JPH0666511B2 - Semiconductor device - Google Patents

Description

The present invention relates to a semiconductor device in which a plurality of semiconductor lasers are monolithically formed.

[Prior Art and Problems] Conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 59-126, a semiconductor laser or a light emitting diode (LE) is used.
In the case of designing an optical scanning device using a plurality of D), as shown in FIG. 5, the light source is arranged so that the emission directions of the light from the light emitting body intersect at one point Po, and a plurality of scanning spots are well connected. It was devised so that the surface to be scanned (not shown) could be scanned while maintaining the image state.

FIG. 5 is a view showing a typical conventional example thereof, and is a view of an optical system between a light source and a polarizer viewed from a direction perpendicular to a deflection scanning plane. Reference numerals 51a and 51b denote semiconductor lasers, and each laser is arranged on the mount 52 such that its light flux generating surface is parallel to the end surface of the mount 52. Mount 52 provided with semiconductor lasers 51a and 51b
End surfaces 52a, 52b of the lasers 51a, 51b are set as if the central rays ha, hb of the divergent light beams from the lasers 51a, 51b have passed through the same point Po. In other words, at the position where the semiconductor lasers (51a, 51b) are provided, the end surface 5
When 2a and 52b have normals, each normal is point P
The end faces 52a and 52b are set so as to pass through o. Further, when viewed from a direction parallel to the deflection scanning plane, the positions on the mount 52 are adjusted so that the positions of the center rays ha and hb of the respective semiconductor lasers passing through Po point are slightly displaced in the direction orthogonal to the deflection scanning plane. The position of the semiconductor laser provided in is set. The point Po and a point P in the vicinity of a predetermined position on the deflecting / reflecting surface 53 of the deflector are kept in an optically conjugate relationship by the imaging lens 54.

As described above, in order to arrange a plurality of semiconductor light emitters (for example, semiconductor lasers) so that the light emitting directions thereof are different from each other, as shown in the above example, they are aligned on the mount to form a hybrid structure. Had to do. Hereinafter, for convenience, the term array laser is used as a plurality of semiconductor light emitting bodies, but in principle it also applies to light emitting bodies such as LED arrays.

Further, when using a monolithically formed array laser, it is necessary to install some optical system in front of the array laser. As an example disclosed in Japanese Patent Laid-Open No. 58-211735, a prism is arranged in front of the array laser. This is shown in FIG.

FIG. 6 is a view showing a cross section of a prism when the semiconductor array laser has five light emitting portions. Reference numeral 61 is a semiconductor array laser having five light emitting portions (61a, 61b, 61c, 61d, 61e), and 62 is a prism.
The central ray ha of the luminous flux from the light emitting portion 61a is an inclined surface 62a.
It is refracted by and is bent as if it came through the point Po. Similarly, the central ray hb from 61b is due to the inclined surface 62b, the central ray hd from 62d is due to the inclined surface 62d, and the central ray he from 61e is equal to the inclined surface 62b.
Each of them is bent by e as if it had passed through the point Po.

The central ray hc from the light emitting portion 61c passes through the plane 62c vertically, and the point Po exists on the extension line of the central ray hc. As described above, the inclined planes having the inclined angles are provided corresponding to the respective light emitting units, and the central rays of the respective luminous fluxes emitted from the prism 62 are controlled in their directions as if they were emitted from the point Po. There is. This point Po is kept conjugate with the desired position P (not shown) in the vicinity of the deflective reflection surface via the optical system as described above.

The problems in this case are the precision and method of fine processing of the prism 62, the method of aligning the prism 62 with the array laser 61, and the method of joining the prism 62. The smaller the array laser bit, the more difficult it becomes. In fact, it is almost impossible if the thickness is 100 μm or less.

On the other hand, FIG. 7 shows an optical system, that is, a relay optical system 73, which is intended to have the same effect.
This is an example in which a relay optical system 73 is interposed between a collimator lens 72 and a cylindrical lens 75 which collimate the light emitted from 1b to form an image, and an image is formed on the polygon surface 74. An image is formed on a surface (not shown).

The problem in this case is the optical path length, which is about 2 in the relay system itself.
It will be 0 cm longer.

That is, in the prior art, when arranging semiconductor light-emitting bodies in a hybrid, the accuracy required for alignment of the arrangement is strict and the integration density is also limited. In the case of a monolithic array, the additional optical system is complicated, and the precision required for microfabrication of the additional optical system, alignment and joining of the array laser and the additional optical system is severe, and relay optical When using the system, there is a problem that the device becomes large.

The purpose of the invention is to solve these problems, to be compact,
It is an object of the present invention to provide a semiconductor device in which the additional optical system is not complicated and which is easy to align and join with the additional optical system.

[Means for solving problems]

In order to achieve the above object, the semiconductor device according to the present invention is a semiconductor device in which a plurality of semiconductor lasers are formed monolithically, and the plurality of semiconductor lasers have different emission directions of light from the respective semiconductor lasers. Therefore, the resonance planes of the respective semiconductor lasers are arranged so as to have a predetermined degree to each other, and each semiconductor laser has a pair of electrodes capable of independently controlling the ratio of the currents to be injected. The semiconductor lasers are arranged in parallel with each other in parallel to the laser resonance direction, and the respective semiconductor lasers are arranged so as to have a predetermined angle with each other, and the emission direction of light from each semiconductor laser is set to a predetermined angle. Set to to simplify the additional optical system, and to further inject current into the pair of electrodes provided in each semiconductor laser. It is possible to easily align and bonding of the additional optical system by controlling the independently.

〔Example〕

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

FIG. 1 is a configuration diagram for explaining a direction in which light emitted from a laser in a semiconductor device of the present invention is deflected by a minute angle, and three lasers 11, 1 monolithically formed.
2 and 13 arrays are shown. In the laser 11, the electrodes 11a and 1 which form a pair with the electrode separation portion 11d sandwiched therebetween.
1b is provided, and the same applies to the lasers 12 and 13. Reference numeral 14 indicates a boundary region, which is a portion for maintaining insulation between adjacent electrode pairs (for example, insulation between the electrodes 11b and 12a, insulation between the electrodes 12b and 13a). Further, 1 indicates an array interval, 11
c, 12c, 13c are lasers 11, 12, 13 respectively.
The light emission direction of is shown.

By appropriately changing the injection current to each electrode pair (11a and 11b, 12a and 12b, 13a and 13b), the light emitting direction of the array laser (11, 12 and 13) is changed by the angle α as shown in FIG. Can be biased.

FIG. 2 is a perspective view including the surface cut along the line AA ′ and the surface cut along the line A′-A ″ of the laser 11 shown in FIG.

Hereinafter, the manufacturing process will be described based on this.

First, on the n-type GaAs substrate 21, an n-type GaAs layer 22 as a buffer layer and an n-type AlxGal- as a clad layer.
The xAs layer 23 is formed. If the molecular beam epitaxy method is used, Si is used as the n-type dopant. Subsequently, a non-doped GaAs layer 24, a P-type (Be-doped) AlxGal-xAs 25, and a P-type GaAs layer 26 are grown as active layers, and then etched to near the non-doped GaAs layer 24 by etching. 27 is SiO
This is an insulating film composed of _two films or the like, and this limits the current injection region to the portions 28A and 28B. Generally, the distance between 28a and 28b is several μm. 2 in the figure
Reference numeral 9 is an electrode.

Array spacing 1 of the semiconductor laser shown in FIG. 1 (see FIG. 1)
Is 100 μm, and the emission direction between the arrays can be changed by α = 2 degrees by the injection current into the pair of electrodes 11a and 11b.

The light deflection angle α of FIG. 1 is difficult to be continuously deflected over a wide range such as ± 10 degrees.
It is preferable to limit the fine adjustment to the deflection direction.

FIG. 3 is a diagram showing a configuration of an embodiment of the present invention utilizing the fine angle deflection technique shown in FIG. In the figure, 31,
Reference numerals 32 and 33 denote three monolithically formed semiconductor lasers, 31a and 31b, 32a and 32b and 33a.
And 33b are electrode separating parts 31d, 32d, and 3b, respectively.
The electrodes are paired with 3d interposed therebetween. Reference numeral 34 indicates a boundary area, and adjacent electrodes (31b and 32a, 32b and 33a)
It is a part to keep the insulation between. Further, 1 indicates an array interval, and 31c, 32c, and 33c indicate light emitting directions of the lasers 31, 32, and 33, respectively.

By providing the boundary region 34 having the angle θ, the light emission direction from each semiconductor laser is different from that in the case of FIG.
The angle θ can be changed in advance.

Furthermore, for each angle θ, each electrode pair (31a and 31b, 3
2a and 32b, 33a and 33b) are appropriately changed to deflect the light emitting directions of the array lasers 31, 32 and 33 by a small angle of ± α as in the case of FIG. be able to.

The cross sections of the individual lasers 31, 32, 33 in this case have the structure shown in FIG. 2 as in the case shown in FIG.

This method is extremely advantageous for changing and setting the emission directions of a large number of array lasers of three or more. This is because (1) the angle θ of the boundary area 34 is determined by a photomask process such as a photolithography process, but it is not necessary to perform precise processing and alignment as shown in FIG.

(2) The angle α can be finely adjusted while observing the image formation state of the scanning optical system.

The value of the angle θ (degrees) depends on the interval 1 (mm) of the array and the focal length of the optical system used, but for a normally used focal length of about 20 mm, 1 ≦ θ / 1 ≦ 50 is suitable. . In the embodiment shown in FIG. 3, 1 = 100 μm and Po = 1.
Good results were obtained at 3 mm and θ = 0.44 degrees.

Since the value of the angle θ is not limited in processing, it is of course possible to set it to a large value such as 30 degrees or 45 degrees.
The value of the angle α usually stays within ± 2 degrees or less.

Needless to say, it is not necessary to limit the optical scanning method to the system using the deflecting / reflecting surface 53 as shown in FIG. For example, it is also possible to install something like a diffraction grating behind the imaging lens 54 to perform the deflection.

Finally, another configuration for deflecting the light emission direction of each laser by the angle α will be described.

FIG. 4 is a view showing a cross section of an example formed in a so-called heterobivora type. The manufacturing process will be described below.

First, P-type InGaAs 42, n-type InP 43, and n-type InGa are formed on the n-type InP substrate 41 by liquid phase epitaxy.
After sequentially stacking AsP44 and forming a mesa structure by chemical etching, p ⁺ I was also formed by the liquid phase epitaxy method.
Filled with nP45. Further, after the SiO ₂ insulating film 46 is formed, the Au—Sn electrodes 48 and 49 and the Au—Zn electrode 47 are formed.
a, 47b were formed.

By independently controlling the currents injected into the electrodes 47a and 47b, the light emission direction of the laser 42 can be slightly deflected by the angle α.

Further, although the preset different angle θ of the light emitting direction is generally shifted by a constant value, for example, θ ₁ ,
Different values may be taken as necessary, such as θ ₂ , θ ₃ ... Further, it goes without saying that such an array laser having different light emission directions is not applied only to an apparatus having a scanning optical system.

That is, the array laser in the semiconductor device according to the present invention is extremely advantageous for an operation of collimating lasers from different light emitting points in substantially the same direction by a single lens.

〔The invention's effect〕

As described above, according to the present invention, in a semiconductor device in which a plurality of semiconductor lasers are formed monolithically, the semiconductor devices are formed by arranging them so that the resonance surfaces of the respective semiconductor lasers have a predetermined angle with each other. In this case, the emission direction of the light from each semiconductor laser can be set to a predetermined angle, and the emission ratio of the light can be further controlled by independently controlling the current ratios injected into the pair of electrodes of each semiconductor laser. Can be fine-tuned.

This makes it possible to simplify the additional optical system at the time of optical scanning and, at the same time, facilitate the positioning and joining with the additional optical system.

Furthermore, since the emission direction of light can be finely adjusted after the semiconductor device is formed, it is possible to relax the accuracy of the arranging angles when forming the semiconductor device monolithically.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining a direction of emitting light from a laser in the semiconductor device of the present invention, which is deflected by a minute angle.
The figure shows lines A-A ', A'-of the individual lasers shown in FIG.
FIG. 3 is a perspective view including a plane cut along a line A ″, FIG. 3 is a view showing a configuration of an embodiment of the present invention, FIG. 4 is a cross-sectional view showing another type of individual laser, and FIG. 5 is a laser hybrid. FIG. 6 is a view showing a conventional example in which an array laser having a constant emitting direction is combined with a prism to make the emitting directions different, and FIG. 7 is an optical system showing an array laser having a constant emitting direction. It is a figure which shows the prior art example at the time of trying to amend.11,12,13,31,32,33 ... Semiconductor laser 11a, 11b, 12a, 12b, 13a, 13b, 3
1a, 31b, 32a, 32b, 33a, 33b ... Electrodes 11c, 12c, 13c, 31c, 32c, 33c ...
Light emission direction 14,34 boundary area

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiichi Miyazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hideaki Nojiri 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Isao Hakada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (56) Reference JP-A-53-39142 (JP, A)

Claims (1)

[Claims] 1. A semiconductor device in which a plurality of semiconductor lasers are monolithically formed, wherein the plurality of semiconductor lasers have resonance planes so that the emission directions of light from the respective semiconductor lasers are different from each other. The semiconductor lasers are arranged so as to have a predetermined angle, and a pair of electrodes that can independently control the ratio of the injected current to each semiconductor laser is provided in parallel to the laser resonance direction and in parallel with each other. A semiconductor device characterized by being provided.