JP3150011B2 - Semiconductor light emitting device and method of manufacturing the same - Google Patents

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 and a method for manufacturing the same. More specifically, the present invention relates to a light emitting diode chip and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 6 shows a typical conventional LED. This LED chip has a so-called double heterostructure, and is formed on a p-GaAs substrate 100.
p-Al _Y Ga _1-Y As clad layer 101, p-Al _X G
a _1-x As active layer 102 and an n-Al _Y Ga _1-y As clad layer 103 are provided in this order (hereinafter, clad layer 10).
1. The three layers of the active layer 102 and the cladding layer 103 are referred to as “light emitting layer”. ). The n-type electrode 10 is provided on the cladding layer 103 side.
4. A p-type electrode 105 is provided on the substrate 100 side.
The LED is mounted on a package in a state of being divided by dicing, and is resin-molded. When a voltage is applied and current is passed between the electrodes 104 and 105, light emitted from the active layer (light emitting portion) 102 in the light emitting layer is emitted to the outside through the surface and the end surface (light emitting surface) of the light emitting layer. Note that the active layer 102 and the cladding layers 101 and 103 are usually
Are set to be about Al = 0.35 and about Y = 0.7, respectively. As a result, red light having a peak wavelength of 660 nm is emitted.

[0003]

However, when the above-mentioned conventional LED is subjected to a high-temperature and high-humidity test required for outdoor use in a package state, the light emitting surface is oxidized despite being molded with resin. Therefore, there is a problem that the luminance is lowered due to the deterioration. That is, since the light-emitting layer containing Al in the composition is exposed on the outer periphery of the chip, the light-emitting layer is oxidized by moisture penetrating through the resin, and a non-light-emitting level is formed in the oxidized portion. Carriers injected from the electrodes 104 and 105 at the time of energization are non-radiatively recombined via this non-light emitting level, and generate heat. Owing to this heat generation, oxidation proceeds from the light emitting surface to the inside of the chip, so that the luminous efficiency is reduced and the luminance is reduced. It should be noted that many defects are introduced into the light emitting surface during dicing, and these also become non-emission levels and cause deterioration.

Here, conventionally, SiO ₂ films and Si ₃ N ₄
Attempts have been made to deposit a film on the light exit surface. However, the process becomes complicated, and the penetration of moisture cannot be completely prevented. In addition, since the process is performed after the light emitting surface is exposed to the atmosphere, the light emitting surface is oxidized before vapor deposition, which is not sufficient.

Accordingly, an object of the present invention is to prevent the light emitting layer from being exposed on the outer periphery of the chip and to prevent defects from occurring at the end face of the light emitting layer when dividing the chip. An object of the present invention is to provide a semiconductor light emitting device that can be manufactured and a method for manufacturing the same.

[0006]

According to a first aspect of the present invention, there is provided a semiconductor light emitting device comprising a semiconductor substrate and an insulating film having an opening of a predetermined shape provided on a surface of the semiconductor substrate. A mask layer that partitions the surface of the semiconductor substrate into a region corresponding to the opening, and a region formed on the substrate surface that is thicker than the thickness of the mask layer, the surface is flat, and the end surface of the opening is A light-emitting layer defined by an edge, a protective layer that covers the surface and the end surface of the light-emitting layer with a predetermined thickness, and that prevents the light-emitting layer from being oxidized; It is characterized by having electrodes provided on the back side respectively.

Further, in the semiconductor light emitting device according to the second aspect, the protective layer is made of a semiconductor material that is less oxidized than at least a part of the light emitting layer.

Further, in the semiconductor light emitting device according to the third aspect, the band gap energy of the protective layer is set to be larger than the band gap energy of the light emitting portion in the light emitting layer.

Further, in the semiconductor light emitting device according to the fourth aspect, the resistivity of the protective layer is set to be higher than the resistivity of a light emitting portion in the light emitting layer.

In the semiconductor light emitting device according to the present invention, when the light emitting wavelength of the light emitting layer is λ and the refractive index at the wavelength λ of the protective layer is n, the thickness of the protective layer is substantially Is set to an odd multiple of λ / 4n.

According to a sixth aspect of the present invention, in the method of manufacturing a semiconductor light emitting device, an insulating film is provided on a surface of the semiconductor substrate, and a plurality of openings having a predetermined shape are formed in the insulating film at a predetermined pitch. A step of forming a mask layer that partitions the surface into a plurality of regions corresponding to the openings, and by a selective vapor deposition method,
In the region partitioned by the mask layer of the semiconductor substrate, a light emitting layer having a thickness greater than the thickness of the mask layer, a flat surface, and an end surface defined by an edge of the opening is formed.
Subsequently, a step of forming a protective layer covering the surface and the end face of the light emitting layer with a predetermined thickness, a step of forming electrodes on the front side of the protective layer and the back side of the substrate, respectively, Cut or cleave where the mask layer is,
A step of dividing the substrate into chips.

In the method of manufacturing a semiconductor light emitting device of the present invention, when growing the light emitting layer and the protective layer, HCl is mixed with a source gas.

[0013]

According to the semiconductor light emitting device of the present invention, the surface and the end face (light emitting surface) of the light emitting layer are covered with the protective layer.
The light emitting surface is less susceptible to oxidation than in the past. Therefore, generation of a non-light-emitting level due to oxidation is suppressed, and a decrease in luminance is suppressed. Since the light emitting layer and the protective layer are separated for each region partitioned by the mask layer in the growth stage, no defect is introduced into the light emitting surface during dicing. Therefore, a decrease in luminance is further suppressed, and reliability is improved.

Further, in the semiconductor light emitting device according to the second aspect, since the protective layer is made of a semiconductor material that is harder to be oxidized than at least a part of the light emitting layer, further generation of non-emission levels due to oxidation is further improved. Is suppressed, and a decrease in luminance is further suppressed.

Further, in the semiconductor light emitting device of the present invention, the band gap energy of the protective layer is set to be larger than the band gap energy of a light emitting portion in the light emitting layer. Therefore, light is not absorbed by the protective layer, and the light emitting characteristics of the element are not adversely affected.

Further, in the semiconductor light emitting device according to the fourth aspect, the resistivity of the protective layer is set to be higher than the resistivity of a light emitting portion in the light emitting layer. Carrier injection is suppressed. Therefore, the light emitting characteristics of the element are not adversely affected.

In the semiconductor light emitting device of the present invention, when the light emitting wavelength of the light emitting layer is λ and the refractive index at the wavelength λ of the protective layer is n, the thickness of the protective layer is substantially λ. / 4
Since it is set to an odd multiple of n, the reflectance of the protective layer is reduced, and the light emitted from the light emitting layer is efficiently emitted out of the chip.

According to the method of manufacturing a semiconductor light emitting device of claim 6, the semiconductor light emitting devices of claims 1 to 5 can be easily manufactured.

Further, when the light emitting layer and the protective layer are grown, when HCl is mixed with the source gas,
The light emitting layer and the protective layer never grow on the surface of the mask layer. That is, complete selective growth is performed.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the semiconductor light emitting device of the present invention and a method of manufacturing the same will be described in detail with reference to embodiments.

FIG. 1A shows a cross section of the LED of the first embodiment.

This LED is formed on a p-type GaAs substrate 1
In the region A partitioned by the i ₃ N ₄ film 2, p-type Al _0.7 Ga _0.3
As clad layer 3, p-type Al _0.35 Ga _0.65 As active layer 4, n-type Al _0.7 Ga _0.3 As clad layer 5, p-type Al
_{A 0.5} Ga _0.5 As protective layer 6 is sequentially provided. The cladding layers 3 and 5 and the active layer 4 as a light emitting portion constitute a light emitting layer. The surface 3a of the cladding layer 3 is the substrate surface 1a.
The end face 3b of the cladding layer 3 reaches the surface 2a of the Si ₃ N ₄ film 2 at a constant angle with respect to the surface 3a. The active layer 4, the cladding layer 5, and the protective layer 6 respectively cover the lower layers. That is, the surface 4a and the end surface 4b of the active layer 4 are the surfaces 3a and 3b of the clad layer 3, respectively, the surface 5a and the end surface 5b of the clad layer 5 are the surfaces 4a and 4b of the active layer 4 and the surface 6a and the end surface of the protective layer 6, respectively. Numerals 6b cover the surface 5a and the end face 5b of the cladding layer 5, respectively. Active layer 4, clad layer 5, end face 4b, 5b, 6 of protective layer 6
b reach the surface 2a of the Si ₃ N ₄ film 2 at the same angle as the end face 3a of the cladding layer 3. Protective layer 6
A p-type electrode 6 is provided at the center of the front surface 6a, and an n-type electrode 7 is provided on the entire back surface 1b of the substrate 1.

This LED is manufactured as follows.

First, as shown in FIG.
0) plane on the p-type GaAs substrate 1 whose principal the Si ₃ N ₄ film 2 having a thickness of 0.1μm is deposited by a plasma CVD method, Si ₃ N ₄ photolithography, lift-off, by etching or the like The film is patterned to form a lattice-shaped mask layer 2 having a width of 30 μm. FIG. 3B is a schematic diagram, and actually a lattice is formed on a 2-inch substrate 1 at a pitch of 300 μm.

Next, as shown in FIG.
By the method D (metal organic chemical vapor deposition), a thickness of 5
μm p-type Al _0.7 Ga _0.3 As clad layer 3, thickness 1.
5 μm p-type Al _0.35 Ga _0.65 As active layer 4, thickness 5 μ
m n-type Al _0.7 Ga _0.3 As clad layer 5, thickness 0.1
A μm p-type Al _0.5 Ga _0.5 As protective layer 6 is sequentially grown. At this time, each of the layers 3, 4, 5, and 6 grows flat in the rectangular area A partitioned by the mask layer 2 without crystal growth on the mask layer 2. The end faces 3b, 4b of each layer 3, 4, 5, 6
5b and 6b are finished in a state inclined at a constant angle with respect to the substrate surface 1a. In general, polycrystals may grow on the mask layer. However, during the growth, a small amount of HCl is mixed into the growth material gas to form the mask layer 2.
It is possible to achieve a completely selective growth that does not grow on the top.

Clad layer 3, active layer 4, clad layer 5,
Since the protective layer 6 is continuously grown in the MOCVD apparatus, the clad layer 3, the active layer 4, and the clad layer 5 are not oxidized during the manufacturing process.

Note that the Al mixed crystal ratio of the protective layer 6
What is necessary is just to set so that band gap energy becomes larger than that. This is because light absorption in the protective layer 6 is eliminated and the light emission characteristics are not affected. In this example, the p-type Al _Z G
In a _1-Z As, Z = 0.5.

Next, an n-type electrode 8 is deposited at the center of the front surface 6a of the protective layer 6, and a p-type electrode 7 is deposited and alloyed on the entire back surface 1b of the substrate 1. Thereafter, the substrate 1 is diced along the pattern of the mask layer 2 to be divided into chips 110.

The LED chip 110 manufactured by the above-described process is, for example, as shown in FIG.
11 is mounted. Wire bond (wire 11
3), and molding with an epoxy resin 112 to obtain an LED lamp. Alternatively, the LED chip 110 is mounted on the wiring 142 of the printed board 141 as shown in FIG. By performing wire bonding (wires are indicated by 145) and housing the package in a package 150 having a reflecting plate 143 and a light diffusing plate 144, a surface-emitting LED element is obtained.

In this LED, as shown in FIG.
Al _0.7 Ga _0.3 As clad layer 3, p-type Al _0.35 Ga
_{The 0.65} As active layer 4 and the n-type Al _0.7 Ga _0.3 As clad layer 5 are covered with the p-type Al _0.5 Ga _0.5 As protective layer 6 which has a lower Al mixed crystal ratio than the clad layers 3 and 5 and is hardly oxidized. ing. As a result, the surface 3a of the cladding layer 3 and the end surfaces 3a, 5a, 4a of the cladding layers 3, 5 and the active layer 4 are formed.
(Light emitting surface) is less likely to be oxidized. Therefore, it is possible to suppress the occurrence of non-light-emitting levels due to oxidation and to suppress a decrease in luminance. In addition, each layer 3, 4, 5,
6 is separated for each rectangular area A at the growth stage,
No defects are introduced into the light exit surface during dicing. Therefore, a decrease in luminance can be further suppressed, and reliability can be improved.

Actually, in order to confirm the effect of the present invention, the LED lamp configured as shown in FIG. As a result, it was found that the traveling time until the emission output was reduced by half can be improved to 10 times or more as compared with the related art.

The material of the protective layer 6 is AlGaAs.
When GaInP containing no Al was used instead of s, the reliability could be further improved. In addition, Al
In the case of GaAs / GaAs, the end faces 3a, 4a, 5a, 6a
The growth rate varies depending on the plane orientation of the crystal, or the growth rate becomes almost zero depending on the growth conditions. On the other hand, GaInP grows stably irrespective of the plane orientation and the like, and is therefore preferable as the material of the protective layer 6 in this sense.
Other materials for the protective layer 6 include AlGaInP,
GaP, a II-VI group semiconductor composed of a mixed crystal of Zn, S, Se, Cd, Mg and the like can also be used.

Although the protective layer 6 is of the p-type, it is preferable to have a relatively high resistance as undoped from the viewpoint of suppressing carriers on the surface. If the protective layer 6 has a high resistance, the series resistance immediately below the electrode 8 increases, which adversely affects the device characteristics. However, by setting the thickness of the protective layer 6 to be thin, the resistance value immediately below the electrode 8 can be reduced when the electrode 8 is alloyed, and the influence on the element characteristics can be avoided.

FIG. 2A is an oblique view of the LED of the second embodiment, and FIG. 2B shows a cross section of the LED.

In this LED, an n-type (Al _0.7) is formed in an area A ′ partitioned by an SiO ₂ film 12 on an n-type GaAs substrate 11.
Ga _0.3 ) _0.5 In _0.5 P clad layer 13, undoped (Al _0.3 Ga _0.7 ) _0.5 In _0.5 P active layer 14, p-type (A
_{l 0.7 Ga 0.3) 0.5 In 0.5} P cladding layer 15, an undoped _{(Al 0.5 Ga 0.5) 0.5 In} 0.5 P protective layer 16, GaA
An s-contact layer 17 is provided in order. Clad layer 1
The active layers 3 and 15 and the active layer 14 as a light emitting portion constitute a light emitting layer. The surface 13a of the cladding layer 13 is parallel to the substrate surface 11a, and the end surface 13b of the cladding layer 13
Reaches the surface 12a of the SiO ₂ film 12 vertically.
The active layer 14, the cladding layer 15, and the protective layer 16 respectively cover the lower layers. That is, the surface 14a of the active layer 14
The end faces 14b are the surfaces 13a, 1 of the cladding layer 13, respectively.
3b, the surface 15a and the end face 15b of the cladding layer 15 respectively cover the surfaces 14a and 14b of the active layer 14, and the surface 16a and the end face 16b of the protective layer 16 respectively cover the surface 15a and the end face 15b of the cladding layer 15. End faces 14b, 15b, 16b of active layer 14, clad layer 15, and protective layer 16
Respectively reach the surface 12a of the Si ₃ N ₄ film 12 vertically. The contact layer 1 is located at the center of the surface 16a of the protective layer 16.
7, a p-type electrode 18, and an n-type electrode 19 are provided on the entire back surface 11 b of the substrate 11.

This LED is manufactured as follows.

First, as shown in FIG.
0) A SiO ₂ film 12 having a thickness of 0.1 μm is deposited on a n-type GaAs substrate 11 having a principal surface by a plasma CVD method, and the SiO ₂ film 12 is patterned by photolithography, a lift-off method, an etching method, or the like. Processing, diameter 20
A mask layer 12 having a circular opening A ′ having a pitch of 0 μm and a pitch of 300 μm is formed.

Next, as shown in FIG.
According to the D method, a 2 μm-thick n-type (Al _0.7
Ga _0.3 ) _0.5 In _0.5 P clad layer 13, thickness 0.6 μm
m undoped (Al _0.3 Ga _0.7 ) _0.5 In _0.5 P active layer 14, 2 μm thick p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5
P cladding layer 15, undoped (Al _0.5 Ga _0.5 ) _0.5
An In _0.5 P protective layer 16 and a GaAs contact layer 17 are sequentially grown. At this time, no crystal grows on the mask layer 12, and each layer 1 is placed in the circular region A 'partitioned by the mask layer 12.
3, 14, 15, 16, 17 grow flat. Each layer 1
3, 14, 15, 16 end faces 13b, 14b, 15b,
16b is finished in a state perpendicular to the substrate surface 11a.

The clad layer 13, active layer 14, clad layer 15, protective layer 16, and contact layer 17 are MOCV
Since it is continuously grown in the D apparatus, the clad layer 13, the active layer 14, and the clad layer 15 are not oxidized during the manufacturing process.

The optical film thickness of the undoped protective layer 16 is substantially λ / 4n (λ / n) so as to be a low reflection film, where λ is the emission wavelength and n is the refractive index of the protective layer 16 at the wavelength λ. 2m
+1) times (odd number times). In this example, λ = 59
0 nm, n = 3.55, and m = 0, the protective layer 1
6 is set to about 0.042 μm.

Next, a circular p-type electrode 18 is deposited at the center of the surface 17a of the contact layer 17, and an n-type electrode 19 is deposited on the entire back surface 11b of the substrate 11. Subsequently, the GaAs contact layer 17 is selectively etched and removed except for a portion immediately below the electrode 18. Thereafter, the electrodes 18 and 19 are alloyed, and the substrate 11 is diced into units of the region A ′ to be divided into chips.

In this LED, the n-type AlGaInP cladding layer 13, the undoped AlGaInP active layer 14, and the p-type AlGaInP
Since it is covered with the GaInP protective layer 16, as in the first embodiment, the surface 13a of the clad layer 13 and the clad layer 1
3, 15 and end faces 13a, 15a, 14 of active layer 14
a (light emitting surface) is not easily oxidized. Therefore, it is possible to suppress the occurrence of non-light-emitting levels due to oxidation and to suppress a decrease in luminance. In addition, each layer 13, 14,
Since the layers 15 and 16 are separated for each circular area A 'at the growth stage, no defects are introduced into the light emitting surface during dicing. Therefore, a decrease in luminance can be further suppressed, and reliability can be improved.

Moreover, this LED has a cladding layer 13,
Since the active layer 15 and the active layer 14 are formed in a columnar shape, the total reflection can be reduced by the curvature of the end faces 13a, 15a, and 14a, and the luminance of the element can be increased as compared with a rectangular column. That is, when the end face is flat, light rays obliquely directed to the end face are totally reflected and are not emitted to the outside, but when the end face has a curvature, the totally reflected light ray component is greatly reduced. As a result, the light component transmitted through the end face increases, and high luminance can be obtained. Actually, it was possible to obtain twice or more luminance as compared with the conventional LED shown in FIG.

The material of the protective layer 16b is Cd
S, ZnS, ZnSe, ZnSSe, ZnCdSSe,
II-VI group semiconductors such as ZnMgSSe can also be used.

FIG. 3A shows a cross section of the LED of the third embodiment.

This LED has G (111) as the main surface.
Region A ″ on the aP substrate 21 partitioned by the Si ₃ N ₄ film 22
An n-type GaP layer 23, a p-type GaP layer 24, and an undoped GaP protective layer 25 are sequentially provided. n-type GaP layer 23
And the p-type GaP layer 24 constitute a light emitting layer.
24 joint surfaces emit light. The surface of the n-type GaP layer 23 is parallel to the substrate surface 21a.
3b reaches the surface 22a of the Si ₃ N ₄ film 22 vertically. The p-type GaP layer 24 and the undoped GaP protective layer 25 respectively cover the lower layers. That is, the p-type GaP layer 2
4 have an n-type GaP layer 2
The surface 23a and the end face 23b of the third element 3 and the surface 25a and the end face 25b of the undoped GaP protective layer 25 cover the surface 24a and the end face 24b of the p-type GaP layer 24, respectively. p-type Ga
P layer 24, end face 24a of undoped GaP protective layer 25,
Reference numerals 25a each vertically reach the surface 22a of the Si ₃ N ₄ film 22. At the center of the surface 24a of the p-type GaP layer 24, a p-type electrode 26 is provided so as to penetrate the protective layer 25.
An n-type electrode 27 having a predetermined pattern is provided on the back surface 21b of the substrate.

This LED is manufactured as follows.

First, as shown in FIG.
On the n-type GaP substrate 11 to 1) plane as a principal the Si ₃ N ₄ film 22 having a thickness of 0.1μm is deposited by a plasma CVD method, Si ₃ N ₄ photolithography, lift-off, by etching or the like The film 22 is patterned to form a mask layer 22 having a triangular opening A ″.

Next, as shown in FIG. 5A, a 20 μm thick n
A GaP layer 23, a p-type GaP layer 24 having a thickness of 20 μm, and an undoped GaP protective layer 25 having a thickness of 1 μm are sequentially grown. At this time, each layer 23, 2 is not grown on the mask layer 22 and is located in the triangular area A ″ partitioned by the mask layer 22.
4, 25 grow flat. The end faces 23b, 24b, 25b of the layers 23, 24, 25 are finished in a state perpendicular to the substrate surface 21a.

The n-type GaP layer 23 and the p-type GaP layer 2
4. Since the undoped GaP protective layer 25 is continuously grown in the VPE device, the n-type GaP layer 23,
The p-type GaP layer 24 is not oxidized.

Next, a circular opening is formed in the center of the surface 25a of the protective layer 25 by etching, and a p-type electrode 26 is formed. Further, the back surface 21bn type electrode 27 of the substrate 21 is formed. Thereafter, the electrodes 26 and 27 are alloyed, and the substrate 21 is diced into units of the region A ″ to be divided into chips.

This LED has an n-type GaP layer 23 and a p-type
Since the n-type GaP layer 24 is covered with the undoped GaP protective layer 25, the surfaces 23a and n
Face 23a, 24 of p-type GaP layer 23 and p-type GaP layer 24
a (light emitting surface) is not easily oxidized. Therefore, similarly to the first and second embodiments, it is possible to suppress the occurrence of the non-light emitting level due to the oxidation and to suppress the decrease in luminance. In addition, since the layers 23, 24, and 25 are separated for each triangular area A ″ at the growth stage, no defect is introduced into the light emitting surface during dicing. And reliability can be improved.

Moreover, this LED has an n-type GaP layer 23.
In addition, since the p-type GaP layer 24 is formed in a triangular prism shape, total reflection can be reduced as compared with a quadrangular prism shape, and the luminance of the element can be increased (however, it does not reach the cylindrical end face). ). Actually, it was possible to obtain twice or more luminance as compared with the conventional LED shown in FIG.

Next, an LED (not shown) of the fourth embodiment will be described.

In this LED, a superlattice (Al) is formed in a region partitioned by a Si ₃ N ₄ film or a SiO ₂ film on a GaP substrate.
P) _n (GaP) _m (n and m are 1, 2, 2,
3) and a protective layer covering the surface and the end face of the active layer. The active layer and the protective layer are formed in a column shape, for example, as shown in FIG. Electrodes are provided at the center of the front surface of the protective layer and the back surface of the substrate.

The active layer and the protective layer are continuously grown by, for example, an ALE method (atomic layer epitaxy method).
The chip is divided into a mask layer, that is, a Si ₃ N ₄ film or a Si layer.
This is performed by dicing the portion of the O ₂ film. Therefore,
The active layer and the protective layer are not cut.

AlGaP is originally an indirect transition type semiconductor, but when it is made to be a superlattice, it can be made a direct transition type by a zone holding effect. This allows
High luminous efficiency can be realized in a green region of 550 nm or less, which has not been obtained with conventional III-V semiconductors. However, since AlP is easily oxidized and deliquescent, conventionally, the exposed portion of the active layer has already been altered during the manufacturing process,
Sufficient light emission was not obtained, and the luminance was significantly reduced. In the LED of the fourth embodiment, since the active layer is not exposed during the manufacturing process, the AlP layer can be formed stably. Further, even after the production, A
Oxidation and deliquescence of the IP layer can be prevented. Therefore,
Extremely high luminance and stable light emission characteristics can be obtained.

[0058]

As is apparent from the above description, in the semiconductor light emitting device of the first aspect, the light emitting surface is covered by the protective layer, so that the light emitting surface is larger than that of the conventional semiconductor light emitting device. It is hard to be oxidized. Therefore, it is possible to suppress the occurrence of non-light-emitting levels due to oxidation and to suppress a decrease in luminance. Since the light emitting layer and the protective layer are separated for each region partitioned by the mask layer in the growth stage, no defect is introduced into the light emitting surface during dicing. Therefore, a decrease in luminance can be further suppressed, and reliability can be improved.

Further, in the semiconductor light emitting device according to the second aspect, since the protective layer is made of a semiconductor material which is harder to be oxidized than at least a part of the light emitting layer, further generation of a non-light emitting level due to oxidation is achieved. Can be suppressed, and a decrease in luminance can be further suppressed.

Further, in the semiconductor light emitting device according to the third aspect, the band gap energy of the protective layer is set to be larger than the band gap energy of the light emitting portion in the light emitting layer. Accordingly, light is not absorbed by the protective layer, and it is possible to prevent the light emitting characteristics of the element from being adversely affected.

In the semiconductor light emitting device according to the fourth aspect, the resistivity of the protective layer is set to be higher than the resistivity of a light emitting portion in the light emitting layer. Injection of carriers into the substrate is suppressed. Therefore, it is possible to prevent the light emitting characteristics of the element from being adversely affected.

In the semiconductor light emitting device according to the present invention, when the light emitting wavelength of the light emitting layer is λ and the refractive index at the wavelength λ of the protective layer is n, the thickness of the protective layer is λ / 4n
Since it is set to an odd multiple of, the reflectance of the protective layer can be reduced, and the light emitted by the light emitting layer can be efficiently emitted out of the chip.

Further, according to the method for manufacturing a semiconductor light emitting device of claim 6, the semiconductor light emitting devices of claims 1 to 5 can be easily manufactured.

Further, when the light emitting layer and the protective layer are grown, when Hcl is mixed with the source gas,
The light emitting layer and the protective layer never grow on the surface of the mask layer. That is, complete selective growth can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross-sectional structure of an LED according to a first embodiment of the present invention and a semiconductor substrate being manufactured.

FIG. 2 is a diagram showing an appearance, a cross-sectional structure, and a semiconductor substrate in the course of manufacture of an LED according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a cross-sectional structure of an LED according to a third embodiment of the present invention and a semiconductor substrate being manufactured.

FIG. 4 is a view showing a schematic structure of an LED lamp.

FIG. 5 is a view showing a schematic structure of an LED surface light emitting device.

FIG. 6 is a diagram showing a cross-sectional structure of a conventional LED.

[Explanation of symbols]

 1, 11, 21 Semiconductor substrate 2, 12, 22 Mask layer 3, 5, 13, 15 Cladding layer 4, 14 Active layer 6, 16, 25 Protection layer 7, 8, 18, 19, 26, 27 Electrode 23 n-type GaP layer 24 p-type GaP layer

Claims (7)

(57) [Claims] 1. A semiconductor substrate, a mask layer made of an insulating film having an opening of a predetermined shape provided on the surface of the semiconductor substrate, and dividing the surface of the semiconductor substrate into a region corresponding to the opening; In the above-mentioned region, a light-emitting layer formed thicker than the thickness of the mask layer, having a flat surface, and an end surface defined by an edge of the opening, and a surface and an end surface of the light-emitting layer having a predetermined thickness. A semiconductor light emitting device comprising: a protective layer that covers and prevents the light emitting layer from being oxidized; and electrodes provided on a front surface side of the protective layer and a back surface side of the substrate. 2. The semiconductor light emitting device according to claim 1, wherein the protective layer is made of a semiconductor material that is less oxidized than at least a part of the light emitting layer. 3. The semiconductor light emitting device according to claim 1, wherein a band gap energy of the protective layer is set to be larger than a band gap energy of a light emitting portion in the light emitting layer. Semiconductor light emitting device. 4. The semiconductor light emitting device according to claim 1, wherein a resistivity of the protective layer is set to be higher than a resistivity of a light emitting portion in the light emitting layer. Characteristic semiconductor light emitting device. 5. The semiconductor light emitting device according to claim 1, wherein the light emitting layer has an emission wavelength of λ, and the protective layer has a refractive index of n at a wavelength of λ. The thickness of the layer is substantially λ
A semiconductor light emitting device characterized by being set to an odd multiple of / 4n. 6. An insulating film is provided on a surface of a semiconductor substrate, and a plurality of openings having a predetermined shape are formed in the insulating film at a predetermined pitch.
Forming a mask layer that partitions the surface of the semiconductor substrate into a plurality of regions corresponding to the openings; and forming the mask layer in the region partitioned by the mask layer of the semiconductor substrate by selective vapor deposition. Forming a light emitting layer having a thickness larger than that of the light emitting layer and having a flat surface and an end face defined by the edge of the opening, and subsequently forming a protective layer covering the surface and the end face of the light emitting layer with a predetermined thickness. Forming electrodes on the front surface side of the protective layer and the back surface side of the substrate; and cutting or cleaving a portion of the substrate where the mask layer exists to divide the substrate into chips. A method for manufacturing a semiconductor light emitting device, comprising: 7. The method for manufacturing a semiconductor light emitting device according to claim 6, wherein when the light emitting layer and the protective layer are grown, HCl is used as a source gas.
And a method for manufacturing a semiconductor light emitting device.