JP2000022207A - Semiconductor light emitting element, and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor light emitting element where the function of current construction and current diffusion hardly drops by the influence of heat at the time of performing crystal growth, migration, or the like and which can be made highly bright, and besides whose manufacture process is simple, and whose manufacture time can be shortened and whose manufacture cost can be reduced, in the case where the semiconductor light emitting element has current constriction structure and current diffusion structure, and its manufacture. SOLUTION: This light emitting element is equipped with a first GaP layer 3 where a recess is made, and a second GaP layer 4 where a projection having a fitting form with this recess is made. Here, this has current constriction structure and current diffusion structure where these first GaP layer 3 and the second GaP layer 4 consist of the same conductivity type different in electric conductivity, and besides the recess and the projection are superposed to lie upon each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device used as a light source of a display device and a method for manufacturing the same.
In particular, the present invention relates to a high brightness GaP light emitting diode and a method for manufacturing the same.

[0002]

2. Description of the Related Art In general, a semiconductor light emitting device used for a display device such as an indoor / outdoor display panel, a vehicle display lamp, a traffic light or the like requires less power consumption as the luminance becomes higher. Light emitting devices are desired. In particular, a semiconductor light emitting device having higher brightness is desired since it is easily affected by disturbance light when used outdoors.

As an example of this type of semiconductor light emitting device, G
There is an aP light emitting diode. The GaP light emitting diode includes a red light emitting diode and a green light emitting diode. A green light emitting diode made of N-doped GaP is mainly used for outdoor display requiring high luminance.

FIG. 8 shows a cross-sectional structure of a conventional GaP light emitting diode (conventional example 1). The GaP light emitting diode of this prior art example 1 has an n-type GaP layer 82 (carrier concentration 5 × 10 5) formed on an n-type GaP substrate 81 by epitaxial growth.
^{16 to} 20 × 10 ¹⁶ cm ⁻³ ), the first p-type GaP layer 83 (carrier concentration of 5 × 10 ¹⁵ to 10 × 10 ¹⁵ cm ⁻³ ), and the second p-type GaP layer 83.
PP GaP layer 84 (carrier concentration 1 × 10 ^{18 to} 3 × 1
0 ¹⁸ cm ⁻³ ) are sequentially laminated, and the second p-type G
On the upper surface of the aP layer 84, a p-type electrode 85 is formed.
On the lower surface of the aP substrate 81, an n-type electrode 86 is formed.

As a method of increasing the luminance of the nitrogen-doped GaP light-emitting diode, a method of increasing the efficiency of light emission by increasing the amount of nitrogen doping, a method of improving the crystallinity of a light-emitting region near a pn junction, an epitaxial growth method, There is a method of forming a current blocking layer inside the layer structure to improve current spreading and enlarge a light emitting region.

As a light emitting diode having a current confinement structure, for example, a light emitting diode disclosed in Japanese Patent Application Laid-Open No. Hei 5-343736 is known (prior art 2). As shown in FIG. 9, the light emitting diode of the conventional example 2 has an n-type GaP substrate 91.
An n-type In _0.5 (Ga _1-x Al
_x ) _0.5 P clad layer 92, n-type In _0.5 (Ga
_1-y Al y) _0.5 active layer 93 made of P, p-type an In _0.5 (G
a _1-z Al _z ) _0.5 P cladding layer 94 is sequentially grown and formed, and on this p-type cladding layer 94, a current blocking layer 95 made of n-type GaAs having a substantially central opening and a p-type G
It has a structure in which a current diffusion layer 96 made of a _{1-u Alu} As is formed, and a p-type electrode 97 is provided on the upper surface of the p-type current diffusion layer 96.
Are formed on the lower surface of the n-type GaP substrate 91.
8 are formed.

In the structure of the conventional example 2, as described above, the opposite conductivity type n for current confinement is formed on the p-type cladding layer 94.
A method of forming a current blocking layer 95 and concentrating the current flowing through the light emitting layer near the center is adopted.

[0008]

SUMMARY OF THE INVENTION G of the above-mentioned prior art example 1
In the aP light emitting diode, when a method of increasing the efficiency of light emission by increasing the nitrogen doping amount is adopted,
There is a problem that the amount of light absorption increases simultaneously with the increase in luminous efficiency. To solve such problems, measures such as reducing the carrier concentration and removing the epitaxial layer serving as the absorption layer are taken. However, such measures reduce the current spread in the light emitting region in the crystal and lower the electrode lower portion. Light emission occurs in the vicinity, and another problem occurs such that the electrode blocks light and reduces the efficiency of light extraction to the outside.

In the case of the light emitting diode having the current confinement structure of the conventional example 2 described above, the n-type and the n-type
It is necessary to form a growth layer of the opposite conductivity type having a relationship opposite to that of the underlying conductivity type, such as a p-type, as a current blocking layer. Such a current blocking layer employs a method in which a crystal serving as a current blocking layer is first grown, then an etching process is performed to form an opening, and a crystal is grown thereon again. For this reason, there is a problem that the possibility of the current blocking layer losing its current blocking function becomes very high due to the diffusion of the dopant in the current blocking layer due to the thermal action when the crystal is grown again.

Further, even after the formation of the light emitting diode,
The current blocking layer may lose its current blocking function due to the diffusion or migration of the dopant during energization.

Further, in order to form a current blocking layer of the opposite conductivity type by liquid layer growth, after epitaxial growth for forming a pn junction, epitaxial growth for forming a current blocking layer is performed, and the current blocking layer is buried after etching. It is necessary to carry out the epitaxial growth of three times in total, so that a total of three epitaxial growths are required, and the number of manufacturing steps is increased and the manufacturing time is lengthened, which causes a problem that the manufacturing cost of the light emitting diode is increased.

The present invention solves the above-mentioned problems of the prior art. In a semiconductor light emitting device having a current confinement structure or a current diffusion structure, the function of current confinement or current diffusion is heat or migration when performing crystal growth. Due to the influence of the like, the semiconductor light emitting device is less likely to deteriorate in function, can increase the brightness of the semiconductor light emitting device, and can simplify the manufacturing process, shorten the manufacturing time, and reduce the manufacturing cost. It is intended to provide a manufacturing method.

[0013]

A semiconductor light emitting device according to the present invention includes a first semiconductor layer having a concave portion formed thereon and a second semiconductor layer having a convex portion formed to fit the concave portion. A current confinement structure or a current constriction in which the first semiconductor layer and the second semiconductor layer are formed of the same conductivity type having different electrical conductivities, and the concave portions and the convex portions are overlapped so as to be combined with each other. It has a diffusion structure, thereby achieving the above object.

[0014] Preferably, in the case of having the current confinement structure, an electrode formed above the second semiconductor layer is provided at a position corresponding to a region of the first semiconductor layer avoiding the concave portion. I do.

Preferably, when the current diffusion structure is provided, an electrode formed above the first semiconductor layer is provided at a position corresponding to the convex region of the second semiconductor layer. I do.

Preferably, when the semiconductor device has the current confinement structure, the carrier concentration of the first semiconductor layer is lower than the carrier concentration of the second semiconductor layer. The carrier concentration of the first semiconductor layer is higher than the carrier concentration of the second semiconductor layer.

[0017] Preferably, in the case where the current confinement structure is provided, the concave portion is arranged at a substantially central portion of the first semiconductor layer so that the light emitting portion is near the central portion, and the current diffusion structure is provided. The projection is arranged substantially at the center of the second semiconductor layer, and the light emitting portion is located near both ends.

[0018] Preferably, the first semiconductor layer and the second semiconductor layer are made of GaP.

According to the method for manufacturing a semiconductor light emitting device of the present invention, a first conductive type semiconductor layer is epitaxially grown on a substrate, and a first second conductive type semiconductor layer is epitaxially grown on the first conductive type semiconductor layer. Forming a convex portion or a concave portion by etching on the first second conductive type semiconductor layer; and forming an electric current on the first second conductive type semiconductor layer on which the convex portion or the concave portion is formed. Epitaxially growing a second second conductivity type semiconductor layer having a different conductivity, thereby achieving the object described above.

Preferably, the first second conductivity type semiconductor layer is formed at a background carrier concentration by liquid layer epitaxial growth, and the second second conductivity type semiconductor layer is formed by a liquid layer epitaxial growth. Is formed so that the carrier concentration of the first second conductivity type semiconductor layer is lower than the carrier concentration of the second second conductivity type semiconductor layer.

Preferably, the first conductive type semiconductor layer, the first second conductive type semiconductor layer, and the second second conductive type semiconductor layer are made of GaP.

The operation of the present invention will be described below.

According to the above configuration, the first portion having the recess is formed.
And the second semiconductor layer on which the convex portion that fits with the concave portion is formed are of the same conductivity type having different electric conductivities. By overlapping the first semiconductor layer and the second semiconductor layer such that the concave portion and the convex portion are brought into contact with each other, the electrical conductivity of the junction between the concave portion and the convex portion and the layer other than the junction is reduced. A difference is created and a current constriction or current spreading function is obtained.

In addition, since the first semiconductor layer and the second semiconductor layer constituting the current confinement structure and the current diffusion structure are of the same conductivity type, diffusion and migration of dopants caused by heat during epitaxial growth of each layer. And the like, so that it is possible to suppress the occurrence of the current constriction and the deterioration of the current diffusion function.

When a current confinement structure is provided, an electrode formed above the second semiconductor layer is provided at a position corresponding to a region of the first semiconductor layer avoiding the concave portion, for example, a structure shown in FIG. Then, as shown by the arrow CF indicating the direction in which the current is injected, the hole injected from the electrode 5 is the first hole.
Due to the difference in electric conductivity between the semiconductor layer 3 and the second semiconductor layer 4, the semiconductor layer 3 is confined at the center and injected with high density. As a result, light is emitted near the center of the semiconductor light emitting device due to recombination with electrons via the energy level formed by the dopant. As a result, the intensity curve I of the emission intensity distribution diagram of FIG.
As shown by a, light can be efficiently extracted to the outside without being blocked by the electrode 5, and the brightness of the semiconductor light emitting element can be increased.

When the current diffusion structure is provided, an electrode formed on the first semiconductor layer is provided at a position corresponding to the convex region of the second semiconductor layer, for example, as shown in FIG. As shown by the arrow CF ′, the direction of current injection is such that holes injected from the electrode 5 ′ are formed at both ends due to the difference in electric conductivity between the first semiconductor layer 4 ′ and the second semiconductor layer 3 ′. It is diffused in the vicinity and becomes dense and injected. As a result, light is emitted near both ends of the semiconductor light emitting device by recombination with electrons via the energy level formed by the dopant.

In the case of having the current confinement structure, the carrier concentration of the first semiconductor layer is made lower than the carrier concentration of the second semiconductor layer, and in the case of having the current diffusion structure, the carrier concentration of the first semiconductor layer is made lower. By making the carrier concentration higher than the carrier concentration of the second semiconductor layer, a desired difference occurs between the electric conductivity of the first semiconductor layer and the electric conductivity of the second semiconductor layer. Can be

Even when the first semiconductor layer and the second semiconductor layer are made of GaP, the function of current confinement or current diffusion can be obtained in a state where the carrier concentration is low. , The concentration or spread of the current is improved, the light extraction efficiency is improved, and the luminance of the semiconductor light emitting element can be increased.

Further, since the current confinement structure and the current diffusion structure are composed of the first semiconductor layer and the second semiconductor layer of the same conductivity type having different electric conductivities, the epitaxial growth is performed twice. Since the current confinement structure or the current diffusion structure can be formed, the manufacturing process can be simplified, the manufacturing time can be reduced, and the manufacturing cost can be reduced.

For example, when the first semiconductor layer is formed by liquid layer epitaxial growth with a background carrier concentration, and the second semiconductor layer is formed by liquid layer epitaxial growth by doping a dopant, Since the carrier concentration becomes lower than the carrier concentration of the second semiconductor layer, and a desired difference occurs in the electric conductivity between the first semiconductor layer and the second semiconductor layer of the same conductivity type,
Each structure provides a current constriction or current diffusion function.

[0031]

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

As shown in FIG. 1, a semiconductor light emitting device of the present invention comprises an n-type GaP
Has a structure in which a first p-type GaP layer 3 on which is formed and a second p-type GaP layer 4 on which a protrusion V is formed are sequentially laminated. A p-type electrode 5 is formed, and an n-type electrode 6 is formed on the lower surface of the n-type GaP substrate 1.

More specifically, the first p-type GaP layer 3 and the second p-type GaP layer 4 are made of the same p-type having the same conductivity and different electrical conductivity, and the first p-type GaP layer 3
And the convex portion V of the second p-type GaP layer 4 have a fitting shape. The first p-type GaP layer 3 and the second p-type GaP
The layer 4 is superimposed to form a current confinement structure.

The p-type electrode 5 formed on the second p-type GaP layer 4 is provided at a position corresponding to a region of the first p-type GaP layer 3 except for the concave portion V. Also, the first p
The concave portion V is arranged substantially at the center of the GaP layer 3 so that the light emitting portion is located near the center.

Here, in order to make the electric conductivity of the first p-type GaP layer 3 and that of the second p-type GaP layer 4 different, the carrier concentration of the first p-type GaP layer 3 is changed to the second p-type GaP layer 3. GaP layer 4
, And specifically, the carrier concentration of the first p-type GaP layer 3 is set to 5 × 10 ¹⁵ to 10 ×
And ¹⁰¹⁵ range cm ^-3, the carrier concentration of the second p-type GaP layer 4, and a range of ^{1 × 10 18 ~3 × 10 18} cm -3.

In the semiconductor light emitting device having the current confinement structure, the first p-type GaP layer 3 having the concave portion V formed thereon and the second p-type GaP layer 3 having the concave portion V formed therein are formed.
And p-type GaP layers 4 of the same conductivity type having different electric conductivity. The first p-type GaP layer 3 and the second p-type GaP layer 4 are overlapped so that the concave portions V and the convex portions V are aligned with each other. A difference in electric conductivity occurs between the other layers and the other layers, and a current constriction function is obtained.

Further, since the first p-type GaP layer 3 and the second p-type GaP layer 4 constituting the current confinement structure are of the same conductivity type p-type, they are caused by heat during epitaxial growth of each layer. Since the influence of the diffusion or migration of the dopant is reduced, it is possible to suppress the occurrence of the current constriction function deterioration.

As shown in FIG. 5, the second p-type GaP layer 4
Is provided at a position corresponding to a region avoiding the concave portion V of the first p-type GaP layer 3, as shown by an arrow CF, the direction in which a current is injected is provided. , P
The hole injected from the mold electrode 5 is the first p-type GaP layer 3.
And the second p-type GaP layer 4 is confined at the center due to the difference in electric conductivity and injected with high density. As a result, light is emitted near the center of the semiconductor light emitting device due to recombination with electrons via the energy level formed by the dopant.
That is, the light emission intensity distribution as shown by the intensity curve Ia in FIG. 6 is obtained, and light can be efficiently extracted to the outside without being blocked by the p-type electrode 5, and the semiconductor light emitting device can have high brightness.

Next, a method for manufacturing a semiconductor light emitting device having a current confinement structure according to the present invention will be specifically described below with reference to FIGS.

The temperature of the first liquid layer epitaxial growth shown in FIG.
First, heat to 1000 ° C as shown in the degree diagram
The n-type GaP substrate 1 is immersed in the GaP solution (see FIG. 2).
(A), see step a in FIG. 3).
Slow cooling was started at a rate of 5 ° C./min, and the temperature of the GaP solution was lowered.
By continuing the slow cooling until time t3 when the temperature reaches 900 ° C,
An n-type GaP layer 2 is epitaxially formed on an n-type GaP substrate 1.
It is grown (see step (b) in FIG. 2B and step b in FIG. 3). this
At this time, hydrogen gas (H_TwoUse the flow rate
Supply at 4.0 L (liter) / min, n-type dopan
Silicon (Si) is used as the gate. This n-type GaP layer
2 has a carrier concentration of 5 × 10¹⁶~ 20 × 10 ¹⁶cm^-3so
is there.

Next, from time t3 when the temperature of the GaP solution reaches 900 ° C., ammonia gas (NH ₃ ) is added together with hydrogen gas.
Is introduced, and Si, which is an n-type dopant, is reacted with ammonia gas to form S into the epitaxial growth layer.
The temperature of the solution is set to 900 so as to eliminate the incorporation of i and to obtain the background carrier concentration for epitaxial growth.
Hold at 30 ° C. for 30 minutes (see step c in FIG. 3).

Next, the supply of ammonia gas was stopped from time t4, and only the carrier gas was hydrogen gas, and the flow rate was 4.0 L.
(Liter) / min, and the GaP solution was added again at 0.1 g / min.
Slowly cooling to 850 ° C. at a rate of 5 ° C./min, the first p-type GaP layer 3 is epitaxially grown based on the background carrier concentration (see step d in FIG. 2C and FIG. 3). The carrier concentration of the first p-type GaP layer 3 is 5
× 10 ¹⁵ to 10 × 10 ¹⁵ cm ⁻³ .

In the epitaxial layers 3, 3 'formed by the above method, the conductivity type of the background carrier is inverted at the final stage of the epitaxial growth, so that the inverted layer 3' is removed by etching (FIG. 2C). reference).

After forming the SiO ₂ film 7 on the surface of the first p-type GaP layer 3 from which the inversion layer 3 ′ has been removed, and performing circular patterning with a diameter of 120 μm (see FIG. 2D), the first The P-type GaP layer 3 is etched to form the recess V
Is formed, and then the SiO ₂ film is removed (see FIG. 2E).

Next, as shown in the temperature diagram of the second liquid layer epitaxial growth in FIG.
The P substrate is immersed in a GaP solution heated to 900 ° C. (FIG. 2)
(E), see step e in FIG. 4). From time t7, the GaP solution is gradually cooled at a rate of 0.5 ° C./min, and is gradually cooled until time t8 when the temperature of the GaP solution becomes 850 ° C. A second p-type GaP layer 4 on the first p-type GaP layer 3.
Is epitaxially grown (see step f in FIG. 2F and FIG. 4). At this time, hydrogen gas is used as a carrier gas and supplied at a flow rate of 4 L (liter) / min. At the same time, ammonia gas is supplied to perform nitrogen doping, and zinc (Zn) is used as a p-type dopant. This second p-type G
The carrier concentration of the aP layer 4 is 1 × 10 ^{18 to} 3 × 10 ¹⁸ c
m ^-3 . Thus, the epitaxial growth step is completed. Next, the first p-type Ga prepared by the above method is used.
A p-type electrode 5 is formed on the second p-type GaP layer 4 at a position corresponding to a region avoiding the concave portion V of the P layer 3, and an n-type Ga
After forming the n-type electrode 6 on the lower surface of the P substrate 1, the p-type electrode 5
0.28 mm × 0.
The semiconductor light-emitting element is divided into chips of 28 mm square (see FIG. 2G).

As a result, in this semiconductor light emitting device, a luminous intensity approximately 1.2 times as high as that of a GaP light emitting diode manufactured by a conventional method was obtained.

As described above, the first p-type GaP layer 3 and the second p-type GaP layer 3 of the same conductivity type having different electric conductivities have different current confinement structures.
, The current confinement structure can be formed by two epitaxial growths.
The manufacturing process is simple, the manufacturing time can be reduced, and the manufacturing cost can be reduced.

To make the electric conductivity of the first p-type GaP layer 3 and the second p-type GaP layer 4 different, for example, the first
When the p-type GaP layer 3 is formed by liquid-layer epitaxial growth with a background carrier concentration and the second p-type GaP layer 4 is formed by doping a dopant by liquid-layer epitaxial growth, the first p-type GaP layer 3 is formed. Is lower than the carrier concentration of the second p-type GaP layer 4, and the electric conductivity of the first p-type GaP layer 3 and the second p-type GaP layer 4 of the same conductivity type is desired. Because of the differences, this structure provides a current constriction function.

The semiconductor light emitting device having the current confinement structure has been described above. Next, the semiconductor light emitting device having the current diffusion structure will be described below.

As shown in FIG. 7, this semiconductor light emitting device has an n-type GaP layer 2 and a projection V ′ on an n-type GaP substrate 1.
Has a structure in which a first p-type GaP layer 3 ′ in which is formed and a second p-type GaP layer 4 ′ in which a concave portion V ′ is formed are sequentially stacked, and a second p-type GaP layer 4 ′ is formed. A p-type electrode 5 ′ is formed on the upper surface of the substrate, and an n-type electrode 6 is formed on the lower surface of the n-type GaP substrate 1.

More specifically, the first p-type GaP layer 3 ′ and the second p-type GaP layer 4 ′ are made of the same p-type having the same conductivity type with different electric conductivity, and the first p-type GaP layer 3 ′ Type Ga
The convex portion V 'of the P layer 3' and the concave portion V 'of the second p-type GaP layer 4' have a fitting shape. These convex portions V '
The first p-type GaP layer 3 ′ and the second p-type GaP layer 4 ′ are overlapped to form a current diffusion structure such that the recesses V ′ are aligned with the first p-type GaP layer 3 ′.

The p-type electrode 5 ′ formed on the second p-type GaP layer 4 ′ is formed by a convex portion V ′ of the first p-type GaP layer 3 ′.
It is provided at a position corresponding to the area. Also, the first p
A convex portion V 'is arranged substantially at the center of the GaP layer 3', and the light emitting portion is located near both ends.

Here, the first p-type GaP layer 3 ′ and the second
In order to make the electric conductivity of the p-type GaP layer 4 ′ different from that of the first p-type GaP layer 3 ′,
The carrier concentration of the P layer 4 ′ is lower than the carrier concentration of the first p-type GaP layer 3 ′.
0 ¹⁵ to 10 × 10 ¹⁵ cm ⁻³ , and the second p-type Ga
The carrier concentration of the P layer 4 ′ is 1 × 10 ^{18 to} 3 × 10 ¹⁸ c
m ⁻³ .

In the case of adopting this current diffusion structure, the holes injected from the p-type electrode 5 'are, for example, as shown by arrows CF' in FIG.
Due to the difference in electrical conductivity between the p-type GaP layer 3 ′ and the second p-type GaP layer 4 ′, it is diffused near both ends and injected with high density.

The semiconductor light emitting device having the current diffusion structure shown in FIG. 7 is different from the semiconductor light emitting device having the current confinement structure shown in FIG. 1 in that the first p-type GaP layer 3 'on which the convex portion V' is formed. A second p-type GaP layer 4 'in which a concave portion V' is formed,
And the shape of the p-type electrode 5 'is different.

Therefore, the semiconductor light emitting device having the current diffusion structure can be manufactured by the same method as the semiconductor light emitting device having the current confinement structure described above with reference to FIGS.

Note that the conductivity type of each semiconductor layer and electrode constituting the semiconductor light emitting device described in each of the above embodiments may be reversed between p type and n type.

[0058]

As described above, according to the semiconductor light emitting device of the present invention, the first semiconductor layer in which the concave portion is formed,
The recess and the second semiconductor layer on which the projection that forms the fitting shape are formed are of the same conductivity type having different electrical conductivities, and the first semiconductor layer and the second semiconductor layer are formed so that the recess and the projection match. By overlapping the second semiconductor layer, a difference in electric conductivity occurs between the junction between the concave portion and the convex portion and a layer other than the junction, and a current constriction or current diffusion function is obtained. The element can have high luminance. For this reason, even in a GaP light-emitting diode, a current constriction or current diffusion function can be obtained in a state where the carrier concentration is low without increasing the doping amount of nitrogen, so that the crystal quality is improved and the light transmittance is improved. As well as improving the concentration or spread of the current, the light extraction efficiency can be improved, thereby increasing the light emission amount, and further efficiently extracting the light to the outside by shifting the position of the light emitting region and the electrode. Can be.

Further, since the current confinement structure and the current diffusion structure are composed of the first semiconductor layer and the second semiconductor layer of the same conductivity type having different electric conductivities, the current is reduced by two epitaxial growths. Since the constriction structure or the current diffusion structure can be formed, the manufacturing process can be simplified, the manufacturing time can be reduced, and the manufacturing cost can be reduced.

In particular, when the first semiconductor layer is formed by liquid-layer epitaxial growth with a background carrier concentration and the second semiconductor layer is formed by doping a dopant by liquid-layer epitaxial growth, The carrier concentration becomes lower than the carrier concentration of the second semiconductor layer, and a desired difference occurs in the electric conductivity between the first semiconductor layer and the second semiconductor layer of the same conductivity type. The function of constriction or current spreading can be obtained.

Further, since the first semiconductor layer and the second semiconductor layer constituting the current confinement structure and the current diffusion structure are of the same conductivity type, diffusion of dopants caused by heat during epitaxial growth of each layer, Since the influence of migration or the like is reduced, it is possible to suppress the occurrence of the current constriction and the deterioration of the current diffusion function.

[Brief description of the drawings]

FIG. 1 is a diagram showing a sectional structure of a semiconductor light emitting device having a current confinement structure according to the present invention.

FIG. 2 is a diagram showing a manufacturing process of a semiconductor light emitting device having a current confinement structure according to the present invention.

FIG. 3 is a temperature diagram of a first liquid layer epitaxial growth in a manufacturing process of a semiconductor light emitting device having a current confinement structure according to the present invention.

FIG. 4 is a temperature diagram of a second liquid layer epitaxial growth in a manufacturing process of a semiconductor light emitting device having a current confinement structure according to the present invention.

FIG. 5 is a diagram illustrating a state of current confinement in a semiconductor light emitting device having a current confinement structure according to the present invention.

FIG. 6 is a graph showing a light emission intensity distribution near a pn junction in a semiconductor light emitting device having a current confinement structure according to the present invention.

FIG. 7 is a diagram illustrating a cross-sectional structure of a semiconductor light emitting device having a current spreading structure according to the present invention and a state of current spreading.

FIG. 8 is a diagram showing a cross-sectional structure of a GaP light emitting diode of Conventional Example 1.

FIG. 9 is a diagram showing a cross-sectional structure of a light emitting diode having a current confinement structure according to Conventional Example 2.

[Explanation of symbols]

 Reference Signs List 1 n-type GaP substrate 2 n-type GaP layer 3 first p-type GaP layer 4 second p-type GaP layer 5 p-type electrode 6 n-type electrode

Claims (9)

[Claims] 1. A semiconductor device comprising: a first semiconductor layer having a recess formed therein; and a second semiconductor layer having a projection formed in a shape fitting the recess, wherein the first semiconductor layer and the second semiconductor layer are provided. A semiconductor light emitting device having a current confinement structure or a current diffusion structure in which a semiconductor layer is made of the same conductivity type having different electric conductivity, and the concave portion and the convex portion are overlapped so as to be matched. 2. An electrode formed above the second semiconductor layer when the current confining structure is provided, the electrode being provided at a position corresponding to a region of the first semiconductor layer avoiding the concave portion. The semiconductor light emitting device according to claim 1. 3. When the current diffusion structure is provided, an electrode formed on the first semiconductor layer is provided at a position corresponding to the convex region of the second semiconductor layer. 2. The semiconductor light emitting device according to 1. 4. The method according to claim 1, wherein the carrier concentration of the first semiconductor layer is lower than the carrier concentration of the second semiconductor layer when the current confinement structure is provided, and the first semiconductor layer is provided when the current diffusion structure is provided. 4. The semiconductor light emitting device according to claim 1, wherein a carrier concentration of the semiconductor layer is higher than a carrier concentration of the second semiconductor layer. 5. When the current confinement structure is provided, the concave portion is arranged at a substantially central portion of the first semiconductor layer to make a light emitting portion near a central portion. The semiconductor light-emitting device according to claim 1, wherein the projection is disposed at a substantially central portion of the second semiconductor layer, and the light-emitting portion is located near both ends. 6. The semiconductor light emitting device according to claim 1, wherein said first semiconductor layer and said second semiconductor layer are made of GaP. 7. A step of epitaxially growing a first conductivity type semiconductor layer on a substrate; a step of epitaxially growing a first second conductivity type semiconductor layer on the first conductivity type semiconductor layer; Forming a convex portion or a concave portion on the conductive type semiconductor layer by an etching process; and forming a second second conductive layer having a different electrical conductivity on the first second conductive type semiconductor layer on which the convex portion or the concave portion is formed. Epitaxially growing a conductive semiconductor layer. 8. The first second conductivity type semiconductor layer is formed with a background carrier concentration by liquid layer epitaxial growth, and the second second conductivity type semiconductor layer is doped with a second conductivity type dopant by liquid layer epitaxial growth. And the carrier concentration of the first second conductivity type semiconductor layer is
8. The method for manufacturing a semiconductor light emitting device according to claim 7, wherein the carrier concentration is lower than the carrier concentration of the second conductivity type semiconductor layer. 9. The semiconductor light emitting device according to claim 7, wherein the first conductive type semiconductor layer, the first second conductive type semiconductor layer, and the second second conductive type semiconductor layer are made of GaP. Device manufacturing method.