JPH0632329B2 - Method for manufacturing optical integrated circuit device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical integrated circuit device.

Configuration of Conventional Example and Problems Thereof In recent years, optical integrated circuit elements have been attracting attention because of advantages such as response speed and noise resistance. Among them, a semiconductor laser with a detector in which a photodiode for a light output monitor and a semiconductor laser are integrated on the same chip is being researched in various fields for practical use.

FIGS. 1 (a) to 1 (c) are sectional views showing respective steps of a conventional method for manufacturing a semiconductor laser with a detector.

In the figure, an n _- type Ga _1-y Al _y As clad layer 2, a Ga _1-x Al _x As active layer 3, a p-type Ga _1-y Al _y As clad layer 4 and a p-type GaAs are formed on an n-type GaAs substrate 1. The contact layer 5 is continuously grown (FIG. 1 (a)).

Next, a groove is formed by etching from the growth surface to the substrate 1 through the resist pattern 6 (see FIG. 1).
(b)). After removing the resist pattern, the driving p-side electrode 8 is on the laser side and the detection p-side electrode 9 is on the detector side.
And the n-side electrode 7 is formed on the substrate side (see FIG. 1).
(c)).

The operation of the conductor laser element with a detector formed as described above will be described below. The electrode 7 is grounded, and a positive voltage is applied to the laser electrode 8 and the detector electrode 9
A negative voltage is applied to (Fig. 2). The laser is oscillated by the current injected from the electrode 8, and the light is emitted not only in the front but also in the rear (on the detector side). Since the detector side is reverse-biased, a current flows only when the light from the laser is incident, which allows the output of the laser to be monitored.

However, the above manufacturing method has the following drawbacks. That is, due to the etching characteristics of GaAs, the side surface of the groove formed by etching is not vertical. This leads to a decrease in the reflectance of the cavity end surface, which causes adverse effects such as an increase in threshold value and a decrease in external differential efficiency.

An object of the present invention is to provide a new method of manufacturing an optical integrated circuit device in which a laser end face is vertical and a detector end face is inclined by chemical etching.

In order to achieve this object, the method of manufacturing an optical integrated circuit device according to the present invention comprises a (100) GaAs substrate, a first GaAlAs cladding layer, and a Ga layer.
Process of forming As active layer, second GaAlAs cladding layer, GaAs contact layer and additional GaAlAs on a part of growth surface
In forming the layer and forming a groove by etching parallel to the <011> direction, one sidewall of the groove is formed by etching through a resist pattern provided on the additional GaAlAs layer. It is characterized in that it comprises a cavity surface of a laser and a step of forming the other side wall of the groove by etching through a resist pattern provided on the GaAs contact layer to form a light receiving surface of the light receiving element.

Description of Embodiments An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 3 (a) to 3 (d) are sectional views showing respective steps of the method for manufacturing an optical integrated circuit device according to the embodiment of the present invention.

On the n-type (100) GaAs substrate 1, the n-type Ga _0.57 Al _0.43 As first clad layer 2 has a thickness of 2 μm and the undoped Ga _0.92 Al _0.08 As active layer 3 has a thickness of 0.1 μm and p-type Ga _0.6 Al _0.4 As. The second clad layer 4 has a thickness of 2 μm, and the p-type GaAs contact layer 5 has a thickness of 2 μm.
m, non-doped Ga _0.5 Al _0.5 As cap layer 10 is continuously grown to a thickness of 1 μm (FIG. 3 (a)).

Next, a resist pattern is formed on the growth surface so that the edges are parallel to the <011> direction, and the cap layer is selectively removed leaving a part (FIG. 3 (b)). A resist pattern having an edge parallel to the resist pattern used above is Ga
A groove is formed on the As contact layer and reaches the substrate by chemical etching through both masks.
A sulfuric acid-based etching solution is used as the etchant. GaAs
Due to the difference in etching rate between GaAlAs and GaAlAs, the side wall of the groove on the cap layer side becomes vertical and the other side wall inclines (Fig. 3).
(c)). The vertical wall becomes the cavity surface of the laser,
An electrode is formed so that the inclined wall becomes the light receiving surface of the light receiving element, and the wafer is cleaved and dicing is performed.

The operation of the semiconductor laser with detector configured as above will be described. Since the cavity surface of the laser formed by etching is vertical, the increase in threshold value and the decrease in efficiency due to the decrease in reflectance as in the conventional example do not occur. In addition, since the light-receiving surface is inclined, the effective light-receiving area is increased and the detection sensitivity is improved. Furthermore, the laser light reflected by the light-receiving surface does not return to the active layer of the laser. It does not cause instability.

As described above, according to the present invention, the GaAlAs layer is provided on a part of the growth surface on which the double hetero structure is formed, while the sidewall is
Etching is done from above the aAlAs layer,
By forming the stripe-shaped groove using chemical etching, it is possible to integrate a laser with a vertical cavity surface and a light-receiving element with an inclined light-receiving surface on the same chip, and the practical effect is great. There is something.

[Brief description of drawings]

1 (a) to 1 (c) are cross-sectional views in each step of a conventional method for manufacturing a semiconductor laser with a detector, FIG. 2 is a circuit diagram of the same semiconductor laser with a detector, and FIGS. 3 (a) to 3 (d). FIG. 4A is a cross-sectional view in each step of the method for manufacturing an optical integrated circuit element in one embodiment of the present invention. 1 ... n-type GaAs substrate, 2 ... n-type Ga _1-y Al _y As first cladding layer, 3 ... non _- doped Ga _1-x Al _x As active layer, 4 ... p
Type Ga _1-y Al _y As second cladding layer, 5 ... P-type GaAs contact layer, 6 ... Resist pattern, 7 ... N-type electrode, 8
...... Laser drive electrode, 9 ・ ・ ・ Light receiving element electrode, 10 ・ ・ ・ Non _- doped Ga _1-z Al _z As cap layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuichi Shimizu 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kunio Ito, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Iwa Teramoto, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-58-116788 (JP, A)

Claims (1)

[Claims] 1. A first GaAl layer on a (100) GaAs substrate.
A step of sequentially forming an As clad layer, a GaAs active layer, a second GaAlAs clad layer, and a GaAs contact layer, a step of forming an additional GaAlAs layer on a part of the growth surface, and a groove by etching parallel to the <011> direction. In forming the above, one side wall of the groove is formed as a laser cavity surface by etching with an etching solution containing sulfuric acid through a resist pattern provided on the additional GaAlAs layer, and the other side of the groove is formed. The method of manufacturing an optical integrated circuit device according to claim 1, further comprising a step of forming a side wall of the substrate through a resist pattern provided on the GaAs contact layer by etching using the etching solution to form a light receiving surface of the light receiving device.