JPS6144489A - Semiconductor laser array device - Google Patents

Abstract

PURPOSE:To obtain the titled device of high output with a large spot ellipticity by a method wherein an N-epitaxial layer is laminated on a P type substrate having a projection, and groove bottoms are made to reach the substrate by forming three parallel ridges; successively, a P-layer, an active layer, and the like are successively laminated. CONSTITUTION:A mesa is formed in the <011> direction by etching the (100) plane of the P type GaAs substrate 1, and an N type blocking GaAs 2 is deposited to a flat surface. The parallel ridges are provided in the <011> direction, thus making grooves among the ridges located on the mesa and the groove bottoms reach the substrate 1. Next, a P type Ga1-xAlxAs clad layer 3, a Ga1-yAlyAs active layer 4, an N type Ga1-xAlxAs clad layer 5, and an N type GaAs layer 6 are laminated, and ohmic electrodes 7 and 8 are attached. Light generated in the active layer 4 by conduction is absorbed to the substrate above the ridges and confined in the grooves, where stable lateral mode oscillation can be obtained. Since the groove interval is very narrow to almost the same degree as the width, beams produced above the grooves become spots of high output in long-elliptic form by the superposition of skirts. This laser array is effective in information erasure.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a semiconductor laser array device.

Conventional configuration and its problems In recent years, the performance of semiconductor lasers has improved (lower threshold value).

(higher output, etc.) and the accompanying expansion of applications I
ζ is something to behold. There are many devices that are currently being developed, such as optical disk devices, that are designed to be equipped with semiconductor lasers. There is a method that uses a semiconductor laser with a large ellipticity. A diagram of this principle is shown in FIG. When recording information, it is heated and rapidly cooled using a circular beam A semiconductor laser.

That part becomes an amorphous state and becomes a recording bit. Further, in order to erase the recorded pits, a semiconductor laser with an elongated elliptical beam B, which is different from that for recording, is used. The amorphous state of the recording portion is heated in the longitudinal direction of the beam and then gradually cooled, so that it crystallizes. The semiconductor laser used for erasing is required to have a long elliptical spot shape of about 1 x 20 x m and to be able to obtain a high output of about 20 mW.

However.

The spot shape of high-power semiconductor lasers currently in practical use is approximately 1×44 m at most, and cannot meet this requirement.

Purpose of the Invention The present invention has been made in view of the above-mentioned drawbacks of conventional semiconductor laser devices.
The object of the present invention is to provide a high-output semiconductor laser array device with a large spot ellipticity.

SUMMARY OF THE INVENTION To achieve this object, a semiconductor laser array device of the present invention has at least one semiconductor layer formed on a semiconductor substrate having protrusions so that conductive patterns are alternately formed. At least eight grooves are formed on the surface of the semiconductor layer, and the bottoms of the grooves between these grooves have parallel ridges reaching the protrusions of the substrate.

Each layer including the active layer is formed on the surface of the semiconductor layer having the ridge so that the first layer is a layer of a conductivity type different from that of the semiconductor layer.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to one drawing. FIG. 2 (- to (ω) are cross-sectional views at each step of the method for manufacturing a semiconductor laser array device according to an embodiment of the present invention. First, etching is performed on the (100) plane of the p-type substrate Lυ to form a pattern of <011 A mesa having a height of 2 ttm and a width of 40 μm as shown in FIG. 2(a) is formed in the > direction.

By the liquid phase epitaxial method on the p-type substrate (υ fζ),
An n-type GaAs blocking 7i1121 is grown on the mesa so that the film thickness is 0.8 am and the surface after growth is flat (Iz diagram (b)). On the surface of the wafer after this first growth, 6 parallel ridges with a width of 1.5 μm and a width of 8 cm are formed by etching in the <OII> direction.
It is formed by sandwiching the am groove. The width of the ridges is 18 am only for the ridges at both ends, and 11 m for the other ridges. The groove between the ridges is located directly above the mesa, and its bottom reaches to the p-type substrate t1) (FIG. 1!2 (C)). Like this Cζ
On the surface of the p-type substrate (υ) on which a ridge was formed, a first layer of p-type Ga, -x
A 4
-y A J y As active Jil L4) about 0.05 gm.

7M8n n-type Ga, -xA transport A8 cladding layer is) with a thickness of approximately 1.5 am, and the fourth layer of n-type GaAs1Ei
Forming layers (same as 618, each layer is continuously grown to a thickness of 0.5 fim. In the above embodiment, x=o, 4a, y-O, OS. This 45th wt pole On the forming layer (6), vapor deposit metal for the n-side!
An alloy treatment is performed to form an n-side ohmic wt electrode (A), a metal for the p-side wt electrode is vapor-deposited on the substrate side, and a p-side ohmic wt electrode (8) is formed by performing an alloy treatment. 2
Semiconductor wafers 5 of the present invention shown in Figure (dl) are obtained.

The operation of the semiconductor laser array device configured as described above will be described below. The current injected from the p-type substrate (1) flows only into the groove between the ridges due to the action of the blocking layer (2), and the active 1g114 on the groove
Eye ζ is injected. The light generated in the active layer I4+ by this current is absorbed by the substrate in the upper part of the ridge and is confined in the groove (ζ), where stable transverse mode oscillation is obtained. Since it is very short, about the same as the width, the beam spots formed on the valley grooves have their bases overlapping each other, resulting in an effectively elongated beam spot (Fig. 8).

With this semiconductor laser array device, the beam shape was elongated to 1×24 μm, and a high total optical output of 60 mW was realized.

Effects of the Invention As described above, according to the present invention, a high-output semiconductor laser array device having an oblong beam spot can be realized using a plurality of closely spaced beams, and it is possible to realize a high-output semiconductor laser array device having an oblong beam spot. It has great practical value as a laser for industrial use, etc.

[Brief explanation of the drawings] Fig. 1 is a principle diagram of the information erasing/recording method using an oblong beam in an optical disk file device, and Fig. 2 (
aJ~(dl is a cross-sectional view of each manufactured culm of a semiconductor laser array device according to an embodiment of the present invention. Fig. 8 shows the distribution of the emission intensity of the laser beam of the same device corresponding to the ridge of the same device. 111- p-type GaAs substrate, +21 ・' n-type G
aAs blocking, Ill, +31- p-type Ga
+ -x A g x A s cladding layer, (IJ・
...Non-doped Ga, l, As active layer, (51-
n-type Ga, -xA 11 x As cladding layer, (61-n-type GaAsFj electrode forming layer. ff)...n-side ohmic electrode, (8)...p-side ohmic electrode

Claims (1)

[Claims] 1. Having at least one semiconductor layer formed so that the conductivity type alternately changes on a semiconductor substrate having a protrusion,
At least three grooves are formed on the surface of the semiconductor layer, and the bottoms of these grooves have parallel ridges reaching the protrusion of the substrate, and each layer including an active layer is formed on the semiconductor surface having the ridges. . A semiconductor laser array device in which a first layer is a layer having a conductivity type different from that of the semiconductor layer.