JPH0316291A - Manufacture of semiconductor laser device - Google Patents

Abstract

PURPOSE:To acquire a uniform film thickness all over a wafer by narrowing a ridge at a part of a fast growth speed on a substrate and by widening a ridge at a part of a slow growth speed. CONSTITUTION:An N-type GaAs blocking layer 2 is formed on a P-type GaAs substrate 1 having a mesa, and two ridges are formed thereon through etching. A ridge at a part of a fast growth speed on the substrate 1 is made narrow and a ridge at a part of a slow growth speed is made wide. A laser structure of double hetero including an active layer is formed on the ridge through liquid phase epitaxial method. The wider ridge is set to a side B which comes into contact with solution first, and the narrower ridge is set to a side A which comes into contact with solution later. Thereby, it is possible to offset difference of growth speed due to difference of solution conditions, by difference of ridge width. A uniform growth film thickness can be acquired all over in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a semiconductor laser device used in optical information processing, optical communication, etc.

2. Description of the Related Art In recent years, in the field of optical information processing such as optical disks, there has been an increasing demand for higher output power from semiconductor lasers. There is a semiconductor laser having an active region.

FIGS. 2A to 2C show a conventional method for manufacturing a ridge structure semiconductor laser. An n-type GaAs blocking layer is grown on a p-type GaAs substrate having a mesa as shown in Fig. 2(a), and two parallel ridges are formed on it by etching (Fig. 2(b)). . By the liquid phase epitaxial method, 11 liters of active water was added onto this ridge! A double-hetero laser ellipse including a layer is formed (Fig. 2 (C)). With this manufacturing method, the anisotropy of the crystal growth is utilized to create a structure suitable for high-power oscillation on the ridge. A thin film active layer can be formed with good controllability.

Problems to be Solved by the Invention However, the above manufacturing method has the following problems.

Normally, in the slide boat method used for growing semiconductor lasers, a substrate of several centimeters square is used, which is much larger than the laser chip size (250 μm square). Therefore, during growth, the state of the solution within the substrate differs between the part that touches the gallium lumelite most and the part that touches it last.

As a result, even if the lengthening speed is suppressed using the conventional method, a certain difference in length and thickness still occurs within the plane of the substrate due to the difference in the state of the solution.

Means for Solving the Problems In order to solve the above problems, the semiconductor of the present invention
In manufacturing a semiconductor laser device having an active region on a groove between two parallel ridges formed on a substrate, the width of the ridge is narrow in a portion of the substrate where the growth rate is high; The ridge width in the slow speed portion is widened.

Effect: With the above configuration, the difference in growth rate caused by the difference in solution state can be offset by the difference in ridge width. This is because the degree of suppression of the longitudinal speed by the ridge depends on the width of the ridge, and the narrower the ridge width, the greater the degree of suppression.

Example One embodiment of the present invention is shown in FIGS. 1(a) to 1(C).

An n-type GaAs blocking layer is grown on a p-type GaAs substrate having a mesa as shown in Fig. 1(a), and two ridges are formed on it by etching (Fig. 1(a)).
b)). As shown in the figure, the width of this ridge is narrow at one end surface of 10 .mu.m and wide at the other end surface of 30 .mu.m.

A double-hetero laser structure including an active layer is formed on this ridge by a liquid phase epitaxial method (Fig. 1 (C)
)). In this second growth, the side with the wider ridge width is set on the side that comes into contact with the solution first (side B), and the side with the narrower ridge width is set on the side that comes into contact with the solution later (side A).

By performing the growth as described above, a uniform grown film thickness can be obtained. The reason for this will be explained next. Second
When the traditional method shown in the figure is used to perform the kasho or cho, the third
This results in a film thickness gradient as shown in the figure. That is,
The film thickness on the B side, which comes into contact with the solution first, is thinner, and the film on the A side, which comes into contact with the solution later, is thinner.
The film thickness on the side becomes thicker. On the other hand, the longitudinal velocity on the ridge depends on the ridge width, and the narrower the ridge width, the slower it becomes.
The film thickness on the ridge changes as shown in FIG. 4 with respect to the ridge width when the growth time is constant. For this reason, by placing a narrow part of the ridge on the A side and a wide part of the ridge on the B side, as in the method of the present invention, the difference in longitudinal velocity between the two is canceled out, resulting in uniform uniformity over the entire surface. It is possible to obtain a long film thickness.

Effects of the Invention As described above, the method for manufacturing a semiconductor laser device of the present invention has the following advantages:
In manufacturing a semiconductor laser device that has an active region on a groove between two parallel ridges formed on a substrate, the ridge width is narrower in the portion of the substrate where the growth rate is faster, and the width of the ridge is narrower in the portion of the substrate where the growth rate is slower. By widening the radius, differences in growth rate caused by differences in solution conditions can be offset by differences in ridge width, and a uniform film thickness can be obtained over the entire wafer surface, which has a great practical effect. .

[Brief explanation of drawings]

FIGS. 1(a) to (C) are process diagrams of a method for manufacturing a semiconductor laser device of the present invention, and FIGS. 2(a) to (C) are process diagrams of a conventional method for manufacturing a semiconductor laser device with a ridge structure. Figure, 3rd
The figure shows the change in film thickness depending on the wafer position when using the conventional manufacturing method, and Figure 4 shows the change in the film thickness on the ridge with respect to the ridge width when the predetermined time is constant. . 1...p-type GaAs substrate, 2...n-type GaAs blocking layer, 3...p-type GaAe
As cladding layer, 4...GaAe A active layer,
5...n-type GaA (!As cladding layer, 6...
...N-type GaAs contact layer.

Claims (1)

[Claims] In a method for manufacturing a semiconductor laser device having an active region on a groove between two parallel ridges formed on a substrate, the width of the ridge is narrow in a portion of the substrate where the growth rate is high;
A method for manufacturing a semiconductor laser device, characterized in that the width of the ridge is widened in a portion where the growth rate is slow.