JPS62268175A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To eliminate an error on positioning and the limitation of integration density by making each optical outgoing direction differ at a point of time when beams from a semiconductor laser are emitted from resonance surfaces, forming one of each resonance surface by cleavage and shaping the other by etching. CONSTITUTION:An N-type GaAs layer 4, an N-type AlGaAs layer 7, a non- doped GaAs layer 8, a P-type AlGaAs layer 9 and a P-type GaAs layer 10 are grown on an N-type GaAs substrate 5 in succession, the whole surface is coated with an silicon nitride plasma CVD film, and current injection regions 11a-11c and photodetector 2a-2c sections are removed through etching, and covered with Cr and Au laminated electrodes 11, 12. The electrodes 11, 12 isolate each laser 1a-1c or the photodetector 2a-2c sections so as to be able to independently drive them. An alloy electrode 13 consisting of Au and Ge is shaped onto the back, the surface is processed vertically in a Cl2 gas atmosphere, and a groove 14 and resonator surfaces 15 are formed, and isolated by cleavage or cutting at every unit. Accordingly, semiconductor emitters and the photodetectors are easily integrated, thus stabilizing an optical output.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device in which a plurality of semiconductor light emitting bodies are monolithically formed.

[Prior Art and Problems] Conventionally, when designing an optical scanning device using a plurality of semiconductor lasers or light emitting diodes (LEDs), as disclosed in Japanese Patent Application Laid-Open No. 59-126, the conventional technique is as shown in FIG. As shown in the figure, the light sources are arranged so that the directions of light emitted from the light emitters intersect at one point PO, so that multiple scanning spots can be scanned on the surface to be scanned (not shown) while maintaining good imaging conditions. It was well thought out.

FIG. 5 shows a typical conventional example, and is a diagram of the optical system between the light source and the deflector, viewed from a direction perpendicular to the deflection scanning plane. Reference numerals 71a and 71b are semiconductor lasers, and each laser is arranged on the mount 72 so that its light beam generating surface is parallel to the end surface of the mount 72. Semiconductor laser 71a.

End surfaces 72a, 7 of the mount 72 where the mount 71b is provided
2b is set as if the central rays ha and hb of the totally lost luminous fluxes from each laser 71a and 71b had passed through the same point P0. In other words, the semiconductor laser (71a,
7 l b) at the position where the end face 72a and ? 2b
The end faces 72a and 72b are set so that each normal line passes through Po. Furthermore, when viewed from a direction parallel to the deflection scanning plane, the mount 72 is arranged so that the position where the 20 points of the central rays ha and hb of each semiconductor device pass through is slightly displaced in the direction perpendicular to the deflection scanning plane. The position of the semiconductor laser provided above is set. The above 20 points and a point P in a predetermined vicinity of the deflection reflection surface 78 of the deflector are maintained in an optically collinear relationship by the imaging lens 74.

In this way, in order to arrange multiple semiconductor light emitters (for example, semiconductor lasers) so that their respective light emission directions are different, they must be aligned on the mount and configured into a hybrid structure, as shown in the example above. There was a need to do that. For convenience, the term "array laser" will be used below to refer to a plurality of semiconductor light emitters, but in principle it also applies to light emitters such as LED arrays.

Furthermore, when using a monolithically formed array laser, it is necessary to install some kind of optical system in front of the array laser. In an example disclosed in Japanese Patent Laid-Open No. 58-211785, a prism is placed in front of an array laser. This is shown in FIG.

FIG. 6 shows a cross section of a prism when a semiconductor array laser has five light emitting parts.

81 is five light emitting parts (81a, 81b, 81c).

It is a semiconductor array laser having 81d and 81e, and 81d and 81e.
2 is a prism. The central ray ha of the luminous flux from the light emitting part 81a is refracted by the inclined surface 82a and bent as if it had passed through Po. Similarly, the central ray hb from 81b is bent by the inclined surface 82b, the central ray hd from 81d is bent by the inclined surface 82d, and the central ray he from 81e is bent by the inclined surface 82e, as if they had passed through Po. . Note that the central ray hc from 81c passes through the plane 82c perpendicularly, and Po exists on an extension of this central ray hc. In this way, an inclined plane with a defined angle of inclination is provided corresponding to each light emitting part, and the direction of the central ray of each luminous flux after exiting the prism 82 is controlled as if it had exited from Po. ing. As described above, this Po is kept conjugate with a desired position P (not shown) near the deflection/reflection surface via the optical system.

Problems in this case include the precision and method of microfabrication of the prism 82, the alignment and bonding method between the prism 82 and the array laser 81, and the smaller the pitch of the array laser, the more difficult it becomes. In fact, it is almost impossible to have a thickness of 100 μm or less.

On the other hand, FIG. 7 shows an attempt to have a similar effect with an optical system, that is, a relay optical system 98, with array lasers 91a, 9
This is an example in which a relay system 98 is interposed between a collimator lens 92 and a cylindrical lens 95 that collimate and image the light emitted from 1b, and an image is formed on a polygon surface 94. (not shown).

The problem in this case is the optical path length, and the relay system itself is approximately 2
0cm long (becomes.

It is an object of the present invention to eliminate alignment errors and limitations on integration density caused by arranging semiconductor light emitters in a hybrid manner, and to eliminate alignment errors and limitations in integration density caused by arranging semiconductor light emitters in a hybrid manner. An object of the present invention is to provide a semiconductor device that makes it possible to avoid the complexity of an additional optical system.

In order to achieve the above object, a semiconductor laser device according to the present invention provides a semiconductor device in which a plurality of semiconductor light emitters are monolithically formed, in which the directions of light emitted from each of the semiconductor light emitters are different. These semiconductor light emitters are formed.

Furthermore, the resonators of these semiconductor lasers are manufactured using the cleavage method on one side.
One side is formed by etching. A photodetector is formed on the side of the resonator surface formed by this etching.

In addition, the expression "the direction of light emitted from each light emitting body is different" used in the following description does not mean that they emit light in the same direction or that there is no set of light emitting bodies, but in a broad sense, it does not mean that the light emitting bodies emit light in different directions. This means that there is one or more pairs.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 3 show the structure of an embodiment of a semiconductor laser according to the present invention, and are a plan view, a front sectional view, and a side sectional view, respectively. In the figure, 1 and 2 are array lasers, respectively.
A photodetection element array is shown, each laser Ia, lb, Ic and each photodetection element 2a.

2b and 2c are monolithically formed on the same substrate,
and a laser la as shown in FIG.

lb, , 1c, and photodetecting elements 2a and 2b.

This is to accurately confront each of the 2Cs. That is,
There is a one-to-one correspondence between a photodetector element for monitoring laser output and a laser. 8 is an active layer, which is a part that generates light. That is, the light generated in the active layer 8 by passing a current between the electrodes 11 and 13 resonates on the surfaces 15 and 16 and is extracted as laser light. 7
and 9 are usually called crat layers, and have the function of concentrating the light generated in the active layer 8 into the vicinity of the active layer 8.

The emitted light 17 out of the emitted light 17 and 18 from each laser passes through the groove 14 and enters each photodetecting element, and the electrode 12 and 1
3 (usually a voltage of opposite polarity to the voltage applied between electrodes 11 and 13) is extracted to the outside as a photocurrent. Appropriate light output can be obtained by adjusting the voltage applied between electrodes 11 and 13 depending on the level of output.

Further, in order to prevent crosstalk between the lasers Ia, lb, and lc, a light shielding portion 4a is provided.

4b is provided in the region between each of the lasers Ia, lb, and Ic and between each of the photodetecting elements 2a, 2b, and 2C, and in the region of the groove 14 described above. Therefore, for example, the light from the laser 1b does not enter the photodetector element 2a due to the light shielding part 4a.

In this case, one point P on the side opposite to the emission side. By forming a resonant surface as if the light were emitted from nearby, additional components such as the prism 82 (FIG. 8) and the relay optical system 98 (FIG. 9) become unnecessary. Then, it becomes possible to realize a light source that can obtain a good imaging state with an apparatus using a simple scanning optical system. In addition, 11a to 11c in the figure
indicates the current injection region.

The spacing λ between array lasers and the deviation θ (θ
1. It is convenient to use a constant value for θ2) in terms of W a design. That is, it becomes θ1-02, or does not necessarily have to be a constant value. The relationship between °C and θ depends on the optical system used, especially the focal length of the collimator lens 92 shown in FIG. 9.

Next, a method for manufacturing a semiconductor laser according to an unexampled example will be described with reference to FIGS. 1 to 3.

First, n-type GaAs was used as the curtain plate 5.

On this n-type GaAs group (anti-5, n-type (Si doped) G
The aAs layer 6 has a thickness of about 2 μm and is made of G'N and n-type AuGa.
As layer (crat layer) 7 is 2 μm, non-doped GaAs
Layer (active layer) 8 is 0.1 μm, p-type (Be-tope) An
After growing a GaAs layer (cladding layer) 9 of 2 μm and a p-type GaAs layer 10 of 0.2 μm by molecular beam epitaxy, the entire surface was covered with a silicon nitride plasma CVD film, and a layer 11a was grown using a photophosphorographic process. ,j
The portions lb, 11c, 2a, 2b, and 2c were removed by etching and covered with laminated electrodes I+ and 12 at the edges. so that parts can be driven independently.
It was also separated using a photolithography process. After forming an alloy electrode 13 of Au and Ge on the back surface, a groove 14 and a resonator surface 15 were formed by vertical processing using a reactive ion beam etching method using a C12 slag 7.

After realizing ohmic by thermal diffusion, as shown in Fig. 1, each unit is divided into several parts or by cutting.
.

Ta. Then, the electrodes were removed using wire bonding.

FIG. 4 shows a modification of the present invention in which one photodetector 2 is arranged for the laser output of each laser 41a, '41b, 41c. The front sectional view and side sectional view are the same as FIGS. 2 and 3.

The present invention has been described using GaAs as an example, or InGaAs.
Needless to say, the present invention is effective not only for other II+/■ group compound semiconductors such as P, but also for semiconductor devices in which a plurality of sets of semiconductor lasers and photodetecting elements are monolithically integrated.

The present invention also includes a semiconductor device in which a plurality of sets of an emitting semiconductor laser without a light shielding part and a photodetecting element are monolithically integrated. Further, in the present invention, a groove portion (etching region) 14 is also formed in each of the lasers la, lb, and lc.
It also includes semiconductor devices in which light shielding parts are formed separately.

〔Effect of the invention〕

As described above, the present invention is capable of collimating light emitted from a large number of points by simply installing a plurality of semiconductor light emitting bodies so that the respective light emission directions are different when monolithically forming them. This has the effect of making it extremely effective as a light source for optical devices (such as laser beam printers) that use a scanning optical system to form and scan an image on a medium. This effect is even more pronounced when using array lasers with different values.

In addition, by forming one of the resonator surfaces by the cleavage method, it is possible to obtain high luminous efficiency and a homogeneous output with good reproducibility in different emission directions.

Furthermore, by forming one of the resonator surfaces using an etching method, it is easy to integrate the semiconductor light emitter and the photodetector, and it is possible to stabilize the light output by receiving pressure feedback from the photodetector. did.

[Brief explanation of drawings]

1 to 3 show the configuration of an embodiment of a semiconductor laser according to the present invention, and are respectively a plan view, a front sectional view taken along line A-X in FIG. 1, and a cross-sectional view taken along line BB' in FIG. Figure 4 is a plan view showing a modified example of the present invention, Figure 5 is a diagram showing a conventional example in which lasers are arranged in a hybrid manner, and Figure 6 is a combination of an array laser with a fixed emission direction and a prism. FIG. 7 is a diagram showing a conventional example in which an array laser whose emission direction is constant is corrected by an optical system.

Claims (1)

[Claims] In a semiconductor laser device in which a plurality of semiconductor lasers are monolithically formed, when the light from each of the semiconductor lasers is emitted from the resonant surface, the respective light emission directions are different; A semiconductor laser device characterized in that one of the resonant surfaces of the laser is formed by cleavage and the other is formed by etching.