JPS63114289A - Semiconductor light emitting element and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve the effect of current stricture layers, by forming a double- stripe state in the upper surface of a substrate, providing a minority-carrier preventing layer in a region corresponding to the lower stage of the double- stripe state, and increasing the thickness of layers constituting the current stricture layers. CONSTITUTION:The upper surface of a substrate 1 of a semiconductor laser having current narrowing layers 6 and 7 is made to be double stripes 15. A minority carrier preventing layer 21 is provided in a region corresponding to the lower stage of the double stripes 15. The thickness of the layers constituting the current narrowing layers is made thick. Since the upper surface of the substrate is made to be the double stripes, a special selective growing method is not required for increasing the thickness of any of the layers constituting the current stricture layers. Thus the effect of the current stricture layers is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] This is an improvement that improves the current confinement effect of a semiconductor laser having a current constriction layer.

The upper surface of the pull plate of the semiconductor laser having the electric current constriction layer is formed into a double stripe shape, and a minority carrier prevention layer is provided in the region corresponding to the lower stage of the double stripe shape, '4! The thickness of the layer constituting the current confinement layer is made thick enough to provide a sufficiently reliable current confinement layer, and the minority carriers injected into the layer constituting the current constriction layer are make it easier to absorb into the layer and reduce the possibility of the thyristor firing,
This is aimed at the effect of the current constriction layer.

[Industrial application field]

The present invention relates to improvements in semiconductor light emitting devices and methods for manufacturing the same. In particular, it relates to improvements that improve the effectiveness of current confinement layers.

[Conventional technology]

Semiconductor light emitting devices, especially semiconductor lasers used for optical communications, need to operate at high speeds, so it is desirable that they have high efficiency, and it is also desirable that they have high output in order to enable long-distance communication. Furthermore, it is particularly desirable for the active layer to have a uniform thickness in a distributed feedback semiconductor laser.

In order to satisfy these requirements, a semiconductor laser according to the prior art is provided with a current confinement layer with a striped active layer sandwiched therebetween, and an example of a semiconductor laser having a current constriction layer is shown in FIG. In the diagram 0, l is n
It is an indium phosphide substrate, 2 is an indium gallium arsenide phosphide active layer, 3 is a first cladding layer of p-type indium phosphide, 4 is a second cladding layer of p-type indium phosphide, and 5 is a p-type indium phosphide second cladding layer. The contact layer is of type indium gallium arsenide phosphide. 6 and 7 are a p-type indium phosphide layer and an n-type indium phosphide layer, which constitute a reverse bias and function as a radio wave narrowing layer. Reference numeral 21 is a minority carrier protection LIl layer, which will be described later, and is the same layer as the active layer 2. 8 is a positive electrode, and 9 is a negative electrode.

To manufacture a semiconductor laser with this structure, on the substrate l,
Active layer 2 and first clad! f! After forming 3, a groove for the current constriction layer is formed, and ? ! After that, the second cladding layer 4 and the contact layer 5 are formed.

By the way, the current constriction layer manufactured as described above is
Second cladding layer4. Since the 'rli flow constriction layers 6 and 7 and the substrate 1 form a pnpn junction (thyristor), carriers are injected into any of the current constriction layers R6 and 7 at the time of large current, and the thyristor turns on. Easy to be arced,
In that case, it had a built-in defect that it did not function as a current constriction layer at all. The minority carrier prevention layer 21 described in L was developed to eliminate this defect.

[The interlayer point that the invention attempts to solve]

However, in the above manufacturing method, it is necessary that the current constriction layers 6 and 7 are not formed in stripes, and on the other hand, the n-type indium phosphide layer 7 is required to be formed seamlessly. ,'fr! , Ryusa Shibori Layer 6 and 7
is not easy to form.

Therefore, although special selective growth is required to form the current narrowing layers 6 and 7, the n-type indium phosphide layer 7 of the two layers 6Φ7 constituting the current narrowing layer is It has the disadvantage that it is difficult to form it completely without any breaks, and it is difficult to achieve a sufficient current constriction effect with good reproducibility.

In addition to this, it has been empirically recognized that the effect of the minority carrier prevention layer is not sufficient.

The purpose of the present invention is to eliminate this drawback,
An object of the present invention is to provide an improvement in a semiconductor laser having a current narrowing layer and a method for manufacturing the same, which improves the effect of the current narrowing layer and makes it possible to realize a semiconductor laser with high efficiency and high output. .

[Means for solving problems]

The first means taken by the present invention to achieve the above object is to form a double stripe 15 on the upper surface of the semiconductor laser substrate 1 having the current confining layers 6 and 7.

The minority carrier prevention layer 21 is provided in a region corresponding to the lower stage of the double stripe 15, and the thickness of the layer constituting the current narrowing M96φ7 is increased.

A second means taken by the present invention to achieve the object described above is to form striped convex portions 13 with a large stripe width on a semiconductor substrate l of one conductivity type, and to
2 and a semiconductor layer 3 of the opposite conductivity type to the active layer 2 are formed, and both sides of the region corresponding to the striped convex portions 13 with a large stripe width are etched to form striped convex portions 14 with a narrow width. A step of forming a double stripe 15, leaving the minority carrier prevention layer 21 in a region corresponding to the lower stage of this double stripe 15, and forming a semiconductor device of opposite conductivity type and a semiconductor layer 7 of one conductivity type is performed. It was decided that a semiconductor light emitting device would be manufactured using this method.

[Effect]

In the present invention, one side of the substrate is a double stripe, and therefore a special selective growth method must be used to make each of the layers constituting the current confining layer sufficiently thick. Therefore, the thickness of the current narrowing layer is easily set to a sufficient value, and since the minority carrier prevention layer is formed apart from the active layer, the minority carriers are absorbed into this layer. The effect of the current confinement layer is improved because the minority carriers are easily absorbed by the neighboring semiconductor layer.

〔Example〕

Hereinafter, a method for manufacturing a semiconductor light emitting device according to an embodiment of the present invention will be further described with reference to the drawings.

Referring to FIG. 2, corrugations 11 are formed on an n-type indium phosphide substrate 1 using a two-beam interference method or the like.

The function of this corrugation is for distributed feedback, and it is formed continuously in the direction perpendicular to the plane of the paper.

As shown in FIG. 3, wide convex stripes 13 are formed so that the width is 15 p layers and the height is 2 l.

Refer to Figure 4. N-type indium gallium arsenide phosphide layer with a thickness of 0.12Bm.
An undoped indium gallium arsenide phosphide layer is formed to a thickness of 0.1 to form the active layer 2, and a p-type indium phosphide layer is formed to a thickness of 1.
2gm to form the upper cladding layer 3, and a p-type indium gallium arsenide phosphide layer 0.5. The contact layer 5 is formed on the intestine.

A convex stripe having a width of 1.2 mm (see FIG. 5) is formed. This depth needs to reach the substrate 1 at its center, as shown.

With this process, the upper surface of the substrate 1 has a double stripe 15
The minority carrier prevention layer 21 is formed in a region separated from the active layer 2 and corresponding to the lower stage of the double stripe 15, and this separation distance is about 7 pm in this example. Note that the minority carrier prevention layer 21 is sandwiched between the p-type indium phosphide layer 31 and the n-type indium phosphide layer 12.

See Figure 6 p-type indium phosphide e6 and n-type indium phosphide layer 7
to form a current constriction layer. For this step, very conventional growth methods can be used, without the need to use special selective growth methods, as is the case in the prior art.

Referring to FIG. 1, a positive electrode 8 made of a triple layer of titanium, platinum, and gold and a negative electrode 9 made of a double layer of gold and germanium are formed.

In the semiconductor laser manufactured as described above, the thickness of the n-type indium 17 layer 6 constituting the current confinement layer can be made sufficiently thick to provide a sufficiently reliable current confinement layer. Also, an n-type indium phosphide layer 6
Minority carriers injected into the minority carrier prevention layer 21 are easily absorbed, and there is less possibility that the thyristor will be fired, improving the effect of the current constriction layer.

〔Effect of the invention〕

As explained above, the semiconductor light emitting device according to the present invention is
The upper surface of the substrate of a semiconductor laser having a current confinement layer is formed into a double stripe, and a minority carrier prevention layer is formed in a region corresponding to the lower stage of the double stripe, separated from the active layer, so that the current constriction is prevented. The thickness of each layer constituting the layer can be made sufficiently thick to provide a sufficiently reliable current confinement layer, and the minority carriers injected into the layers constituting the current confinement layer can be It is easily absorbed by other layers adjacent to the current constriction layer, and there is less possibility that the thyristor will be fired, improving the effectiveness of the current constriction layer.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a semiconductor laser according to an embodiment of the present invention. 2 to 6 are process diagrams for manufacturing a semiconductor laser according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of a semiconductor laser according to the prior art. L・E・1 conductivity type semiconductor substrate. 11--Corrugation, 121-Lower guide layer, 13--Wide stripe. 14--Narrow striped convex portion, 15-Double stripe, 21-Active layer. 21...Minority carrier protection 1F layer. 3. Upper cladding layer, p-type indium phosphide layer adjacent to 31110 and minority carriers, 4..Q second cladding layer. 5-ΦΦ contact layer, 6...1! One conductivity type semiconductor layer forming a flow narrowing layer, 7.+
Opposite conductivity type semiconductor layer forming a 1Φ current constriction layer. 8...Φ positive electrode. 9 working - negative electrode. Prior art Fig. 7 Process diagram Atsushi 2: A Process diagram No. 38 Process diagram Fig. 4 Process diagram G5

Claims (1)

[Claims] [1] In a semiconductor light emitting device having current confinement layers (6) and (7), the upper surface of the substrate (1) has a double stripe (15), and the double stripe (15) A minority carrier prevention layer (21) is provided in a region corresponding to the lower stage of the semiconductor light emitting device, and the layers constituting the current narrowing layers (6) and (7) are thickened. element. [2] A striped convex portion (13) with a large stripe width is formed on a semiconductor substrate (1) of one conductivity type, and a semiconductor layer (12) of one conductivity type and a semiconductor of an opposite conductivity type to the active layer (2) are formed. forming a layer (3), and the striped convex portion (13) having a large stripe width.
A narrow striped convex portion (14) is formed by etching both sides of the area corresponding to the double stripe (
15), a minority carrier prevention layer (21) remains in a region corresponding to the lower stage of the double stripe (15), and a semiconductor layer (6) of opposite conductivity type and a semiconductor layer (7) of one conductivity type are formed.
1. A method for manufacturing a semiconductor light emitting device, comprising the step of forming.