JPWO2015194244A1 - Light emitting device and manufacturing method thereof - Google Patents

Abstract

The light emitting element is formed over the GaN substrate 11, the plurality of selective growth mask layers 43, the first light reflecting layer 41 including one of the plurality of selective growth mask layers 43, and the plurality of selective growth mask layers. The laminated structure 20, the second electrode 32, and the second light reflecting layer 42 are provided, and a GaN substrate is provided at the bottom of the selective growth mask layer opening region 51 located between the selective growth mask layers 43. 11 is provided with a seed crystal layer growth region 52 composed of a part of the exposed surface, a seed crystal layer 61 is formed on the seed crystal layer growth region 52, and the lower layer 21 of the laminated structure 20 is The seed crystal layer 61 is formed based on lateral epitaxial growth, and the thickness of the seed crystal layer 61 is smaller than the thickness of the selective growth mask layer 43.

Description

  The present disclosure relates to a light emitting device (specifically, a vertical cavity laser, a surface emitting laser device also called a VCSEL) and a manufacturing method thereof.

  In a surface emitting laser element, laser oscillation generally occurs by resonating light between two light reflecting layers (Distributed Bragg Reflector layer, DBR layer). Therefore, it is necessary to smooth the semiconductor surface for forming the DBR layer on the sub-nanometer order. If an appropriate smoothness cannot be obtained, the light reflectivity of each DBR layer is lowered, and variations in characteristics (e.g., oscillation threshold) are increased, and it is difficult to obtain laser oscillation.

A method of manufacturing a nitride surface emitting laser using a selective growth method is known from Japanese Patent Laid-Open No. 10-308558. That is, the manufacturing method of the nitride semiconductor laser element disclosed in this patent publication is as follows:
Selectively forming a multilayer film made of a dielectric on the substrate surface;
Growing a nitride semiconductor layer on top of the multilayer film;
Growing a nitride semiconductor layer including an active layer on top of the nitride semiconductor layer formed on the multilayer film;
A step of making the multilayer film a reflecting mirror of at least one of the light emission of the active layer,
Including.

  Then, in order to grow the nitride semiconductor layer on the multilayer film, a seed crystal layer is formed on the surface of the portion of the substrate located between the multilayer film and based on the lateral epitaxial growth from the seed crystal layer. A method of growing a nitride semiconductor layer is often employed.

JP-A-10-308558

  When the seed crystal layer is thick, the nitride semiconductor layer (compound semiconductor layer) formed on the multilayer film (selective growth mask layer) becomes thick (see FIG. 16), and the nitride semiconductor laser element (light emitting element) ) As a result, the light emitting element is adversely affected. That is, if the compound semiconductor layer is too thick, there are problems that the compound semiconductor layer itself absorbs light and that light that propagates through the waveguide is diffracted. Although it is possible to thin the compound semiconductor layer by polishing or dry etching, such post-epitaxial growth processing not only impairs precise film thickness controllability of epitaxial growth, but also damage caused by polishing and etching. A new problem of giving to the semiconductor layer is generated. Further, when the seed crystal layer is thick, when a compound semiconductor layer is grown from this seed crystal layer based on lateral epitaxial growth, dislocations from the seed crystal layer are aligned in the horizontal direction of the compound semiconductor layer on the selective growth mask layer. As a result of extending to the deep part (see FIG. 16), the characteristics of the light emitting element are adversely affected. The seed crystal layer can be made thinner by narrowing the portion of the substrate located between the selective growth mask layer and the selective growth mask layer. In this case, however, the selective growth mask layer and the selective growth mask are considered. It is difficult to form a selective growth mask layer having a narrow substrate portion located between the layers and a seed crystal layer.

  Accordingly, it is an object of the present disclosure to reduce the thickness of the entire compound semiconductor layer including the active layer, and to reliably ensure the portion of the substrate located between the selective growth mask layer and the selective growth mask layer. It is another object of the present invention to provide a light emitting device having a structure and structure capable of forming a seed crystal layer, and a method for manufacturing the same.

In order to achieve the above object, a light-emitting element of the present disclosure is provided.
GaN substrate,
A plurality of selective growth mask layers formed on a GaN substrate, each of which is provided apart from each other;
A first light reflecting layer comprising one of a plurality of selective growth mask layers;
A stacked structure including a first compound semiconductor layer, an active layer, and a second compound semiconductor layer formed over a plurality of selective growth mask layers; and
A second electrode and a second light reflecting layer formed on the second compound semiconductor layer;
At least,
At the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer, a seed crystal layer growth region composed of a part of the exposed surface of the GaN substrate is provided. And
A seed crystal layer is formed on the seed crystal layer growth region,
The first compound semiconductor layer is formed based on lateral epitaxial growth from the seed crystal layer,
The seed crystal layer is thinner than the selective growth mask layer. The thickness of the seed crystal layer refers to the distance from this interface to the top surface (or apex) of the seed crystal layer with reference to the interface between the selective growth mask layer and the GaN substrate. The thickness of the selective growth mask layer refers to the distance from this interface to the top surface of the selective growth mask layer. The same applies to the following description.

In order to achieve the above object, a method for manufacturing a light-emitting element of the present disclosure includes:
A plurality of selective growth mask layers, each of which is provided on the GaN substrate so as to be separated from each other and function as a first light reflecting layer, are formed together with the selective growth mask layer and the selective growth mask layer. After forming the seed crystal layer growth region on the surface of a part of the portion of the GaN substrate exposed at the bottom of the selective growth mask layer opening region located between
Forming a seed crystal layer thinner than the thickness of the selective growth mask layer on the seed crystal layer growth region;
Forming a first compound semiconductor layer from the seed crystal layer based on lateral epitaxial growth;
An active layer, a second compound semiconductor layer, a second electrode, and a second light reflecting layer are sequentially formed on the first compound semiconductor layer;
At least each step is included. The first compound semiconductor layer may be entirely covered with the selective growth mask layer, or a part of the selective growth mask layer may be covered. In addition, the top surface of the first compound semiconductor layer covering the selective growth mask layer may be flat or may have a recess in part.

  In the light emitting device and the manufacturing method thereof of the present disclosure, a seed crystal layer growth region is provided, and a seed crystal layer is formed on the seed crystal layer growth region, and the thickness of the seed crystal layer is selected. It is thinner than the thickness of the growth mask layer. Therefore, the thickness of the first compound semiconductor layer formed from the seed crystal layer based on the lateral epitaxial growth can be reduced. As a result, the entire thickness of the compound semiconductor layer including the active layer can be reduced. In addition, the seed crystal layer can be reliably formed in the portion of the substrate located between the selective growth mask layer and the selective growth mask layer. Note that the effects described in the present specification are merely examples and are not limited, and may have additional effects.

1A and 1B are a schematic partial cross-sectional view of the light-emitting element of Example 1, and a schematic partial end face in which a selective growth mask layer opening region and the like in the light-emitting element of Example 1 are enlarged. FIG. 2A, 2 </ b> B, and 2 </ b> C are schematic partial end views of a laminated structure and the like for describing the method for manufacturing the light-emitting element of Example 1. FIG. 3A and 3B are schematic partial end views of the laminated structure and the like for explaining the method for manufacturing the light-emitting element of Example 1, following FIG. 2C. 4A and 4B are schematic partial end views of a laminated structure and the like for explaining the method for manufacturing the light-emitting element of Example 1, following FIG. 3B. 5A and 5B are a schematic partial cross-sectional view of the light-emitting element of Example 2, and a schematic partial end face in which a selective growth mask layer opening region and the like in the light-emitting element of Example 2 are enlarged. FIG. 6A and 6B are a schematic partial cross-sectional view of the light-emitting element of Example 3, and a schematic partial end face in which a selective growth mask layer opening region and the like in the light-emitting element of Example 3 are enlarged. FIG. 7A and 7B are a schematic partial cross-sectional view of the light-emitting element of Example 4, and a schematic partial end face in which the selective growth mask layer opening region and the like in the light-emitting element of Example 4 are enlarged. FIG. FIG. 8 is a schematic partial cross-sectional view of the light-emitting element of Example 5. 9A and 9B are schematic partial cross-sectional views of the light-emitting element of Example 6 and its modification, respectively. 10A and 10B are schematic partial end views of a laminated structure and the like for describing the method for manufacturing the light-emitting element of Example 6. FIG. 11A and 11B are a schematic partial cross-sectional view of the light-emitting element of Example 7, and a schematic partial end face in which the selective growth mask layer opening region and the like in the light-emitting element of Example 1 are enlarged. FIG. 12A and 12B are schematic partial cross-sectional views of modifications of the light emitting element of Example 1. FIG. 13A and 13B are schematic partial end views of another modification of the light-emitting element of Example 1. FIG. 14A and 14B are schematic partial cross-sectional views of still another modification example of the light-emitting element of Example 1. FIG. FIG. 15 is a schematic plan view of the selective growth mask layer. FIG. 16 is a schematic partial end view of a light-emitting element for explaining problems in the conventional technology.

Hereinafter, although this indication is explained based on an example with reference to drawings, this indication is not limited to an example and various numerical values and materials in an example are illustrations. The description will be given in the following order.
1. 1. General description of the light emitting device of the present disclosure and the manufacturing method thereof. Example 1 (Light Emitting Element of the Present Disclosure and Method for Producing the Same)
3. Example 2 (Modification of Example 1)
4). Example 3 (another modification of Example 1)
5). Example 4 (another modification of Example 1)
6). Example 5 (Modification of Examples 1 to 4)
7). Example 6 (Modification of Examples 1 to 5)
8). Example 7 (modification of Example 1 to Example 6), others

[Description of Light-Emitting Element of the Present Disclosure and Method for Manufacturing the Same]
Hereinafter, the light-emitting element of the present disclosure or the light-emitting element obtained by the method for manufacturing the light-emitting element of the present disclosure may be collectively referred to as “light-emitting element of the present disclosure”. The surface of the first compound semiconductor layer facing the active layer is called the second surface of the first compound semiconductor layer, and the surface of the first compound semiconductor layer facing the second surface of the first compound semiconductor layer is the first compound semiconductor layer. May be referred to as the first surface. The surface of the second compound semiconductor layer facing the active layer is called the first surface of the second compound semiconductor layer, and the surface of the second compound semiconductor layer facing the first surface of the second compound semiconductor layer is the second compound semiconductor layer. May be referred to as the second surface.

In the light emitting device of the present disclosure, when the thickness of the seed crystal layer is T _seed and the thickness of the selective growth mask layer is T ₁ ,
0.1 ≦ T _seed / T ₁ <1
Is preferably satisfied.

And in the light emitting element of the present disclosure including the above preferred form,
An uneven portion is formed on the exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer,
It can be set as the structure by which the seed crystal layer growth area | region is comprised by the convex part. That is, this convex portion corresponds to a part of the exposed surface of the GaN substrate. In addition, the light emitting element of this indication of such a form is called "the light emitting element etc. which concern on the 1st structure of this indication" for convenience. In the light emitting element according to the first configuration of the present disclosure,
The exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers The cross-sectional shape is a shape in which concave portions, convex portions and concave portions are arranged in this order,
The seed crystal layer growth region can be configured by the top surface of the convex portion. Further, in this case, the length of the convex portion in the virtual vertical plane is L _cv , and the total length of the concave portions is L _{When cc}
0.2 ≦ L _cv / (L _cv + L _cc ) ≦ 0.9
It can be set as the structure which satisfies these. The number of convex portions formed on the exposed surface portion of the GaN substrate located at the bottom of the selective growth mask layer opening region may be two or more. Examples of the cross-sectional shape of the recess when the recess is cut in the virtual vertical plane include a rectangle, a triangle, a trapezoid (the upper side is the bottom surface of the recess), a shape with rounded corners, and a fine uneven shape in these shapes Can do. Examples of the depth of the recess include 0.1 μm or more, preferably 0.5 μm or more.

Alternatively, in the light-emitting element of the present disclosure including the above preferred form,
An uneven portion is formed on the exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer,
It can be set as the structure by which the seed crystal layer growth area | region is comprised by the recessed part. That is, this recess corresponds to a part of the exposed surface of the GaN substrate. In addition, the light emitting element of this indication of such a form is called "the light emitting element etc. which concern on the 2nd structure of this indication" for convenience. In the light emitting element according to the second configuration of the present disclosure,
The exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers The cross-sectional shape is a shape in which convex portions, concave portions and convex portions are arranged in this order,
The seed crystal layer growth region may be constituted by the bottom surface of the concave portion. In this case, the length of the concave portion in the virtual vertical plane is L _cc , and the total length of the convex portions is L _cv . When
0.2 ≦ L _cc / (L _cv + L _cc ) ≦ 0.9
It can be set as the structure which satisfies these. The number of recesses formed in the exposed surface portion of the GaN substrate located at the bottom of the selective growth mask layer opening region may be two or more. Examples of the shape of the top surface of the convex portion when the convex portion is cut on the virtual vertical plane include a flat shape, a shape curved upward, a shape curved downward, and a fine uneven shape. Examples of the depth of the recess include 0.1 μm or more, preferably 0.5 μm or more.

Alternatively, in the light-emitting element of the present disclosure including the above preferred form,
The exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers The cross-sectional shape is a shape in which an amorphous growth layer, a flat portion, and an amorphous growth layer are arranged in this order,
It can be set as the structure by which the seed crystal layer growth area | region is comprised by the flat part. That is, this flat portion corresponds to a part of the exposed surface of the GaN substrate. In addition, the light emitting element of this indication of such a form is called "the light emitting element etc. which concern on the 3rd structure of this indication" for convenience. In the light emitting element and the like according to the third configuration of the present disclosure, when the length of the flat portion in the virtual vertical plane is L _flat and the total length of the amorphous growth layer is L _nov ,
0.2 ≦ L _flat / (L _flat + L _no ) ≦ 0.9
It can be set as the structure which satisfies these. The number of flat portions in the exposed surface portion of the GaN substrate located at the bottom of the selective growth mask layer opening region may be two or more.

Alternatively, in the light-emitting element of the present disclosure including the above preferred form,
The exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers The cross-sectional shape is a shape in which uneven portions, flat portions and uneven portions are arranged in this order,
It can be set as the structure by which the seed crystal layer growth area | region is comprised by the flat part. That is, this flat portion corresponds to a part of the exposed surface of the GaN substrate. In addition, the light emitting element of this indication of such a form is called "the light emitting element etc. which concern on the 4th structure of this indication" for convenience. In the light emitting element and the like according to the fourth configuration of the present disclosure, when the length of the flat portion in the virtual vertical plane is L _flat and the total length of the uneven portions is L _cc-cv ,
0.2 ≦ L _flat / (L _flat + L _cc-cv ) ≦ 0.9
It can be set as the structure which satisfies these. The number of flat portions in the exposed surface portion of the GaN substrate located at the bottom of the selective growth mask layer opening region may be two or more.

  Furthermore, in the light emitting device of the present disclosure including the various preferable forms and configurations described above, the cross-sectional shape of the seed crystal layer (specifically, the cross-sectional shape of the seed crystal layer in the virtual vertical plane) is , Isosceles triangles, isosceles trapezoids or rectangles.

Furthermore, in the light-emitting element of the present disclosure including the various preferable modes and configurations described above,
L ₀ , the length of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers.
In the virtual vertical plane, the dislocation density in the region of the first compound semiconductor layer located above the selective growth mask layer opening region is represented by D ₀ ,
In the virtual vertical plane, the dislocation density in the region of the first compound semiconductor layer from the edge of the selective growth mask layer to the distance L ₀ is D ₁ ,
When
D ₁ / D ₀ ≦ 0.2
Can be obtained. still,
L ₀ = L _cv + L _cc
And
L ₀ = L _flat + L _cc-cv
It is.

  By the way, in the method for manufacturing a nitride semiconductor laser element disclosed in the above patent publication, a substrate different from the nitride semiconductor is used. However, when such a substrate is used, specifically, for example, when a sapphire substrate is used, many dislocations are generated due to lattice mismatch between the GaN-based compound semiconductor layer and the sapphire substrate, which greatly increases the reliability of the light-emitting element. Adversely affect. In addition, the sapphire substrate has a lower thermal conductivity than a normal semiconductor substrate, and the thermal resistance of the light emitting element becomes very large, causing an increase in oscillation threshold current, a decrease in light output, a deterioration in element life, and the like. . In addition, since the sapphire substrate does not have electrical conductivity, the n-side electrode cannot be provided on the back surface of the substrate, and the n-side electrode needs to be provided on the same side as the p-side electrode, thereby increasing the element area. However, there is a problem that productivity is poor. Furthermore, the problem of peeling of the multilayer film (selective growth mask layer) from the substrate due to the difference between the linear thermal expansion coefficient of the substrate and the linear thermal expansion coefficient of the multilayer film (selective growth mask layer), and the active layer are included. The above-mentioned patent publication does not mention any problem such as characteristic variation (for example, light reflectance variation) due to the surface roughness of the nitride semiconductor layer when the nitride semiconductor layer is grown. .

In the light-emitting element of the present disclosure including various preferable modes and configurations described above,
The off angle of the surface orientation of the GaN substrate surface is within 0.4 degrees, preferably within 0.40 degrees.
When the area of the GaN substrate is S ₀ , the area of the selective growth mask layer is 0.8 S ₀ or less,
A thermal expansion relaxation film is formed on the GaN substrate as the lowermost layer of the selective growth mask layer (for the sake of convenience, the light-emitting element according to the fifth configuration of the present disclosure is referred to as the light-emitting element of the present disclosure having such a form) The linear thermal expansion coefficient CTE of the bottom layer of the selective growth mask layer in contact with the GaN substrate is
1 × 10 ⁻⁶ / K ≦ CTE ≦ 1 × 10 ⁻⁵ / K
Preferably,
1 × 10 ⁻⁶ / K <CTE ≦ 1 × 10 ⁻⁵ / K
(The light-emitting element of the present disclosure having such a configuration is preferably referred to as “light-emitting element according to the sixth configuration of the present disclosure” for convenience). Moreover, in the manufacturing method of the light-emitting element of the present disclosure including the various preferable modes and configurations described above,
The off angle of the surface orientation of the GaN substrate surface is within 0.4 degrees, preferably within 0.40 degrees.
When the area of the GaN substrate is S ₀ , the area of the selective growth mask layer is 0.8 S ₀ or less,
As the lowermost layer of the selective growth mask layer, a thermal expansion relaxation film is formed on the GaN substrate, or the linear thermal expansion coefficient CTE of the lowermost layer of the selective growth mask layer in contact with the GaN substrate is:
1 × 10 ⁻⁶ / K ≦ CTE ≦ 1 × 10 ⁻⁵ / K
Preferably,
1 × 10 ⁻⁶ / K <CTE ≦ 1 × 10 ⁻⁵ / K
Satisfied.

  Thus, the surface roughness of the second compound semiconductor layer can be reduced by defining the off-angle of the crystal plane orientation of the GaN substrate surface and the area ratio of the selective growth mask layer. That is, a second compound semiconductor layer having an excellent surface morphology can be formed. Therefore, the second light reflecting layer having excellent smoothness can be obtained, that is, a desired light reflectance can be obtained, and the characteristic variation hardly occurs. In addition, by forming a thermal expansion mitigating film or defining the CTE value, it is selected from the GaN substrate due to the difference between the linear thermal expansion coefficient of the GaN substrate and the linear thermal expansion coefficient of the mask layer for selective growth. Occurrence of problems such as peeling of the growth mask layer can be avoided, and a light-emitting element with high reliability can be provided. Furthermore, since a GaN substrate is used, the problem that dislocation does not easily occur in the compound semiconductor layer and the thermal resistance of the light emitting element increases can be avoided, and high reliability can be imparted to the light emitting element. The n-side electrode can be provided on a different side from the p-side electrode with respect to the GaN substrate.

The off-angle of the surface orientation of the GaN substrate surface refers to the angle formed by the crystal surface orientation of the GaN substrate surface and the normal of the GaN substrate surface viewed macroscopically. Further, in the light emitting elements and the like according to the fifth configuration to the sixth configuration of the present disclosure, when the area of the GaN substrate is S ₀ , the area of the selective growth mask layer is defined as 0.8 S ₀ or less. However, the “area S _{0 of the} GaN substrate” refers to the area of the GaN substrate left when the light emitting element is finally obtained. In the light emitting elements and the like according to the fifth configuration to the sixth configuration of the present disclosure, the lowermost layer of the first light reflecting layer does not have a function as the light reflecting layer.

In the light emitting element and the like according to the fifth configuration of the present disclosure, the thermal expansion relaxation film includes silicon nitride (SiN _x ), aluminum oxide (AlO _x ), niobium oxide (NbO _x ), tantalum oxide (TaO _x ), and titanium oxide. (TiO _x ), magnesium oxide (MgO _x ), zirconium oxide (ZrO _x ), and aluminum nitride (AlN _x ) may be used to form at least one material. In addition, the value of the subscript “X” attached to the chemical formula of each substance, the subscript “Y”, and the subscript “Z”, which will be described later, is based not only on the stoichiometry but also on the stoichiometry. Includes values that deviate from the value. The same applies to the following. In the light emitting element according to the fifth configuration of the present disclosure including such a preferable form, the thickness of the thermal expansion relaxation film is t ₁ , the emission wavelength of the light emission element is λ ₀ , and the refractive index of the thermal expansion relaxation film is Is n ₁ ,
t ₁ = λ ₀ / (4n ₁ )
Preferably,
t ₁ = λ ₀ / (2n ₁ )
It is desirable to satisfy However, the value of the thickness t ₁ of the thermal expansion relaxation film can be essentially arbitrary, for example, 1 × 10 ⁻⁷ m or less.

In the light emitting element and the like according to the sixth configuration of the present disclosure, the lowermost layer of the selective growth mask layer (first light reflecting layer) is silicon nitride (SiN _x ), aluminum oxide (AlO _x ), niobium oxide (NbO _x ). ), Tantalum oxide (TaO _x ), titanium oxide (TiO _x ), magnesium oxide (MgO _x ), zirconium oxide (ZrO _x ), and aluminum nitride (AlN _x ). It can be in the form. In the light emitting element according to the sixth configuration of the present disclosure including such a preferable form, the thickness of the lowermost layer of the selective growth mask layer (first light reflecting layer) is t ₁ , and the emission wavelength of the light emitting element Is λ ₀ , and the refractive index of the lowermost layer of the selective growth mask layer (first light reflecting layer) is n ₁ ,
t ₁ = λ ₀ / (4n ₁ )
Preferably,
t ₁ = λ ₀ / (2n ₁ )
It is desirable to satisfy However, the value of the thickness t ₁ of the lowermost layer of the selective growth mask layer (first light reflection layer) can be essentially arbitrary, for example, 1 × 10 ⁻⁷ m or less.

  In the manufacturing method of the light emitting element of the present disclosure including the various preferable modes described above, the GaN substrate may be left or the active layer, the second compound semiconductor layer, the second compound semiconductor layer may be left on the first compound semiconductor layer. After sequentially forming the electrode and the second light reflecting layer, the GaN substrate may be removed using the selective growth mask layer as a stopper layer. Specifically, an active layer, a second compound semiconductor layer, a second electrode, and a second light reflection layer are sequentially formed on the first compound semiconductor layer, and then the second light reflection layer is fixed to the support substrate. The GaN substrate may be removed using the selective growth mask layer as a stopper layer to expose the first compound semiconductor layer (the first surface of the first compound semiconductor layer) and the selective growth mask layer. Furthermore, the first electrode may be formed on the first compound semiconductor layer (the first surface of the first compound semiconductor layer).

  The removal of the GaN substrate can be performed based on a chemical / mechanical polishing method (CMP method). First, alkaline aqueous solution such as sodium hydroxide aqueous solution or potassium hydroxide aqueous solution, ammonia solution + hydrogen peroxide solution, sulfuric acid solution + hydrogen peroxide solution, hydrochloric acid solution + hydrogen peroxide solution, phosphoric acid solution + hydrogen peroxide solution A part of the GaN substrate is removed by a wet etching method using a dry etching method, a dry etching method, a lift-off method using a laser, a mechanical polishing method, or a combination thereof, or the thickness of the GaN substrate. Then, the first compound semiconductor layer (the first surface of the first compound semiconductor layer) and the selective growth mask layer may be exposed by executing a chemical / mechanical polishing method.

  Furthermore, in the light emitting device of the present disclosure including the various preferable modes and configurations described above, the surface roughness Ra of the second compound semiconductor layer (the second surface of the second compound semiconductor layer) is 1.0 nm or less. It is preferable that The surface roughness Ra is defined in JIS B-610: 2001, and can be specifically measured based on observation based on AFM or cross-section TEM.

  Furthermore, in the light-emitting element of the present disclosure including the various preferable forms and configurations described above, the planar shape of the selective growth mask layer may be various polygons including regular hexagons, circles, ellipses, and lattices ( A rectangular shape), an island shape, or a stripe shape. Although the cross-sectional shape of the selective growth mask layer may be rectangular, it is more preferable that the selective growth mask layer has a trapezoidal shape, that is, the side surface of the selective growth mask layer has a forward tapered shape. Examples of a method for forming a mask layer for selective growth 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. be able to.

When the thickness of the top layer of the selective growth mask layer is t ₂ and the refractive index of the top layer of the selective growth mask layer is n ₂ ,
t ₂ = λ ₀ / (4n ₂ )
It is preferable to satisfy
t ₂ = λ ₀ / (2n ₂ )
By satisfying the above, the uppermost layer of the first light reflecting layer becomes an absent layer with respect to light having the wavelength λ ₀ . The uppermost layer (the layer in contact with the first compound semiconductor layer) of the selective growth mask layer may be formed of a silicon nitride film.

  In the light emitting element of the present disclosure including the various preferable modes and configurations described above, the distance from the first light reflecting layer to the second light reflecting layer is preferably 0.15 μm or more and 50 μm or less.

  Furthermore, in the light emitting device of the present disclosure including the various preferable modes and configurations described above, the second light is on the normal line to the first light reflecting layer passing through the center of gravity of the area of the first light reflecting layer. The center of gravity of the area of the reflective layer may be absent.

  Furthermore, in the light-emitting element of the present disclosure including the various preferable modes and configurations described above, the active layer has a normal line on the normal to the first light reflecting layer passing through the center of gravity of the area of the first light reflecting layer. The area centroid point may not exist.

  When the first compound semiconductor layer is formed on the GaN substrate on which the selective growth mask layer is formed by lateral growth using a lateral epitaxial growth method such as the ELO (Epitaxial Lateral Overgrowth) method, the selective growth is performed. When the first compound semiconductor layer epitaxially grows from the edge of the mask layer for etching toward the center of the mask layer for selective growth, many crystal defects may occur in the associated portion. If the meeting part where many crystal defects exist is located at the center of the element region (described later), there is a possibility that the characteristics of the light emitting element are adversely affected. As described above, the form in which the area centroid of the second light reflecting layer does not exist on the normal to the first light reflecting layer passing through the area centroid of the first light reflecting layer, and the first passing through the area centroid of the first light reflecting layer. By adopting a configuration in which the area centroid of the active layer does not exist on the normal line to the one light reflecting layer, it is possible to reliably suppress the adverse effect on the characteristics of the light emitting element.

  In the light emitting element of the present disclosure including the various preferable forms and configurations described above, the light generated in the active layer is emitted to the outside through the second light reflection layer (hereinafter, for convenience, A second light reflecting layer emitting type light-emitting element), and a form that is emitted to the outside through the first light reflecting layer (hereinafter referred to as “first light reflecting layer emitting type” for convenience). It may also be referred to as a “light emitting element”. In the first light reflection layer emission type light emitting element, the GaN substrate may be removed as described above in some cases.

The area of the portion of the first light reflecting layer (the portion of the first light reflecting layer facing the second light reflecting layer) in contact with the first surface of the first compound semiconductor layer is defined as S ₁ , when the area of the portion of the second light reflecting layer opposite (part of the first light reflecting layer facing the second light reflecting layer) was S ₂ in two surfaces, when the first light reflection layer emitting type light-emitting element ,
S ₁ > S ₂
In the case of the light emitting element of the second light reflecting layer emission type,
S ₁ <S ₂
However, the present invention is not limited to this.

In addition, a form in which the area centroid of the second light reflecting layer does not exist on the normal to the first light reflecting layer passing through the area centroid of the first light reflecting layer, the first light passing through the area centroid of the first light reflecting layer The portion of the first light reflecting layer that is in contact with the first surface of the first compound semiconductor layer (the first light reflecting layer facing the second light reflecting layer) in a form in which the area centroid of the active layer does not exist on the normal line to the reflecting layer And the area of the portion constituting the element region (described later) is S ₃ , and the portion of the second light reflecting layer facing the second surface of the second compound semiconductor layer (facing the first light reflecting layer) In the case of a light emitting element of the first light reflecting layer emission type, where the area of the portion constituting the element region is S ₄ ,
S ₃ > S ₄
In the case of the light emitting element of the second light reflecting layer emission type,
S ₃ <S ₄
However, the present invention is not limited to this.

In the first light reflection layer emission type light emitting element, when the GaN substrate is removed, the second light reflection layer may be fixed to the support substrate. When the GaN substrate is removed in the light emitting element of the first light reflecting layer emission type, the first light reflecting layer and the first electrode are arranged as the arrangement state of the first light reflecting layer and the first electrode on the first surface of the first compound semiconductor layer. A state in which one electrode is in contact with each other can be given, or a state in which the first light reflecting layer and the first electrode are separated from each other can be mentioned. A state where the first electrode is formed up to the edge of the first electrode and a state where the first light reflecting layer is formed up to the edge of the first electrode can also be mentioned. Here, when the first light reflecting layer is formed even on the edge of the first electrode, the first electrode has a certain degree so as not to absorb the fundamental mode light of laser oscillation as much as possible. It is necessary to have an opening having a size of. The size of the opening varies depending on the wavelength of the fundamental mode and the light confinement structure in the lateral direction (the in-plane direction of the first compound semiconductor layer), but is not limited, but is approximately several times the emission wavelength λ ₀ . An order is preferred. Alternatively, the first light reflection layer and the first electrode may be separated from each other, that is, have an offset, and the separation distance may be within 1 mm.

  Furthermore, in the light emitting device of the present disclosure including the various preferable modes and configurations described above, the first electrode can be made of a metal or an alloy, and the second electrode can be made of a transparent conductive material. It can be in the form. By constituting the second electrode from a transparent conductive material, the current can be expanded in the lateral direction (in-plane direction of the second compound semiconductor layer), and the current is efficiently supplied to the element region (described below). be able to.

  The “element region” is a region where a confined current is injected, a region where light is confined due to a difference in refractive index, or a region sandwiched between the first light reflection layer and the second light reflection layer. Of these, the region where laser oscillation occurs or the region between the first light reflection layer and the second light reflection layer that actually contributes to laser oscillation is indicated.

  As described above, the light emitting element can be configured by a surface emitting laser element (vertical cavity laser, VCSEL) that emits light from the top surface of the first compound semiconductor layer through the first light reflecting layer. Alternatively, it may be configured by a surface emitting laser element that emits light from the top surface of the second compound semiconductor layer through the second light reflecting layer.

In the light emitting device of the present disclosure including the various preferable modes and configurations described above, the stacked structure including the first compound semiconductor layer, the active layer, and the second compound semiconductor layer is specifically a GaN-based compound semiconductor. It can be set as the structure which consists of. The seed crystal layer can be composed of the same compound semiconductor as the compound semiconductor composing the first compound semiconductor layer. Here, more specifically, examples of the GaN compound semiconductor include GaN, AlGaN, InGaN, and AlInGaN. Furthermore, these compound semiconductors may contain boron (B) atoms, thallium (Tl) atoms, arsenic (As) atoms, phosphorus (P) atoms, and antimony (Sb) atoms as desired. . The active layer desirably has a quantum well structure. Specifically, it may have a single quantum well structure (QW structure) or a multiple quantum well structure (MQW structure). An active layer having a quantum well structure has a structure in which at least one well layer and a barrier layer are stacked. However, as a combination of (a compound semiconductor constituting a well layer, a compound semiconductor constituting a barrier layer), In _y Ga _(1-y) N, GaN), (In _y Ga _(1-y) N, In _z Ga _(1-z) N) [where y> z], (In _y Ga _{(1-y )} N, AlGaN). The first compound semiconductor layer is composed of a compound semiconductor of a first conductivity type (for example, n-type), and the second compound semiconductor layer is composed of a compound semiconductor of a second conductivity type (for example, p-type) different from the first conductivity type. Can be configured. The first compound semiconductor layer and the second compound semiconductor layer are also called a first cladding layer and a second cladding layer. A current confinement structure is preferably formed between the second electrode and the second compound semiconductor layer. The first compound semiconductor layer and the second compound semiconductor layer may be a layer having a single structure, a layer having a multilayer structure, or a layer having a superlattice structure. Furthermore, it can also be set as the layer provided with the composition gradient layer and the density | concentration gradient layer.

In order to obtain a current confinement structure, a current confinement layer made of an insulating material (for example, SiO _x , SiN _x , AlO _x ) may be formed between the second electrode and the second compound semiconductor layer, or Alternatively, the mesa structure may be formed by etching the second compound semiconductor layer by the RIE method or the like, or a part of the laminated second compound semiconductor layer is partially oxidized from the lateral direction. Thus, a current confinement region may be formed, a region with reduced conductivity may be formed by ion implantation of impurities into the second compound semiconductor layer, or these may be combined as appropriate. However, the second electrode needs to be electrically connected to the portion of the second compound semiconductor layer through which current flows due to current confinement.

  Although it is known that the characteristics of a GaN substrate vary depending on the growth surface, that is, polarity / nonpolarity / semipolarity, any main surface of the GaN substrate can be used for forming a compound semiconductor layer. Further, regarding the main surface of the GaN substrate, depending on the crystal structure (for example, cubic type, hexagonal type, etc.), names such as so-called A plane, B plane, C plane, R plane, M plane, N plane, S plane, etc. A plane (including the case where the off angle is 0 degree) in which the plane orientation of the crystal plane is called off in a specific direction is used. As a method for forming various compound semiconductor layers constituting the light emitting element, metal organic chemical vapor deposition (MOCVD method, MOVPE method), molecular beam epitaxy method (MBE method), hydride gas in which halogen contributes to transport or reaction. Examples include a phase growth method. The seed crystal layer and the first compound semiconductor layer made of the same compound semiconductor material can be formed by changing the formation conditions of the seed crystal layer and the formation conditions of the first compound semiconductor layer.

Here, trimethylgallium (TMG) and triethylgallium (TEG) can be mentioned as the organic gallium source in the MOCVD method, and ammonia gas and hydrazine can be mentioned as the nitrogen source gas. In forming a GaN-based compound semiconductor layer having n-type conductivity, for example, silicon (Si) may be added as an n-type impurity (n-type dopant), or a GaN-based compound semiconductor having p-type conductivity. In forming the layer, for example, magnesium (Mg) may be added as a p-type impurity (p-type dopant). When aluminum (Al) or indium (In) is contained as a constituent atom of the GaN-based compound semiconductor layer, trimethylaluminum (TMA) may be used as the Al source, and trimethylindium (TMI) may be used as the In source. Furthermore, monosilane gas (SiH ₄ gas) may be used as the Si source, and biscyclopentadienyl magnesium, methylcyclopentadienyl magnesium, or biscyclopentadienyl magnesium (Cp ₂ Mg) may be used as the Mg source. . In addition to Si, examples of n-type impurities (n-type dopants) include Ge, Se, Sn, C, Te, S, O, Pd, and Po. As p-type impurities (p-type dopants), In addition to Mg, Zn, Cd, Be, Ca, Ba, C, Hg, and Sr can be mentioned.

The support substrate may be composed of various substrates such as a GaN substrate, a sapphire substrate, a GaAs substrate, a SiC substrate, an alumina substrate, a ZnS substrate, a ZnO substrate, a LiMgO substrate, a LiGaO ₂ substrate, a MgAl ₂ O ₄ substrate, and an InP substrate. Alternatively, an insulating substrate made of AlN or the like, a semiconductor substrate made of Si, SiC, Ge or the like, a metal substrate, or an alloy substrate can be used, but it is preferable to use a conductive substrate. Alternatively, it is preferable to use a metal substrate or an alloy substrate from the viewpoints of mechanical properties, elastic deformation, plastic deformability, heat dissipation, and the like. Examples of the thickness of the support substrate include 0.05 mm to 0.5 mm. As a method for fixing the second light reflecting layer to the support substrate, a known method such as a solder bonding method, a room temperature bonding method, a bonding method using an adhesive tape, or a bonding method using wax bonding can be used. From the viewpoint of securing the property, it is desirable to employ a solder bonding method or a room temperature bonding method. For example, when a silicon semiconductor substrate which is a conductive substrate is used as a support substrate, it is desirable to employ a method capable of bonding at a low temperature of 400 ° C. or lower in order to suppress warping due to a difference in thermal expansion coefficient. When a GaN substrate is used as the support substrate, the bonding temperature may be 400 ° C. or higher.

  The first electrode is, for example, gold (Au), silver (Ag), palladium (Pd), platinum (Pt), nickel (Ni), Ti (titanium), vanadium (V), tungsten (W), chromium (Cr ), Al (aluminum), Cu (copper), Zn (zinc), tin (Sn) and at least one metal selected from the group consisting of indium (In) (including alloys) or It is desirable to have a multilayer structure, specifically, for example, Ti / Au, Ti / Al, Ti / Al / Au, Ti / Pt / Au, Ni / Au, Ni / Au / Pt, Ni / Pt, Pd / Pt and Ag / Pd can be exemplified. In addition, the layer before “/” in the multilayer structure is located closer to the active layer side. The same applies to the following description. The first electrode can be formed by, for example, a PVD method such as a vacuum evaporation method or a sputtering method.

As the transparent conductive material constituting the second electrode, indium-tin oxide (including ITO, Indium Tin Oxide, Sn-doped In ₂ O ₃ , crystalline ITO, and amorphous ITO), indium-zinc oxide (IZO, Indium Zinc Oxide), IFO (F-doped In ₂ O ₃ ), tin oxide (SnO ₂ ), ATO (Sb-doped SnO ₂ ), FTO (F-doped SnO ₂ ), zinc oxide (ZnO, Al-doped ZnO) And B-doped ZnO). Alternatively, as the second electrode, a transparent conductive film having a base layer of gallium oxide, titanium oxide, niobium oxide, nickel oxide, or the like can be given. However, the material constituting the second electrode depends on the arrangement state of the second light reflecting layer and the second electrode, but is not limited to the transparent conductive material, and palladium (Pd), platinum (Pt), Metals such as nickel (Ni), gold (Au), cobalt (Co), and rhodium (Rh) can also be used. The second electrode may be composed of at least one of these materials. The second electrode can be formed by, for example, a PVD method such as a vacuum evaporation method or a sputtering method.

  A pad electrode may be provided on the first electrode or the second electrode for electrical connection with an external electrode or circuit. The pad electrode includes a single layer containing at least one metal selected from the group consisting of Ti (titanium), aluminum (Al), Pt (platinum), Au (gold), Ni (nickel), and Pd (palladium). It is desirable to have a configuration or a multi-layer configuration. Alternatively, the pad electrode may be a Ti / Pt / Au multilayer structure, a Ti / Au multilayer structure, a Ti / Pd / Au multilayer structure, a Ti / Pd / Au multilayer structure, a Ti / Ni / Au multilayer structure, A multi-layer structure exemplified by a multi-layer structure of Ti / Ni / Au / Cr / Au can also be used. When the first electrode is composed of an Ag layer or an Ag / Pd layer, for example, a cover metal layer made of Ni / TiW / Pd / TiW / Ni is formed on the surface of the first electrode, and on the cover metal layer, For example, it is preferable to form a pad electrode having a multilayer structure of Ti / Ni / Au or a multilayer structure of Ti / Ni / Au / Cr / Au.

The light reflecting layer (distributed Bragg reflector layer, distributed Bragg reflector layer, DBR layer) and selective growth mask layer are composed of, for example, a semiconductor multilayer film or a dielectric multilayer film. Examples of the dielectric material include oxides and nitrides such as Si, Mg, Al, Hf, Nb, Zr, Sc, Ta, Ga, Zn, Y, B, and Ti (for example, SiN _x , AlN _x , and AlGaN). GaN _x , BN _x etc.) or fluorides. _{Specifically,} there can be mentioned _{SiO X, TiO X, NbO X} , ZrO X, TaO X, ZnO X, AlO X, HfO X, SiN X, the AlN _X, and the like. Of these dielectric materials, two or more types of dielectric films made of dielectric materials having different refractive indexes are alternately laminated, whereby a light reflecting layer and a selective growth mask layer can be obtained. For example, a multilayer film such as SiO _x / SiN _y , SiO _x / NbO _y , SiO _x / ZrO _y , SiO _x / AlN _y is preferable. In order to obtain a desired light reflectance, the material, the film thickness, the number of stacked layers, and the like constituting each dielectric film may be appropriately selected. The thickness of each dielectric film, a material or the like to be used, as appropriate, can be adjusted, the light emission wavelength lambda _0, is determined by the refractive index n of the light-emitting wavelength lambda ₀ of the material used. Specifically, an odd multiple of λ ₀ / (4n) is preferable. For example, in a light emitting device having an emission wavelength λ ₀ of 410 nm, when the light reflecting layer and the selective growth mask layer are made of SiO _x / NbO _Y, about 40 nm to 70 nm can be exemplified. The number of stacked layers is 2 or more, preferably about 5 to 20. Examples of the total thickness of the light reflection layer and the selective growth mask layer include about 0.6 μm to 1.7 μm. What is necessary is just to select the material which comprises an amorphous growth layer suitably from the material which comprises a light reflection layer.

Alternatively, the selective growth mask layer preferably includes a dielectric film containing at least N (nitrogen) atoms. Further, the dielectric film containing N atoms is the outermost layer of the dielectric multilayer film. The upper layer is more desirable. Alternatively, the selective growth mask layer is preferably covered with a dielectric material layer containing at least N (nitrogen) atoms. Alternatively, the surface of the selective growth mask layer is subjected to nitriding treatment, whereby the surface of the selective growth mask layer is referred to as a layer containing at least N (nitrogen) atoms (hereinafter referred to as “surface layer” for convenience). ) Is desirable. The thickness of the dielectric film or dielectric material layer containing at least N atoms, or the surface layer is preferably an odd multiple of λ ₀ / (4n). Specific examples of the material constituting the dielectric film or the dielectric material layer containing at least N atoms include SiN _x and SiO _{x NZ} . Thus, when the compound semiconductor layer that covers the selective growth mask layer is formed by forming the dielectric film or dielectric material layer containing at least N atoms, or the surface layer, the compound that covers the selective growth mask layer. The deviation between the crystal axis of the semiconductor layer and the crystal axis of the GaN substrate can be improved, and the quality of the laminated structure serving as a resonator can be improved.

  The selective growth mask layer can be formed based on a known method. Specifically, for example, a vacuum deposition method, a sputtering method, a reactive sputtering method, an ECR plasma sputtering method, a magnetron sputtering method, an ion beam assisted deposition. PVD methods such as ion method, ion plating method, laser ablation method, etc .; various CVD methods; coating methods such as spray method, spin coating method, dipping method; method combining two or more of these methods; Or a method of combining any one or more of partial pretreatment, inert gas (Ar, He, Xe, etc.) or plasma irradiation, oxygen gas or ozone gas, plasma irradiation, oxidation treatment (heat treatment), and exposure treatment Etc.

Moreover, you may coat | cover the side surface and exposed surface of a laminated structure with an insulating film. The insulating film can be formed based on a known method. The refractive index of the material constituting the insulating film is preferably smaller than the refractive index of the material constituting the laminated structure. Examples of the material constituting the insulating film include SiO _x -based materials containing SiO ₂ , SiN _x -based materials, SiO _x N _z -based materials, TaO _x , ZrO _x , AlN _x , AlO _x , and GaO _x. Alternatively, organic materials such as polyimide resin can also be mentioned. As a method for forming the insulating film, for example, a PVD method such as a vacuum vapor deposition method or a sputtering method, or a CVD method can be given, and it can also be formed based on a coating method.

  Example 1 relates to the light-emitting element of the present disclosure and a method for manufacturing the light-emitting element, and more specifically to a light-emitting element according to the first configuration of the present disclosure. FIG. 1A shows a schematic partial cross-sectional view of the light-emitting element of Example 1, and FIG. 1B shows a schematic partial end view in which the selective growth mask layer opening region and the like in the light-emitting element of Example 1 are enlarged. .

The light-emitting elements of Example 1 or Examples 2 to 7 described later are specifically surface-emitting laser elements (vertical cavity lasers, VCSELs),
GaN substrate 11,
A plurality of selective growth mask layers 43 formed on the GaN substrate 11 and provided separately from each other;
A first light reflection layer 41 made of one of a plurality of selective growth mask layers 43;
A stacked structure 20 composed of a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22 formed over a plurality of selective growth mask layers 43, and
A second electrode 32 and a second light reflecting layer 42 formed on the second compound semiconductor layer 22;
At least.

And in Example 1 or the light emitting element of Example 2-Example 7 mentioned later,
At the bottom of the selective growth mask layer opening region 51 located between the selective growth mask layer 43 and the selective growth mask layer 43, a seed crystal layer growth region composed of a part of the exposed surface of the GaN substrate 11. 52 is provided,
A seed crystal layer 61 is formed on the seed crystal layer growth region 52.
The first compound semiconductor layer 21 is formed from the seed crystal layer 61 based on lateral epitaxial growth,
The seed crystal layer 61 is thinner than the selective growth mask layer 43.

Here, when the thickness of the seed crystal layer 61 is T _seed and the thickness of the selective growth mask layer 43 is T ₁ ,
0.1 ≦ T _seed / T ₁ <1
Is satisfied. In particular,
T _seed / T ₁ = 0.67
However, it is not limited to this value.

  The plane orientation of the crystal plane of the surface 11a of the GaN substrate 11 was [0001]. That is, the selective growth mask layer 43 and the laminated structure 20 are formed on the (0001) plane (C plane) of the GaN substrate 11. The planar shape of the selective growth mask layer 43 is a regular hexagon. The regular hexagons are arranged or arranged so that the compound semiconductor layer epitaxially grows laterally in the [11-20] direction or a crystallographically equivalent direction.

In the light emitting device of Example 1, on the exposed surface of the GaN substrate 11 located at the bottom of the selective growth mask layer opening region 51 located between the selective growth mask layer 43 and the selective growth mask layer 43. Has a concavo-convex portion 53, and a seed crystal layer growth region 52 is constituted by the convex portion 53A. That is, the convex portion 53 </ b> A corresponds to a part of the exposed surface of the GaN substrate 11. Then, selection when the light emitting element is cut at a virtual vertical plane (hereinafter simply referred to as “virtual vertical plane”) including two normal lines passing through the center point of two adjacent selective growth mask layers 43. The cross-sectional shape of the exposed surface of the GaN substrate 11 located at the bottom of the growth mask layer opening region 51 is such that the concave portion 53B, the convex portion 53A, and the concave portion 53B are arranged in this order. Furthermore, the seed crystal layer growth region 52 is configured by the top surface of the convex portion 53A. When the length of the convex portion 53A is L _cv and the total length of the concave portion 53B is L _cc in the virtual vertical plane. ,
0.2 ≦ L _cv / (L _cv + L _cc ) ≦ 0.9
Satisfied. In particular,
L _cv / (L _cv + L _cc ) = 0.7
It was.

In the light-emitting elements of Example 1 or Examples 2 to 7 described later, the cross-sectional shape of the seed crystal layer 61 (specifically, the cross-sectional shape of the seed crystal layer 61 in the virtual vertical plane) It is a trapezoid [inclination angle of leg (inclined surface): 58 degrees]. The crystal plane of the isosceles trapezoidal leg portion (inclined surface) is the {11-22} plane. Furthermore, in the light emitting device of Example 1 or Example 2 to Example 7 described later,
The length of the selective growth mask layer opening region 51 when the light emitting element is cut at the virtual vertical plane is set to L ₀ ,
In the virtual vertical plane, the dislocation density in the region of the first compound semiconductor layer 21 located above the selective growth mask layer opening region 51 is represented by D ₀ ,
In the virtual vertical plane, the dislocation density in the region of the first compound semiconductor layer 21 from the edge of the selective growth mask layer 43 to the distance L _{0 is} represented by D ₁ ,
When
D ₁ / D ₀ ≦ 0.2
Satisfied.

The laminated structure 20 includes a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22. More specifically,
A first compound semiconductor layer 21 made of a GaN-based compound semiconductor and having a first surface 21a and a second surface 21b facing the first surface 21a;
An active layer (light emitting layer) 23 made of a GaN-based compound semiconductor and in contact with the second surface 21b of the first compound semiconductor layer 21, and
A second compound semiconductor layer 22 made of a GaN-based compound semiconductor, having a first surface 22a and a second surface 22b opposite to the first surface 22a, the first surface 22a being in contact with the active layer 23;
Are laminated. A second light reflecting layer 42 including a second electrode 32 and a multilayer film is formed on the second surface 22b of the second compound semiconductor layer 22, and the GaN substrate 11 on which the multilayer structure 20 is formed. A first electrode 31 is formed on the other surface 11b of the GaN substrate 11 facing the surface 11a. The first light reflecting layer 41 made of a multilayer film is formed on the surface 11 a of the GaN substrate 11 and is in contact with the first surface 21 a of the first compound semiconductor layer 21.

  Here, Example 1 is a light emitting element of a second light reflecting layer emission type that emits light from the second surface 22 b of the second compound semiconductor layer 22 through the second light reflecting layer 42. The GaN substrate 11 remains.

In the light-emitting elements of Example 1 or Examples 2 to 7 described later, a current constriction made of an insulating material such as SiO _x , SiN _x , and AlO _x is provided between the second electrode 32 and the second compound semiconductor layer 22. Layer 24 is formed. An opening 24A is formed in the current confinement layer 24, and the second compound semiconductor layer 22 is exposed at the bottom of the opening 24A. The second electrode 32 is formed over the current confinement layer 24 from the second surface 22 b of the second compound semiconductor layer 22, and the second light reflecting layer 42 is formed on the second electrode 32. Further, a pad electrode 33 for electrically connecting to an external electrode or a circuit is connected on the edge of the second electrode 32. In the light-emitting elements of Example 1 or Examples 2 to 7 described later, the planar shape of the element region is a regular hexagon, and is provided in the first light reflection layer 41, the second light reflection layer 42, and the current confinement layer 24. The planar shape of the opening 24A is circular. The first light reflection layer 41 and the second light reflection layer 42 have a multilayer structure, but are shown as one layer for the sake of simplicity of the drawing. The formation of the current confinement layer 24 is not essential.

  In the light emitting device of Example 1, the distance from the first light reflecting layer 41 to the second light reflecting layer 42 is not less than 0.15 μm and not more than 50 μm, and specifically, for example, 10 μm.

The first compound semiconductor layer 21 is composed of an n-type GaN layer having a thickness of 5 μm, and the active layer 23 having a total thickness of 180 nm includes an In _0.04 Ga _0.96 N layer (barrier layer) and an In _0.16 Ga _0.84 N layer (well layer). The second compound semiconductor layer 22 has a two-layer structure of a p-type AlGaN electron barrier layer (thickness 10 nm) and a p-type GaN layer. The electron barrier layer is located on the active layer side. The first electrode 31 is made of Ti / Pt / Au, the second electrode 32 is made of a transparent conductive material, specifically, ITO, and the pad electrode 33 is made of Ti / Pd / Au or Ti / Pt / Au. The first light reflection layer 41 and the second light reflection layer 42 have a stacked structure of SiN _X layers and SiO _Y layers (total number of stacked dielectric films: 20 layers). The thickness of each layer is λ ₀ / (4n). The seed crystal layer 61 is also made of n-type GaN.

  Hereinafter, with reference to FIGS. 2A, 2B, 2C, 3A, 3B, 4A, and 4B, which are schematic partial end views of a laminated structure and the like, a method for manufacturing the light-emitting element of Example 1 will be described below. Will be explained.

[Step-100]
First, a plurality of selective growth mask layers 43 each of which is provided on the GaN substrate 11 so as to function as the first light reflecting layer 41 are formed, and the selective growth mask layer 43 is also formed. A seed crystal layer growth region 52 is formed on the surface of a part of the portion of the GaN substrate 11 exposed at the bottom of the selective growth mask layer opening region 51 located between the selective growth mask layer 43 and the selective growth mask layer 43.

[Step-100A]
Specifically, first, a plurality of selective growth mask layers 43 made of a multilayer film are formed on the GaN substrate 11. One of the plurality of selective growth mask layers 43 functions as the first light reflection layer 41. Then, the selective growth mask layer 43 is patterned. In this way, the structure shown in FIG. 2A can be obtained. As shown in a schematic plan view in FIG. 15, the shape of the selective growth mask layer 43 is a regular hexagon. However, the shape of the selective growth mask layer 43 is not limited to this, and may be, for example, a circular shape, a lattice shape, or a stripe shape. In FIG. 15, the selective growth mask layer 43 is hatched in order to clearly display the selective growth mask layer 43. The GaN substrate 11 is exposed between the selective growth mask layer 43 and the selective growth mask layer 43, and this region corresponds to the selective growth mask layer opening region 51.

[Step-100B]
Next, based on a well-known method, an etching mask is formed in the selective growth mask layer opening region 51, and a portion where the convex portion 53A in the selective growth mask layer opening region 51 is to be formed is covered with the etching mask. The portion of the GaN substrate 11 where the recess 53B is to be formed is exposed. Then, based on a well-known method, after etching the portion of the GaN substrate 11 where the recess 53B is to be formed, the etching mask is removed. In this way, the state shown in FIG. 2B can be obtained. That is, the concavo-convex portion 53 is formed on the exposed surface of the GaN substrate 11 located at the bottom of the selective growth mask layer opening region 51, and the seed crystal layer growth region 52 is constituted by the convex portion 53A.

  The execution order of [Step-100B] and [Step-100A] may be reversed.

[Step-110]
Next, a seed crystal layer 61 thinner than the thickness of the selective growth mask layer 43 is formed on the seed crystal layer growth region 52. Specifically, the seed crystal layer 61 is formed on the seed crystal layer growth region 52 based on the MOCVD method using TMG gas and SiH ₄ gas using an MOCVD apparatus. Although depending on the film formation conditions in the MOCVD method, the cross-sectional shape of the seed crystal layer 61 in the virtual vertical plane is an isosceles trapezoid [the inclination angle of the leg (inclined surface): 58 degrees]. In this way, the state shown in FIG. 2C can be obtained. Note that a seed crystal 62 having an isosceles trapezoidal cross section is also generated on the bottom surface of the recess 53B. Further, in [Step-100B], after etching the portion of the GaN substrate 11 to form the recess 53B, the bottom surface of the recess 53B is further roughened to form a fine uneven portion on the bottom surface of the recess 53B. It is difficult to produce a seed crystal on the bottom surface of the recess 53B.

[Step-120]
Subsequently, the film formation conditions in the MOCVD method are changed, and the first compound semiconductor layer 21 is formed from the seed crystal layer 61 based on the lateral epitaxial growth. FIG. 3A shows a state during the film formation of the first compound semiconductor layer 21, and FIG. 3B shows a state after the film formation of the first compound semiconductor layer 21 is completed. In FIG. 3A, the hatching of the first compound semiconductor layer 21 is omitted. Reference numeral 63 indicates a dislocation extending from the seed crystal layer 61 in a substantially horizontal direction. Since the thickness of the seed crystal layer 61 is thinner than the thickness of the selective growth mask layer 43, the dislocation 63 generally extends to the side wall of the selective growth mask layer 43 and stops there, and above the selective growth mask layer 43. It does not extend to the portion of the first compound semiconductor layer 21 that is formed.

[Step-130]
Subsequently, the film forming conditions in the MOCVD method are changed to form the active layer 23 and the second compound semiconductor layer 22 on the first compound semiconductor layer 21, and the second electrode 32 and the second light reflecting layer 42 are sequentially formed. Form. Specifically, based on an epitaxial growth method, an active layer 23 is formed on the first compound semiconductor layer 21 using TMG gas and TMI gas, and then electrons are generated using TMG gas, TMA gas, and Cp ₂ Mg gas. The second compound semiconductor layer 22 is obtained by forming a barrier layer and forming a p-type GaN layer using TMG gas and Cp ₂ Mg gas. The laminated structure 20 can be obtained through the above steps. That is, on the GaN substrate 11 including the selective growth mask layer 43,
A first compound semiconductor layer 21 made of a GaN-based compound semiconductor and having a first surface 21a and a second surface 21b facing the first surface 21a;
An active layer 23 made of a GaN-based compound semiconductor and in contact with the second surface 21b of the first compound semiconductor layer 21, and
A second compound semiconductor layer 22 made of a GaN-based compound semiconductor, having a first surface 22a and a second surface 22b opposite to the first surface 22a, the first surface 22a being in contact with the active layer 23;
The laminated structure 20 formed by laminating is epitaxially grown. Next, a current confinement layer 24 made of an insulating material having a thickness of 0.2 μm and having an opening 24A is formed on the second surface 22b of the second compound semiconductor layer 22 based on a known method. In this way, the structure shown in FIG. 4A can be obtained.

  Thereafter, the second light reflecting layer 42 including the second electrode 32 and the multilayer film is formed on the second surface 22 b of the second compound semiconductor layer 22. Specifically, for example, based on the lift-off method, the second electrode 32 made of ITO having a thickness of 50 nm is formed on the current confinement layer 24 from the second surface 22b of the second compound semiconductor layer 22; Further, the pad electrode 33 is formed over the current confinement layer 24 from the second electrode 32 based on a known method. In this way, the structure shown in FIG. 4B can be obtained. Thereafter, the second light reflection layer 42 is formed on the pad electrode 33 from the second electrode 32 based on a known method. On the other hand, the first electrode 31 is formed on the other surface 11b of the GaN substrate 11 based on a known method. Thus, the structure shown in FIG. 1A can be obtained.

[Step-140]
Thereafter, the light emitting element is separated by performing so-called element separation, and the side surface and the exposed surface of the laminated structure are covered with an insulating film made of, for example, SiO _x . Then, in order to connect the first electrode 31 and the pad electrode 33 to an external circuit or the like, a terminal or the like is formed based on a well-known method, and packaged or sealed, whereby the light emitting element of Example 1 is completed.

  As described above, in the light-emitting element of Example 1 and the manufacturing method thereof, the seed crystal layer growth region is provided, and the seed crystal layer is formed on the seed crystal layer growth region. Is smaller than the thickness of the selective growth mask layer 43. Therefore, the thickness of the first compound semiconductor layer formed from the seed crystal layer based on the lateral epitaxial growth can be reduced. As a result, the thickness of the stacked structure can be reduced. In addition, since the thickness of the seed crystal layer is thinner than the thickness of the selective growth mask layer 43, when the compound semiconductor layer is grown from the seed crystal layer based on the lateral epitaxial growth, dislocations from the seed crystal layer are for selective growth. It does not extend to the compound semiconductor layer above the mask layer, and does not adversely affect the characteristics of the light emitting element. In addition, the seed crystal layer can be reliably formed in the seed crystal layer growth region, which is the portion of the substrate located between the selective growth mask layer and the selective growth mask layer. Furthermore, since the size of the seed crystal layer can be reduced even when the area of the selective growth mask layer is large, it is possible to reliably cover the selective growth mask layer with the thin first compound semiconductor layer. it can.

Example 2 is a modification of Example 1, and relates to a light-emitting element and the like according to the second configuration of the present disclosure. In the light emitting device of Example 2, as shown in FIG. 5A, a schematic partial cross-sectional view is shown in FIG. 5A, and a schematic partial end view in which the selective growth mask layer opening region and the like are enlarged is shown in FIG. An uneven portion 54 is formed on the exposed surface of the GaN substrate 11 located at the bottom of the selective growth mask layer opening region 51 located between the selective growth mask layer 43 and the selective growth mask layer 43. The seed crystal layer growth region 52 is configured by 54B. That is, the recess 54 </ b> B corresponds to a part of the exposed surface of the GaN substrate 11. The cross-sectional shape of the exposed surface of the GaN substrate 11 located at the bottom of the selective growth mask layer opening region 51 when the light emitting element is cut along the virtual vertical plane is as follows: the convex portion 54A, the concave portion 54B, and the convex portion 54A It is a side-by-side shape. Furthermore, the seed crystal layer growth region 52 is configured by the bottom surface of the recess 54B, and when the length of the recess 54B is L _cc and the total length of the projection 54A is L _cv in the virtual vertical plane,
0.2 ≦ L _cc / (L _cv + L _cc ) ≦ 0.9
Satisfied. In particular,
L _cc / (L _cv + L _cc ) = 0.7
It was.

  Except for the above points, the configuration and structure of the light-emitting element of Example 2 can be the same as the configuration and structure of the light-emitting element of Example 1, and the method for manufacturing the light-emitting element of Example 2 is substantially the same. Since it can be the same as that of the manufacturing method of the light emitting element of Example 1, detailed description is abbreviate | omitted.

  In the same step as [Step-100A] of Example 1, the selective growth mask layer 43 is patterned to expose the GaN substrate 11, and then fine irregularities are formed on the exposed surface of the GaN substrate 11. Then, if the concave portion 54B is formed in the same manner as in [Step-100B] of the first embodiment, it is difficult to produce a seed crystal on the top surface of the convex portion 54A where the concave and convex portions are formed.

Example 3 is also a modification of Example 1, but relates to a light emitting element and the like according to the third configuration of the present disclosure. In the light emitting device of Example 3, as shown in FIG. 6A, a schematic partial sectional view is shown in FIG. 6A, and a schematic partial end view in which the selective growth mask layer opening region and the like are enlarged is shown in FIG. 6B. The cross-sectional shapes of the exposed surface of the GaN substrate 11 located at the bottom of the selective growth mask layer opening region 51 when the light emitting element is cut along the virtual vertical plane are the amorphous growth layer 55B, the flat portion 55A, and the amorphous growth layer 55B. Are arranged in this order, and the seed crystal layer growth region 52 is configured by the flat portion 55A. That is, the flat portion 55A corresponds to a part of the exposed surface of the GaN substrate. In the virtual vertical plane, when the length of the flat portion 55A is L _flat and the total length of the amorphous growth layer 55B is L _nov ,
0.2 ≦ L _flat / (L _flat + L _no ) ≦ 0.9
Satisfied. In particular,
L _flat / (L _flat + L _no ) = 0.7
It was. The amorphous growth layer 55B is made of silicon nitride (SiN _x ). When the amorphous growth layer 55B is also formed on the uppermost layer of the selective growth mask layer 43 (the layer in contact with the first compound semiconductor layer 21), the amorphous growth layer 55B (the uppermost layer of the selective growth mask layer 43). ) Is t ₂ and the refractive index of the amorphous growth layer 55B is n ₂ .
t ₂ = λ ₀ / (4n ₂ )
It is preferable to satisfy
t ₂ = λ ₀ / (2n ₂ )
If satisfied, the uppermost layer 41B of the first light reflecting layer 41 becomes an absent layer with respect to light having the wavelength λ ₀ .

  Specifically, in Example 3, in a step similar to [Step-100B] of Example 1, a lift-off mask is formed in the selective growth mask layer opening region 51 based on a well-known method, A portion where the flat portion 55A is to be formed in the selective growth mask layer opening region 51 is covered with a lift-off mask. The portion of the GaN substrate 11 on which the amorphous growth layer 55B is to be formed is exposed. Then, after forming the amorphous growth layer 55B on the entire surface based on a known method, the lift-off mask and the portion of the amorphous growth layer 55B formed thereon are removed.

  Except for the above points, the configuration and structure of the light-emitting device of Example 3 can be the same as the configuration and structure of the light-emitting device of Example 1, and the method for manufacturing the light-emitting device of Example 3 is substantially the same. Since it can be the same as that of the manufacturing method of the light emitting element of Example 1, detailed description is abbreviate | omitted.

  In the same step as [Step-100A] in Example 1, the lowermost layer or the lower layer of the selective growth mask layer is formed on the GaN substrate 11 and patterned to form the uppermost layer of the selective growth mask layer. An amorphous growth layer 55B and a flat portion 55A extending from the lower layer or the lower layer may be formed. Thereafter, the remaining portion of the selective growth mask layer may be formed on the lowermost layer or the lower layer of the selective growth mask layer. Alternatively, in Example 7 which will be described later, the thermal expansion relaxation film 44 constituting the lowermost layer of the selective growth mask layer 43 is formed on the GaN substrate 11 and patterned, whereby the expansion of the thermal expansion relaxation film 44 is achieved. A non-crystalline growth layer 55B composed of the existing portion and a flat portion 55A may be formed. Thereafter, the remaining portion of the selective growth mask layer may be formed on the thermal expansion relaxation film 44.

Example 4 is also a modification of Example 1, but relates to a light emitting element and the like according to the fourth configuration of the present disclosure. In the light emitting device of Example 4, as shown in FIG. 7A, a schematic partial sectional view is shown in FIG. 7A, and a schematic partial end view in which the selective growth mask layer opening region and the like are enlarged is shown in FIG. As for the cross-sectional shape of the exposed surface of the GaN substrate 11 located at the bottom of the selective growth mask layer opening region 51 when the light emitting element is cut along the virtual vertical plane, the uneven portion 56B, the flat portion 56A, and the uneven portion 56B are arranged in this order. The seed crystal layer growth region 52 is formed by the flat portion 56A. That is, the flat portion 56 </ b> A corresponds to a part of the exposed surface of the GaN substrate 11. A seed crystal is unlikely to be generated in the uneven portion 56B. When the length of the flat portion 56A in the virtual vertical plane is L _flat and the total length of the concavo-convex portion 56B is L _cc-cv ,
0.2 ≦ L _flat / (L _flat + L _cc-cv ) ≦ 0.9
Satisfied. In particular,
L _flat / (L _flat + L _cc-cv ) = 0.7
It was.

  Specifically, in Example 4, in the same process as [Step-100B] of Example 1, an etching mask is formed in the selective growth mask layer opening region 51 based on a known method, The flat portion 56A in the selective growth mask layer opening region 51 is covered with an etching mask. The portion of the GaN substrate 11 where the uneven portion 56B is to be formed is in an exposed state. Then, based on a well-known method, after etching the portion of the GaN substrate 11 where the uneven portion 56B is to be formed, the etching mask is removed.

  Except for the above points, the configuration and structure of the light-emitting element of Example 4 can be the same as the configuration and structure of the light-emitting element of Example 1, and the method for manufacturing the light-emitting element of Example 4 is substantially the same. Since it can be the same as that of the manufacturing method of the light emitting element of Example 1, detailed description is abbreviate | omitted.

  As described above, the first compound semiconductor layer 21 is epitaxially grown in the lateral direction such as the ELO method on the GaN substrate 11 on which the selective growth mask layer 43 (or the first light reflection layer 41) is formed. When the first compound semiconductor layer 21 epitaxially grows from the edge of the selective growth mask layer 43 toward the center of the selective growth mask layer 43 when formed by lateral growth, crystal defects are formed in the associated portion. May occur frequently.

In the light emitting device of Example 5, as shown in FIG. 8 as a modification of the light emitting device of Example 1 shown in FIG. 1A, the first light reflecting layer passing through the center of gravity of the area of the first light reflecting layer 41. On the normal line LN _{1 with} respect to 41, the area center of gravity of the second light reflecting layer 42 does not exist. Alternatively, the area center of gravity of the active layer 23 does not exist on the normal LN _{1 with} respect to the first light reflecting layer 41 passing through the area center of gravity of the first light reflecting layer 41. The normal to the second light reflecting layer 42 passing through the area centroid of the second light reflecting layer 42 and the normal to the active layer 23 passing through the area centroid of the active layer 23 coincide with each other. LN ₂ ". Needless to say, the configuration and structure of the light-emitting element of Example 5 can be applied to the light-emitting elements shown in FIGS. 5A, 6A, and 7A. Except for the above points, the configuration and structure of the light-emitting element of Example 5 can be the same as the configuration and structure of the light-emitting element of Example 1, and thus detailed description thereof is omitted.

In Example 5, the meeting portion where there are many crystal defects (specifically, located on or near the normal line LN ₁ ) is not located in the center of the device region, and the light emitting device The adverse effect on the characteristics is eliminated, or the adverse effect on the characteristics of the light emitting element is reduced.

  The sixth embodiment is a modification of the first to fifth embodiments. As shown in a schematic partial cross-sectional view of FIG. 9A, in the light emitting device of Example 6, specifically, the light generated in the active layer 23 is emitted from the top surface of the first compound semiconductor layer 21. The light is emitted to the outside through the first light reflection layer 41. That is, the light emitting element of Example 6 composed of a surface emitting laser element (vertical cavity laser, VCSEL) is a first light reflecting layer emission type light emitting element. In the light emitting device of Example 6, the second light reflecting layer 42 is formed of a silicon semiconductor substrate through a bonding layer 25 made of a solder layer containing a gold (Au) layer or tin (Sn). 26 is fixed based on the solder bonding method.

  In Example 6, the active layer 23, the second compound semiconductor layer 22, the second electrode 32, and the second light reflecting layer 42 are sequentially formed on the first compound semiconductor layer 21, and then the first light reflecting layer 41 is formed. Is used as a stopper layer to remove the GaN substrate 11. Specifically, the active layer 23, the second compound semiconductor layer 22, the second electrode 32, and the second light reflecting layer 42 are sequentially formed on the first compound semiconductor layer 21, and then the second light reflecting layer 42 is supported. After fixing to the substrate 26, the GaN substrate 11 is removed using the first light reflection layer 41 as a stopper layer, and the first compound semiconductor layer 21 (the first surface of the first compound semiconductor layer 21) and the first light reflection layer 41 are removed. To expose. Then, the first electrode 31 is formed on the first compound semiconductor layer 21 (the first surface of the first compound semiconductor layer 21).

  The distance from the first light reflection layer 41 to the second light reflection layer 42 is not less than 0.15 μm and not more than 50 μm, and specifically, for example, 10 μm. In the light emitting device of Example 6, the first light reflection layer 41 and the first electrode 31 are separated from each other, that is, have an offset, and the separation distance is within 1 mm, specifically, for example, The average is 0.05 mm.

  Hereinafter, a method for manufacturing the light-emitting element of Example 6 will be described with reference to FIGS. 10A and 10B which are schematic partial end views of a laminated structure and the like.

[Step-600]
First, the structure shown in FIG. 1A is obtained by performing the same processes as [Step-100] to [Step-130] of the first embodiment. However, the first electrode 31 is not formed.

[Step-610]
Thereafter, the second light reflecting layer 42 is fixed to the support substrate 26 through the bonding layer 25. In this way, the structure shown in FIG. 10A can be obtained.

[Step-620]
Next, the GaN substrate 11 is removed to expose the first surface 21 a of the first compound semiconductor layer 21 and the first light reflecting layer 41. Specifically, first, the thickness of the GaN substrate 11 is reduced based on the mechanical polishing method, and then the remaining portion of the GaN substrate 11 is removed based on the CMP method. In this way, the first surface 21a (not shown in FIG. 10B) of the first compound semiconductor layer 21, the first light reflecting layer 41, and the selective growth mask layer 43 are exposed to obtain the structure shown in FIG. 10B. it can.

[Step-630]
Thereafter, the first electrode 31 is formed on the first surface 21a of the first compound semiconductor layer 21 based on a known method. Thus, the light-emitting element of Example 6 having the structure shown in FIG. 9A can be obtained.

[Step-640]
Thereafter, the light emitting element is separated by performing so-called element separation, and the side surface and the exposed surface of the laminated structure are covered with an insulating film made of, for example, SiO _x . Then, in order to connect the first electrode 31 and the pad electrode 33 to an external circuit or the like, a terminal or the like is formed based on a well-known method, and packaged or sealed, thereby completing the light emitting element of Example 6.

  In the method for manufacturing the light emitting device of Example 6, the GaN substrate is removed in a state where the first light reflection layer and the selective growth mask layer are formed. Therefore, the first light reflection layer and the selective growth mask layer function as a kind of stopper when removing the GaN substrate. As a result, the GaN substrate removal variation in the GaN substrate surface, and further the thickness of the first compound semiconductor layer. Occurrence of variation can be suppressed and the length of the resonator can be made uniform. As a result, the characteristics of the obtained light-emitting element can be stabilized. In addition, since the surface (flat surface) of the first compound semiconductor layer at the interface between the first light reflecting layer and the first compound semiconductor layer is flat, light scattering on the flat surface can be minimized. .

  In the example of the light emitting element shown in FIG. 9A, the end portion of the first electrode 31 is separated from the first light reflecting layer 41. On the other hand, in the example of the light emitting element shown in FIG. 9B, the end portion of the first electrode 31 extends to the outer edge of the first light reflecting layer 41. Alternatively, the first electrode may be formed so that the end portion of the first electrode is in contact with the first light reflecting layer.

Example 7 is a modification of Examples 1 to 6, but relates to a light emitting element and the like according to the fifth configuration and the sixth configuration of the present disclosure. FIG. 11A shows a schematic partial cross-sectional view of the light-emitting element of Example 7, and FIG. 11B shows a schematic partial end view in which the selective growth mask layer opening region and the like in the light-emitting element of Example 1 are enlarged. . In the light emitting device of Example 7, the off-angle of the crystal orientation of the surface 11a of the GaN substrate 11 is within 0.4 degrees, preferably within 0.40 degrees, and the area of the GaN substrate 11 is S ₀ . At this time, the area of the selective growth mask layer 43 is 0.8 S ₀ or less. Although not limited, 0.004 × S ₀ can be exemplified as a lower limit value of the area of the selective growth mask layer 43. A thermal expansion relaxation film 44 is formed on the GaN substrate 11 as the lowermost layer of the selective growth mask layer 43 (such as a light-emitting element according to the fifth configuration of the present disclosure), and the first layer in contact with the GaN substrate 11. The linear thermal expansion coefficient CTE of the lowermost layer (corresponding to the thermal expansion relaxation film 44) of the one light reflecting layer 41 is
1 × 10 ⁻⁶ / K ≦ CTE ≦ 1 × 10 ⁻⁵ / K
Preferably,
1 × 10 ⁻⁶ / K <CTE ≦ 1 × 10 ⁻⁵ / K
(The light emitting element according to the sixth configuration of the present disclosure).

Specifically, the thermal expansion relaxation film 44 (the lowermost layer of the selective growth mask layer 43) is, for example,
t ₁ = λ ₀ / (2n ₁ )
It consists of silicon nitride (SiN _x ) that satisfies The thermal expansion relaxation film 44 (the lowermost layer of the selective growth mask layer 43) having such a film thickness is transparent to light having a wavelength λ ₀ and does not have a function as a light reflection layer. . The values of CTE of silicon nitride (SiN _x ) and GaN substrate 11 are as shown in Table 1 below. The value of CTE is a value at 25 ° C.

[Table 1]
GaN substrate: 5.59 × 10 ⁻⁶ / K
Silicon nitride (SiN _x ): 2.6 to 3.5 × 10 ⁻⁶ / K

  Hereinafter, the manufacturing method of the light emitting element of Example 7 will be described.

[Step-700]
First, the selective growth mask layer 43 is formed on the GaN substrate 11. Specifically, a thermal expansion relaxation film 44 constituting the lowermost layer of the selective growth mask layer 43 is formed on the GaN substrate 11, and the selective growth mask made of a multilayer film is further formed on the thermal expansion relaxation film 44. The remainder of the layer 43 (which functions as the first light reflecting layer 41) is formed. Then, the selective growth mask layer 43 is patterned. The GaN substrate 11 is exposed between the selective growth mask layer 43 and the selective growth mask layer 43, and this region corresponds to the selective growth mask layer opening region 51.

[Step-710]
Then, the light emitting element of Example 7 can be obtained by performing the process similar to [Step-100B]-[Step-140] of Example 1.

  In Example 7, the relationship between the off angle and the surface roughness Ra of the second compound semiconductor layer 22 was examined. The results are shown in Table 2 below. From Table 2, it can be seen that when the off-angle exceeds 0.4 degrees, the value of the surface roughness Ra of the second compound semiconductor layer 22 increases. That is, by setting the off angle to 0.4 degrees or less, preferably within 0.40 degrees, step bunching during the growth of the compound semiconductor layer can be suppressed, and the surface roughness Ra of the second compound semiconductor layer 22 can be suppressed. As a result, the second light reflecting layer 42 having excellent smoothness can be obtained, and variations in characteristics such as light reflectance are unlikely to occur.

[Table 2]
Off angle (degree) Surface roughness Ra (nm)
0.35 0.87
0.38 0.95
0.43 1.32
0.45 1.55
0.50 2.30

Further, the relationship between the area S ₀ of the GaN substrate 11, the area of the selective growth mask layer 43, and the surface roughness Ra of the second compound semiconductor layer 22 was examined. The results are shown in Table 3 below. From Table 3, it was found that the surface roughness Ra of the second compound semiconductor layer 22 can be reduced by setting the area of the selective growth mask layer 43 to 0.8 S ₀ or less.

[Table 3]
Area ratio of selective growth mask layer 43 Surface roughness Ra (nm)
0.88S ₀ 1.12
0.83S ₀ 1.05
0.75S ₀ 0.97
0.69S ₀ 0.91
0.63S ₀ 0.85

  From the above results, it can be seen that the surface roughness Ra of the second compound semiconductor layer 22 (the second surface of the second compound semiconductor layer 22) is preferably 1.0 nm or less.

Furthermore, without forming the thermal expansion relaxation film 44, the lowermost layer of the selective growth mask layer 43 is composed of SiO _x (CTE: 0.51 to 0.58 × 10 ⁻⁶ / K). When a light-emitting element having the same configuration and structure as in Example 7 was manufactured, the selective growth mask layer 43 might be peeled off from the GaN substrate 11 during film formation of the laminated structure, depending on the manufacturing conditions. It was. On the other hand, in Example 7, the selective growth mask layer 43 did not peel from the GaN substrate 11 during the formation of the laminated structure.

  As described above, in the light emitting device of Example 7 and the manufacturing method thereof, the off-angle of the crystal orientation of the GaN substrate surface and the area ratio of the mask layer for selective growth are defined. The surface roughness of the two-compound semiconductor layer can be reduced. That is, a second compound semiconductor layer having an excellent surface morphology can be formed. As a result, the second light reflecting layer having excellent smoothness can be obtained, so that a desired light reflectance can be obtained and the characteristics of the light emitting element are unlikely to vary. In addition, since the thermal expansion relaxation film is formed or the value of CTE is defined, the GaN substrate is separated from the GaN substrate due to the difference between the linear thermal expansion coefficient of the GaN substrate and the linear thermal expansion coefficient of the selective growth mask layer. Occurrence of a problem that the selective growth mask layer is peeled off can be avoided, and a light-emitting element having high reliability can be provided. Furthermore, since a GaN substrate is used, the problem that dislocations hardly occur in the compound semiconductor layer and the thermal resistance of the light-emitting element increases can be avoided, so that high reliability can be imparted to the light-emitting element. Then, the n-side electrode can be provided on the side different from the p-side electrode with respect to the GaN substrate.

  Although the present disclosure has been described based on the preferred embodiments, the present disclosure is not limited to these embodiments. The configurations and structures of the light-emitting elements described in the examples are exemplifications, and can be changed as appropriate. The methods for manufacturing the light-emitting elements in the examples can also be changed as appropriate.

In each example, the cross-sectional shape of the selective growth mask layer 43 is rectangular, but is not limited to this, and may be trapezoidal as shown in FIG. 12A. Further, as shown in FIG. 12B, the uppermost layer (layer in contact with the first compound semiconductor layer 21) 45 of the first light reflecting layer 41 (selective growth mask layer 43) may be formed of a silicon nitride film. In this case, when the thickness of the uppermost layer 45 of the first light reflecting layer 41 is t ₂ and the refractive index of the uppermost layer 45 of the first light reflecting layer 41 is n ₂ ,
t ₂ = λ ₀ / (2n ₂ )
Is preferably satisfied, whereby the uppermost layer 45 of the first light reflecting layer 41 is transparent to light having the wavelength λ ₀ . Further, in the example shown in FIG. 1A, the selective growth mask layer 43 is completely covered with the first compound semiconductor layer 21, but a part of the selective growth mask layer 43 may be exposed (FIG. 1). 13A), the first compound semiconductor layer 21 on the selective growth mask layer 43 may not be completely flat (see FIG. 13B). 13A and 13B, the current confinement layer 24, the second electrode 32, the pad electrode 33, the second light reflecting layer 42, and the first electrode 31 are not shown. The light emitting element may be manufactured by removing the exposed region of the first light reflecting layer 41 and the region where the first compound semiconductor layer 21 is not completely flat. Specifically, it is preferable to apply Example 5.

  The cross-sectional shape of the seed crystal layer 61 in the virtual vertical plane is not limited to an isosceles trapezoid, and a schematic partial end view may be an isosceles triangle as shown in FIGS. 14A and 14B. Can be rectangular. When the cross-sectional shape of the seed crystal layer 61 is an isosceles triangle, the crystal growth of the seed crystal layer 61 may be further advanced than the cross-sectional shape is an isosceles trapezoid. When the cross-sectional shape of the seed crystal layer 61 is rectangular, the formation conditions of the seed crystal layer 61 may be different from the formation conditions for forming the isosceles trapezoidal cross-sectional shape of the seed crystal layer 61.

In addition, this indication can also take the following structures.
[A01] << Light emitting element >>
GaN substrate,
A plurality of selective growth mask layers formed on a GaN substrate, each of which is provided apart from each other;
A first light reflecting layer comprising one of a plurality of selective growth mask layers;
A stacked structure including a first compound semiconductor layer, an active layer, and a second compound semiconductor layer formed over a plurality of selective growth mask layers; and
A second electrode and a second light reflecting layer formed on the second compound semiconductor layer;
A light emitting device comprising at least
At the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer, a seed crystal layer growth region composed of a part of the exposed surface of the GaN substrate is provided. And
A seed crystal layer is formed on the seed crystal layer growth region,
The first compound semiconductor layer is formed based on lateral epitaxial growth from the seed crystal layer,
The seed crystal layer is a light-emitting element having a thickness smaller than that of the selective growth mask layer.
[A02] When T _{seed is} the thickness of the seed crystal layer and T ₁ is the thickness of the mask layer for selective growth,
0.1 ≦ T _seed / T ₁ <1
The light emitting element as described in [A01] satisfying
[A03] An uneven portion is formed on the exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer,
The light-emitting element according to [A01] or [A02], in which a seed crystal layer growth region is configured by the protrusions.
[A04] A GaN substrate positioned at the bottom of the selective growth mask layer opening region when the light emitting element is cut along a virtual vertical plane including two normal lines passing through the center point of two adjacent selective growth mask layers The cross-sectional shape of the exposed surface is a shape in which concave portions, convex portions and concave portions are arranged in this order,
The light-emitting element according to [A03], in which a seed crystal layer growth region is configured by the top surface of the convex portion.
[A05] When the length of the convex portion is L _cv and the total length of the concave portion is L _cc in the virtual vertical plane,
0.2 ≦ L _cv / (L _cv + L _cc ) ≦ 0.9
The light emitting element as described in [A04] satisfying
[A06] An uneven portion is formed on the exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer,
The light-emitting element according to [A01] or [A02], in which a seed crystal layer growth region is configured by the recesses.
[A07] GaN substrate positioned at the bottom of the selective growth mask layer opening region when the light emitting element is cut along a virtual vertical plane including two normal lines passing through the center point of two adjacent selective growth mask layers The cross-sectional shape of the exposed surface is a shape in which convex portions, concave portions and convex portions are arranged in this order,
The light emitting device according to [A06], in which a seed crystal layer growth region is configured by the bottom surface of the recess.
[A08] When the length of the concave portion is L _cc and the total length of the convex portion is L _cv in the virtual vertical plane,
0.2 ≦ L _cc / (L _cv + L _cc ) ≦ 0.9
The light emitting element as described in [A07] satisfying
[A09] A GaN substrate positioned at the bottom of the selective growth mask layer opening region when the light emitting element is cut along a virtual vertical plane including two normal lines passing through the center point of two adjacent selective growth mask layers The cross-sectional shape of the exposed surface is a shape in which an amorphous growth layer, a flat portion, and an amorphous growth layer are arranged in this order,
The light-emitting element according to [A01] or [A02], in which the seed crystal layer growth region is configured by the flat portion.
[A10] When the length of the flat portion in the virtual vertical plane is L _flat and the total length of the amorphous growth layer is L _nov ,
0.2 ≦ L _flat / (L _flat + L _no ) ≦ 0.9
The light emitting element as described in [A09] satisfying
[A11] A GaN substrate positioned at the bottom of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normal lines passing through the center point of two adjacent selective growth mask layers The cross-sectional shape of the exposed surface is a shape in which uneven portions, flat portions and uneven portions are arranged in this order,
The light-emitting element according to [A01] or [A02], in which the seed crystal layer growth region is configured by the flat portion.
[A12] When the length of the flat portion is L _flat and the total length of the concavo-convex portions is L _cc-cv in the virtual vertical plane,
0.2 ≦ L _flat / (L _flat + L _cc-cv ) ≦ 0.9
The light emitting element as described in [A11] satisfying
[A13] The light-emitting element according to any one of [A01] to [A12], wherein the cross-sectional shape of the seed crystal layer is an isosceles triangle, an isosceles trapezoid, or a rectangle.
[A14] The length of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normal lines passing through the center point of two adjacent selective growth mask layers is represented by L ₀ ,
In the virtual vertical plane, the dislocation density in the region of the first compound semiconductor layer located above the selective growth mask layer opening region is represented by D ₀ ,
In the virtual vertical plane, the dislocation density in the region of the first compound semiconductor layer from the edge of the selective growth mask layer to the distance L ₀ is D ₁ ,
When
D ₁ / D ₀ ≦ 0.2
The light-emitting element according to any one of [A01] to [A13], wherein:
[B01] The off-angle of the surface orientation of the GaN substrate surface is within 0.4 degrees, preferably within 0.40 degrees.
When the area of the GaN substrate is S ₀ , the area of the selective growth mask layer is 0.8 S ₀ or less,
The light-emitting element according to any one of [A01] to [A14], wherein a thermal expansion relaxation film is formed on a GaN substrate as a lowermost layer of the selective growth mask layer.
[B02] The thermal expansion relaxation film is made of [B01] made of at least one material selected from the group consisting of silicon nitride, aluminum oxide, niobium oxide, tantalum oxide, titanium oxide, magnesium oxide, zirconium oxide, and aluminum nitride. The light emitting element of description.
[B03] When the thickness of the thermal expansion relaxation film is t ₁ , the emission wavelength of the light emitting element is λ ₀ , and the refractive index of the thermal expansion relaxation film is n ₁ ,
t ₁ = λ ₀ / (2n ₁ )
The light emitting element as described in [B01] or [B02] which satisfies these.
[B04] The off-angle of the surface orientation of the GaN substrate surface is within 0.4 degrees, preferably within 0.40 degrees.
When the area of the GaN substrate is S ₀ , the area of the selective growth mask layer is 0.8 S ₀ or less,
The linear thermal expansion coefficient CTE of the lowermost layer of the selective growth mask layer in contact with the GaN substrate is
1 × 10 ⁻⁶ / K ≦ CTE ≦ 1 × 10 ⁻⁵ / K
Preferably,
1 × 10 ⁻⁶ / K <CTE ≦ 1 × 10 ⁻⁵ / K
[A01] to [A14] according to any one of [A01] to [A14].
[B05] The lowermost layer of the selective growth mask layer is made of at least one material selected from the group consisting of silicon nitride, aluminum oxide, niobium oxide, tantalum oxide, titanium oxide, magnesium oxide, zirconium oxide and aluminum nitride. The light-emitting element according to [B04].
[B06] When the thickness of the lowermost layer of the selective growth mask layer is t ₁ , the emission wavelength of the light emitting element is λ ₀ , and the refractive index of the lowermost layer of the selective growth mask layer is n ₁ ,
t ₁ = λ ₀ / (2n ₁ )
The light emitting element as described in [B04] or [B05] satisfying the above.
[B07] The light emitting element according to any one of [B01] to [B06], wherein the surface roughness Ra of the second compound semiconductor layer is 1.0 nm or less.
[C01] << Method for Manufacturing Light-Emitting Element >>
A plurality of selective growth mask layers, each of which is provided on the GaN substrate so as to be separated from each other and function as a first light reflecting layer, are formed together with the selective growth mask layer and the selective growth mask layer. After forming the seed crystal layer growth region on the surface of a part of the portion of the GaN substrate exposed at the bottom of the selective growth mask layer opening region located between
Forming a seed crystal layer thinner than the thickness of the selective growth mask layer on the seed crystal layer growth region;
Forming a first compound semiconductor layer from the seed crystal layer based on lateral epitaxial growth;
An active layer, a second compound semiconductor layer, a second electrode, and a second light reflecting layer are sequentially formed on the first compound semiconductor layer;
A method for manufacturing a light-emitting element including at least each step.
[C02] When the thickness of the seed crystal layer is T _seed and the thickness of the selective growth mask layer is T ₁ ,
0.1 ≦ T _seed / T ₁ <1
The manufacturing method of the light emitting element as described in [C01] which satisfies these.
[C03] forming an uneven portion on the exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer;
The method for manufacturing a light-emitting element according to [C01] or [C02], in which a seed crystal layer growth region is configured by the protrusions.
[C04] A GaN substrate positioned at the bottom of the selective growth mask layer opening region when the light emitting element is cut along a virtual vertical plane including two normals passing through the center points of two adjacent selective growth mask layers The cross-sectional shape of the exposed surface is a shape in which concave portions, convex portions and concave portions are arranged in this order,
The method for manufacturing a light-emitting element according to [C03], in which a seed crystal layer growth region is configured by the top surface of the convex portion.
[C05] When the length of the convex portion is L _cv and the total length of the concave portion is L _cc in the virtual vertical plane,
0.2 ≦ L _cv / (L _cv + L _cc ) ≦ 0.9
The manufacturing method of the light emitting element as described in [C04] which satisfies these.
[C06] forming a concavo-convex portion on the exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer;
The method for manufacturing a light-emitting element according to [C01] or [C02], in which the seed crystal layer growth region is configured by the recesses.
[C07] GaN substrate positioned at the bottom of the selective growth mask layer opening region when the light emitting element is cut along a virtual vertical plane including two normal lines passing through the center point of two adjacent selective growth mask layers The cross-sectional shape of the exposed surface is a shape in which convex portions, concave portions and convex portions are arranged in this order,
The method for manufacturing a light-emitting element according to [C06], wherein the seed crystal layer growth region is configured by the bottom surface of the recess.
[C08] When the length of the concave portion is L _cc and the total length of the convex portion is L _cv in the virtual vertical plane,
0.2 ≦ L _cc / (L _cv + L _cc ) ≦ 0.9
The manufacturing method of the light emitting element as described in [C07] which satisfies these.
[C09] A GaN substrate positioned at the bottom of the selective growth mask layer opening region when the light emitting element is cut along a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers The cross-sectional shape of the exposed surface is a shape in which an amorphous growth layer, a flat portion, and an amorphous growth layer are arranged in this order,
The method for manufacturing a light-emitting element according to [C01] or [C02], in which the seed crystal layer growth region is configured by the flat portion.
[C10] When the length of the flat portion in the imaginary vertical plane is L _flat and the total length of the amorphous growth layer is L _nov ,
0.2 ≦ L _flat / (L _flat + L _no ) ≦ 0.9
The manufacturing method of the light emitting element as described in [C09] which satisfies these.
[C11] A GaN substrate positioned at the bottom of the selective growth mask layer opening region when the light emitting element is cut along a virtual vertical plane including two normal lines passing through the center point of two adjacent selective growth mask layers The cross-sectional shape of the exposed surface is a shape in which uneven portions, flat portions and uneven portions are arranged in this order,
The method for manufacturing a light-emitting element according to [C01] or [C02], in which the seed crystal layer growth region is configured by the flat portion.
[C12] When the length of the flat portion in the virtual vertical plane is L _flat and the total length of the concavo-convex portions is L _cc-cv ,
0.2 ≦ L _flat / (L _flat + L _cc-cv ) ≦ 0.9
The manufacturing method of the light emitting element as described in [C11] which satisfies these.
[C13] The method for manufacturing a light-emitting element according to any one of [C01] to [C12], wherein the cross-sectional shape of the seed crystal layer is an isosceles triangle, an isosceles trapezoid, or a rectangle.
[C14] The length of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normal lines passing through the center point of two adjacent selective growth mask layers is represented by L ₀ ,
In the virtual vertical plane, the dislocation density in the region of the first compound semiconductor layer located above the selective growth mask layer opening region is represented by D ₀ ,
In the virtual vertical plane, the dislocation density in the region of the first compound semiconductor layer from the edge of the selective growth mask layer to the distance L ₀ is D ₁ ,
When
D ₁ / D ₀ ≦ 0.2
The manufacturing method of the light emitting element of any one of [C01] thru | or [C13] which satisfy | fills.
[D01] The off-angle of the surface orientation of the GaN substrate surface is within 0.4 degrees, preferably within 0.40 degrees.
When the area of the GaN substrate is S ₀ , the area of the selective growth mask layer is 0.8 S ₀ or less,
The method for manufacturing a light-emitting element according to any one of [C01] to [C14], wherein a thermal expansion relaxation film is formed on a GaN substrate as the lowermost layer of the selective growth mask layer.
[D02] The thermal expansion relaxation film is made of [D01] made of at least one material selected from the group consisting of silicon nitride, aluminum oxide, niobium oxide, tantalum oxide, titanium oxide, magnesium oxide, zirconium oxide, and aluminum nitride. The manufacturing method of the light emitting element of description.
[D03] When the thickness of the thermal expansion relaxation film is t ₁ , the emission wavelength of the light emitting element is λ ₀ , and the refractive index of the thermal expansion relaxation film is n ₁ ,
t ₁ = λ ₀ / (2n ₁ )
The manufacturing method of the light emitting element as described in [D01] or [D02] which satisfies these.
[D04] The off-angle of the surface orientation of the GaN substrate surface is within 0.4 degrees, preferably within 0.40 degrees.
When the area of the GaN substrate is S ₀ , the area of the selective growth mask layer is 0.8 S ₀ or less,
The linear thermal expansion coefficient CTE of the lowermost layer of the selective growth mask layer in contact with the GaN substrate is
1 × 10 ⁻⁶ / K ≦ CTE ≦ 1 × 10 ⁻⁵ / K
Preferably,
1 × 10 ⁻⁶ / K <CTE ≦ 1 × 10 ⁻⁵ / K
The manufacturing method of the light emitting element of any one of [C01] thru | or [C14] which satisfy | fills.
[D05] The lowermost layer of the selective growth mask layer is made of at least one material selected from the group consisting of silicon nitride, aluminum oxide, niobium oxide, tantalum oxide, titanium oxide, magnesium oxide, zirconium oxide, and aluminum nitride. The manufacturing method of the light emitting element as described in [D04].
[D06] When the thickness of the lowermost layer of the selective growth mask layer is t ₁ , the emission wavelength of the light emitting element is λ ₀ , and the refractive index of the lowermost layer of the selective growth mask layer is n ₁ ,
t ₁ = λ ₀ / (2n ₁ )
The manufacturing method of the light emitting element as described in [D04] or [D05] which satisfies these.
[D07] After sequentially forming an active layer, a second compound semiconductor layer, a second electrode, and a second light reflecting layer on the first compound semiconductor layer, the GaN substrate is removed using the first light reflecting layer as a stopper layer. The method for manufacturing a light-emitting element according to any one of [D01] to [D06].
[D08] The method for manufacturing a light-emitting element according to any one of [D01] to [D07], wherein the surface roughness Ra of the second compound semiconductor layer is 1.0 nm or less.
[D09] The method for manufacturing a light-emitting element according to any one of [D01] to [D08], in which the planar shape of the selective growth mask layer is a regular hexagon, a circle, a lattice, or a stripe.

DESCRIPTION OF SYMBOLS 11 ... GaN substrate, 20 ... Laminated structure, 21 ... 1st compound semiconductor layer, 21a ... 1st surface of 1st compound semiconductor layer, 21b ... 1st compound semiconductor layer 1st surface 2 surface, 22 ... 2nd compound semiconductor layer, 22a ... 1st surface of 2nd compound semiconductor layer, 22b ... 2nd surface of 2nd compound semiconductor layer, 23 ... active layer (light emitting layer) 24... Current confinement layer, 24 A... Opening provided in the current confinement layer, 25... Bonding layer, 26... Support substrate, 31. 2 electrodes 33 ... pad electrodes 41 ... first light reflecting layer 42 ... second light reflecting layer 43 ... selective growth mask layer 44 ... thermal expansion relaxation film 45 ... uppermost layer of first light reflecting layer (selective growth mask layer), 51 ... selective growth mask layer opening region, 52 ... seed crystal layer Long region, 53, 54 ... Uneven portion, 53A, 54A ... Convex portion, 53B, 54B ... Concavity, 55A ... Flat portion, 55B ... Non-crystalline growth layer, 56A ... Flat Part, 56B ... uneven part, 61 ... seed crystal layer, 62 ... seed crystal, 63 ... dislocation

Claims (15)

GaN substrate,
A plurality of selective growth mask layers formed on a GaN substrate, each of which is provided apart from each other;
A first light reflecting layer comprising one of a plurality of selective growth mask layers;
A stacked structure including a first compound semiconductor layer, an active layer, and a second compound semiconductor layer formed over a plurality of selective growth mask layers; and
A second electrode and a second light reflecting layer formed on the second compound semiconductor layer;
A light emitting device comprising at least
At the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer, a seed crystal layer growth region composed of a part of the exposed surface of the GaN substrate is provided. And
A seed crystal layer is formed on the seed crystal layer growth region,
The first compound semiconductor layer is formed based on lateral epitaxial growth from the seed crystal layer,
The seed crystal layer is a light-emitting element having a thickness smaller than that of the selective growth mask layer. When the thickness of the seed crystal layer is T _seed and the thickness of the selective growth mask layer is T ₁ ,
0.1 ≦ T _seed / T ₁ <1
The light emitting device according to claim 1, wherein: An uneven portion is formed on the exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer,
The light-emitting element according to claim 1, wherein the seed crystal layer growth region is constituted by the convex portion. The exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers The cross-sectional shape is a shape in which concave portions, convex portions and concave portions are arranged in this order,
The light emitting device according to claim 3, wherein the seed crystal layer growth region is constituted by the top surface of the convex portion. In the virtual vertical plane, when the length of the convex portion is L _cv and the total length of the concave portion is L _cc ,
0.2 ≦ L _cv / (L _cv + L _cc ) ≦ 0.9
The light emitting device according to claim 4, wherein: An uneven portion is formed on the exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region located between the selective growth mask layer and the selective growth mask layer,
The light emitting device according to claim 1, wherein a seed crystal layer growth region is constituted by the recess. The exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers The cross-sectional shape is a shape in which convex portions, concave portions and convex portions are arranged in this order,
The light emitting device according to claim 6, wherein the seed crystal layer growth region is constituted by the bottom surface of the recess. In the virtual vertical plane, when the length of the concave portion is L _cc and the total length of the convex portion is L _cv ,
0.2 ≦ L _cc / (L _cv + L _cc ) ≦ 0.9
The light emitting device according to claim 7 satisfying The exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers The cross-sectional shape is a shape in which an amorphous growth layer, a flat portion, and an amorphous growth layer are arranged in this order,
The light-emitting element according to claim 1, wherein the flat crystal portion includes a seed crystal layer growth region. In the virtual vertical plane, when the length of the flat portion is L _flat and the total length of the amorphous growth layer is L _nov ,
0.2 ≦ L _flat / (L _flat + L _no ) ≦ 0.9
The light emitting device according to claim 9, wherein: The exposed surface of the GaN substrate located at the bottom of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers The cross-sectional shape is a shape in which uneven portions, flat portions and uneven portions are arranged in this order,
The light-emitting element according to claim 1, wherein the flat crystal portion includes a seed crystal layer growth region. In the virtual vertical plane, when the length of the flat part is L _flat and the total length of the uneven parts is L _cc-cv ,
0.2 ≦ L _flat / (L _flat + L _cc-cv ) ≦ 0.9
The light emitting device according to claim 11, wherein:   The light-emitting element according to claim 1, wherein a cross-sectional shape of the seed crystal layer is an isosceles triangle, an isosceles trapezoid or a rectangle. L ₀ , the length of the selective growth mask layer opening region when the light emitting element is cut at a virtual vertical plane including two normals passing through the center point of two adjacent selective growth mask layers.
In the virtual vertical plane, the dislocation density in the region of the first compound semiconductor layer located above the selective growth mask layer opening region is represented by D ₀ ,
In the virtual vertical plane, the dislocation density in the region of the first compound semiconductor layer from the edge of the selective growth mask layer to the distance L ₀ is D ₁ ,
When
D ₁ / D ₀ ≦ 0.2
The light emitting device according to claim 1, wherein: A plurality of selective growth mask layers, each of which is provided on the GaN substrate so as to be separated from each other and function as a first light reflecting layer, are formed together with the selective growth mask layer and the selective growth mask layer. After forming the seed crystal layer growth region on the surface of a part of the portion of the GaN substrate exposed at the bottom of the selective growth mask layer opening region located between
Forming a seed crystal layer thinner than the thickness of the selective growth mask layer on the seed crystal layer growth region;
Forming a first compound semiconductor layer from the seed crystal layer based on lateral epitaxial growth;
An active layer, a second compound semiconductor layer, a second electrode, and a second light reflecting layer are sequentially formed on the first compound semiconductor layer;
A method for manufacturing a light-emitting element including at least each step.

Images