JP2010050255A - Semiconductor light-emitting element and manufacturing method of the same, and convex part provided in ground, and convex part forming method in ground - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor light-emitting element which has high flexibility of design and moreover, which has less variations within a plane, moreover using a simple process. <P>SOLUTION: This method of manufacturing the semiconductor light-emitting element contains: a process of forming a convex part on a principal plane of a substrate 110 for manufacturing the element; and subsequently a process of forming a light-emitting part on a crest plane of the convex part. The process of forming the convex part comprises each process of: (a) forming a mask layer 161, extending in parallel with the substrate 110 direction on the principal plane of the substrate for manufacturing the element; (b) performing wet-etching by using an etchant, and forming a convex part upper layer, in which a cross-sectional shape thereof is an isosceles trapezoid and an inclination of a side surface thereof is θ<SB>U</SB>; and subsequently (c) changing a temperature of the etchant, performing the wet-etching by using side surfaces of the mask layer and the convex part upper layer as a mask for etching, and forming a convex part lower layer, in which a cross section shape thereof is an isosceles trapezoid and the inclination of a side surface thereof is θ<SB>D</SB>(where θ<SB>D</SB>≠θ<SB>U</SB>). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a semiconductor light emitting device, a method for manufacturing the same, a convex portion provided on a base, and a method for forming a convex portion on the base.

As a semiconductor laser having a low threshold current I _th , a semiconductor laser having an SDH (Separated Double Hetero Junction) structure (hereinafter referred to as an SDH type semiconductor laser) that can be formed by one epitaxial growth process is disclosed in, for example, Japanese Patent No. 2990837. Is well known.

In this SDH type semiconductor laser, first, a convex portion extending in the {110} A plane direction is formed on an element manufacturing substrate having a {100} plane as a main surface. Then, when crystal growth is performed on the main surface of the element manufacturing substrate, a compound semiconductor layer is laminated on the {100} plane (referred to as “convex top surface” for convenience) that is the top surface of the convex portion. Is formed. The light emitting unit has a structure in which, for example, a first compound semiconductor layer having a first conductivity type, an active layer, and a second compound semiconductor layer having a second conductivity type are sequentially stacked. The cross-sectional shape when the light emitting part is cut in a virtual plane (corresponding to {110} plane) perpendicular to the direction in which the convex part extends is, for example, an isosceles triangle, and the side surface (slope) of the light emitting part is { 111} B surface. In general, in the MOCVD method (also referred to as MOVPE method), the {111} B plane is known as a non-growth plane except for special crystal growth conditions. Therefore, in the case of the SDH type semiconductor laser, when the light emitting part whose side surface is the {111} B surface is formed, the crystal growth of the light emitting part is maintained as “self-growth stop” even if MOCVD is continued thereafter. . Here, the inclination angle (θ _111B ) of the {111} B plane is 54.7 degrees.

を、便宜上、本明細書においては、（ｈｋｌ）面、（ｈｋ−ｌ）面と表記し、以下に例示する方向の表記、

を、便宜上、本明細書においては、［ｈｋｌ］方向、［ｈｋ−ｌ］方向と表記する。 In addition, the notation of the crystal plane,

Are expressed as (hkl) plane and (hk-1) plane in this specification for convenience,

Are expressed as [hkl] direction and [hk-1] direction in this specification for convenience.

  On the other hand, there is no non-growth surface in the {100} plane portion (referred to as a concave surface for convenience), which is the main surface of the element manufacturing substrate excluding the convex portion. The growing compound semiconductor layer completely fills the light emitting portion where self-growth is stopped. The compound semiconductor layer crystal-grown from the concave surface has a structure in which a current blocking layer position adjusting layer, a current blocking layer, and a buried layer are sequentially formed on the second compound semiconductor layer. Here, usually, by controlling the thickness of the current blocking layer position adjusting layer, the compound semiconductor layer crystal-growing from the concave surface is in the middle stage before filling the light emitting portion (in particular, the activity formed in the light emitting portion). By forming the current blocking layer (when approaching the vicinity of both side surfaces of the layer), it is possible to form a structure that allows current injection only in the active layer of the light emitting portion.

  Thus, in the SDH type semiconductor laser, each compound semiconductor layer can be formed based on a single crystal growth step, and the compound semiconductor layer (first compound semiconductor layer) sandwiching the active layer vertically in the light emitting portion. And a second compound semiconductor layer), and a material having an energy band gap sufficiently higher than that of the active layer as a material used for a current blocking layer, a buried layer, and a current blocking layer position adjusting layer located outside the light emitting portion. That is, by selecting a material having a low refractive index, the active layer can be completely surrounded by a compound semiconductor layer convenient for light confinement. As a result, the shape of the beam emitted from the semiconductor laser having the end face of the convex portion as the light emission surface can be brought close to a perfect circle. That is, θ // ≈θ⊥ can be achieved in a far field pattern (FFP).

  Alternatively, for example, depending on the coupling efficiency with the lens and the like, it may be required that the shape of the beam emitted from the semiconductor laser be an ellipse. In such a case, for example, by adopting a so-called flare stripe structure in which the width near the end face of the convex portion is increased (see, for example, Japanese Patent No. 3399018), θ // of FFP is controlled to be small. Can do. Moreover, high light output can be achieved by adopting a flare stripe structure.

Patent No. 2990837 Japanese Patent No. 3399018 JP 2001-332530 A

By the way, as described above, in the SDH type semiconductor laser, first, a convex portion extending in the {110} A plane direction is formed on an element manufacturing substrate having a {100} plane as a main surface ((A) of FIG. 17). reference). Therefore, the size of the light emitting part is defined by the width (W _P ) of the convex part. On the other hand, the width (W _A ) of the active layer is determined based on the specifications of the SDH type semiconductor laser. Therefore, when the width of the convex portion (W _P ) is narrow, when an active layer having a desired width (W _A ) is formed, the distance (H ₁ ) from the active layer to the convex portion is naturally shortened (FIG. 17). (See (B)). Here, H _1, W _P, the W _A, the following relationship.
H ₁ = {(W _P −W _A ) / 2} × tan (θ _111B )
Then, when the distance from the active layer to the convex portion (H ₁₎ is short, the light generated in the active layer is absorbed in the element fabrication substrate which constitutes the convex portion, the light confinement effect is incomplete, the luminous efficiency ( There is a problem in that the slope efficiency expressed by the optical output / injection current decreases. Therefore, at present, for example, when the width of the active layer W _A and 1.2 [mu] m, the minimum value of the distance (H ₁₎ is about 1.4 [mu] m.

The height (H ₂ ) of the light emitting part is also defined by the width (W _P ) of the convex part. Here, H ₂ and W _P have the following relationship.
H ₂ = (W _P / 2) × tan (θ _111B )
Therefore, as shown in FIG. 18A, the SDH type semiconductor laser is based on a so-called low aspect ratio convex portion in which the convex portion has a low height (H ₀ ) and a wide convex portion width (W _P ). 18B, there is a case where there is no room for forming a current blocking layer on the side surface of the active layer, as illustrated in FIG.

Furthermore, when the integration of the SDH type semiconductor laser is attempted, that is, when the number of SDH type semiconductor lasers per unit area is increased, that is, the SDH type semiconductor laser as shown in FIG. If you try to reduce the formation pitch PT ₁ in formation pitch PT _2, the size of the light emitting portion (for example, W values of _a) it is necessary to reduce the keep such a case, the width of the active layer constant the, as shown in (B) of FIG. 19, since the distance from the active layer to the convex portion must be as short as from H ₁ to H ₁ ', again, there arises a problem described above. Alternatively, in order to ensure a sufficient distance from the active layer to the convex portion so that light is not absorbed by the element manufacturing substrate constituting the convex portion, as shown in FIG. Since the height has to be lowered from H ₀ to H ₀ ′, the above-mentioned problem still occurs.

These problems can be solved if the height (H ₀ ) of the convex portion can be set arbitrarily. However, forming the convex part having a high height while holding the side surface of the convex part on the {111} B surface, that is, the element manufacturing substrate while holding the side surface of the convex part on the {111} B surface. It is extremely difficult to etch deeply. In order to eliminate such difficulties, for example, Japanese Patent Laid-Open No. 2001-332530 discloses a technique for forming a convex portion by two types of wet etching methods. Although this technique is extremely effective, the etching process is complicated because the convex portions are formed by two types of wet etching methods. Therefore, there is a need for a technique for forming a high convex portion by a simpler process. In addition, in one element manufacturing substrate, the variation in the dimensions of the convex portions extending in the {110} A plane direction (the above-described convex portion width (W _P ) and convex portion height (H ₀ )). Furthermore, there is also a strong demand for minimizing as much as possible the in-plane variation such as the ratio between the width (W _P ) of the convex portion and the height (H ₀ ) of the convex portion. In particular, the etching technique for keeping the ratio of the width (W _P ) of the protrusions to the height (H ₀ ) of the protrusions constant in the element manufacturing substrate is the design of the width (W _P ) of each protrusion The degree of difficulty tends to increase as the specification increases or as the design specification of the height (H ₀ ) of the convex portion increases. Here, when such a variation in the size of each part of the convex portion occurs, the size of the light emitting portion varies, and as a result, the shape of the laser beam emitted from the SDH type semiconductor laser and the FFP θ // Variations, variations in threshold currents of SDH type semiconductor lasers, and the like occur.

  Further, in a semiconductor light emitting device including a light emitting portion that includes a first compound semiconductor layer, an active layer, and a second compound semiconductor layer, and a top surface of the second compound semiconductor layer is a {100} plane, There is a semiconductor light emitting element in which a convex portion extending in parallel with the <110> direction needs to be formed in a part of the thickness direction. In the manufacture of buried hetero type (Burried Hetero type) lasers, surface emitting laser elements (vertical cavity lasers, VCSELs), heterojunction bipolar transistors (HBTs), photodiodes (PDs), and solar cells In some cases, high convex portions (or deep concave portions or element isolation regions) must be formed on the surface. Even in these semiconductor light emitting devices and various devices, a technique for forming a high convex portion (or deep concave portion or element isolation region) by a simpler process is required as described above. In addition, there is a strong demand for minimizing the dimensional variation (in-plane variation) of each part of the convex portion in one element manufacturing substrate.

  Accordingly, an object of the present invention is to provide a base having a high degree of design freedom, a simple process, a small in-plane variation, and a high height convex part on the base, and the base obtained by such a method. Another object of the present invention is to provide a semiconductor light emitting device obtained by a method for manufacturing a semiconductor light emitting device to which the method is applied, and a method for manufacturing the semiconductor light emitting device.

In order to achieve the above object, the method for forming a convex portion on the base of the present invention (hereinafter referred to as “the method for forming a convex portion of the present invention”) is applied to a base having a {100} plane as the top surface. A method of forming a protrusion extending in parallel with the direction,
(A) After forming a mask layer extending in parallel with the <110> direction on the base,
(B) Using the mask layer as an etching mask, the base is etched by a wet etching method using an etchant, and the cross-sectional shape when cut along the {110} plane is such that the bottom is longer than the upper. Is a long isosceles trapezoid, and forms a convex upper layer whose side slope angle is θ _U ,
(C) The cross-sectional shape when the temperature of the etching solution is changed and the base layer is further etched by the wet etching method using the side surfaces of the mask layer and the convex upper layer as an etching mask and cut by the {110} plane is obtained. Forming a convex lower layer that is an isosceles trapezoid whose base is longer than the top and whose side surface has an inclination angle θ _D (where θ _D ≠ θ _U ).
It consists of each process.

In the convex portion forming method of the present invention, the base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the top side in the cross-sectional shape when the convex lower layer is cut along the {110} plane; When the inclination angle of the side surface when the side surface of the part is the (111) B surface is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
In this case, the temperature of the etching solution in the step (b) is preferably higher than the temperature of the etching solution in the step (c). The degree to which the etching temperature should be increased depends on the etching solution to be used and the material to be etched, and therefore may be determined as appropriate by conducting various tests. The same applies to the following.

Alternatively, in the convex portion forming method of the present invention, the base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane. Yes; when the inclination angle of the side surface when the side surface of the convex portion is the (111) B surface is θ _111B ,
θ _U ≦ θ _111B ≦ θ _D (However, θ _D ≠ θ _U )
In this case, the temperature of the etching solution in the step (b) is preferably lower than the temperature of the etching solution in the step (c). The degree to which the etching temperature should be lowered depends on the etching solution to be used and the material to be etched, and therefore may be determined as appropriate by conducting various tests. The same applies to the following.

In order to achieve the above object, a method for manufacturing a semiconductor light emitting device according to the first aspect of the present invention includes:
(A) forming a convex portion extending in parallel with the <110> direction of the element manufacturing substrate on the main surface of the element manufacturing substrate having a {100} plane as a main surface;
(B) On the top surface of the convex portion, a light emitting portion is formed by sequentially laminating a first compound semiconductor layer having a first conductivity type, an active layer, and a second compound semiconductor layer having a second conductivity type. In addition, the first compound semiconductor layer having the first conductivity type, the active layer, and the second compound semiconductor layer having the second conductivity type are formed on the main surface portion of the element manufacturing substrate on which no protrusion is formed. Are sequentially stacked to form a laminated structure, and then
(C) forming a current blocking layer covering at least the side surface of the active layer constituting the light emitting portion on the laminated structure;
Comprising steps,
The step (A)
(A) After forming a mask layer extending in parallel with the <110> direction on the main surface of the element manufacturing substrate,
(B) Using the mask layer as an etching mask, the main surface of the device manufacturing substrate is etched by a wet etching method using an etchant, and the cross-sectional shape when cut along the {110} plane is the length of the bottom. Is an isosceles trapezoid whose length is longer than the length of the upper side, and forms a convex upper layer whose side slope angle is θ _U ,
(C) Varying the temperature of the etching solution, using the side surfaces of the mask layer and the convex upper layer as an etching mask, further etching the main surface of the element manufacturing substrate by the wet etching method, and cutting at the {110} plane The cross-sectional shape is an isosceles trapezoid whose base is longer than the top and the side slope is θ _D (where θ _D ≠ θ _U ) to form a convex lower layer ,
It consists of each process.

In the method for manufacturing a semiconductor light emitting device according to the first aspect of the present invention, the base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the same as that when the convex lower layer is cut along the {110} plane. it is the upper side in the cross-sectional shape; when the side surface of the protrusion is the inclination angle of the side surface of the case (111) B surface is a theta _111B,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
In this case, the temperature of the etching solution in the step (b) is preferably lower than the temperature of the etching solution in the step (c).

In the method for manufacturing a semiconductor light emitting device according to the first aspect of the present invention, including the above-described preferred form and configuration, or, in the semiconductor light emitting device according to the first aspect of the present invention described later, When the thickness is H _U and the thickness of the convex lower layer is H _D ,
H _U / (H _U + H _D ) ≧ 0.5
Preferably,
H _U / (H _U + H _D ) ≧ 0.7
It is desirable to satisfy

Furthermore, in the manufacturing method of the semiconductor light emitting device according to the first aspect of the present invention including the various preferable modes and configurations described above, or alternatively, the semiconductor light emitting device according to the first aspect of the present invention described later. In the above, when the thickness of the convex upper layer is H _U , the thickness of the convex lower layer is H _D , and the width of the convex upper layer is W _U ,
(H _U + H _D ) / W _U ≧ 0.4
Preferably,
(H _U + H _D ) / W _U ≧ 0.9
It is desirable to satisfy

A method for manufacturing a semiconductor light emitting device according to the second aspect of the present invention for achieving the above object comprises a first compound semiconductor layer, an active layer, and a second compound semiconductor layer, and the top surface of the second compound semiconductor layer. A semiconductor light-emitting device including a light-emitting portion having a {100} plane, including a step of forming a convex portion extending in parallel with the <110> direction in a part of the second compound semiconductor layer in the thickness direction A manufacturing method of
The formation process of the convex part
(A) After forming a mask layer extending in parallel with the <110> direction on the top surface of the second compound semiconductor layer,
(B) Using the mask layer as an etching mask, the second compound semiconductor layer is partially etched in the thickness direction by a wet etching method using an etchant, and the cross-sectional shape when cut along the {110} plane is Forming a convex upper layer having an isosceles trapezoid in which the length of the base is longer than the length of the upper side, and the inclination angle of the side surface is θ _U ;
(C) The second compound semiconductor layer is partially etched in the thickness direction by a wet etching method by changing the temperature of the etching solution and using the side surfaces of the mask layer and the convex upper layer as an etching mask, and { 110} plane, the cross-sectional shape is an isosceles trapezoid whose base is longer than the top, and the slope of the side is θ _D (where θ _D ≠ θ _U ) Forming subordinates,
It consists of each process.

In the method for manufacturing a semiconductor light emitting device according to the second aspect of the present invention, the bottom in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the same as that when the convex lower layer is cut along the {110} plane. It is the upper side in the cross-sectional shape; when the inclination angle of the side surface when the side surface of the convex portion is the (111) B surface is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
In this case, the temperature of the etching solution in the step (b) is preferably higher than the temperature of the etching solution in the step (c).

Alternatively, in the method for manufacturing a semiconductor light emitting device according to the second aspect of the present invention, the bottom in the cross-sectional shape when the convex upper layer is cut along the {110} plane is cut along the {110} plane at the convex lower layer. When the inclination angle of the side surface when the side surface of the convex portion is the (111) B surface is θ _111B ,
θ _U ≦ θ _111B ≦ θ _D (However, θ _D ≠ θ _U )
In this case, the temperature of the etching solution in the step (b) is preferably lower than the temperature of the etching solution in the step (c).

  In the method for manufacturing a semiconductor light emitting device according to the second aspect of the present invention, the second compound semiconductor layer has a multilayer structure of three or more layers, a convex portion is formed on the upper layer, a middle layer is formed by a wet etching method. And may function as an etching stop layer when formed.

The convex portion provided on the base according to the first aspect of the present invention for achieving the above object is provided on the base having the {100} plane as the top surface and extends in parallel with the <110> direction of the base. A convex part,
It has a two-layer structure of a convex lower layer and a convex upper layer,
The cross-sectional shape when the convex upper layer is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The cross-sectional shape when the lower layer of the convex portion is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface of the convex upper layer is θ _U , the inclination angle of the side surface of the convex lower layer is θ _D , and the inclination angle of the side surface when the side surface of the convex portion is the (111) B plane is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
Satisfied.

The convex portion provided on the base according to the second aspect of the present invention for achieving the above object is provided on the base having the {100} plane as the top surface and extends in parallel with the <110> direction of the base. A convex part,
It has a two-layer structure of a convex lower layer and a convex upper layer,
The cross-sectional shape when the convex upper layer is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The cross-sectional shape when the lower layer of the convex portion is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface of the convex upper layer is θ _U , the inclination angle of the side surface of the convex lower layer is θ _D , and the inclination angle of the side surface when the side surface of the convex portion is the (111) B plane is θ _111B ,
θ _U ≦ θ _111B ≦ θ _D (However, θ _D ≠ θ _U )
Satisfied.

In order to achieve the above object, a semiconductor light emitting device according to the first aspect of the present invention includes:
(A) A convex portion provided on the main surface of the element manufacturing substrate having a {100} plane as a main surface and extending parallel to the <110> direction of the element manufacturing substrate;
(B) a light emitting unit in which a first compound semiconductor layer having a first conductivity type, an active layer, and a second compound semiconductor layer having a second conductivity type are sequentially stacked on a top surface of a convex portion;
(C) a first compound semiconductor layer having a first conductivity type, an active layer, and a second compound semiconductor having a second conductivity type, which are formed on a main surface portion of the element manufacturing substrate on which no protrusion is formed. A laminated structure in which the layers are sequentially laminated, and a current blocking layer formed on the laminated structure and covering at least the side surface of the active layer constituting the light emitting unit,
It has
The convex part has a two-layer structure of a convex part lower layer and a convex part upper layer,
The cross-sectional shape when the convex upper layer is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The cross-sectional shape when the lower layer of the convex portion is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface of the convex upper layer is θ _U , the inclination angle of the side surface of the convex lower layer is θ _D , and the inclination angle of the side surface when the side surface of the convex portion is the (111) B plane is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
Satisfied.

The semiconductor light emitting device according to the second aspect of the present invention for achieving the above object comprises a first compound semiconductor layer, an active layer, and a second compound semiconductor layer, and the top surface of the second compound semiconductor layer is {100. } Is a semiconductor light emitting device provided with a light emitting portion that is a surface and provided with a convex portion extending in parallel to the <110> direction in the second compound semiconductor layer,
The convex part has a two-layer structure of a convex part lower layer and a convex part upper layer,
The cross-sectional shape when the convex upper layer is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The cross-sectional shape when the lower layer of the convex portion is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface of the convex upper layer is θ _U , the inclination angle of the side surface of the convex lower layer is θ _D , and the inclination angle of the side surface when the side surface of the convex portion is the (111) B plane is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
Satisfied.

The semiconductor light emitting device according to the third aspect of the present invention for achieving the above object comprises a first compound semiconductor layer, an active layer, and a second compound semiconductor layer, and the top surface of the second compound semiconductor layer is {100. } Is a semiconductor light emitting element provided with a convex portion extending in parallel with the <110> direction on the second compound semiconductor layer,
It has a two-layer structure of a convex lower layer and a convex upper layer,
The cross-sectional shape when the convex upper layer is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The cross-sectional shape when the lower layer of the convex portion is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface of the convex upper layer is θ _U , the inclination angle of the side surface of the convex lower layer is θ _D , and the inclination angle of the side surface when the side surface of the convex portion is the (111) B plane is θ _111B ,
θ _U ≦ θ _111B ≦ θ _D (However, θ _D ≠ θ _U )
Satisfied.

  In the semiconductor light emitting device according to the second aspect or the third aspect of the present invention, current flows from the convex portion to the remaining portion of the second compound semiconductor layer, the active layer, and the first compound semiconductor layer. Thus, the active layer can be configured to emit light, or the convex portion corresponds to a region where current is confined, that is, the convex portion is a region where no current flows, and the convex portion and the convex portion. A current is caused to flow from the third compound semiconductor layer formed between the remaining portion of the second compound semiconductor layer, the active layer, and the first compound semiconductor layer to cause light emission in the active layer. be able to. An example of the semiconductor light emitting device having the former form is an ISAN (Inverted-Self-Aligned-Narrow stripe) type semiconductor laser, and an example of the semiconductor light emitting device having the latter form is a SAN (Self-Aligned-Narrow). stripe) type semiconductor laser.

Projection forming method of the present invention, method of manufacturing a semiconductor light emitting device according to the first aspect of the present invention, method of manufacturing a semiconductor light emitting device according to the second aspect of the present invention, and base according to the first aspect of the present invention A convex portion provided on the underlayer according to the second aspect of the present invention, a semiconductor light emitting element according to the first aspect of the present invention, a semiconductor light emitting element according to the second aspect of the present invention, Alternatively, in the semiconductor light emitting device according to the third aspect of the present invention (hereinafter, these may be collectively referred to simply as “the present invention”), θ _D ≦ θ _111B ≦ θ _U (where θ _D ≠ θ _U ), specifically,
θ _D <θ _111B <θ _U
θ _D = θ _111B <θ _U
θ _D <θ _111B = θ _U
3 aspects are included. Here, the value of θ _111B is specifically 54.7 degrees. as the value of theta _U in the case of θ _111B <θ _U, can be exemplified 56 degrees to 64 degrees, as the value of theta _D in the case of θ _D <θ _111B, may be mentioned 46 ° to 54 ° .

On the other hand, when θ _U ≦ θ _111B ≦ θ _D (where θ _U ≠ θ _D ), specifically,
θ _U <θ _111B <θ _D
θ _U = θ _111B <θ _D
θ _U <θ _111B = θ _D
3 aspects are included. as the value of theta _D in the case of θ _111B <θ _D, can be exemplified 56 degrees to 64 degrees, the value of theta _U in the case of θ _U <θ _111B, may be mentioned 46 ° to 54 ° .

Protrusion upper layer of thickness H _U, as the value of the thickness H _D of the convex subordinate layer, specifically, as described above,
H _U / (H _U + H _D ) ≧ 0.5
In addition to satisfying
0.1 μm ≦ H _U ≦ 6 μm
0.1 μm ≦ H _D ≦ 3 μm
More preferably,
0.1 μm ≦ H _D ≦ 6 μm
0.1 μm ≦ W _U ≦ 2.5 μm
More preferably,
0.1μm ≦ H _D ≦ 3μm
0.1 μm ≦ W _U ≦ 2.5 μm
It is desirable to satisfy Furthermore, as mentioned above,
H _U / (H _U + H _D ) ≧ 0.7
In addition to satisfying
0.1 μm ≦ H _U ≦ 6 μm
0.1 μm ≦ H _D ≦ 3 μm
More preferably,
0.1 μm ≦ H _D ≦ 6 μm
0.1 μm ≦ W _U ≦ 2.5 μm
More preferably,
0.1 μm ≦ H _D ≦ 3 μm
0.1 μm ≦ W _U ≦ 2.5 μm
It is desirable to satisfy

The convex portion as a whole extends in parallel to the <110> direction of the base or the element manufacturing substrate, but the thickness direction of the convex portion is parallel to the <100> direction of the base or the element manufacturing substrate. Is the {100} plane which is the main surface of the base or the element manufacturing substrate. In addition, when the extending direction of the convex portion is the X direction and the thickness direction of the convex portion is the Z direction, the width direction of the convex portion corresponds to the Y direction. The convex portion is not limited to the two-layer configuration of the upper layer and the lower layer, and may be composed of three or more layers. In this case, a certain layer constituting the convex portion (referred to as the Mth layer for convenience) the inclination angle theta _M side of, the (M-1) -th angle of inclination of the side surface of the layer theta _(M-1), and, the (M + 1) th angle of inclination of the side surfaces of the layers θ _{(M + 1)} Is different. And the side surface (inclined surface) of the Mth layer, the side surface (inclined surface) of the (M-1) th layer, the side surface (inclined surface) of the (M-2) th layer,. All of the side surface (inclined surface) of the (M−n) th layer (where M> n, M and n are integers of 1 or more), the mask layer (first etching mask), etc. A side surface having an inclination angle θ _M of the _Mth layer is formed, which functions as an etching mask. In the following description, a portion of the main surface of the element manufacturing substrate on which no convex portion is formed may be referred to as a “concave surface”.

  In the trapezoidal shape, generally, the upper side and the bottom side (lower side) are parallel, but in the present invention, the upper side and the bottom side (lower side) are not completely parallel due to the formation condition of the convex portion. However, such a shape is also included in the “trapezoid”. In addition, there may occur a case where the lengths along the slopes of the two side surfaces are not completely the same due to the formation conditions of the convex portions, and such a shape is also included in the “isopod trapezoid”. In the semiconductor light emitting device or the manufacturing method thereof according to the first aspect of the present invention, the cross-sectional shape of the light emitting part when the obtained light emitting part is cut along the {110} plane is an isosceles triangle, Due to the formation conditions of the light emitting portion, the case where the triangle is not an exact isosceles triangle may occur.

In the present invention, as a device manufacturing substrate, a GaN substrate, a GaAs substrate, a GaP substrate, an AlN substrate, an AlP substrate, an InN substrate, an InP substrate, an AlGaInN substrate, an AlGaN substrate, an AlInN substrate, a GaInN substrate, an AlGaInP substrate, an AlGaP substrate, an AlInP A substrate, a GaInP substrate, a ZnS substrate, a sapphire substrate, a SiC substrate, an alumina substrate, a ZnO substrate, a LiMgO substrate, a LiGaO ₂ substrate, a MgAl ₂ O ₄ substrate, a Si substrate, and a Ge substrate can be given. Furthermore, a substrate in which a buffer layer and an intermediate layer are formed on the surface (main surface) of these substrates can be used as a device manufacturing substrate. In addition, regarding the main surface of these substrates, depending on the crystal structure (for example, cubic or hexagonal type), the so-called A plane, B plane, C plane, R plane, M plane, N plane, S plane, etc. It is also possible to use a crystal orientation plane called by the name or a plane in which these are turned off in a specific direction. In the semiconductor light emitting device or the manufacturing method thereof according to the first aspect of the present invention, in particular, a substrate having a zinc blende (zinc blend) type crystal structure or a substrate on which a crystal film is formed is used. Preferably, here, at least As, Sb, Bi, or the like can be cited as atoms constituting the substrate having a zinc blend type crystal structure. In such a substrate in which atoms such as As, Sb, or Bi are added and thus included as a mixed crystal, it is easy to form a convex portion having a specific slope as a side surface by etching. In addition, when a crystal containing atoms such as As, Sb, or Bi and thus mixed crystals is regrown on the protrusion formed by etching, for example, a group V trimer is formed on the outermost surface { Since a non-growth surface such as a 111} B surface tends to appear, the present invention also makes it possible to manufacture an SDH type semiconductor laser that actively utilizes this property. As described above, a material such as As, Sb, or Bi is used as a constituent element of a substrate having a convex portion, and a material such as As, Sb, or Bi is used as a constituent element on the convex portion. Even in the case of crystal regrowth, if the design (processing) is performed to suppress light absorption in a substrate having high light absorption according to the emission wavelength, the performance and uniformity of the characteristics of the semiconductor light emitting element can be achieved. be able to. In the present invention, the {100} plane of the element manufacturing substrate is the main surface. However, the main surface has a surface with an off angle including 0 degrees, and further has an off angle of ± 5 (degrees). The face within is included. In addition, examples of the base include the main surface of the element manufacturing substrate or the second compound semiconductor layer.

  As various compound semiconductor layers including the active layer, for example, a GaN-based compound semiconductor (including AlGaN mixed crystal, AlGaInN mixed crystal, and GaInN mixed crystal), a GaInNAs-based compound semiconductor (including GaInAs mixed crystal or a GaNAs mixed crystal), AlGaInP-based, etc. Compound semiconductor, AlAs compound semiconductor, AlGaInAs compound semiconductor, AlGaAs compound semiconductor, GaInAs compound semiconductor, GaInAsP compound semiconductor, GaInP compound semiconductor, GaP compound compound semiconductor, InP compound semiconductor, InN compound semiconductor, AlN compound Compound semiconductors can be exemplified. Examples of n-type impurities added to the compound semiconductor layer include silicon (Si), sulfur (S), selenium (Se), tellurium (Te), and tin (Sn). As p-type impurities, Examples include carbon (C), 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 active layer (film formation method), metal organic chemical vapor deposition (MOCVD method, MOVPE method), metal organic molecular beam epitaxy method (MOMBE method), halogen transport or reaction Hydride vapor phase epitaxy method (HVPE method) and plasma assisted physical vapor phase epitaxy method (PPD method) which contribute to the above. The first conductivity type may be n-type, the second conductivity type may be p-type, the first conductivity type may be p-type, and the second conductivity type may be n-type.

As a material constituting the mask layer, a semiconductor oxide or semiconductor nitride such as SiO ₂ , SiN, or SiON; a metal such as Ti, W, Ni, Au, or Pt, a refractory metal, or these metals are adjusted with an appropriate composition. Alloys (for example, TiW, TiWCr, TiWNi, NiCr, TiNiCr, or alloys thereof and Au, or alloys of these alloys and Pt); refractory metal (alloy) oxides; refractory metal (alloy) nitriding A multilayer film formed by combining these different metals, alloys, alloy oxides, and alloy nitrides; and resist materials. Examples of the method for forming the mask layer include a combination of a physical vapor deposition method (PVD method) such as a sputtering method, a chemical vapor deposition method (CVD method), a coating method, and a lithography technique or an etching technique. . Further, the removal of the mask layer may employ a wet etching method, a dry etching method, or an ashing technique depending on the material constituting the mask layer. The mask layer may have a one-dimensional arrangement such as a band shape, or has a dotted or scattered curved shape (circular, elliptical, etc.) or polygonal shape (triangular, quadrangular, hexagonal, etc.). A two-dimensional arrangement may be used. Note that the mask layer may or may not be finally removed. In the latter case, by leaving the mask layer as it is, the mask layer can be used as a selective growth mask layer or a metal electrode layer, such as a semiconductor laser (LD) or a light emitting diode (LED). The light emitting device can be used for manufacturing a light emitting device, or it can be used as a part of a component of the light emitting device as it is.

  Examples of the etching solution include so-called citric acid perhydrogenated mixture of citric acid, hydrogen peroxide water and water, and tartaric acid, acetic acid, oxalic acid, formic acid, succinic acid, malic acid instead of citric acid. And carboxylic acids such as adipic acid. The etching solution may be exchanged between the formation of the convex upper layer and the formation of the convex lower layer, and the object to be etched may be washed with water. Or you may perform formation of a convex part upper layer, and formation of a convex part lower layer with a different etching apparatus.

  In the semiconductor light emitting device of the present invention, the first compound semiconductor layer is electrically connected to the first electrode, and the second compound semiconductor layer is electrically connected to the second electrode. The first electrode may be formed on the first compound semiconductor layer, or may be connected to the first compound semiconductor layer via a conductive element manufacturing substrate. The second compound semiconductor layer may be formed on the top surface of the second compound semiconductor layer, or may be connected to the second compound semiconductor layer through a conductive material layer.

  When the first conductivity type is n-type and the second conductivity type is p-type, the first electrode is an n-side electrode and the second electrode is a p-side electrode. On the other hand, when the first conductivity type is p-type and the second conductivity type is n-type, the first electrode is a p-side electrode and the second electrode is an n-side electrode. Here, as the p-side electrode, Au / AuZn, Au / Pt / Ti (/ Au) / AuZn, Au / Pt / TiW (/ Ti) (/ Au) / AuZn, Au / AuPd, Au / Pt / Ti ( / Au) / AuPd, Au / Pt / TiW (/ Ti) (/ Au) / AuPd, Au / Pt / Ti, Au / Pt / TiW (/ Ti), Au / Pt / TiW / Pd / TiW (/ Ti ). Further, as an n-side electrode, Au / Ni / AuGe, Au / Pt / Ti (/ Au) / Ni / AuGe, Au / Pt / TiW (/ Ti) / Ni / AuGe, or an interface between these metal layers, In particular, an electrode structure in which an Al layer, a Pd layer, or an Ag layer is inserted in the lowermost layer can be given. Regardless of the n-side electrode or the p-side electrode, the composition of each alloy used for the electrode may be appropriately selected according to the material of the base of the electrode so as not to damage the base. It should be noted that the layer before “/” is located at a position electrically separated from the active layer. Alternatively, the first electrode can be made of a transparent conductive material such as ITO, IZO, ZnO: Al, ZnO: B. When a layer made of a transparent conductive material is used as a current diffusion layer and the first electrode is an n-side electrode, the metal laminate structure described in the case where the first electrode is a p-side electrode may be combined.

  Further, for the first electrode, the second electrode, or the second electrode extension portion, for example, a Ti layer / Pt layer / Au layer or the like [adhesion layer (Ti layer, Cr layer, etc.) ] / [Barrier metal layer (Pt layer, Ni layer, TiW layer, Mo layer, etc.)] / [Multilayer metal layer having a laminated structure such as a metal layer (for example, Au layer) that is compatible with mounting] A contact portion (pad portion) may be provided. The first electrode, the second electrode including the second electrode extension portion, and the contact portion (pad portion) are, for example, various PVD methods such as a vacuum deposition method and a sputtering method, and various chemical vapor deposition methods (CVD methods). ), And can be formed by a plating method.

  Examples of the semiconductor light emitting device of the present invention include an edge emitting semiconductor laser (LD) and a light emitting diode (LED). More specifically, the semiconductor light emitting device according to the first aspect of the present invention or the semiconductor light emitting device in the manufacturing method thereof may include an SDH type semiconductor laser, although not limited thereto. Examples of the semiconductor light emitting device according to the second aspect or the third aspect or the semiconductor light emitting device in the method for manufacturing the semiconductor light emitting device according to the second aspect of the present invention include the above-mentioned SAN type semiconductor laser or ISAN type semiconductor laser. it can. Further, the convex portion provided on the base according to the first aspect or the second aspect of the present invention, and the convex portion forming method of the present invention include, for example, a buried hetero laser and a manufacturing method thereof, a surface emitting laser element, and a High etching control technology is required for controlling the width and height of convex portions of a semiconductor material such as a manufacturing method, a heterojunction bipolar transistor and a manufacturing method thereof, a photodiode and a manufacturing method thereof, a solar cell and a manufacturing method thereof. It can be applied to all manufacturing methods and manufacturing techniques.

  In the present invention, since the convex portion composed of at least a two-layer structure of the convex portion upper layer and the convex portion lower layer is provided, the height of the convex portion (the etching depth of the substrate or the device manufacturing substrate), the top surface of the convex portion Therefore, the degree of freedom in designing the semiconductor light emitting element can be increased, and semiconductor light emitting elements that meet various specifications and requirements can be provided. Also, by using the same etching solution and changing the etching temperature, it is possible to provide a convex part consisting of at least a two-layer structure of the convex part upper layer and the convex part lower layer. Can be formed. In addition, the side surface of the convex upper layer is an etching stable crystal plane in wet etching, and the side surface of the mask layer and the convex upper layer can be used as an etching mask. Variation in dimensions (in-plane variation) can be made extremely small. As a result, it is possible to manufacture semiconductor light-emitting elements and various elements having uniform characteristics.

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

  Example 1 relates to a method for forming a convex portion according to the present invention, a convex portion provided on a base according to the first aspect of the present invention, a semiconductor light emitting device according to the first aspect of the present invention, and a method for manufacturing the same.

  As shown in a schematic partial cross-sectional view in FIG. 1, the convex portion 111 is a base having a {100} plane (specifically, a (100) plane, the same applies hereinafter) as a top surface. And extends parallel to the <110> direction of the base. Here, in Example 1, specifically, the base is the element manufacturing substrate 110, and the convex portion 111 of Example 1 provided on the element manufacturing substrate 110 mainly has a {100} plane. It is a convex portion provided on this main surface of the element manufacturing substrate 110 as a surface and extending in parallel with the <110> direction of the element manufacturing substrate 110. And it has the two-layer structure of convex part lower layer 111A and convex part upper layer 111B.

The semiconductor light emitting device of Example 1 is composed of a semiconductor laser, more specifically, an SDH type semiconductor laser. As shown in a schematic partial sectional view of FIG.
(A) The <110> direction (specifically, for example, the [011] direction of the element manufacturing substrate 110 is provided on this main surface of the element manufacturing substrate 110 having the {100} plane as a main surface. The same applies to the projections (projections) 111 extending in parallel with
(B) On the top surface of the convex portion 111, the first compound semiconductor layer 121, the active layer 123, and the second layer having the first conductivity type (specifically, n-type in the first embodiment). A light emitting unit 120 in which a second compound semiconductor layer 122 having a conductivity type (specifically, p-type in Example 1) is sequentially stacked; and
(C) A first conductive type (n-type) formed on a portion of the main surface of the element manufacturing substrate 110 on which no convex portion is formed (sometimes referred to as a concave surface or an exposed surface of the element manufacturing substrate 110). A stacked structure 120 ′ formed by sequentially stacking a first compound semiconductor layer 121 having active layers, an active layer 123, and a second compound semiconductor layer 122 having a second conductivity type (p-type), and the stacked structure 120 A current blocking layer 140 which is formed on and covers at least a side surface of the active layer 123 constituting the light emitting unit 120;
It has. The convex portion 111 has a two-layer structure of a convex lower layer 111A and a convex upper layer 111B.

  Here, in Example 1, the cross-sectional shape when the convex upper layer 111B is cut along the {110} plane (specifically, the (011) plane, the same applies to the following) is the length of the base. Is an isosceles trapezoid that is longer than the length of the upper side, and the cross-sectional shape when the convex lower layer 111A is cut along the {110} plane is an isosceles trapezoid whose base is longer than the length of the upper side. The base in the cross-sectional shape when the upper layer 111B is cut along the {110} plane is the upper side in the cross-sectional shape when the convex portion lower layer 111A is cut along the {110} plane.

In Example 1, the inclination angle of the side surface 111b of the convex upper layer 111B is θ _U , the inclination angle of the side surface 111a of the convex lower layer 111A is θ _D , and the side surface of the convex part is the (111) B surface. When the inclination angle of the side surface is θ _111B ,
θ _D ≠ θ _U
In particular,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
Satisfied. More specifically,
θ _D <θ _111B <θ _U
Satisfied. More specifically, in Example 1, θ _111B = 54.7 degrees, θ _D = 50 degrees, and θ _U = 60 degrees.

In Example 1, when the thickness of the convex upper layer 111B is H _U , the thickness of the convex lower layer 111A is H _D , and the width of the convex upper layer 111B is W _U ,
H _U / (H _U + H _D ) ≧ 0.5
(H _U + H _D ) / W _U ≧ 0.4
Is satisfied. More specifically, H _U = 2 μm, H _D = 2 μm, and W _U = 4 μm.

In the semiconductor light emitting device of Example 1, the first compound semiconductor layer 121, the active layer 123, and the second compound semiconductor layer 122A are sequentially formed on the top surface of the convex upper layer 111B, and the second compound semiconductor layer is formed. A second compound semiconductor layer 122B is further formed on 122A to form a vertex. Here, when the light emitting unit 120 is cut along the {110} plane, the cross-sectional shape of the light emitting unit 120 including the second compound semiconductor layer 122B is an isosceles triangle, and the side surface of the light emitting unit 120 has a {111} B plane ( More specifically, it is composed of (11-1) B surface and (1-11) B surface). By changing the composition of the second compound semiconductor layer 122A and the second compound semiconductor layer 122B, it is possible to accurately form the light emitting section 120 whose cross-sectional shape is an isosceles triangle. In general, in the MOCVD method (also referred to as MOVPE method), the {111} B surface is known as a non-growth surface covered with an As trimmer, except for special crystal growth conditions. Therefore, in the case of the SDH type semiconductor laser, when the light emitting portion 120 whose slope (side surface) is the {111} B surface is formed, the crystal growth of the light emitting portion 120 is “self-growth stop” even if MOCVD is continued thereafter. Is retained. The angle θ _111B of the {111} B plane is 54.7 degrees.

  On the other hand, in the {100} plane (the (100) plane in the illustrated example) which is the concave surface of the element manufacturing substrate 110, the laminated structure 120 ′ having the same structure as the light emitting unit 120, the current A block layer position adjusting layer 130 (substantially a continuation of the second compound semiconductor layer 122), a current blocking layer 140, and an embedded layer (embedded cladding layer) 131 are sequentially formed. The whole is covered with a contact layer (cap layer) 132 made of GaAs having the second conductivity type. In Example 1, the element manufacturing substrate 110 including the convex portion 111 is made of n-GaAs. Furthermore, the first electrode 151 (specifically, the first electrode 151 formed on the back surface of the conductive element manufacturing substrate 110) electrically connected to the first compound semiconductor layer 121 is Ti / TiW / Pt / Au, and is electrically connected to the second compound semiconductor layer 122. The second electrode 152 (specifically, above the second compound semiconductor layer 122, more specifically, The second electrode 152) formed on the contact layer (cap layer) 132 is made of Au / Ni / AuGe or Au / AuZn.

  The composition of the compound semiconductor layer constituting the light emitting unit 120 and the stacked structure 120 ′ is illustrated in Table 1 below. “Zn, Mg, C” may be added with zinc (Zn), magnesium (Mg), or carbon (C) as impurities. means.

[Table 1]
(Configuration of light emitting part)
Second compound semiconductor layer 122B... P-Al _0.47 Ga _0.53 As: Zn, Mg, C
Second compound semiconductor layer 122A... P-Al _0.4 Ga _0.6 As: Zn, Mg, C
Active layer 123 ... [active layer-A]
First compound semiconductor layer 121... N-Al _0.4 Ga _0.6 As: Si
(Configuration of current block)
Buried layer 131... P-Al _0.47 Ga _0.53 As: Zn, Mg, C
Current blocking layer 140... N-Al _0.47 Ga _0.53 As: Si
Current block layer position adjusting layer 130... P-Al _0.47 Ga _0.53 As: Zn, Mg, C

[Active layer-A]
Confinement layer: p-Al _0.3 Ga _0.7 As: Zn, Mg, C
Confinement layer ... i-Al _0.3 Ga _0.7 As
Multiple quantum well structure: i-Al _0.1 Ga _0.9 As (well layer)
i-Al _0.3 Ga _0.7 As (barrier layer) and
i-Al _0.1 Ga _0.9 As (well layer)
Confinement layer ... i-Al _0.3 Ga _0.7 As
Confinement layer ... n-Al _0.3 Ga _0.7 As: Si

In addition, as shown in FIG. 2B, the compound semiconductor layer constituting a part of the current blocking layer 140 is
{311} B crystal plane region (more specifically, (31-1) B plane and (3-11) B plane) extending from the side surface of the light emitting unit 120,
A {100} crystal plane region extending along the main surface of the element manufacturing substrate 110, and
{H11} B crystal plane region located between the {311} B crystal plane region and the {100} crystal plane region (more specifically, in the (h1-1) B plane and (h-11) B plane) Where h is an integer greater than or equal to 4),
It is composed of Note that the {h11} B crystal plane region (where h is an integer of 4 or more) may be referred to as a higher-order crystal plane region for convenience.

  Here, in the semiconductor light emitting device of Example 1, the active layer 123 formed on the convex portion 111 is surrounded in the lateral direction (side surface) by the current blocking layer 140 having a refractive index lower than that of the active layer 123. The vertical direction is surrounded by the first compound semiconductor layer 121 and the second compound semiconductor layers 122A and 122B having a refractive index lower than that of the active layer 123. Therefore, the vertical direction and the horizontal direction of the active layer 123 have a complete light confinement structure. In addition, above the concave surface of the element manufacturing substrate 110, the vicinity of the side surface of the active layer 123 has a pn-pn structure (p-type buried layer 131-n-type current blocking layer 140-p-type). A so-called thyristor structure of the current block layer position adjusting layer 130-n-type first compound semiconductor layer 121) is formed. Therefore, the current is prevented from flowing in the concave surface of the element manufacturing substrate 110, whereby the current is concentrated in the active layer 123, and a low threshold current can be achieved.

  Hereinafter, the convex portion forming method of Example 1 in which a convex portion extending in parallel with the <110> direction of the base is formed on the base having the {100} plane as the top surface, and the semiconductor light emitting device of Example 1 and its manufacture A method will be described.

[Step-100]
First, a convex portion 111 extending in parallel to the <110> direction of the element manufacturing substrate 110 is formed on this main surface of the element manufacturing substrate 110 having the {100} plane as a main surface. Hereinafter, [Step-100] will be described by being divided into [Step-100A] to [Step-100C].

[Step-100A]
For this purpose, first, a mask layer 161 extending in parallel with the <110> direction is formed on the main surface of the element manufacturing substrate 110. Alternatively, a mask layer 161 extending in parallel with the <110> direction is formed on the base. Specifically, in Example 1, a mask layer 161 made of SiO ₂ is formed on the main surface (underlying) of the element manufacturing substrate 110 by a CVD method, and then a lithography technique and a dry etching technique are used. A mask layer 161 extending in parallel with the <110> direction (more specifically, the [011] A direction) is formed on this main surface of the element manufacturing substrate 110 having the 100} surface as the main surface (FIG. 3). (See (A)).

[Step-100B]
Next, using the mask layer 161 as an etching mask, the main surface of the element manufacturing substrate 110 (the exposed main surface portion of the element manufacturing substrate 110 is also a base) by a wet etching method using an etching solution. ) Is etched. As the etching solution, citric acid: pure water: hydrogen peroxide solution = 3: 3: 2 (volume ratio) was used, and the wet etching was performed at an etching solution of 6 to 9 ° C. As a result, as shown in FIG. 3B, the cross-sectional shape when cut along the {110} plane is an isosceles trapezoid whose base is longer than the top, and the inclination angle of the side surface 111b is A convex upper layer 111B having θ _U can be formed.

[Step-100C]
Next, the temperature of the etching solution is changed, and the main surface (base) of the element manufacturing substrate 110 is further etched by a wet etching method using the mask layer 161 and the side surface 111b of the convex upper layer 111B as an etching mask. More specifically, citric acid perwater having the above-described composition was used, and wet etching was performed at an etching solution of 2 to 5 ° C. By the way, the side surface 111b of the convex upper layer 111B obtained in [Step-100B] is an etching stable crystal plane in wet etching, and wet etching is performed using the mask layer 161 and the side surface 111b of the convex upper layer 111B as an etching mask. In [Step-100C], the side surface 111b of the convex upper layer 111B is not etched. Thus, the cross-sectional shape when cut along the {110} plane is an isosceles trapezoid whose base is longer than the top, and the inclination angle of the side surface 111a is θ _D (where θ _D ≠ θ _U ), Which is a convex lower layer 111A (see FIG. 3C). Since the temperature of the etching solution in [Step-100B] was higher than the temperature of the etching solution in [Step-100C], θ _D <θ _111B <θ _U was obtained. In this way, a double trapezoidal convex portion 111 extending in the [011] A direction and having a desired top surface width and overall height can be formed. Here, the width direction of the convex portion 111 is parallel to the [0-11] B direction.

[Step-110]
Next, after removing the mask layer 161 based on the wet etching method, the first compound semiconductor layer 121 having the first conductivity type, the active layer 123, and the second conductivity type are formed on the top surface of the convex portion 111. The light emitting portion 120 is formed by sequentially laminating the second compound semiconductor layer 122, and at the same time, the main surface portion (concave surface, exposed surface) of the element manufacturing substrate 110 where the convex portion 111 is not formed is formed on the first surface. A stacked structure 120 ′ is formed by sequentially stacking a first compound semiconductor layer 121 having one conductivity type, an active layer 123, and a second compound semiconductor layer 122 having a second conductivity type.

Specifically, each of these compound semiconductor layers is formed by MOCVD. In the MOCVD method, for example, trimethylaluminum (TMAl) or triethylaluminum (TEAl) is used as a source gas for an aluminum (Al) source, and trimethylgallium (TMGa) or triethylgallium (TEGa) is used as a gallium (Ga) source. As a source gas, tertiary butyl arsine (TBAs) or arsine (AsH ₃ ) may be used as a source gas for an arsenic (As) source. Further, as gas for doping n-type impurities, disilane (Si ₂ H ₆ ), monosilane (SiH ₄ ) or trimethyltin (TMSn), hydrogen sulfide (H ₂ S), hydrogen selenide (H ₂ Se) or telluride Hydrogen (H ₂ Te) may be used. On the other hand, as a p-type impurity doping gas, for example, trimethylzinc (TMZn), triethylzinc (TEZn), bis-cyclopenta-dienylmagnesium (Cp ₂ Mg), bis-ethyl-cyclopenta-dienylmagnesium (EtCp ₂₎ Mg), bis-isopropyl-cyclopenta-dienylmagnesium (i-PrCp ₂ Mg), bis-methylcyclopenta-dienylmagnesium (MeCp ₂ Mg), trimethyl manganese (TMMn), carbon tetrachloride (CCl ₄ ), four Carbon bromide (CBr ₄ ) or carbon tetraiodide (CI ₄ ) may be used. Then, as described above, based on the MOCVD method, these group III gas, group V gas, and impurity gas are introduced into the reaction chamber, and are subjected to thermal decomposition reaction in a temperature range of 600 ° C. to 900 ° C. to grow crystals. Thus, the first compound semiconductor layer 121, the active layer 123, the second compound semiconductor layer 122A, on the top surface of the convex upper layer 111B, on the side surface of the convex 111, and on the concave surface of the element manufacturing substrate 110, 122B is epitaxially grown.

Since the side surface of the convex portion 111 is not a {111} B plane but a crystal growth surface, the first compound semiconductor layer 121, the active layer 123, and the second compound semiconductor layers 122A and 122B are formed on the side surface of the convex portion 111. However, crystals grow sequentially. That is, as schematically illustrated in FIGS. 4A to 4C, the side surface 111b and the side surface 111a constituting the side surface of the convex portion 111 are not {111} B non-growth surfaces, In the case of growth, both grow crystals. In particular, as shown in FIGS. 4A to 4C, when the side surface 111b satisfying θ _111B ≦ θ _U grows, the crystal grows while maintaining the tilt angle (θ _U ). At the same time, crystal growth is continued while forming a {111} B non-growth surface on the side surface (see FIG. 4A). On the other hand, in the side surface 111a, which is another side surface constituting the side surface, as shown in FIG. 4A, when θ _D ≦ θ _111B is satisfied, a {111} B non-growth surface cannot be formed. The crystal grows while maintaining the tilt angle (θ _D ).

Therefore, in actuality, when the crystal growth of the side surface 111b and the crystal growth of the side surface 111a proceed simultaneously, the side surface 111b having the inclination angle θ _U is not grown by {111} B while growing on the surface. With the formation of a surface. Therefore, the area occupied by the side surface 111b having the inclination angle θ _U sandwiched between the {111} B non-growth surface and the crystal growth of the side surface 111a may gradually decrease and disappear. That is, the side surface 111b may be covered with another crystal plane. Such a state is referred to as “annihilation pattern 1” for convenience. Alternatively, before the side surface 111b having the tilt angle θ _U disappears, the side surface 111a is covered with newly generated {311} B-plane crystal growth (corresponding to the compound semiconductor layer 173). As the crystal growth of the {311} B plane (compound semiconductor layer 173) and the crystal growth of the {111} B non-growth plane disappear, the area occupied by the side surface 111b having the inclination angle θ _U gradually decreases and disappears. In some cases. Such a state is referred to as “annihilation pattern 2” for convenience. Thus, the side surface shape when either one of the side surface 111b having the inclination angle θ _U or the side surface 111a disappears first is the entire side surface by the side surface 111a having the inclination angle θ _D and the {111} B non-growing surface. There forms are constructed or, the form in which the entire side surface by the side 111b is configured to have an inclination angle theta _U and {311} B plane (the compound semiconductor layer 173). Although not shown, this state corresponds to an intermediate state between FIG. 4A and FIG. 4B.

Thereafter, in the annihilation pattern 1, the remaining side surface 111a undergoes crystal growth while maintaining the inclination angle θ _D so as to embed the {111} B non-growth surface formed during crystal growth of the side surface 111b. Continue to gradually occupy the {111} B non-growth surface. However, the side surface 111a where the crystal grows while maintaining the tilt angle θ _D is rapidly caught up by the {311} B-plane crystal growth (compound semiconductor layer 173) generated from the lowermost end. Therefore, finally, the side surface of the convex portion is composed only of the {311} B surface and the {111} B non-growth surface. On the other hand, in the annihilation pattern 2, the remaining side surface 111b grows while maintaining the inclination angle θ _U , but the {111} B non-growth surface formed along with the crystal growth of the side surface 111b, and The side surface 111a is sandwiched by {311} B growth surfaces that have disappeared, and the occupied area gradually decreases and disappears. Therefore, finally, the side surface of the convex portion is composed only of the {311} B surface and the {111} B non-growth surface. FIG. 4B shows the final form of the annihilation pattern 1 and the annihilation pattern 2, and a {311} B plane is formed at the boundary between the compound semiconductor layer 171 and the compound semiconductor layer 172. The compound semiconductor layer 173 that appears on the outermost surface is illustrated. On the other hand, the top surface of the convex upper layer 111B and the concave surface of the element manufacturing substrate 110 are {100} planes. Therefore, a special surface is formed on the top surface of the convex upper layer 111B and the concave surface of the element manufacturing substrate 110. The generation and disappearance of crystal planes do not occur, and the compound semiconductor layers are simply stacked in order.

  Accordingly, when the formation of the light emitting unit 120 and the stacked structure 120 ′ is started, first, the crystal growth of the compound semiconductor layer on the side surface of the convex portion 111, the top surface of the convex upper layer 111B, and the element manufacturing substrate 110 Crystal growth starts simultaneously at three main locations such as the compound semiconductor layer on the concave surface, and finally, as described above, the surface of the compound semiconductor layer on the side surface of the convex portion 111 is {111} B by crystal growth of the compound semiconductor layer. A compound semiconductor layer 171 composed of a surface is formed on the side surface of the convex portion 111. On the other hand, a compound semiconductor layer 172 having a surface composed of a {100} plane is formed on the concave surface of the element manufacturing substrate 110, and a surface is formed from the {100} plane on the top surface of the convex upper layer 111B. The configured compound semiconductor layer 174 is formed with the formation of a {111} B non-growth surface. Note that the formation of the {111} B non-growth surface is independent from the crystal growth of the side surface 111b accompanied by the formation of the {111} B non-growth surface, as described above, and the location where it occurs is different. Needless to say.

As shown in FIG. 4C, finally, with respect to all crystal growth around the convex portion 111, crystal growth proceeds at three locations of the compound semiconductor layer 172, the compound semiconductor layer 173, and the compound semiconductor layer 174. To do. As a result, since the {111} B surface is a non-growth surface, the first compound semiconductor layer 121, the active layer 123, and the second compound semiconductor layers 122A and 122B In the region on the concave surface of the substrate 110, the substrate 110 is formed (laminated) in a divided state. In this way, the structure shown in FIG. 5 can be obtained. Incidentally, by appropriately selecting the ratio between the width W _U of the top surface of the convex portion 111 and the height (H _U + H _D ) of the convex portion 111, the cross-sectional shape is an isosceles triangular shape as shown in FIG. When the light emitting portion is completed, a structure in which the position (height) of the second compound semiconductor layer 122 is located lower than the position (height) of the active layer 123 can be obtained. As a result, the current blocking layer can be reliably formed on the side surface of the active layer 123, so that a structure in which the current path is concentrated on the active layer is obtained. In addition, by appropriately selecting the constituent ratios of H _U and H _{D at} the height (H _U + H _D ), as described above, the timing at which the two side surfaces 111b and 111a disappear can be generated early. In addition, the order of disappearance can be controlled. In particular, when the side surface 111a disappears while the tilt angle θ _D is maintained, the timing of extinction of the side surface 111a is delayed, and if the side surface 111a remains indefinitely and crystal growth on other surfaces continues, the side surface 111a may eventually disappear. Even if it is possible, there may be a structure in which a surface having an inclination angle θ _D is inserted in a spike shape between the current blocking layer 140 and the side surface of the active layer 123 shown in FIG. If such a structure is formed, it causes current leakage. Therefore, the constituent ratios of H _U and H _{D at} the height (H _U + H _D ) play an important role for preventing current leakage. On the top surface of the convex portion 111, by appropriately selecting the thicknesses of the first compound semiconductor layer 121, the active layer 123, and the second compound semiconductor layers 122A and 122B, {111} B It is possible to obtain a stacked structure of the light emitting unit 120 having a cross section with two sides of the non-growing surface being an isosceles triangle.

[Step-120]
Thereafter, the current blocking layer 140 that covers at least the side surface of the active layer 123 that constitutes the light emitting unit 120 is formed on the stacked structure 120 ′. Specifically, following the formation of the second compound semiconductor layer 122B, the current block layer position adjusting layer 130 is formed on the entire surface based on the MOCVD method, and further, for example, the current block layer 140 is sequentially formed by the MOCVD method. (See FIG. 6). The current blocking layer 140 does not grow on the {111} B plane. In addition, the current blocking layer 140 is formed so that the end surface of the current blocking layer 140 covers at least the side surface of the active layer 123. Such a configuration and structure is obtained by appropriately selecting the width W _U of the top surface of the convex upper layer 111B, the height of the convex 111 (H _U + H _D ), and the thickness of the current blocking layer position adjusting layer 130. Can be achieved. The effect at this time is also as described above.

[Step-130]
Next, the buried layer 131 and the contact layer (cap layer) 132 are sequentially formed on the entire surface based on the MOCVD method. If the MOCVD is continued, the embedded layer 131 made of a compound semiconductor that grows crystals above the concave surface of the element manufacturing substrate 110 eventually completely fills the light emitting section 120 that has stopped self-growth. After that, the second electrode 152 is formed on the contact layer 132 based on the vacuum deposition method. On the other hand, after the device manufacturing substrate 110 is lapped to an appropriate thickness from the back surface side, the first electrode 151 is formed based on the vacuum deposition method. To do.

[Step-150]
Thereafter, the semiconductor light emitting element can be obtained by separating the semiconductor light emitting element. The semiconductor light emitting elements may be separated one by one, or a large number (for example, 4, 8, 16, 32, 64, etc.) are grouped together and separated into each other. Also good.

In Example 1, the convex part 111 is formed in order to form the light emitting part 120. By the way, the convex part 111 has a two-layer structure of a convex part upper layer 111B and a convex part lower layer 111A. Therefore, the width W _U of the top surface of the projection upper 111B, the height H _U of the convex portion upper 111B, the height H _D of the projections underlying 111A, widely selected, may be combined. Therefore, when the active layer 123 having a desired width is formed above the narrow convex portion 111, the distance from the active layer 123 to the convex portion 111 can be designed to be long. It is possible to prevent the generated light from being absorbed by the convex portion 111. As a result, it is possible to suppress the occurrence of a problem that the light emission efficiency is lowered. Further, as described above, the height (size) of the light emitting portion 120 is defined by the width W _U of the convex upper layer 111B, but the height from the concave surface of the element manufacturing substrate 110 to the top surface of the convex portion 111. A device manufacturing substrate having an aspect ratio {(H _U + H _D ) / W _U }, which is a ratio of (H _U + H _D ) and the top width W _U at the height, within a desired aspect ratio. 110 can be adjusted by controlling the wet etching. That is, in order to enable the formation of the current blocking layer 140 on the side surface of the active layer 123, the aspect ratio of the convex portion 111 corresponding to the desired width of the active layer 123 (for example, the value of “height / width”) Since there is a certain range, the aspect ratio must be included in the range, but the degree of freedom in designing the aspect ratio is high. Therefore, by optimizing the aspect ratio, it is possible to suppress the occurrence of a problem that the current blocking layer 140 cannot be formed on the side surface of the active layer 123. Thus, conventionally, the aspect ratio of the concavo-convex substrate obtained by etching the device manufacturing substrate 110 (etching with fluctuations in control) varies within the device manufacturing substrate with respect to the width and height of the protrusions, As a result, in some element manufacturing substrate regions, there has been a problem that a current blocking layer cannot be formed on the side surface of the active layer in the light emitting portion formed on the top surface of the convex portion. However, in the first embodiment, the aspect ratio of the desired convex portion 111 corresponding to the desired width of the active layer 123 can be controlled by controlling the wet etching of the device manufacturing substrate 110, and the device manufacturing method. The in-plane uniformity of the concavo-convex structure in the substrate can be greatly improved. Furthermore, even if the formation pitch of the convex portions 111 is reduced for high integration, the optimum distance from the active layer 123 to the convex portions 111 is prevented so that light generated in the active layer 123 is not absorbed by the convex portions 111. Therefore, it is possible to suppress the occurrence of a problem that the light emission efficiency is reduced, and the aspect ratio of the convex portion 111 can be controlled within a desired aspect ratio range. As a result of suppressing the occurrence of a problem that the current blocking layer 140 cannot be formed on the side surface of the active layer 123, high integration of the semiconductor light emitting device can be achieved.

  Example 2 is a modification of the method for forming a convex portion of the present invention, a deformation of the convex portion provided on the base according to the first aspect of the present invention, the semiconductor light emitting device according to the second aspect of the present invention, and the present invention. The present invention relates to a method for manufacturing a semiconductor light emitting device according to a second aspect of the invention.

  As shown in a schematic partial cross-sectional view in FIG. 7, the convex portion 211 of Example 2 provided on the second compound semiconductor layer 222 which is the base is also the base (second side) having the {100} plane as the top surface. The protrusion is provided on the compound semiconductor layer 222) and extends in parallel with the <110> direction of the base (second compound semiconductor layer 222). And it has 2 layer structure of the convex part lower layer 211A and the convex part upper layer 211B.

  The semiconductor light emitting device of Example 2 is composed of a semiconductor laser, more specifically, an ISAN type semiconductor laser. As shown in the schematic partial cross-sectional view of FIG. 221, an active layer 223, and a second compound semiconductor layer 222, and the second compound semiconductor layer 222 includes a light emitting unit 220 whose top surface is a {100} plane, and the second compound semiconductor layer 222 includes <110> This is a semiconductor light emitting device provided with convex portions 211 extending in parallel with the direction. The convex portion 211 has a two-layer structure of a convex lower layer 211A and a convex upper layer 211B.

  Here, in Example 2, the cross-sectional shape when the convex upper layer 211B is cut along the {110} plane is an isosceles trapezoid whose base is longer than the upper side, and the convex lower layer 211A is {110 } The cross-sectional shape when cut by the plane is an isosceles trapezoid whose base is longer than the length of the top, and the bottom of the cross-sectional shape when the convex upper layer 211B is cut by the {110} plane is the convex This is the upper side in the cross-sectional shape when the lower layer 211A is cut along the {110} plane.

In Example 2, the inclination angle of the side surface 211b of the convex portion upper layer 211B is θ _U , the inclination angle of the side surface 211a of the convex portion lower layer 211A is θ _D , and the side surface of the convex portion is the (111) B surface. When the inclination angle of the side surface is θ _111B ,
θ _D ≠ θ _U
In particular,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
Satisfied. More specifically,
θ _D <θ _111B <θ _U
More specifically, even in Example 2, θ _111B = 54.7 degrees, θ _D = 50 degrees, and θ _U = 60 degrees.

For ISAN semiconductor laser, since the design concept different from that of the SDH type semiconductor laser, totally different role of _{sides, H U / (H U +} H D) and, like _{(H U + H D) /} W U There are no strict restrictions on conditions. However, a design that effectively causes current constriction is important. Specifically, shortening the bottom of the convex lower layer 211A and bringing the bottom closer to the active layer 223 may be an important point for suppressing the diffusion current. For example, FIG. 7 shows an ISAN type semiconductor laser that conducts current confinement by insulating the entire recess (the surface including the side surface 211b and the side surface 211a) with the insulating layer 212. In order to make the structure more effective than the optical confinement control effect based on such a structure, instead of covering the recess with the insulating layer 212, as shown in a schematic partial sectional view in FIG. An n-type compound semiconductor layer, a p-type compound semiconductor layer, an n-type compound semiconductor layer, a p-type compound semiconductor layer,... That are easily lattice-matched with the base of the recess and have a lower refractive index than the material of the active layer 223. What is necessary is just to make it the structure which embeds a recessed part with a laminated structure (henceforth "junction type compound semiconductor layer laminated structure"). Note that in the junction-type compound semiconductor layer stacked structure 270, the number of repetitions of stacking the compound semiconductor layers having an np junction may be at least one or more. In the example shown in FIG. 8, the compound semiconductor layer has an npn structure. This
It is possible to achieve a buried structure having two roles of (1) role as a current blocking layer and (2) role as an optical confinement control layer. Crystal growth methods for the compound semiconductor layer that fills the recess include LPE (liquid phase growth), MOCVD (metal organic chemical vapor deposition), MBE (molecular beam epitaxy), PPD (Plasma Assisted Physical Deposition) ).

In the case of the embedded crystal growth in which the recess is filled with the junction type compound semiconductor layer stacked structure 270, the mask layer 261 (see FIG. 10) may be used as it is as a selective growth mask. In this case, after the embedded crystal growth is completed, the mask layer 261 is removed by a normal etching method, and then the second electrode 252 may be formed on the convex portion, and the mask layer 261 is made of a conductive material. In this case, the second electrode 252 can be used as it is after the embedded crystal is grown. Alternatively, as shown in FIG. 8, after the structure shown in FIG. 10 is formed, the mask layer 261 may be removed by a normal etching method, and the recess may be filled with the junction type compound semiconductor layer stacked structure 270. FIG. 8 shows an example of embedding with an npn structure. However, in this case, a triangular junction type compound semiconductor layer laminated structure 271 (in the example shown in FIG. 8, a triangular shape of an npn structure) is also formed on the top surface of the convex portion. Therefore, it is necessary to remove the junction type compound semiconductor layer laminated structure 271 until the layer 211B on the top surface of the convex portion is exposed by etching after the filling of the concave portion is completed. Note that after the removal, the second electrode 252 may be formed so that a current flows through the convex portion in the same manner as described above. In Example 2, when the thickness of the convex upper layer 211B is H _U , the thickness of the convex lower layer 211A is H _D , and the width of the convex upper layer 211B is W _U , H _U = 1.5 μm or Typical examples include 1 μm, H _D = 0.5 μm, and W _U = 0.5 μm.

  The light emitting unit 220 is formed on an element manufacturing substrate 210 made of n-GaAs. Further, the first electrode 251 electrically connected to the first compound semiconductor layer 221 (specifically, the first electrode 251 formed on the back surface of the conductive element manufacturing substrate 210) is Ti / TiW / Pt / Au, and the second electrode 252 electrically connected to the twenty-first compound semiconductor layer 222 (specifically, above the second compound semiconductor layer 222, more specifically, The second electrode 252) formed on the contact layer (cap layer) is made of Au / Ni / AuGe or Au / AuZn. An electrode structure in which an Al layer, a Pd layer, or an Ag layer is inserted at the interface of these metal layers, particularly the lowermost layer, can also be used. Regardless of the n-side electrode and the p-side electrode, the composition of each alloy used for the electrode may be appropriately selected according to the material of the base of the electrode so as not to damage the base.

  The composition of the compound semiconductor layer constituting the light emitting unit 220 is illustrated in Table 2 below.

[Table 2]
Second compound semiconductor layer 222... P-Al _0.47 Ga _0.53 As: Zn, Mg, C
Active layer 223
Multiple quantum well structure: i-Al _0.3 Ga _0.7 As (barrier layer)
i-Al _0.1 Ga _0.9 As (well layer)
i-Al _0.3 Ga _0.7 As (barrier layer)
First compound semiconductor layer 221... N-Al _0.4 Ga _0.6 As: Se or Si

The second compound semiconductor layer 222 has a three-layer structure of p-Al _0.47 Ga _0.53 As: Zn / i-Al _0.30 Ga _0.70 As (carbon autodope) / i-Al _0.47 Ga _0.53 As (carbon autodope) ( i-Al _0.47 Ga _0.53 As may be used as the active layer side), and i-Al _0.30 Ga _0.70 As may function as the etching stop layer (also serving as the light guide layer). The same applies to the following embodiments.

In Example 2, light is generated in the active layer 223 by flowing current from the convex portion 211 to the remaining portion of the second compound semiconductor layer 222, the active layer 223, and the first compound semiconductor layer 221. Let Accordingly, in order to effectively cause current confinement, θ _D ≦ θ _111B ≦ θ _U (provided that θ _D ≠ θ so that the bottom of the convex lower layer 211A is shortened and the base is brought closer to the active layer 223. _In the case of _U ), it is preferable to select a large value for H _U / (H _U + H _D ), θ _D , θ _U and a small value for W _U. Specifically, H _U = 1.5 μm or 1 μm, H _D = 0.5 μm, W _U = 0.5 μm can be given as typical examples. Since the bottom of the convex lower layer 211A may be targeted in the vicinity of the active layer 223, if θ _D and θ _U change, it is necessary to obtain a value completely different from the above-described values by back calculation. Needless to say, there are cases.

  Hereinafter, a method for forming a convex portion of Example 2, in which a convex portion extending in parallel with the <110> direction of the base is formed on the base having the {100} plane as a top surface, and the semiconductor light emitting device of Example 2 and its manufacture A method will be described.

[Step-200]
First, based on a known method, on the main surface of the element manufacturing substrate 210 having a {100} plane as a main surface, a first compound semiconductor layer 221, an active layer 223, and a second compound semiconductor layer 222 are formed. The light emitting unit 220 having the {100} plane as the top surface of the second compound semiconductor layer 222 is formed.

[Step-210]
Next, a convex portion 211 extending in parallel with the <110> direction is formed in a part of the second compound semiconductor layer 222 in the thickness direction. Hereinafter, [Step-210] will be described by being divided into [Step-210A] to [Step-210C].

[Step-210A]
Specifically, a mask layer 261 extending in parallel with the <110> direction is formed on the second compound semiconductor layer 222 that is a base. Specifically, in Example 2, after a mask layer 261 made of SiO ₂ is formed on the second compound semiconductor layer 222 (base) by the CVD method, the base layer is formed by lithography and dry etching techniques. A mask layer 261 extending in parallel with the <110> direction (more specifically, the [011] A direction) is formed on the second compound semiconductor layer 222 (see FIG. 9A).

[Step-210B]
Next, using the mask layer 261 as an etching mask, the second compound semiconductor layer 222 is etched by a wet etching method using an etchant. Even in Example 2, citric acid: pure water: hydrogen peroxide solution = 3: 3: 2 (volume ratio) was used as the etching solution, and the etching solution was 6 to 9 ° C. Wet etching was performed. As a result, as shown in FIG. 9B, the cross-sectional shape when cut along the {110} plane is an isosceles trapezoid whose base is longer than the top, and the inclination angle of the side surface 211b is A convex upper layer 211B having θ _U can be formed.

[Step-210C]
Next, the temperature of the etching solution is changed, and the second compound semiconductor layer 222 as a base is further etched by a wet etching method using the mask layer 261 and the side surface 211b of the convex upper layer 211B as an etching mask. More specifically, citric acid perwater having the above-described composition was used, and wet etching was performed at an etching solution of 2 to 5 ° C. By the way, the side surface 211b of the convex upper layer 211B obtained in [Step-210B] is an etching stable crystal plane in wet etching, and wet etching is performed using the mask layer 261 and the side surface 211b of the convex upper layer 211B as an etching mask. In [Step-210C], the side surface 211b of the convex upper layer 211B is not etched. Thus, the cross-sectional shape when cut along the {110} plane is an isosceles trapezoid whose base is longer than the top, and the inclination angle of the side surface 211a is θ _D (where θ _D ≠ θ _U ) Which is a convex lower layer 211A (see FIG. 10). Since the temperature of the etching solution in [Step-210B] was set higher than the temperature of the etching solution in [Step-210C], θ _D <θ _111B <θ _U was satisfied. Thus, a double trapezoidal convex portion 211 extending in the [011] A direction and having a desired top face width and overall height can be formed. Here, the width direction of the convex portion 211 is parallel to the [0-11] B direction.

[Step-220]
Thereafter, an insulating film 212 made of SiO ₂ is formed on the entire surface, and the insulating film 212 on the top surface of the convex upper layer 211B is removed. Then, the second electrode 252 is formed on the top surface of the exposed convex upper layer 211B based on the vacuum deposition method, and on the other hand, the element manufacturing substrate 210 is lapped from the back side to an appropriate thickness, and then the first electrode 251 is formed. It forms based on a vacuum evaporation method.

[Step-230]
Thereafter, the semiconductor light emitting element can be obtained by separating the semiconductor light emitting element. The semiconductor light emitting elements may be separated one by one, or a large number (for example, 4, 8, 16, 32, 64, etc.) are grouped together and separated into each other. Also good.

Example 3 relates to a convex portion provided on a base according to the second aspect of the present invention, a semiconductor light emitting element according to the third aspect of the present invention, and a modification of the convex portion forming method of the present invention. The present invention relates to a modification of the method for manufacturing a semiconductor light emitting device according to the second aspect. In Example 2, θ _D <θ _111B <θ _U was set. On the other hand, in Example 3, θ _U <θ _111B <θ _D is set, as shown in a schematic partial cross-sectional view in FIG. The semiconductor light emitting device of Example 3 is also composed of an ISAN type semiconductor laser as in Example 2. Here, when the constituent elements in the semiconductor light emitting element of Example 3 and the constituent elements in the semiconductor light emitting element of Example 2 are substantially the same, the reference numerals of the constituent elements in the semiconductor light emitting element of Example 3 The digit and the last two digits of the component reference numbers in the semiconductor light emitting device of Example 2 are the same.

  The convex portion 311 provided on the base of Example 3 is provided on the base (second compound semiconductor layer 322) having the {100} plane as the top surface, and the <110> direction of the base (second compound semiconductor layer 322). It is the convex part extended in parallel. And it has a two-layer structure of the convex lower layer 311A and the convex upper layer 311B, and the cross-sectional shape when the convex upper layer 311B is cut along the {110} plane is an equal leg whose base is longer than the upper side. It is trapezoidal, and the cross-sectional shape when the convex lower layer 311A is cut along the {110} plane is an isosceles trapezoid whose base is longer than the upper side, and the convex upper layer 311B is cut along the {110} plane. The bottom side in the cross-sectional shape is the top side in the cross-sectional shape when the convex lower layer 311A is cut along the {110} plane.

  The semiconductor light emitting device of Example 3 includes the first compound semiconductor layer 321, the active layer 323, and the second compound semiconductor layer 322, and the top surface of the second compound semiconductor layer 322 is a {100} plane. And the second compound semiconductor layer 322 is provided with a convex portion 311 extending in parallel with the <110> direction. And it has a two-layer structure of the convex lower layer 311A and the convex upper layer 311B, and the cross-sectional shape when the convex upper layer 311B is cut along the {110} plane is an equal leg whose base is longer than the upper side. It is trapezoidal, and the cross-sectional shape when the convex lower layer 311A is cut along the {110} plane is an isosceles trapezoid whose base is longer than the upper side, and the convex upper layer 311B is cut along the {110} plane. The bottom side in the cross-sectional shape is the top side in the cross-sectional shape when the convex lower layer 311A is cut along the {110} plane.

The above configuration and structure are the same as those in the second embodiment. In Example 3, the inclination angle of the side surface 311b of the convex portion upper layer 311B is θ _U , the inclination angle of the side surface 311a of the convex portion lower layer 311A is θ _D , and the side surface of the convex portion is the (111) B surface. When the inclination angle of the side surface is θ _111B ,
θ _D ≠ θ _U
In particular,
θ _U ≦ θ _111B ≦ θ _D (However, θ _D ≠ θ _U )
Satisfied. More specifically,
θ _U <θ _111B <θ _D
Satisfied. More specifically, in Example 3, θ _111B = 54.7 degrees, θ _U = 50 degrees, and θ _D = 60 degrees.

As described above, in the case of an ISAN type semiconductor laser, the design philosophy is different from that in the case of an SDH type semiconductor laser, so the role played by the side face is completely different, and H _U / (H _U + H _D ) or (H _U + H _There are no strict restrictions on conditions such as _D ) / W _U. However, a design that effectively causes current constriction is important. Specifically, shortening the bottom of the convex lower layer 311A and bringing the bottom close to the active layer 323 may be an important point for suppressing the diffusion current. For example, FIG. 11 shows an ISAN type semiconductor laser that performs current confinement by insulating an entire recess (a surface including the side surface 311b and the side surface 311a) with an insulating layer 312. In order to obtain a structure that is more effective than the optical confinement control effect by such a structure, instead of covering the recess with the insulating layer 312, as shown in a schematic partial cross-sectional view in FIG. And a structure in which a recess is embedded by a junction type compound semiconductor layer laminated structure 370 (in the example shown in FIG. 12, an npn structure) that is easily lattice-matched with the underlying layer and has a lower refractive index than the material of the active layer 323. do it. This
It is possible to achieve a buried structure having two roles of (1) role as a current blocking layer and (2) role as an optical confinement control layer.

In the case of embedded crystal growth in which the recess is filled with the junction type compound semiconductor layer laminated structure 370, the mask layer may be used as it is as a selective growth mask. In this case, after the embedded crystal growth is completed, the mask layer is removed by a normal etching method, and then the second electrode 352 may be formed on the convex portion, and the mask layer is made of a conductive material. In some cases, the second electrode 352 can be used as it is after the embedded crystal is grown. Alternatively, as shown in FIG. 12, after forming the structure shown in FIG. 11 (however, the insulating film 312 and the second electrode 352 are not formed), the mask layer is removed by a normal etching method, and the recess is formed. The junction type compound semiconductor layer stack structure 370 may be embedded. FIG. 12 shows an example of embedding with an npn structure. However, in this case, a triangular junction-type compound semiconductor layer laminated structure 371 (in the example shown in FIG. 12, a triangular shape of an npn structure) is also formed on the top surface of the convex portion. Therefore, it is necessary to remove the junction type compound semiconductor layer stacked structure 371 until the layer 311B on the top surface of the convex portion is exposed by etching after the filling of the concave portion is completed. Note that after the removal, the second electrode 352 may be formed so that a current flows through the convex portion as described above. In Example 3, when the thickness of the convex upper layer 311B is H _U , the thickness of the convex lower layer 311A is H _D , and the width of the convex upper layer 311B is W _U , H _U = 0.5 μm, A typical example is H _D = 1.5 μm or 1 μm and W _U = 0.5 μm.

Except for the above points, the configuration and structure of the semiconductor light-emitting device of Example 3 can be the same as the configuration and structure of the semiconductor light-emitting device of Example 2, and thus detailed description thereof is omitted. By the way, as in the case of Example 2, in order to effectively cause current confinement, the bottom side of the convex lower layer 311A is shortened and the bottom side is brought close to the active layer 323, so that θ _U ≦ θ _111B ≦ When θ _D (where θ _D ≠ θ _U ), select a small value for H _U / (H _U + H _D ), a large value for θ _D and θ _U , and a small value for W _U It is preferable to do. Specifically, for example, H _U = 0.5 μm, H _D = 1.5 μm or 1 μm, and W _U = 0.5 μm can be given as typical examples. In addition, since it is only necessary to aim at shortening the bottom of the convex lower layer 311A in the vicinity of the active layer 323, if θ _D and θ _U are changed, it is necessary to obtain values completely different from the above-described values by back calculation. Needless to say, there are cases.

  In Example 3, the etchant temperature during wet etching in [Step-210B] in Example 2 was set to 2 to 5 ° C., and the etchant temperature during wet etching in [Step-210C] in Example 2 May be 6-9 ° C.

  Example 4 is a modification of the method for forming a convex portion of the present invention, a deformation of the convex portion provided on the base according to the first aspect of the present invention, a deformation of the semiconductor light emitting device according to the second aspect of the present invention, and The invention relates to a modification of the method for manufacturing a semiconductor light emitting device according to the second aspect of the present invention.

  The semiconductor light emitting device of Example 4 is composed of a SAN type semiconductor laser. That is, as shown in a schematic partial cross-sectional view in FIG. 13 or FIG. 14, in Example 4, the convex portion 411 corresponds to a region for confining current, that is, the convex portion 411 passes current. There is no area. The convex portion 411 is formed by previously growing a first compound semiconductor layer 421 and an active layer 423 on a substrate and then bonding-type compound semiconductor layer stacked structure (in FIG. 13 or FIG. 14, the first compound semiconductor layer 421 layer). The above npn structure) is crystal-grown, and after forming a mask layer, for example, it can be obtained by performing etching in the same manner as in [Step-210] of Example 2.

The SAN type semiconductor laser is composed of two convex portions 411 and a concave portion sandwiched between these convex portions 411. Here, in the example shown in FIGS. 13 and 14, the concave portion sandwiched between the two convex portions 411 is embedded in the third compound semiconductor layer 424. Note that light is generated in the active layer 423 by flowing current through the third compound semiconductor layer 424, the remaining portion of the second compound semiconductor layer 422, the active layer 423, and the first compound semiconductor layer 421. Therefore, in the SAN type semiconductor laser, in the case of θ _D ≦ θ _111B ≦ θ _U (where θ _D ≠ θ _U ), the pitch of the two convex portions 411 is set to effectively generate current confinement. It is preferable to select a large value for H _D / (H _U + H _D ), θ _D , and θ _U so as to reduce the length, make the bottom of the convex lower layer 411A longer, and bring the base closer to the active layer 423. . Specifically, for example, the same outer shape of the convex portion as that of the ISAN type semiconductor laser shown in Example 2 or Example 3 can be mentioned.

However, in the case of a SAN type semiconductor laser, the convex portion 411 is only a current blocking layer. Therefore, when there is a limit to reducing the pitch of the two convex portions 411 sandwiching the concave portion that is the current injection region, the bottom side of the convex lower layer 411A is long in order to more effectively confine the current in the concave portion. Should be the target. Therefore, the slopes with small inclination angles θ _D and θ _U are appropriately selected and etched as deeply as possible, or the slope with the extremely small inclination is used for the final bottom surface formation, or the slope with the extremely small inclination is the convex portion. What is necessary is just to employ | adopt the structure where the ratio which occupies all the sides of 411 is high. In any case, in the case of a SAN type semiconductor laser, if the junction type compound semiconductor layer laminated structure is a multi-layered structure having a sufficient number of laminated layers, for example, the current blocking layer is etched by the same etching as [Step-210] in Example 2. The bottom surface of the concave portion sandwiched between the two convex portions 411 having the above function can be shortened to the maximum, and a current confinement structure more optimized than that of an ISAN type semiconductor laser can be formed. It is advantageous.

  In the fourth embodiment, the outer shape of the convex portion 411 by etching can be the same as the outer shape of the convex portion 211 of the second embodiment. The semiconductor light emitting device of Example 4 is different from the semiconductor light emitting device of Example 2 in that a p-type third compound semiconductor layer 424 is formed between the convex portions 411 and 411, and p The second electrode 452 is formed on the type third compound semiconductor layer 424. Further, after forming a junction type compound semiconductor layer laminated structure 470 (see FIGS. 13 and 14) having a current blocking structure in advance, the junction type compound semiconductor layer laminated structure 470 is etched by the etching method according to the present invention. A convex portion 411 having the same shape or the same shape as the convex portion 211 is formed, and the current injection layer (p-type third compound semiconductor layer 424) is embedded in the concave portion. In FIG. 13, the p-type third compound semiconductor layer 424 that fills the recess may be a high-concentration p-type low-refractive-index compound semiconductor layer that can be stacked using the second compound semiconductor layer 422 as a base layer. The crystal growth method may be the LPE method, the MOCVD method, or the PPD method as long as it can be embedded and grown. The example shown in FIG. 13 is an example in which a recess for current injection is embedded using the MOCVD method, but when embedded by the LPE method, the shape is simply flatly embedded. In addition, when performing the buried growth of the concave portion for current injection using the MOCVD method, if the mask layer is removed, it is the same as when forming the SDH type semiconductor laser on the top surface of the convex portion 411 having the current blocking function. Since the {111} B non-growth surface appears, a triangular layer 424 'is formed. Then, after completion of the recess burying growth for current injection, the triangular layer 424 ′ is removed by ordinary etching, and then a second electrode (transparent electrode layer) 452 is laminated on the third compound semiconductor layer 424. Alternatively, the second electrode (transparent electrode layer) 452 may be formed on the third compound semiconductor layer 424 without removing the triangular layer 424 ′. Further, in the case of a light emitting diode, in particular, crystal growth is performed in advance so that the second electrode can be formed in the recessed portion formed by etching without performing embedded growth in the recessed portion. You may form a 2nd electrode (transparent electrode layer) on a recessed part after the recessed part formation based on. Here, when the shape or the component in the semiconductor light emitting device of Example 4 is substantially the same as the shape or the component in the semiconductor light emitting device of Example 2, the components of the semiconductor light emitting device of Example 4 The last two digits of the reference number are the same as the last two digits of the component reference numbers in the semiconductor light emitting device of Example 2.

Also in the case of a SAN type semiconductor laser, the design philosophy is different from that in the case of an SDH type semiconductor laser, so the roles played by the side faces are completely different, and H _U / (H _U + H _D ) or (H _U + H _D ) / W _There are no strict restrictions on conditions such as _U. However, in order to design the current confinement structure while paying attention to the difference from the current confinement structure in the ISAN type semiconductor laser, first, the pitch of the convex portion is designed to be narrow, and then the inclination angle constituting the side surface of the convex portion. It is necessary to increase the ratio of the small slope of the entire surface of the convex portion to narrow the concave portion. In Example 4, when the thickness of the convex upper layer 411B is H _U , the thickness of the convex lower layer 411A is H _D , and the width of the convex upper layer 411B is W _U , specifically, Typical examples are H _U = 1.5 μm or 1 μm, H _D = 0.5 μm, W _U = 0.5 μm, or H _U = 0.5 μm, H _D = 1.5 μm or 1 μm, W _U = 0.5 μm Can be mentioned.

  Example 5 is a modification of the method for forming a convex portion of the present invention, a deformation of the convex portion provided on the base according to the second aspect of the present invention, a deformation of the semiconductor light emitting device according to the third aspect of the present invention, and The invention relates to a modification of the method for manufacturing a semiconductor light emitting device according to the second aspect of the present invention.

  The semiconductor light emitting device of Example 5 is also composed of a SAN type semiconductor laser, as in Example 4. That is, as shown in the schematic partial cross-sectional views in FIGS. 15 and 16, even in Example 5, the convex portion 511 corresponds to a region where current is constricted, that is, the convex portion 511 passes current. From the third compound semiconductor layer 524 formed between the protrusions 511 and 511 to the rest of the second compound semiconductor layer 522, the active layer 523, and the first compound semiconductor layer 521, By passing a current, light is emitted in the active layer 523.

  In the fifth embodiment, the outer shape of the protruding portion 511 by etching can be the same as the outer shape of the protruding portion 311 of the third embodiment. The semiconductor light emitting device of Example 5 is different from the semiconductor light emitting device of Example 3 in that a p-type third compound semiconductor layer 524 is formed between the convex portions 511 and 511, and p The second electrode 552 is formed on the type third compound semiconductor layer 524. Further, after forming a junction type compound semiconductor layer stack structure 570 (see FIGS. 15 and 16) having a current blocking structure in advance, the junction type compound semiconductor layer stack structure 570 is etched by the etching method according to the present invention. A convex portion 511 having the same shape or the same shape as the convex portion 311 is formed, and a current injection layer (p-type third compound semiconductor layer 524) is embedded in the concave portion. In addition, when the component in the semiconductor light emitting element of Example 5 and the component in the semiconductor light emitting element of Example 3 are substantially the same, the last two digits of the reference number of the component in the semiconductor light emitting element of Example 5 And the last two digits of the component reference numbers in the semiconductor light emitting device of Example 2 are the same.

  Also, the difference between the configuration and structure of the semiconductor light emitting device of Example 5 and the configuration and structure of the semiconductor light emitting device of Example 4 is the relationship between the angle of the upper and lower slopes of the convex portion 411 of Example 4, and The relationship between the angles of the upper and lower slopes of the convex portion 511 of Example 5 is merely opposite. The detailed description of the design method for designing the concave portion constricted by the two convex portions 511 and the points to be noted are the same as in the description of the fourth embodiment, and a description thereof will be omitted.

  As mentioned above, although this invention was demonstrated based on the preferable Example, this invention is not limited to these Examples. The configurations and structures of the semiconductor light emitting elements described in the examples, the materials constituting the semiconductor light emitting elements, the manufacturing conditions and various numerical values of the semiconductor light emitting elements are examples, and can be changed as appropriate. In the embodiment, the first conductivity type is n-type and the second conductivity type is p-type. Conversely, the first conductivity type may be p-type and the second conductivity type may be n-type.

  The convex portion provided on the base according to the first aspect or the second aspect of the present invention, and the convex portion forming method of the present invention include, for example, a buried hetero laser, a manufacturing method thereof, a surface emitting (laser) element, and a The present invention can also be applied to a manufacturing method, an LED and a manufacturing method thereof, a heterojunction bipolar transistor and a manufacturing method thereof, a photodiode and a manufacturing method thereof, a solar cell and a manufacturing method thereof. Specifically, in the case where the formation of recesses or isolation grooves for separating these elements, particularly when etching control such as width, depth, pitch, etc., is required over a wide area in the wafer surface, the projections of the present invention are required. The part forming method can be effectively applied. And what is necessary is just to form these elements in the convex part provided in the foundation | substrate which concerns on the 1st aspect or 2nd aspect of this invention.

FIG. 1 is a schematic partial cross-sectional view of a convex portion in the first embodiment. 2A and 2B are schematic partial cross-sectional views of an SDH type semiconductor laser that is a semiconductor light emitting device of Example 1. FIG. 3A to 3C are schematic partial cross-sectional views of an element manufacturing substrate and the like for explaining the method for manufacturing the semiconductor light emitting element of Example 1. FIG. 4A to 4C are schematic partial views of a device manufacturing substrate, etc., schematically showing the process of crystal growth of the laminated structure in the manufacture of the semiconductor light emitting device of Example 1. FIG. It is sectional drawing. FIG. 5 is a schematic partial cross-sectional view of an element manufacturing substrate and the like for explaining the method for manufacturing the semiconductor light emitting element of Example 1 following FIG. FIG. 6 is a schematic partial cross-sectional view of an element manufacturing substrate and the like for explaining the method for manufacturing the semiconductor light emitting element of Example 1 following FIG. FIG. 7 is a schematic partial cross-sectional view of an ISAN type semiconductor laser which is a semiconductor light emitting device of Example 2. FIG. 8 is a schematic partial cross-sectional view of a modified example of an ISAN type semiconductor laser that is a modified example of the semiconductor light emitting device of the second embodiment. FIGS. 9A and 9B are schematic partial cross-sectional views of an element manufacturing substrate and the like for explaining a method for manufacturing a semiconductor light emitting element of Example 2. FIG. FIG. 10 is a schematic partial cross-sectional view of an element manufacturing substrate and the like for explaining the method for manufacturing the semiconductor light emitting element of Example 2 following FIG. 9B. FIG. 11 is a schematic partial cross-sectional view of an ISAN type semiconductor laser which is a semiconductor light emitting device of Example 3. FIG. 12 is a schematic partial cross-sectional view of a modified example of an ISAN type semiconductor laser that is a modified example of the semiconductor light emitting device of the third embodiment. FIG. 13 is a schematic partial cross-sectional view of a SAN type semiconductor laser that is a semiconductor light emitting element of Example 4. FIG. 14 is a schematic partial cross-sectional view of a modification of a SAN type semiconductor laser that is a modification of the semiconductor light emitting device of the fourth embodiment. FIG. 15 is a schematic partial cross-sectional view of a SAN type semiconductor laser that is a semiconductor light emitting device of Example 5. FIG. 16 is a schematic partial cross-sectional view of a modification of a SAN type semiconductor laser that is a modification of the semiconductor light emitting element of Example 5. 17A and 17B are schematic partial cross-sectional views of a light-emitting element manufacturing substrate and the like for explaining problems in a conventional semiconductor light-emitting element. 18A and 18B are schematic partial sectional views of a light emitting element manufacturing substrate and the like for explaining another problem in the conventional semiconductor light emitting element. 19A to 19C are conceptual diagrams of a substrate for manufacturing a light-emitting element, which summarizes problems in the conventional semiconductor light-emitting element.

Explanation of symbols

110, 210, 310, 410, 510... Device manufacturing substrate, 111, 211, 311, 411, 511... Convex part, 111A, 211A, 311A, 411A, 511A ... Convex part lower layer, 111a, 211a, 311a, 411a, 511a ... the side of the convex lower layer, 111B, 211B, 311B, 411B, 511B ... the convex upper layer, 111b, 211b, 311b, 411b, 511b ... the side of the convex upper layer, 212, 312 ... insulating film, 120, 220, 320, 420, 520 ... light emitting part, 120 ', ... laminated structure, 121, 221, 321, 421, 521 ... first compound semiconductor Layer 122, 122A, 122B, 222, 322, 422, 522 ... second compound semiconductor layer, 424, 544 ... third compound half Body layer, 123, 223, 323, 423, 523 ... active layer, 130, ... current blocking layer position adjusting layer, 131, ... buried layer, 132, ... contact layer (cap layer) , 140,... Current blocking layer, 151.251, 351, 451, 551 ... first electrode, 152, 252, 352, 452, 552 ... second electrode, 161, 261 ... mask layer 270, 271, 370, 371, 470, 570... Junction type compound semiconductor layer laminated structure, 424 ′, 524 ′... Triangular layer

Claims (28)

A method of forming a protrusion extending in parallel with the <110> direction of a base on a base having a {100} plane as a top surface,
(A) After forming a mask layer extending in parallel with the <110> direction on the base,
(B) Using the mask layer as an etching mask, the base is etched by a wet etching method using an etchant, and the cross-sectional shape when cut along the {110} plane is such that the bottom is longer than the upper. Is a long isosceles trapezoid, and forms a convex upper layer whose side slope angle is θ _U ,
(C) The cross-sectional shape when the temperature of the etching solution is changed and the base layer is further etched by the wet etching method using the side surfaces of the mask layer and the convex upper layer as an etching mask and cut by the {110} plane is obtained. Forming a convex lower layer that is an isosceles trapezoid whose base is longer than the top and whose side surface has an inclination angle θ _D (where θ _D ≠ θ _U ).
A method for forming a convex portion on a ground, comprising each step. The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface when the side surface of the convex portion is the (111) B surface is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
The convex part formation method in the base | substrate of Claim 1 which satisfies these.   The method for forming a protrusion on a base according to claim 2, wherein the temperature of the etching solution in the step (b) is higher than the temperature of the etching solution in the step (c). The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface when the side surface of the convex portion is the (111) B surface is θ _111B ,
θ _U ≦ θ _111B ≦ θ _D (However, θ _D ≠ θ _U )
The convex part formation method in the base | substrate of Claim 1 which satisfies these.   The method for forming a protrusion on a base according to claim 4, wherein the temperature of the etching solution in the step (b) is lower than the temperature of the etching solution in the step (c). (A) forming a convex portion extending in parallel with the <110> direction of the element manufacturing substrate on the main surface of the element manufacturing substrate having a {100} plane as a main surface;
(B) On the top surface of the convex portion, a light emitting portion is formed by sequentially laminating a first compound semiconductor layer having a first conductivity type, an active layer, and a second compound semiconductor layer having a second conductivity type. In addition, the first compound semiconductor layer having the first conductivity type, the active layer, and the second compound semiconductor layer having the second conductivity type are formed on the main surface portion of the element manufacturing substrate on which no protrusion is formed. Are sequentially stacked to form a laminated structure, and then
(C) forming a current blocking layer covering at least the side surface of the active layer constituting the light emitting portion on the laminated structure;
Comprising steps,
The step (A)
(A) After forming a mask layer extending in parallel with the <110> direction on the main surface of the element manufacturing substrate,
(B) Using the mask layer as an etching mask, the main surface of the device manufacturing substrate is etched by a wet etching method using an etchant, and the cross-sectional shape when cut along the {110} plane is the length of the bottom. Is an isosceles trapezoid whose length is longer than the length of the upper side, and forms a convex upper layer whose side slope angle is θ _U ,
(C) Varying the temperature of the etching solution, using the side surfaces of the mask layer and the convex upper layer as an etching mask, further etching the main surface of the element manufacturing substrate by the wet etching method, and cutting at the {110} plane The cross-sectional shape is an isosceles trapezoid whose base is longer than the top and the side slope is θ _D (where θ _D ≠ θ _U ) to form a convex lower layer ,
A method for manufacturing a semiconductor light-emitting device, which comprises each step. The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface when the side surface of the convex portion is the (111) B surface is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
The manufacturing method of the semiconductor light-emitting device according to claim 6 satisfying the above.   The method of manufacturing a semiconductor light emitting element according to claim 7, wherein the temperature of the etching solution in the step (b) is higher than the temperature of the etching solution in the step (c). When the thickness of the protrusion upper and H _U, the thickness of the convex subordinate layer and H _D,
H _U / (H _U + H _D ) ≧ 0.5
The manufacturing method of the semiconductor light-emitting device according to claim 6 satisfying the above. H _U / (H _U + H _D ) ≧ 0.7
The manufacturing method of the semiconductor light-emitting device according to claim 9 satisfying When the thickness of the convex upper layer is H _U , the thickness of the convex lower layer is H _D , and the width of the convex upper layer is W _U ,
(H _U + H _D ) / W _U ≧ 0.4
The manufacturing method of the semiconductor light-emitting device according to claim 6 satisfying the above. (H _U + H _D ) / W _U ≧ 0.9
The manufacturing method of the semiconductor light-emitting device according to claim 11, wherein: A thickness of the second compound semiconductor layer in a semiconductor light emitting device including a light emitting portion that includes a first compound semiconductor layer, an active layer, and a second compound semiconductor layer, and a top surface of the second compound semiconductor layer is a {100} plane. A method of manufacturing a semiconductor light emitting device, comprising forming a protrusion extending in parallel with the <110> direction in a part of the direction,
The formation process of the convex part
(A) After forming a mask layer extending in parallel with the <110> direction on the top surface of the second compound semiconductor layer,
(B) Using the mask layer as an etching mask, the second compound semiconductor layer is partially etched in the thickness direction by a wet etching method using an etchant, and the cross-sectional shape when cut along the {110} plane is Forming a convex upper layer having an isosceles trapezoid in which the length of the base is longer than the length of the upper side, and the inclination angle of the side surface is θ _U ;
(C) The second compound semiconductor layer is partially etched in the thickness direction by a wet etching method by changing the temperature of the etching solution and using the side surfaces of the mask layer and the convex upper layer as an etching mask, and { 110} plane, the cross-sectional shape is an isosceles trapezoid whose base is longer than the top, and the slope of the side is θ _D (where θ _D ≠ θ _U ) Forming subordinates,
A method for manufacturing a semiconductor light-emitting device, which comprises each step. The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface when the side surface of the convex portion is the (111) B surface is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
The method for manufacturing a semiconductor light emitting device according to claim 13, wherein:   The method of manufacturing a semiconductor light emitting element according to claim 14, wherein the temperature of the etching solution in the step (b) is higher than the temperature of the etching solution in the step (c). The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface when the side surface of the convex portion is the (111) B surface is θ _111B ,
θ _U ≦ θ _111B ≦ θ _D (However, θ _D ≠ θ _U )
The method for manufacturing a semiconductor light emitting device according to claim 13, wherein:   The method of manufacturing a semiconductor light emitting element according to claim 16, wherein the temperature of the etching solution in the step (b) is lower than the temperature of the etching solution in the step (c). A convex portion provided on a base having a {100} plane as a top surface and extending in parallel with the <110> direction of the base;
It has a two-layer structure of a convex lower layer and a convex upper layer,
The cross-sectional shape when the convex upper layer is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The cross-sectional shape when the lower layer of the convex portion is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface of the convex upper layer is θ _U , the inclination angle of the side surface of the convex lower layer is θ _D , and the inclination angle of the side surface when the side surface of the convex portion is the (111) B plane is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
Convex part provided on the ground that satisfies the requirements. A convex portion provided on a base having a {100} plane as a top surface and extending in parallel with the <110> direction of the base;
It has a two-layer structure of a convex lower layer and a convex upper layer,
The cross-sectional shape when the convex upper layer is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The cross-sectional shape when the lower layer of the convex portion is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface of the convex upper layer is θ _U , the inclination angle of the side surface of the convex lower layer is θ _D , and the inclination angle of the side surface when the side surface of the convex portion is the (111) B plane is θ _111B ,
θ _U ≦ θ _111B ≦ θ _D (However, θ _D ≠ θ _U )
Convex part provided on the ground that satisfies the requirements. (A) A convex portion provided on the main surface of the element manufacturing substrate having a {100} plane as a main surface and extending parallel to the <110> direction of the element manufacturing substrate;
(B) a light emitting unit in which a first compound semiconductor layer having a first conductivity type, an active layer, and a second compound semiconductor layer having a second conductivity type are sequentially stacked on a top surface of a convex portion;
(C) a first compound semiconductor layer having a first conductivity type, an active layer, and a second compound semiconductor having a second conductivity type, which are formed on a main surface portion of the element manufacturing substrate on which no protrusion is formed. A laminated structure in which the layers are sequentially laminated, and a current blocking layer formed on the laminated structure and covering at least the side surface of the active layer constituting the light emitting unit,
It has
The convex part has a two-layer structure of a convex part lower layer and a convex part upper layer,
The cross-sectional shape when the convex upper layer is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The cross-sectional shape when the lower layer of the convex portion is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface of the convex upper layer is θ _U , the inclination angle of the side surface of the convex lower layer is θ _D , and the inclination angle of the side surface when the side surface of the convex portion is the (111) B plane is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
A semiconductor light emitting device that satisfies the requirements. When the thickness of the protrusion upper and H _U, the thickness of the convex subordinate layer and H _D,
H _U / (H _U + H _D ) ≧ 0.5
21. The semiconductor light emitting device according to claim 20, wherein H _U / (H _U + H _D ) ≧ 0.7
The semiconductor light-emitting device according to claim 21, wherein: When the thickness of the convex upper layer is H _U , the thickness of the convex lower layer is H _D , and the width of the convex upper layer is W _U ,
(H _U + H _D ) / W _U ≧ 0.4
21. The semiconductor light emitting device according to claim 20, wherein (H _U + H _D ) / W _U ≧ 0.9
24. The semiconductor light emitting device according to claim 23, wherein: The first compound semiconductor layer includes an active layer and a second compound semiconductor layer. The second compound semiconductor layer includes a light emitting portion whose top surface is a {100} plane, and the second compound semiconductor layer has a <110> direction. A semiconductor light emitting element provided with a convex portion extending in parallel with
The convex part has a two-layer structure of a convex part lower layer and a convex part upper layer,
The cross-sectional shape when the convex upper layer is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The cross-sectional shape when the lower layer of the convex portion is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface of the convex upper layer is θ _U , the inclination angle of the side surface of the convex lower layer is θ _D , and the inclination angle of the side surface when the side surface of the convex portion is the (111) B plane is θ _111B ,
θ _D ≦ θ _111B ≦ θ _U (However, θ _D ≠ θ _U )
A semiconductor light emitting device that satisfies the requirements. The first compound semiconductor layer includes an active layer and a second compound semiconductor layer. The second compound semiconductor layer includes a light emitting portion whose top surface is a {100} plane, and the second compound semiconductor layer has a <110> direction. A semiconductor light emitting element provided with a convex portion extending in parallel with
It has a two-layer structure of a convex lower layer and a convex upper layer,
The cross-sectional shape when the convex upper layer is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The cross-sectional shape when the lower layer of the convex portion is cut along the {110} plane is an isosceles trapezoid whose base is longer than the top.
The base in the cross-sectional shape when the convex upper layer is cut along the {110} plane is the upper side in the cross-sectional shape when the convex lower layer is cut along the {110} plane,
When the inclination angle of the side surface of the convex upper layer is θ _U , the inclination angle of the side surface of the convex lower layer is θ _D , and the inclination angle of the side surface when the side surface of the convex portion is the (111) B plane is θ _111B ,
θ _U ≦ θ _111B ≦ θ _D (However, θ _D ≠ θ _U )
A semiconductor light emitting device that satisfies the requirements.   27. The semiconductor light emitting device according to claim 25 or 26, wherein a light is caused to flow in the active layer by flowing a current from the convex portion to the remainder of the second compound semiconductor layer, the active layer, and the first compound semiconductor layer. element. The convex portion corresponds to a region where current is confined,
By emitting current from the third compound semiconductor layer formed between the protrusions to the rest of the second compound semiconductor layer, the active layer, and the first compound semiconductor layer, light is emitted in the active layer. 27. The semiconductor light emitting device according to claim 25 or 26, which is generated.

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