the base layer 112. Therefore, interference with the laser beam emitted from the end face is suppressed. More specifically, a portion 112A of the base layer 112 in which In is segregated (in FIG. 1A, schematically shown by a dotted white outline ellipse) The refractive index is higher than that of the portion 112B. Therefore, in the laser light generated in the active layer 23 and incident on the base layer 112 via the n-type compound semiconductor layer 21, the laser light that has passed through the base layer portion 112A in which In is segregated. Changes in the direction of travel. Therefore, such laser light is randomly scattered in the base layer 112.

  A method for manufacturing the semiconductor laser device of Example 1 will be described below.

In the following examples, when various compound semiconductor layers are grown by MOCVD, for example, ammonia gas is used as a nitrogen source, and trimethyl gallium (TMG) gas or triethyl gallium (TEG) gas is used as a gallium source. Using trimethylaluminum (TMA) gas as the aluminum source, using trimethylindium (TMI) gas as the In source, using monosilane gas (SiH ₄ gas) as the silicon source, and using cyclopentadienylmagnesium gas as the Mg source Good.

[Step-100]
A base layer 112 made of a compound semiconductor layer containing In is formed on the substrate 110. Specifically, first, a substrate 110 made of an n-type GaN substrate having a C-plane as a main surface is carried into an MOCVD apparatus, and substrate cleaning is performed in a carrier gas made of hydrogen. Thereafter, the substrate temperature is lowered, and the buffer layer 111 made of low-temperature GaN is crystal-grown on the substrate 110 based on the MOCVD method. Next, a base layer 112 made of an undoped or n-type In _x Ga _(1-x) N layer having a thickness of 0.2 μm or more is grown on the buffer layer 111.

[Step-110]
In Example 1, energy is given to the base layer 112 by irradiating an electron beam thereafter, and In is segregated. Specifically, the substrate 110 is unloaded from the MOCVD apparatus and loaded into the electron beam irradiation apparatus. Then, the base layer 112 is irradiated with an electron beam having an energy of 1 × 10 ⁵ eV or more at an irradiation dose of 35 A / cm ² or more. As a result, In (indium) is segregated in the base layer 112.

[Step-120]
Thereafter, the n-type compound semiconductor layer 21, the active layer 23, and the p-type compound semiconductor layer 22 are sequentially stacked on the base layer 112 to obtain the light emitting unit 20 configured by a stacked structure. Specifically, the substrate is unloaded from the electron beam irradiation apparatus and loaded into the MOCVD apparatus again. Then, an n-side contact layer 24 made of Si-doped GaN (GaN: Si) is crystal-grown, and subsequently, an n-type cladding layer 21A made of an n-type AlGaN layer and silicon (Si) as an n-type impurity are added. The n-type compound semiconductor layer 21 can be obtained by sequentially growing the n-type guide layer 21B made of the n-type GaN layer. Thereafter, an active layer 23 having a multiple quantum well structure composed of a well layer made of In _0.2 Ga _0.8 N and a barrier layer made of GaN is crystal-grown on the n-type compound semiconductor layer 21. Here, the emission wavelength λ is 520 nm. Thereafter, a p-type guide layer 22B made of p-type GaN doped with magnesium (Mg) as a p-type impurity and a p-type AlGaN layer doped with magnesium (Mg) as a p-type impurity on the active layer 23. The p-type cladding layer 22A is sequentially crystallized to obtain the p-type compound semiconductor layer 22, and then the p-side contact layer 25 made of a p-type GaN layer to which magnesium (Mg) is added as a p-type impurity is formed. Crystal growth.

[Step-130]
After crystal growth is completed in this way, annealing is performed at 800 ° C. for about 10 minutes in a nitrogen gas atmosphere to activate the p-type impurity (p-type dopant). Thereafter, in order to form a region for confining current to the p-type compound semiconductor layer 22, ion implantation of boron ions or hydrogen ions is performed, and the ion implanted region is made to have a high resistance region or an insulating region. . Alternatively, the current confinement may be performed by forming a stripe structure based on an etching technique such as the RIE method.

[Step-140]
Next, in the same manner as a normal semiconductor laser device wafer process and chip forming process, formation of a protective film (not shown), photolithography process and etching process, formation of the first electrode 31 on the back surface of the substrate 110 by metal deposition, The second electrode 32 is formed on the top surface of the second compound semiconductor layer 22 (specifically, on the p-side contact layer 25), and further formed into chips by cleaving and dicing, and the resin mold, package By performing the process, the semiconductor laser device of Example 1 can be manufactured.

  Instead of performing [Step-110], the substrate is unloaded from the MOCVD apparatus and loaded into a heating furnace. Then, heat treatment is performed at 750 ° C. to 1000 ° C. for 5 minutes to 1 hour in a nitrogen gas atmosphere of 1 atm. Also by this, In can be segregated in the underlayer 112.

  Alternatively, the execution of [Step-110] is omitted, and instead of [Step-110], in the same process as [Step-130], in a nitrogen gas atmosphere at 1 atm, 750 ° C. to 1000 ° C. Then, heat treatment is performed for 5 minutes to 1 hour. Also by this, In can be segregated in the underlayer 112.

  In some cases, a semiconductor laser element having a mesa structure may be used. Specifically, for example, a sapphire substrate is used as the substrate 110 ′, and in [Step-140], the p-side contact layer 25, the p-type compound semiconductor layer 22, the active layer 23, and the n-type compound semiconductor layer 21, In addition, a part of the n-side contact layer 24 is exposed by etching a part of the n-side contact layer 24. Then, the first electrode 31 is formed on the exposed n-side contact layer 24, and the second electrode 32 is formed on the top surface of the p-type compound semiconductor layer 22 (specifically, on the p-side contact layer 25). To do. Thus, a semiconductor laser element having a structure shown in a schematic partial cross-sectional view in FIG. 1B can be obtained.

  Further, as shown on the right side of the conceptual diagram of FIG. 2A, in some cases, the maximum light intensity peak (center of the light field) in the light intensity distribution of the laser light emitted from the end face is an n-type compound semiconductor. It can be configured to be located in a layer. Specifically, for example, the thickness of the p-type compound semiconductor layer 22 is made thinner than the thickness of the n-type compound semiconductor layer 21 (a schematic partial cross-sectional view of the semiconductor laser device in FIG. 2B). reference). The left side of the conceptual diagram of FIG. 2A shows the light emission state of a conventional semiconductor laser element in which the maximum light intensity peak in the light intensity distribution of the laser light emitted from the end face is located in the active layer. . In general, the loss of light is greater in the p-type compound semiconductor layer 22 than in the n-type compound semiconductor layer 21. Moreover, it is large in the active layer 23 containing In. Therefore, the maximum light intensity peak in the light intensity distribution of the laser light emitted from the end face is positioned on the end face of the n-type compound semiconductor layer 21, so that the loss of the laser light generated in the active layer 23 in the compound semiconductor layer is reduced. Can be reduced, and resistance to COD can be improved. In addition, since the p-type compound semiconductor layer 22 usually has a higher resistance than the n-type compound semiconductor layer 21, the thickness of the p-type compound semiconductor layer 22 is made thinner than the thickness of the n-type compound semiconductor layer 21. Thus, heat generation in the p-type compound semiconductor layer 22 can be suppressed, and low voltage driving and low heat generation of the semiconductor laser element can be achieved. As a result of the above, a semiconductor laser element can be provided. In addition, the Al (aluminum) content in the n-type compound semiconductor layer 22 can be reduced, and the distortion of the entire light emitting portion can be reduced. As a result, the lifetime of the edge-emitting semiconductor laser element is increased. can do. The configurations and structures of the n-type compound semiconductor layer 21 and the p-type compound semiconductor layer 22 can also be applied to semiconductor laser elements of Examples 2 to 4 described later.

  Example 2 relates to a semiconductor laser device according to the second aspect of the present invention and a method for manufacturing the semiconductor laser device according to the second aspect of the present invention. A schematic partial sectional view of the semiconductor laser device of Example 2 is shown in FIG.

The semiconductor laser device of Example 2 is
(A) A base layer 212 made of a compound semiconductor layer and having a concave portion and / or a convex portion 212A, and
(B) The light emitting unit 20 configured by a stacked structure in which the n-type compound semiconductor layer 21, the active layer 23, and the p-type compound semiconductor layer 22 are sequentially stacked on the base layer 212.
It has. The laser light generated in the active layer 23 and reaches the interface between the n-type compound semiconductor layer 21 and the base layer 212 via the n-type compound semiconductor layer 21 is a concave portion and / or a convex portion 212A of the base layer 212. Therefore, interference with the laser light emitted from the end face is suppressed.

  More specifically, in Example 2, the recesses and / or protrusions 212 </ b> A are discontinuous protrusions (specifically, truncated quadrangular pyramids) protruding from the surface of the base layer 212. That is, as shown in a schematic partial perspective view in FIG. 4A, in Example 2, the island-shaped convex portions having a truncated quadrangular pyramid shape are formed from the surface of the base layer 212. It protrudes. The underlayer 212 is formed on the substrate 210. The recesses and / or projections 212A are drawn to have regularity in the drawing, but it is desirable to form them so as to be randomly arranged and arranged in one semiconductor laser element.

  Hereinafter, a method for manufacturing the semiconductor laser device of Example 2 will be described.

[Step-200]
On the substrate 210, a base layer 212 made of a compound semiconductor layer having a concave portion and / or a convex portion 212A is formed. Specifically, first, the substrate 210 is cleaned and the buffer layer 211 is grown on the substrate 210 in the same manner as in [Step-100] of the first embodiment. Next, the base layer 212 made of crystals composed of BAlGaInN is grown.

[Step-210]
After that, by etching the surface of the base layer 212, concave portions and / or convex portions 212A formed of island-shaped convex portions (truncated quadrangular pyramids) are formed in the base layer 212 (see FIG. 4A). Specifically, an etching mask (not shown) is formed based on a sputtering method and a lithography technique, the base layer 212 is etched, and then the etching mask is removed, so that the surface of the base layer 212 has an island-like convex shape. Etched.

[Step-220]
Thereafter, the n-type compound semiconductor layer 21, the active layer 23, and the p-type compound semiconductor layer 22 are sequentially stacked on the base layer 212 to obtain the light emitting unit 20 configured by a stacked structure. Specifically, a cap layer (not shown) made of a crystal composed of BAlGaInN is grown on the base layer 212, and then the n-side contact layer is formed in the same manner as in [Step-120] in Example 1. 24, a first compound semiconductor layer 21 composed of an n-type cladding layer 21A and an n-type guide layer 21B, an active layer 23, a second compound semiconductor layer 22 composed of a p-type guide layer 22B and a p-type cladding layer 22A, a p-side contact layer 25 are sequentially crystal-grown.

[Step-230]
Next, by performing the same steps as [Step-130] and [Step-140] of Example 1, the semiconductor laser device of Example 2 can be obtained.

  In [Step-210], as shown in the schematic partial perspective view of FIG. 4B, a discontinuous recess (specifically, a truncated quadrangular pyramid that is recessed from the surface of the base layer 212). May be formed, or as shown in a schematic partial perspective view in FIG. 5A, a concave-convex portion in which a quadrangular pyramid (pyramid shape) is continuous is formed. You can also.

  In some cases, the semiconductor laser device having the mesa structure can be used in the second embodiment as in the first embodiment. Specifically, for example, a sapphire substrate is used as the substrate 210 ′, and in the same step as [Step-140], the p-side contact layer 25, the p-type compound semiconductor layer 22, the active layer 23, and the n-type compound are used. A part of the n-side contact layer 24 is exposed by etching the semiconductor layer 21 and a part of the n-side contact layer 24. Then, the first electrode 31 is formed on the exposed n-side contact layer 24, and the second electrode 32 is formed on the top surface of the p-type compound semiconductor layer 22 (specifically, on the p-side contact layer 25). To do. In this way, a semiconductor laser device having a structure shown in a schematic partial cross-sectional view in FIG. 3B can be obtained.

Alternatively, in [Step-200], as shown in a schematic partial cross-sectional view in FIG. 6A, the substrate is formed on the substrate 210 (more specifically, on the buffer layer 211) and the substrate on the bottom. A selective growth mask layer 230 having an opening exposed on the surface of 210 and made of SiO _{2 is} formed based on a well-known sputtering technique, a lithography technique, and an etching technique, and then formed on the exposed substrate 210 (more specifically, In addition, by forming (selectively growing) the base layer 212 (on the buffer layer 211), the base layer 212 having a concave portion and / or a convex portion 212A can be obtained (see FIG. 6B). .

  Alternatively, in [Step-200], the first underlayer is formed on the substrate 210 (more specifically, on the buffer layer 211) as shown in a schematic partial sectional view in FIG. After forming 213, a selective growth mask layer 231 having an opening in which the surface of the first underlayer 213 is exposed at the bottom is formed on the first underlayer 213 based on a well-known sputtering technique, lithography technique, and etching technique. Then, by forming (selectively growing) the second base layer 214 on the exposed first base layer 213, the first base layer 213 and the second base layer 214 have a two-layer structure, and Alternatively, an underlayer having a convex portion 212A can be obtained (see FIG. 7B).

  In some cases, in [Step-200], it is also possible to obtain a ground layer having a convex portion only by crystal growth of the ground layer on the substrate 210 (more specifically, on the buffer layer 211).

  Example 3 relates to a semiconductor laser device according to the third aspect of the present invention and a method for manufacturing the semiconductor laser device according to the third aspect of the present invention. A schematic partial cross-sectional view of the semiconductor laser device of Example 3 is shown in FIG.

The semiconductor laser device of Example 3 is
(A) Substrate 310 provided with concave and / or convex portions 310A on the surface, and
(B) The light emitting unit 20 including a stacked structure in which the n-type compound semiconductor layer 21, the active layer 23, and the p-type compound semiconductor layer 22 are sequentially stacked on the substrate 310,
It has. Then, the laser light generated in the active layer 23 and reaching the surface of the substrate 310 via the n-type compound semiconductor layer 21 is scattered in the concave portion and / or the convex portion 310A of the surface of the substrate 310, and thus the end face Interference with the laser beam emitted from is suppressed.

  More specifically, in Example 3, the recesses and / or projections 310 </ b> A are discontinuous projections (specifically, truncated hexagonal pyramids) protruding from the surface of the substrate 310. That is, as shown in a schematic partial perspective view in FIG. 5B, in Example 3, the island-shaped convex portion having a truncated hexagonal pyramid shape protrudes from the surface of the substrate 310. ing. The recesses and / or projections 310A are drawn to have regularity in the drawing, but it is desirable to form them so as to be randomly arranged and arranged in one semiconductor laser element.

  A method for manufacturing the semiconductor laser device of Example 3 will be described below.

[Step-300]
First, by etching the surface of the substrate 310 made of n-type GaN, recesses and / or projections 310A made up of island-like projections are formed on the surface of the substrate 310. Specifically, an etching mask (not shown) is formed based on a sputtering method and a lithography technique, the substrate 310 is etched, and then the etching mask is removed, so that the surface of the substrate 310 is etched into an island-like convex shape. The

[Step-310]
Thereafter, the n-type compound semiconductor layer 21, the active layer 23, and the p-type compound semiconductor layer 22 are sequentially stacked on the substrate 310 to obtain the light emitting unit 20 configured by the stacked structure. Specifically, a buffer layer 311 made of GaN is crystal-grown on the substrate 310, and then a cap layer (not shown) is crystallized on the buffer layer 311 in the same manner as in [Step-220] in Example 2. Then, in the same manner as in [Step-120] in Example 1, the first compound semiconductor layer 21 including the n-side contact layer 24, the n-type cladding layer 21A and the n-type guide layer 21B, the active layer 23, p The second compound semiconductor layer 22 and the p-side contact layer 25 made up of the type guide layer 22B and the p-type cladding layer 22A are sequentially crystal-grown.

[Step-320]
Next, by performing the same steps as [Step-130] and [Step-140] of Example 1, the semiconductor laser device of Example 3 can be obtained.

  In some cases, the semiconductor laser device having the mesa structure can be used in the third embodiment as well as the first embodiment. Specifically, for example, a sapphire substrate is used as the substrate 310 ′, and in the same step as [Step-140], the p-side contact layer 25, the p-type compound semiconductor layer 22, the active layer 23, and the n-type compound are used. A part of the n-side contact layer 24 is exposed by etching the semiconductor layer 21 and a part of the n-side contact layer 24. Then, the first electrode 31 is formed on the exposed n-side contact layer 24, and the second electrode 32 is formed on the top surface of the p-type compound semiconductor layer 22 (specifically, on the p-side contact layer 25). To do. Thus, a semiconductor laser element having a structure shown in a schematic partial cross-sectional view in FIG. 8B can be obtained.

  Example 4 relates to a semiconductor laser device according to the fourth aspect of the present invention and a method for manufacturing the semiconductor laser device according to the fourth aspect of the present invention. A schematic partial cross-sectional view of the semiconductor laser device of Example 4 is shown in FIG.

The semiconductor laser device of Example 4 is
(A) a base layer 412 made of a compound semiconductor layer containing In (indium), a base layer made of an n-type compound semiconductor layer (specifically, a cap layer 414), and
(B) The light emitting unit 20 including a stacked structure in which the n-type compound semiconductor layer 21, the active layer 23, and the p-type compound semiconductor layer 22 are sequentially stacked on the base layer (cap layer 414).
It has. A cavity 413 is formed inside the base layer 412, and the laser light generated in the active layer 23 and incident on the base layer 412 through the n-type compound semiconductor layer 21 and the base layer (cap layer 414) The light is scattered in the cavity 413 inside the base layer 412, and thus interference with the laser light emitted from the end face is suppressed. Note that the base layer 412 is formed on the substrate 410.

  A method for manufacturing the semiconductor laser device of Example 4 will be described below.

[Step-400]
First, a base layer 412 made of a compound semiconductor layer containing In is formed on the substrate 410. Specifically, first, as in [Step-100] of Example 1, the substrate 410 made of an n-type GaN substrate is carried into an MOCVD apparatus, and the substrate is cleaned in a carrier gas made of hydrogen. Thereafter, a buffer layer 411 made of n-type GaN and having a thickness of about 1 μm is grown on the substrate 410. Next, a base layer 412 (provided that x> 0) made of an undoped or n-type In _x Ga _(1-x) N layer having a thickness of 0.2 μm or more is grown, and then a crystal composed of BAlGaInN is grown. A cap layer (base layer) 414 made of crystal is grown.

[Step-410]
After that, the cavity 413 is formed in the base layer 412 by heating in a hydrogen gas atmosphere, an ammonia gas atmosphere, or a hydrogen gas and ammonia gas atmosphere. Specifically, in a hydrogen gas atmosphere at 1 atm or lower pressure, an ammonia gas atmosphere, or a hydrogen gas and ammonia gas atmosphere, at 750 ° C. to 1200 ° C. for 5 minutes to 1 Heat for hours. As a result, In (indium) evaporates through the cap layer (base layer) 414 in the base layer 412, and a cavity 413 is formed inside the base layer 412.

[Step-420]
Next, the n-type compound semiconductor layer 21, the active layer 23, and the p-type compound semiconductor layer 22 are sequentially stacked on the cap layer (base layer) 414 to obtain the light emitting unit 20 configured by the stacked structure. Specifically, in the same manner as in [Step-120] in Example 1, the first compound semiconductor layer 21 including the n-side contact layer 24, the n-type cladding layer 21A, and the n-type guide layer 21B is formed on the cap layer 414. Then, the active compound 23, the second compound semiconductor layer 22 composed of the p-type guide layer 22B and the p-type cladding layer 22A, and the p-side contact layer 25 are successively grown.

[Step-430]
Next, by performing the same steps as [Step-130] and [Step-140] of Example 1, the semiconductor laser device of Example 3 can be obtained.

  In some cases, the semiconductor laser device having the mesa structure may be used in the fourth embodiment as in the first embodiment. Specifically, for example, a sapphire substrate is used as the substrate 410 ′, and in the same step as [Step-140], the p-side contact layer 25, the p-type compound semiconductor layer 22, the active layer 23, and the n-type compound are used. A part of the n-side contact layer 24 is exposed by etching the semiconductor layer 21 and a part of the n-side contact layer 24. Then, the first electrode 31 is formed on the exposed n-side contact layer 24, and the second electrode 32 is formed on the top surface of the p-type compound semiconductor layer 22 (specifically, on the p-side contact layer 25). To do. In this way, a semiconductor laser device having a structure shown in a schematic partial cross-sectional view in FIG. 9B can be obtained.

  As mentioned above, although this invention was demonstrated based on the preferable Example, this invention is not limited to these Examples. The configuration, structure, structure of the light emitting section, structure, material constituting the edge emitting semiconductor laser element, manufacturing conditions for the edge emitting semiconductor laser element, etc. described in the embodiments are examples, Can be changed. For example, in the edge-emitting semiconductor laser device described in the embodiments, the final form of the edge-emitting semiconductor laser device is described as being formed on the substrate. Alternatively, the substrate is polished or etched. Alternatively, the first electrode 31 may be formed on the exposed underlayer or the like.

1A and 1B are schematic partial cross-sectional views of an edge-emitting semiconductor laser device according to Example 1 and its modifications. 2A and 2B are diagrams schematically showing the light intensity distribution of laser light emitted from the end face of the edge-emitting semiconductor laser device, and another modification of the first embodiment. It is a typical partial sectional view of an edge emitting semiconductor laser device. 3A and 3B are schematic partial cross-sectional views of the edge-emitting semiconductor laser device of Example 2 and its modification. FIGS. 4A and 4B are schematic perspective views of the underlayer for explaining the method for manufacturing the edge-emitting semiconductor laser device of Example 2. FIGS. FIGS. 5A and 5B are schematic perspective views of the base layer and the substrate for explaining the method of manufacturing the edge-emitting semiconductor laser device of Example 2 and Example 3, respectively. 6A and 6B are schematic partial cross-sectional views of a substrate and the like for explaining a modification of the method for manufacturing the edge-emitting semiconductor laser device according to the second embodiment. FIGS. 7A and 7B are schematic partial cross-sectional views of a substrate and the like for explaining another modification of the method for manufacturing the edge-emitting semiconductor laser device of Example 2. FIGS. 8A and 8B are schematic partial cross-sectional views of the edge-emitting semiconductor laser device of Example 3 and its modifications. FIGS. 9A and 9B are schematic partial cross-sectional views of the edge-emitting semiconductor laser device of Example 4 and its modifications.

Explanation of symbols

110, 110 ', 210, 210', 310, 310 ', 410, 410' ... substrate, 111, 211, 311, 411 ... buffer layer, 112, 212, 312, 412 ... underlayer, 112A: a portion of the underlayer on which In is segregated, 112B ... other portions of the underlayer, 20 ... a light emitting portion, 21 ... an n-type compound semiconductor layer, 21A ... an n-type cladding Layer, 21B ... n-type guide layer, 22 ... p-type compound semiconductor layer, 22A ... p-type cladding layer, 22B ... p-type guide layer, 23 ... active layer, 24 ... n-side contact layer, 25... p-side contact layer, 31... first electrode (n-side electrode), 32... second electrode (p-side electrode), 212 A, 310 A. Convex part, 213... First underlayer, 214... Second underlayer 230 ... selective growth mask layer, 413 ... cavity, 414 ... base (cap layer)

Claims (20)

(A) an underlayer composed of a compound semiconductor layer containing In, and
(B) a light-emitting unit composed of a stacked structure in which an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on a base layer;
With
An edge-emitting semiconductor laser device in which In is segregated in the underlayer.   The laser light generated in the active layer and incident on the base layer via the n-type compound semiconductor layer is scattered or absorbed or scattered and absorbed in the base layer, and is thus emitted from the end face. The edge-emitting semiconductor laser device according to claim 1, wherein interference with laser light is suppressed.   The edge-emitting semiconductor laser device according to claim 1, wherein the maximum light intensity peak in the light intensity distribution of the laser light emitted from the end face is located in the n-type compound semiconductor layer. (A) An underlayer comprising a compound semiconductor layer, having a recess, or a protrusion, or a combination of a recess and a protrusion, and
(B) a light-emitting unit composed of a stacked structure in which an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on a base layer;
With
The laser light generated in the active layer and having reached the interface between the n-type compound semiconductor layer and the base layer via the n-type compound semiconductor layer is a concave portion of the base layer, or a convex portion, or a concave portion and a convex portion. An edge-emitting semiconductor laser device in which interference with a laser beam emitted from an end face is suppressed by being scattered, absorbed, or scattered and absorbed in combination.   The edge-emitting semiconductor laser device according to claim 4, wherein the maximum light intensity peak in the light intensity distribution of the laser light emitted from the end face is located in the n-type compound semiconductor layer. (A) A substrate provided with a concave portion or a convex portion, or a combination of a concave portion and a convex portion on the surface, and
(B) a light-emitting unit composed of a stacked structure in which an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on a substrate;
With
The laser light generated in the active layer and reaching the substrate surface via the n-type compound semiconductor layer is scattered in the concave portion of the substrate surface, or the convex portion, or the combination of the concave portion and the convex portion. An edge-emitting semiconductor laser device in which interference with laser light emitted from the surface is suppressed.   The edge-emitting semiconductor laser device according to claim 6, wherein the maximum light intensity peak in the light intensity distribution of the laser light emitted from the end face is located in the n-type compound semiconductor layer. (A) a base layer composed of a compound semiconductor layer containing In, a base layer composed of an n-type compound semiconductor layer, and
(B) a light-emitting unit composed of a stacked structure in which an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on a base layer;
With
A cavity is formed inside the underlayer,
The laser light generated in the active layer and incident on the underlayer through the n-type compound semiconductor layer and the base layer is scattered in the cavity inside the underlayer, and thus interferes with the laser light emitted from the end surface. An edge-emitting semiconductor laser device in which the generation is suppressed.   9. The edge-emitting semiconductor laser device according to claim 8, wherein the maximum light intensity peak in the light intensity distribution of the laser light emitted from the end face is located in the n-type compound semiconductor layer. (A) forming a base layer made of a compound semiconductor layer containing In on a substrate;
(B) An n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on the base layer to obtain a light-emitting portion configured from a stacked structure.
With each process,
A method of manufacturing an edge-emitting semiconductor laser device comprising a step of segregating In by applying energy to an underlayer.   11. The method for manufacturing an edge-emitting semiconductor laser device according to claim 10, wherein energy is applied to the underlayer by irradiating an electron beam between the step (a) and the step (b).   11. The method for manufacturing an edge-emitting semiconductor laser device according to claim 10, wherein energy is applied to the underlayer by heating the underlayer between the steps (a) and (b).   11. The method of manufacturing an edge-emitting semiconductor laser device according to claim 10, wherein after the step (b), the underlayer is heated to give energy to the underlayer. (A) On the substrate, a base layer made of a compound semiconductor layer having a concave portion, a convex portion, or a combination of the concave portion and the convex portion is formed;
(B) An n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked on the base layer to obtain a light-emitting portion configured from a stacked structure.
It has each process,
The laser light generated in the active layer and having reached the interface between the n-type compound semiconductor layer and the base layer via the n-type compound semiconductor layer is a concave portion of the base layer, or a convex portion, or a concave portion and a convex portion. A method of manufacturing an edge-emitting semiconductor laser device in which interference with a laser beam emitted from an end face is suppressed by being scattered or absorbed in a combination or scattered and absorbed.   In the step (a), after forming a base layer on the substrate, the base layer surface is etched to obtain a concave layer, a convex portion, or a base layer having a combination of the concave portion and the convex portion. 14. A method for producing an edge-emitting semiconductor laser device according to 14.   In the step (a), a mask layer for selective growth is formed on a substrate, and then a base layer is formed, whereby a base layer having a recess, a convex portion, or a combination of a concave portion and a convex portion is formed. The manufacturing method of the edge-emitting semiconductor laser element of Claim 14 obtained.   In the step (a), after the first underlayer is formed on the substrate, a selective growth mask layer is formed on the first underlayer, and then the second underlayer is formed. 15. The method for manufacturing an edge-emitting semiconductor laser device according to claim 14, wherein a base layer having a two-layer structure of a base layer and a second base layer and having a recess, a convex portion, or a combination of a concave portion and a convex portion is obtained. . (A) After providing a concave portion, a convex portion, or a combination of a concave portion and a convex portion on the surface of the substrate,
(B) On the substrate, an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked to obtain a light emitting unit configured from a stacked structure.
It has each process,
The laser light generated in the active layer and reaching the substrate surface via the n-type compound semiconductor layer is scattered in the concave portion of the substrate surface, or the convex portion, or the combination of the concave portion and the convex portion. A method for manufacturing an edge-emitting semiconductor laser device in which interference with laser light emitted from the surface is suppressed.   19. The edge-emitting semiconductor laser device according to claim 18, wherein in the step (a), a concave portion, a convex portion, or a combination of the concave portion and the convex portion is provided on the surface of the substrate by etching the substrate surface. Production method. (A) After forming a base layer made of a compound semiconductor layer containing In and a base layer made of an n-type compound semiconductor layer on a substrate,
(B) A cavity is formed inside the underlayer by heating in a hydrogen gas atmosphere, an ammonia gas atmosphere, or a hydrogen gas and ammonia gas atmosphere,
(C) On the base layer, an n-type compound semiconductor layer, an active layer, and a p-type compound semiconductor layer are sequentially stacked to obtain a light-emitting portion configured from a stacked structure.
It has each process,
The laser light generated in the active layer and incident on the underlayer through the n-type compound semiconductor layer and the base layer is scattered in the cavity inside the underlayer, and thus interferes with the laser light emitted from the end surface. For manufacturing an edge-emitting semiconductor laser device in which the generation of light is suppressed.

Images