JPH03187283A - Method of forming active region - Google Patents

Abstract

PURPOSE:To narrow the drive region and to improve controllability by stopping the first growth at the point of time when a film is grown on an active layer so as to diffusion, and then performing the drive at the same time during the second crystal growth. CONSTITUTION:When making a semiconductor laser inclusive of diffusion, the first crystal growth is stopped at the thickness of 0.5mum or less above an active layer, and next selective diffusion is done to the level of not reaching the active layer. Next, the second crystal growth is done, and at the same time with the growth the diffusion source is made to reach the active layer selectively. In this case, in the second crystal growth, the drive is also done naturally at the same time with the crystal growth, whereby an active region is made. Hereby, the width of the drive region can be narrowed, and it can be made with favorable controllability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor laser in which an active region is formed by diffusion.

[Conventional technology]

3 and 4 are cross-sectional views of a semiconductor laser showing the steps of a conventional method for forming an active region of a semiconductor laser. In the figure, (1) is a semiconductor substrate of a first conductivity type, (2) is a cladding layer of a first conductivity type, (3) is an active layer of a first conductivity type, and (4) is a semiconductor substrate of a first conductivity type. A cladding layer of a conductive type, (5) a current blocking layer of a second conductive type, (6) a contact layer of a first conductive type, (7) a mask of a diffusion source such as Si3N4, and (8) a mask of, for example, Si3N4. a diffusion source of the second conductivity type of ZnO, (9
) is for example 5in2 to prevent the diffusion source (8) from scattering into the air.
, 00 is the diffusion source, (8) is the diffused area,
OL) is a cover of Si, N4, for example, for the drive, and is the drive region formed by the diffusion and drive f.

Next, the formation method will be explained. First, as shown in FIG. 3, a cladding layer (2) and an active layer m (
31. A mask (7
), and a diffusion source (8) and a cover (9) are formed by vapor deposition.

Next, by heating the whole to about 600-700°C, the diffusion source (8) spreads the contact layer (6111E flow prevention layer (5), cladding m (
4). Next, as shown in Figure 4, the cover (9
), remove the diffusion source (8) and mask (7), and cover θ
υ is deposited on the entire surface. And the whole 900-950
℃ to produce a diffusion region (drive region 02 further expanded from lα and formed by the drive).

This drive region a, first conductivity type active layer (3)
Therefore, only this portion can change to the second conductivity type and form an active region.

[Problem to be solved by the invention]

The conventional active region forming method is carried out as follows, so the cladding layer and the current blocking layer cannot be made thinner than 1, for example, 11 tm, in order not to attenuate the light in the active layer. If the region is diffused and driven so as to advance into the active layer, the drive region will spread laterally to about 2 to 3 meters, making it difficult to narrow it. There were problems such as the width of the active region changed significantly and controllability was poor.

The present invention was made to solve the above-mentioned problems, and it is an object of the present invention to provide a method by which the width of the drive area can be narrowed and the width can be formed with good controllability.

[Means to solve the problem]

In the active region forming method according to the present invention, the first crystal growth is stopped when a thin film is grown on the active layer, the diffusion is performed using a conventional method, and the second crystal growth is performed without going through a special drive process. It is about growth.

[For production]

In the second crystal growth in this invention, driving is performed naturally at the same time as the crystal growth, and an active region is formed.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
1 and 2 are cross-sectional views of a semiconductor laser showing steps of an active region forming method. In the figure, the steps (1) to 02) are the same as those shown in the conventional example of FIGS. 3 and 4, and therefore their explanation will be omitted. (4a) is a cladding layer of the first conductivity type formed in the first crystal growth, and (4b) is a cladding layer of the first conductivity type formed in the second crystal growth.

Next, a method for forming the active region will be explained. First, the first
As shown in the figure, the cladding layer (2) is placed on the hill of the semiconductor substrate (1).
), an active layer (3), and a cladding layer (4a) are successively crystal-grown, a mask (7) is formed on the L, and a diffusion source (8) and a cover (9) are formed by vapor deposition. Then about 600-7
By heating the whole to 00° C., the diffusion source (8) diffuses into the cladding layer (4a) only from the area where there is no mask (7). Next, as shown in Figure 2, cover (9).

Remove the diffusion source (8) and the mask (7), and put Clara on its L)'11 (4b), [Flow prevention/1 (51,:1
A contact layer (6) is crystal grown. The temperature during this crystal growth is, for example, 750 to 850° C., and a diffusion region (101 is naturally driven to form a drive region 02) while the crystal is being formed. This drive area 02:J is
Since it reaches the active layer (3), only this portion changes to the second conductivity type, and an active region 0○ can be formed. In this way, you only need to drive the diffusion in a small area.

A narrow active region can be realized, and the transverse mode can be stabilized. In addition, the diffusion region 001. Since the drive area 02) is small, controllability is also improved.

〔Effect of the invention〕

As described above, according to the present invention, the first growth is stopped when a thin film is grown on the active layer, and the conventional method is used for diffusion, but the driving is performed simultaneously during the second crystal growth. This has the effect of realizing a narrow active region and improving controllability.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 and 2 are cross-sectional views of a semiconductor laser showing steps of an active region forming method according to an embodiment of the present invention, and FIGS. 3 and 4 are sectional views of a conventional active region forming method. FIG. 3 is a cross-sectional view of a semiconductor laser showing the process of FIG. In the figure, (1) is a semiconductor substrate, f21, (4), (4a), (4b) are cladding layers, (3) is an active layer, (5) is a current blocking layer, (6)
) is the contact layer, (7) is the mask, (8) is the diffusion source,
(9). (II) is a cover, (101 is a diffusion area, and phantom a is a drive area. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In the semiconductor laser manufacturing process that includes diffusion, the first crystal growth is stopped at a thickness of 0.5 μm or less above the active layer, then selective diffusion is performed to the extent that it does not reach the active layer, and then the second crystal growth is performed.
A method for forming an active region, characterized in that an active region is produced by performing a second crystal growth, and simultaneously causing a diffusion source to selectively reach the active layer using heat at the same time as the crystal growth.