JP2002314126A - InGaAlP-BASED OPTICAL SEMICONDUCTOR ELEMENT AND ITS MANUFACTURING METHOD - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the luminance of an LED using an InGaAlP-based compound semiconductor material from being deteriorated by Zn used as a p-type dopant. SOLUTION: The LED has a double hetro-structure composed of the InGaAlP- based compound semiconductor in which an active layer 13 is sandwiched between n- and p-type clad layers 12 and 14 and uses Zn as the p-type dopant. In the LED, the lattice constant of the active layer 13 is made smaller than that of the p-type clad layer 14 by making the percentage composition of In in the active layer 13 larger than that of In in the clad layer 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device and a light receiving device made of an InGaAlP-based compound semiconductor material, and more particularly to an optical semiconductor device using Zn as a p-type dopant.

[0002]

2. Description of the Related Art In recent years, various light emitting devices in the visible region using InGaAlP-based materials have been proposed. FIG. 5 is a sectional view of an element structure showing an example of a conventional InGaAlP visible light LED. An active layer 53 is formed on an n-type GaAs substrate 50.
Is sandwiched between n-type and p-type cladding layers 52, 54.
a AlP-based double hetero structure is formed, a p-side electrode 61 is provided on the p-type cladding layer 54, and n-type GaAs is formed.
An n-side electrode 62 is provided on the lower surface of the substrate 50.

Although not shown in FIG. 1, a buffer layer and a reflective layer for improving luminance are provided between the substrate 50 and the double hetero structure according to required specifications in order to obtain a high quality light emitting layer. May be provided. A layer for diffusing current between the p-side electrode 61 and the p-type cladding layer 54;
Often, a layer for making electrical contact is provided.

The active layer 53 in the double hetero structure portion emits light by recombining carriers and emits light.
The cladding layers 52 and 54 sandwiching the layer have a wider band gap than the active layer 53 in order to confine carriers and increase luminous efficiency. In order to inject carriers into the active layer 53, the cladding layer 52 is doped n-type and the cladding layer 54 is doped p-type. Generally, n-type dopants are S
i is used, and Zn, Mg, C, etc. are used as the p-type dopant.

In addition, a quantum well structure (MQW structure) in which a thin well layer and a barrier layer are repeatedly laminated may be used instead of the structure in which the active layer is formed as a single layer as shown in FIG.

Each layer 52, 5 in the double heterostructure portion
No. 3,54 requires that the band gap be optimally selected according to the design in order to adjust the emission wavelength and confine carriers. For good epitaxial growth, it is desirable that the lattice constant of each layer matches the lattice constant of substrate 50. InGaAlP, a III-V compound,
Since it contains three kinds of In, Ga, and Al as Group III components,
By selecting these composition ratios, the band gap and the lattice constant can be independently designed.

[0007] For example, when representing the composition of the epitaxial growth layer by the following formula _{In x (Ga 1-y Al} y) 1-x P ... (1), Ga by the In composition ratio x of 0.5
The band gap can be controlled by adjusting the composition ratio y of Al and Ga while keeping the lattice constant substantially equal to that of the As substrate and keeping x = 0.5. Red light emission L with a wavelength of 644 nm
To obtain ED, the composition ratio of the active layer 53 is set to x = 0.
5, y = 0,043, and the composition of the cladding layers 52, 54 should be x = 0.5, y = 0.7. In addition, wavelength 5
To obtain a 62 nm green light emitting LED, the active layer 53
Is set to x = 0.5, y = 0.454, and the composition of the cladding layers 52, 54 is set to x = 0.5, y = 1.00, that is, InAlP.

Incidentally, InGaAs, which is the object of the present invention,
In general, it is known that not only the IP system but also a light-emitting element such as an LED or a laser has a so-called deterioration, in which the luminance gradually decreases as the light emission continues. InGa
In the AlP-based light-emitting device, when Zn is used as a p-type dopant, particularly when the p-type cladding layer or the p-type current diffusion layer adjacent to the cladding layer is doped with high concentration of Zn, the deterioration is remarkable. In addition, as described below, InGa of a method of bonding a transparent substrate to a wafer by high-temperature heat treatment is used.
In the case of AlP-based LEDs, the deterioration is more remarkable.

A GaAs substrate used as a substrate for a quaternary LED has a disadvantage of absorbing light in the visible light region.
For this reason, since a part of the light emitted from the InGaAlP-based active layer is absorbed by the GaAs substrate, a decrease in the brightness of the LED is inevitable. In order to avoid a decrease in luminance, a material transparent to the visible light region may be used for the substrate. As a general transparent material, GaP is used.
Good epitaxial growth is difficult because lattice matching with the aAlP system cannot be achieved. In order to solve this problem, InG
A method has been devised in which the aAlP-based epitaxial growth layer and the GaP substrate are bonded to a wafer (Wafer Bonding), and then the GaAs substrate is removed.

An example of a method of manufacturing an LED having an InGaAlP-based epitaxial growth layer adhered to a GaP substrate by using direct wafer bonding will be described with reference to FIG. First, as shown in FIG. 6A, n-type GaAs
On the substrate 50, an n-type contact layer 51, an n-type clad layer 52, an active layer 53, a p-type clad layer 54, and a p-type adhesive layer 71 are grown. Next, as shown in FIG. 6B, a p-type GaP substrate 70 is directly bonded to the surface of the adhesive layer 71, and then, as shown in FIG. 6C, the GaAs substrate 50 is removed by polishing or etching. I do. When the n-side electrode 62 is provided on the upper surface of the n-type contact layer 51 upside down and the p-side electrode 61 is provided on the lower surface of the GaP substrate 70,
As shown in FIG. 6 (d), In using GaP as the substrate 70 is used.
A GaAlP-based LED is obtained.

In this way, a bright LED with little light absorption on the substrate can be obtained.
A high temperature of 0 ° C. or higher is required. Further, not only the p-type cladding layer but also the p-type adhesive layer and the p-type GaP substrate are doped with Zn. In particular, the bonding layer, which is the surface to be bonded, and Ga
For the P substrate, 1 × 10 ¹⁸ /
High concentration doping of cm ³ or more is required. For this reason, the bonding type InGaAlP-based LED is more susceptible to so-called thermal deterioration in which the luminous efficiency after bonding is lower than before bonding.

The presence or absence and degree of deterioration in the bonding process are compared by measuring the lifetime of the InGaAlP active layer before and after bonding, for example, by obtaining the lifetime from the decay of PL light emission excited by a pulse laser. You can ask for it.

[0013]

As described above, in the conventional InGaAlP-based light-emitting device using Zn as the p-type dopant, a decrease in luminance due to Zn doping has been a serious problem. In addition, this problem is not necessarily limited to a light emitting element, and InGaAs using Zn as a p-type dopant may be used.
The same can be said for an IP light receiving element.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a light emitting element and a light receiving element using an InGaAlP-based compound semiconductor material.
It is an object of the present invention to provide an optical semiconductor device capable of suppressing characteristic deterioration due to Zn doping as a p-type dopant.

[0015]

(Structure) In order to solve the above-mentioned problem, the present invention employs the following structure.

That is, the present invention provides an InGaAlP-based optical semiconductor device having a double heterostructure composed of an InGaAlP-based compound semiconductor in which an active layer is sandwiched between p-type and n-type clad layers, and using Zn as a p-type dopant. Wherein the lattice constant of the active layer is smaller than the lattice constant of the p-type cladding layer.

Here, preferred embodiments of the present invention include the following. (1) The In composition ratio of the active layer must be larger than the In composition ratio of the p-type cladding layer. (2) The lattice constant of the active layer is about 0.1% smaller and the lattice constant of the p-type cladding layer is about 0.2% larger than the element forming substrate for forming the double heterostructure. (3) With respect to the p-type cladding layer, p-type Ga
The P substrate is bonded.

The present invention also provides an InGaAlP-based optical semiconductor device having a double heterostructure composed of an InGaAlP-based compound semiconductor in which an active layer is sandwiched between p-type and n-type clad layers and using Zn as a p-type dopant. Wherein Zn is located between the active layer and a p-type layer or a p-type substrate containing Zn.
Having a smaller lattice constant than a p-type layer or a p-type substrate containing
It is characterized in that a diffusion block layer is inserted.

Here, preferred embodiments of the present invention include the following. (1) The blocking layer must be inserted between the active layer and the cladding layer. (2) In the case of an adhesive LED or the like, a block layer is inserted between the p-type adhesive layer and the p-type clad layer. (3) In the case of an adhesive LED or the like, a material having a smaller lattice constant than the active layer is used for the p-type adhesive layer, and this p-type adhesive layer is used as a block layer.

The present invention also provides an InGaAlP-based optical semiconductor device having a double heterostructure composed of an InGaAlP-based compound semiconductor with an active layer sandwiched between p-type and n-type clad layers and using Zn as a p-type dopant. Wherein a compressive stress is applied to the active layer. Here, as a means for applying compressive stress to the active layer, a substrate having a larger thermal expansion coefficient than the InGaAlP-based material forming the double hetero structure is used, and this substrate is bonded to the double hetero structure at a high temperature, Applying compressive stress to the active layer at room temperature may be mentioned.

Further, according to the present invention, there is provided a step of sequentially growing an n-type clad layer, an active layer, and a Zn-doped p-type clad layer on an element forming substrate to form a double heterostructure portion made of an InGaAlP-based compound semiconductor. InGaAlP having
A method of manufacturing an optical semiconductor device, wherein the supply amount of the In material when growing the active layer is slightly larger than the supply amount of the In material when growing the clad layer. I do.

(Operation) According to the present invention, in an InGaAlP-based optical semiconductor device using Zn as a p-type dopant, the active layer has a smaller lattice constant than the Zn-containing layer so that the Zn activity is reduced. It is possible to prevent abnormal diffusion into the layer and to prevent characteristic deterioration (luminance deterioration in the case of a light-emitting element) due to heat treatment or energization.

Hereinafter, a mechanism capable of preventing the characteristic deterioration, which is an object of the present invention, will be described with reference to FIG. FIG.
The band structure of an InGaAlP-based LED having a double heterostructure is shown, and the band structures of an n-type cladding layer, an active layer, and a p-type cladding layer are shown from the left. The band structure of the p-type epitaxial layer such as the current diffusion layer and the adhesive layer on the right side of the p-type clad layer is not shown because there are various cases depending on the material.

When Zn is doped into the p-type layer, I
Substitution with group III atoms of n, Ga, and Al forms a p-type shallow level 1 to serve as a donor. This Zn is diffused into the active layer by heat or current, but is replaced by a group III atom (shallow level 2) as a donor in a normal diffusion. However, when Zn abnormally diffuses into the active layer, a deep level 3 is formed. When the deep level 3 increases in the active layer, the carriers recombine via the level 3, so that the carrier cannot contribute to light emission and the light emission efficiency decreases.

Although the detailed mechanism of the anomalous diffusion is unknown, it is well known that the anomalous diffusion of Zn into GaAs, which is the same III-V compound, is well known. The theory of diffusion is influential. Therefore, InG
Abnormal diffusion of Zn into the aAlP active layer is also diffusion via interstitial, and it is considered that Zn located between interstitial forms a deep level. Therefore, in order to prevent luminance degradation, it is only necessary to prevent interstitial diffusion of Zn. Interstitial diffusion literally means that Zn passes between lattices, so that lattice spacing,
That is, reducing the lattice constant is effective in suppressing abnormal diffusion of Zn and deterioration of luminance. This is the luminance degradation suppressing mechanism of the present invention.

As described above, the lattice constant of the active layer is desirably as small as possible in order to prevent luminance degradation. However, when the lattice constant difference from the GaAs substrate becomes large, good epitaxial growth cannot be performed. Although the allowable lattice constant difference depends on the epitaxial growth thickness, empirically, the ratio of the lattice constant to GaAs is −0.1.
% To + 0.2%. That is, for a lattice constant of GaAs of 0.56533 nm, 0.56476 n
From m to 0.56646, good epitaxial growth is possible.

In practice, it is not the absolute value of the lattice constant of the active layer, but rather the active layer and a layer containing Zn, for example, a p-type cladding layer,
The magnitude relationship between the lattice constants of the current diffusion layer and the adhesive layer is important. In particular, the magnitude relationship with the p-type cladding layer adjacent to the active layer is important. This is because if the lattice constant of the p-type cladding layer is larger than that of the active layer, Zn is unlikely to diffuse from the lattices of the cladding layer to the lattices of the active layer, thereby suppressing anomalous diffusion related to luminance degradation. is there. From the viewpoint of preventing anomalous diffusion, the lattice constant of the p-type cladding layer is set to 0.566.
46 nm (+ 0.2%), lattice constant of active layer 0.56
It is desirable to set it to 476 nm (-1%).

In the above description, the lattice constant of the active layer is made smaller than that of the p-type cladding layer in order to prevent the characteristic deterioration due to Zn doping. Similar effects can be obtained by inserting a Zn-containing p-type layer or a Zn diffusion block layer having a smaller lattice constant than the p-type substrate between the layer and the p-type substrate. In this case, particularly, abnormal diffusion from the p-type layer or the p-type substrate can be prevented. Further, from the viewpoint of narrowing the lattice spacing of the active layer, the same effect can be expected by applying a compressive stress to the active layer.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments.

(First Embodiment) FIG. 2 shows a first embodiment of the present invention.
It is sectional drawing which shows the manufacturing process of the InGaAlP type | system | group LED which concerns on embodiment.

First, as shown in FIG.
An n-type buffer layer 11, an n-type cladding layer 12, an active layer 13, a p-type cladding layer 14, and a p-type contact layer 15 are sequentially formed on an As substrate 10 by MOCVD (Metal Organic Chloride).
Emica1 Vapor Deposition).

The n-type GaAs substrate 10 has a size of 2
Inch, thickness 250 μm, Si is doped as an impurity at a carrier concentration of about 1 × 10 ¹⁸ / cm ³ , and its main surface is mirror-finished. The buffer layer 11 is made of GaAs and has a thickness of 0.5 μm. The composition ratio of the n-type cladding layer 12 expressed by the above equation (1) is x = 0.5, y = 1.0, and the thickness is 0.6 μm. The active layer 13 has a composition ratio of x = 0.5, y = 0.28.
And the thickness is 0.6 μm. The p-type cladding layer 14
The composition ratio was x = 0.5, y = 1.0, and the thickness was 0.6 μm. The contact layer 15 is GaAs having a thickness of 0.5 μm.

Here, the In composition of the cladding layer and the active layer was basically set to 0.5, but TMI (Tri-Methil) which is an In material at the time of epitaxial growth of the cladding layer and the active layer.
The supply amount of In) was slightly changed, and the lattice mismatch ratio with respect to the GaAs substrate was controlled so that the active layer was -0.1% and the p-type cladding layer was + 0.2%. Specifically, when forming the cladding layer, the supply amount of TMI was slightly reduced, and when forming the active layer, the supply amount of TMI was slightly increased. Thus, the In composition ratio in the active layer is slightly larger than 0.5, and the In composition ratio in the cladding layer is slightly smaller than 0.5.

The lattice mismatch is determined by X
Line diffraction was measured and determined from the difference between the peak position of each epitaxial layer and the peak position of GaAs. The correlation between the TMI supply amount and the lattice mismatch rate was determined in advance by this method, epitaxial growth was performed under conditions in accordance with this correlation, and the lattice mismatch rate was measured and confirmed after the epitaxial growth.

As a comparative example, an epitaxial wafer having the same structure and a lattice mismatch ratio of 0% for both the active layer and the cladding layer was prepared. FIG. 2 shows both the embodiment and the comparative example.
As shown in (b), gold electrodes 21 and 22 are provided on the upper surface of the contact layer 15 and the lower surface of the GaP substrate 10, and the gold electrode 2 on the upper surface is formed.
1 was processed into a circular shape having a diameter of 100 μm as shown in (c), and cut into LED chips having a pitch of 250 μm by dicing.

The luminance was measured by taking each of 10 LED chips, and the degree of deterioration was examined by comparing the luminance with the luminance after the current of 20 mA was continued at 100 ° C. for 168 hours. In the comparative example, the luminance was reduced by 30 to 60%, and on average by 44%, and a clear deterioration was observed. On the other hand, in the present embodiment, 4 to 18%,
The deterioration was only 9% on average, and the effect of the present invention was confirmed.

As described above, according to the present embodiment, in the InGaAlP-based LED using Zn as the p-type dopant, the lattice constant of the active layer 13 is smaller than the lattice constants of the cladding layers 12 and 14, so that p Abnormal diffusion of Zn, which is a type dopant, into active layer 13 can be prevented. For this reason, it is possible to suppress luminance degradation due to heat treatment or energization due to Zn doping.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
It is sectional drawing which shows the manufacturing process of the adhesion type InGaAlP type LED which concerns on embodiment. The same parts as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

First, as a bonding wafer, FIG.
An epitaxial wafer having the structure described above was prepared. The manufacturing process is basically the same as that of the first embodiment.
A buffer layer (contact layer) 11, an n-type cladding layer 12, an active layer 13, a p-type cladding layer 14, an adhesive layer 31, and a surface cover layer 32 are sequentially laminated on a substrate 10. These epitaxial growth layers are, for example, MOC
It is formed by the VD method.

The n-type GaAs substrate 50 has a size of 2
Inch, thickness 250 μm, Si is doped as an impurity at a carrier concentration of about 1 × 10 ¹⁸ / cm ³ , and its main surface is mirror-finished. The buffer layer 51 is made of GaAs and has a thickness of 0.5 μm. The composition ratio of the n-type cladding layer 52 represented by the above equation (1) is x = 0.5, y = 1.0, and the thickness is 0.6 μm. The active layer 13 has a composition ratio of x = 0.5, y = 0.28.
And the thickness is 0.6 μm. The p-type cladding layer 14
Composition ratio x = 0.5, y = 1.0, thickness 0.6 μm
And The adhesive layer 31 is made of InGaP having a thickness of 0.05 μm.
2 × 10 ¹⁸ / cm ³ of Zn. The uppermost surface cover layer 32 has a double structure, and the lower side has a thickness of 0.1 μm.
m of GaAs, and the upper side is a 0.2 μm InGaAlP layer.

Here, the In composition of the cladding layer and the active layer was basically set to 0.5. However, during epitaxial growth of the cladding layer and the active layer, the supply amount of the TMI, which is an In material, was slightly changed. As in the embodiment, the lattice mismatch rate with respect to the GaAs substrate was controlled so that the active layer was -0.1% and the p-type cladding layer was + 0.2%. As a comparative example, as in the first embodiment, an epitaxial wafer having a lattice mismatch ratio of 0% for both the active layer and the cladding layer was prepared.

Hereinafter, the wafer bonding process will be described. First, the epitaxial wafer is immersed in a mixture of ammonia and hydrogen peroxide to remove deposits on the back side, and then the epitaxial wafer is washed with a surfactant.
The InGaAlP cover layer of the surface cover layer 32 was etched with phosphoric acid at 0 ° C. This etching is performed on the underlying GaAs
Selectively stop at layer. Then, ammonia 1 by volume ratio,
The epitaxial wafer is immersed in a mixed solution of hydrogen peroxide solution 15 to perform etching, and as shown in FIG.
The lower GaAs cover layer was removed. This mixture is G
Although the aAs cover layer was selectively etched, it was observed that the surface cover layer 32 was removed in a few seconds.
By continuing the immersion for one minute, the surface of the adhesive layer 31 was completely exposed.

Next, direct bonding between the epitaxial wafer from which the surface cover layer 32 was removed and the GaP substrate 30 on which a high-concentration GaP layer having a thickness of 0.2 μm and a carrier concentration of 2 × 10 ¹⁸ / cm ³ was grown was performed. Then, the adherend shown in FIG. 3 (c) was obtained.

Here, the step of direct bonding will be described in more detail. As a pretreatment for direct bonding, the GaP substrate 30 was washed with a surfactant, immersed in dilute hydrofluoric acid to remove a natural oxide film on the surface, washed with water, and dried with a spinner. Also,
After removing the surface cover layer 32 by the above-described method, the epitaxial wafer on which the double heterostructure was formed
Dilute hydrofluoric acid treatment was performed to remove the oxide film in the same manner as in the case of the P substrate 30, and washing with water and spinner drying were performed. All of these pretreatments were performed under a clean atmosphere in a clean room.

Next, the epitaxial wafer having been subjected to the pretreatment was placed so that the epitaxial growth layer was directed upward, and the GaP substrate 30 was placed thereon such that the mirror surface faced downward, and was brought into close contact at room temperature. Since GaP is transparent, the adhered state can be visually observed. When the GaP substrate 30 is placed on the epitaxial wafer, the epitaxial wafer is warped so as to form a convex shape in a front view.
The central part of the GaP substrate 30 first came into close contact. The adhesive portion naturally spreads toward the peripheral portion of the GaP substrate 30 just by being left as it is, and the entire surface was adhered to the GaP substrate 30 within one minute except for the chamfered peripheral portion.

As a final step of the direct bonding, the adherend adhered at room temperature was placed in a diffusion furnace and heat-treated at 800 ° C. The atmosphere is argon containing 10% of hydrogen. Thereafter, as shown in FIG. 3D, the GaAs substrate 10 is selectively etched and removed with a mixed solution of ammonia and hydrogen peroxide solution, and mirror polishing is performed on the lower side (upper side in the figure) and lower side of the GaP substrate 30. did. A laser pulse is irradiated from the polished side of the GaP substrate 30, the lifetime of the active layer is determined from the decay curve of the excited PL emission, and compared with the lifetime measured by the same method before bonding, the bonding process is performed. Thermal degradation was compared.

In both the comparative example and the embodiment, the lifetime before bonding was 28 to 31 ns. On the other hand, the life time after bonding was as small as 9 to 21 ns in the comparative example and the variation was large, whereas the life time after bonding was 24 to 27 in the embodiment.
nm, the effect of the present invention was confirmed.

Further, after the step shown in FIG.
As shown in (e), the p-side electrode 21 is provided on the back surface of the GaP substrate 30 and the n-side electrode 2 is provided on the surface of the n-type contact layer 11.
2 and the n-side electrode 22 is processed into a circular shape to form InGaAl.
P-type LED was completed. When the light emission characteristics of the LED were examined, it was confirmed that the deterioration of the luminance was sufficiently reduced as in the first embodiment.

The present invention is not limited to the above embodiments. In the embodiment, the lattice constant of the active layer is made smaller than that of the p-type cladding layer. Alternatively, as shown in FIG.
A Zn diffusion block layer 41 whose lattice constant is smaller than that of the p-type cladding layer 14 may be provided between them. Further, the block layer 41 may be provided between the active layer 13 and the p-type clad layer 14.

From the viewpoint of narrowing the lattice spacing of the active layer,
A compressive stress may be applied to the active layer. Specifically, by bonding a substrate having a large thermal expansion coefficient to the active layer at a high temperature, a compressive stress can be applied to the active layer at room temperature. Further, it is also possible to use an appropriate combination of the three methods of making the lattice constant of the active layer smaller than that of the p-type cladding layer, providing a Zn diffusion block layer, and applying a compressive stress to the active layer.

In the embodiment, the LE as the light emitting element is used.
Although D has been described, it is naturally applicable to a laser as long as an InGaAlP-based compound semiconductor material using Zn as a p-type dopant is used. Further, the present invention can be similarly applied to a light receiving element. Others
Various modifications can be made without departing from the scope of the present invention.

[0052]

As described above, according to the present invention, InGaAl having an active layer sandwiched between p-type and n-type cladding layers is provided.
It has a double hetero structure part composed of a P-based compound semiconductor,
In an InGaAlP-based optical semiconductor device using Zn as a p-type dopant, Zn is placed between an active layer and a p-type layer or a p-type substrate containing Zn so that the lattice constant of the active layer is smaller than that of the p-type cladding layer. By inserting a Zn diffusion block layer having a smaller lattice constant than a p-type layer or a p-type substrate containing, or by applying a compressive stress to the active layer,
It is possible to suppress characteristic deterioration due to Zn doping as a p-type dopant. Especially in light emitting devices,
Luminance degradation due to Zn doping can be suppressed, and the effect is significant.

[Brief description of the drawings]

FIG. 1 is a band structure diagram for explaining a mechanism capable of preventing characteristic deterioration in the present invention.

FIG. 2 is an InGaAlP-based LE according to the first embodiment;
Sectional drawing which shows the manufacturing process of D.

FIG. 3 shows an adhesive type InGaAlP according to a second embodiment.
Sectional drawing which shows the manufacturing process of a system LED.

FIG. 4 is a sectional view of an element structure showing a modification of the present invention.

FIG. 5 is a sectional view of an element structure showing a conventional InGaAlP-based LED.

FIG. 6 is a sectional view showing a manufacturing process of a conventional adhesive-type InGaAlP-based LED.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... n-type GaAs substrate 11 ... n-type buffer layer (contact layer) 12 ... n-type InAlP clad layer 13 ... InGaAlP active layer 14 ... p-type InAlP clad layer 15 ... p-type GaAs contact layer 21 ... p-side electrode 22 ... n Side electrode 31 p-type InGaP adhesive layer 32 GaAs / InGaAlP surface cover layer 41 Zn diffusion block layer

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yasuhiko Akaike 1-Front Term, Toshiba Microelectronics Center, Komukai Toshiba-cho, Saisaki-ku, Kawasaki-shi, Kanagawa 5F041 AA44 CA04 CA34 CA49 CA53 CA65 5F045 AA04 AB18 AC07 CA10 DA52 EE12 5F073 CA14 CB02 CB14 DA05 EA29

Claims (7)

[Claims] An InG having a double heterostructure comprising an InGaAlP-based compound semiconductor in which an active layer is sandwiched between p-type and n-type cladding layers, and using Zn as a p-type dopant.
aAlP-based optical semiconductor device, wherein the lattice constant of the active layer is smaller than the lattice constant of the p-type cladding layer.
P-based optical semiconductor element. 2. The InGaAlP-based optical semiconductor device according to claim 1, wherein an In composition ratio of said active layer is made larger than an In composition ratio of said p-type cladding layer. 3. The active layer has a lattice constant of 0.1% with respect to an element forming substrate for forming the double heterostructure.
The lattice constant of the p-type cladding layer is 0.2%
2. The InGaAs according to claim 1, wherein the InGaAs is large.
1P optical semiconductor element. 4. The InGaAlP-based optical semiconductor device according to claim 1, wherein a p-type GaP substrate is bonded to said p-type cladding layer on a side opposite to said active layer. 5. An InG layer having a double heterostructure composed of an InGaAlP-based compound semiconductor with an active layer sandwiched between p-type and n-type cladding layers, and using Zn as a p-type dopant.
aAlP-based optical semiconductor element, wherein between the active layer and a p-type layer or a p-type substrate containing Zn,
I. A p-type layer containing Zn or a Zn diffusion block layer having a smaller lattice constant than a p-type substrate is inserted.
nGaAlP-based optical semiconductor device. 6. An InG layer having a double heterostructure composed of an InGaAlP-based compound semiconductor having an active layer sandwiched between p-type and n-type cladding layers, and using Zn as a p-type dopant.
An InGaAlP-based optical semiconductor device, wherein a compressive stress is applied to the active layer. 7. An n-type cladding layer, an active layer, and a Zn-doped p-type cladding layer are sequentially grown on an element forming substrate to form an I-type cladding layer.
A method for manufacturing an InGaAlP-based optical semiconductor device, comprising a step of forming a double heterostructure portion made of an nGaAlP-based compound semiconductor, wherein the active layer is grown more than the supply amount of an In material when growing the clad layer. A method for manufacturing an InGaAlP-based optical semiconductor device, characterized in that the supply amount of the In source at this time is slightly increased.