JPS62269376A - Semiconductor device - Google Patents

Abstract

PURPOSE:To easily form and compose an optical system of shorter optical path length in combination with lens and the like by making angles between resonance face and direction different and the angles between two resonance faces different respectively. CONSTITUTION:Luminous parts 11-13 corresponding to a single laser form an array laser 14 and with the increase of reflectance, a coating 15 for protecting one end face 16 of array laser 14 uses alpha (amorphous)-Si and SiO2 and permits reflectance to be maintained at 80%. An emitting end face 17 of array laser 14 is processed to have an inclination of angle theta at both sides and the inclined emitting face 17 is arranged so that a desired angle phi is mutually held among light emitting directions 11a, 12a, and 13a of the array laser 14. This approach makes laser beams coming from various points parallel and makes such an optical arrangement significantly effective as a luminous source of optical device, through which an image-formation and scanning are carried out on media by using scanning systems.

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 elements 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 method shown in FIG. As shown, the light sources are arranged so that the directions of light emitted from the light emitters intersect at one point PO, and a device is devised so that multiple scanning spots can be scanned on the surface to be scanned (not shown) while maintaining good imaging conditions. It had been.

FIG. 12 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. 121a.

121b is a semiconductor laser, and each laser is a mount) 1
22, the light beam generating surface thereof is arranged parallel to the end surface of the mount 122. Semiconductor laser 121a
, 121b of the mount 122.
2a.

122b is set as if the central rays ha and hb of the diverging light beams from the respective lasers 121a and 121b had passed through the same point PO. In other words, the semiconductor laser (12
1a, 121b) At the installed kerarel position, the end surface 122a,
! = 122b, each normal line is P
The end surfaces 122a and 122b are set so as to pass through O. Furthermore, when viewed from a direction parallel to the deflection scanning plane,
The positions of the semiconductor lasers provided on the mount 122 are set so that the positions where the center beams ha and hb of each semiconductor laser pass through 20 points are slightly displaced in a direction perpendicular to the deflection scanning plane. ” - PO point and a point P in a predetermined vicinity of the deflection reflection surface 123 of the deflector are
4, an optically conjugate relationship is maintained.

In this way, in order to arrange multiple semiconductor light emitting devices (for example, semiconductor lasers) so that their respective light emission directions are different, it is necessary to align them with the mounts as shown in the example. It had to be configured as a hybrid.

For convenience, the term "array laser" will be used below to refer to a plurality of semiconductor light emitting elements, but in principle it also applies to light emitters such as LED arrays.

Furthermore, when using a monolithically formed 7-ray 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. 573-211735, a prism is placed in front of an array laser. This is shown in FIG.

FIG. 13 shows a cross section of a prism when a semiconductor array laser has five light emitting parts.

131 is five light emitting parts (431a, 131b).

131c, 131d, 131e), and 132 is a prism. Light emitting section 131
The central ray ha of the luminous flux from a is refracted by the inclined surface 132a, as if it were P.

It is bent as if it had passed through. Also 131b
The central ray hb from 131d is caused by the inclined surface 132b.
The central ray hd from 131e is caused by the inclined surface 132d.
The central rays he from are bent by the inclined surface 132e as if they had passed through the PO. Note that the central ray he from 131c passes through the plane 132c perpendicularly, and Po
exists. 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 132 is controlled as if it were exiting from Po. . As described above, this Pa 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 132, the alignment and bonding method between the prism 132 and the array laser 131, and the smaller the pitch of the array laser, the more difficult it becomes. In fact, it is almost impossible below loOpLm.

On the other hand, FIG. 14 shows an attempt to have a similar effect with an optical system, that is, a relay optical system 143, and an array laser 141
A relay optical system 143 is interposed between a collimator lens 142 and a cylindrical lens 145 that collimate and image the light emitted from 141b and 141b.
4, and the image is formed on the scanned surface (not shown) in a good imaging state.

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

On the other hand, in order to solve the problems mentioned in "-", the present applicant has proposed, in Japanese Patent Application No. 59-240418, Japanese Patent Application No. 60-424, etc., that a plurality of semiconductor lasers are monolithically formed.
Moreover, a semiconductor device in which each semiconductor laser has a different emission direction has already been proposed.

[Summary of the invention]

The object of the present invention is to provide a semiconductor laser device that can be easily manufactured and that can be combined with a lens etc. to form an optical system with a short optical path length. This will further improve performance.

In order to achieve the above object, a semiconductor device according to the present invention includes a semiconductor device in which a plurality of semiconductor light emitting elements are monolithically formed, wherein the angles formed between the resonance plane of the semiconductor light emitting elements and the resonance direction are different; Furthermore, it is assumed that the angles formed by the resonant surfaces are different, and that the respective light emitting directions are different when the light from each of the semiconductor light emitting elements whose resonant surfaces are formed by etching is pointed from the emitting end face. Features.

Note that the expression that the directions of light emitted from each light emitting element and the mutual angles are different, which is also used in the following description, does not mean that there are no sets of the same light emitting elements, but in a broad sense, it means that there are at least one set of different light emitting elements. It means to exist.

〔Example〕

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

FIG. 1 is a diagram schematically showing an embodiment of a semiconductor device according to the present invention. Portions 11, 12, and 13 are light emitting portions corresponding to a single laser, and these form an array laser 14. 15 is a coating 45 (hereinafter referred to as a multilayer reflective layer) for increasing reflectance and protecting one end surface 16 of the array laser 14;
In this example, α (amorphous)-3i and S i O2
was used so that the reflectance was 80%.

Reference numeral 17 indicates an output end face of the array laser 14 (hereinafter referred to as an oblique output end), which is machined so as to have an inclination of an angle θ on both sides. Note that the angle is exaggerated in the figure. This oblique end 17 is in the light emission direction 11a of the array laser 14.

This is the core part of the present invention for creating a desired angle φ between 12a and 13a.

That is, the respective light emission directions 11a and 13a from the light emission parts 11 and 13 are bent outward by φ with respect to the light emission direction 12a from the light emission part 12, as shown in the figure. However, according to Snell's law, φ is sin (
It is given by θ+φ)=1 or SiH6. Therefore, conversely, φ
If you want to have an angle of 1, you can determine θ from this formula and process it. If φ and θ are extremely small, then
The above equation approximately becomes (θ + φ) = nθ, so θ = φ/
θ may be determined from (n-1). In this example, φ−
5°.

The angle was set to θ-2° with n=3.5.

Note that the mutual spacing between the light emitting parts 11-13, that is, the array spacing, was set to 20 gm in this embodiment, but it was set to 50 gm.
pm, 1100p is also possible. In this case θ is lθ°
In order to maintain the same level, only a few m near the tips of the light emitting parts 11 and 13 should be sloped, and the remaining parts should be sloped at the end surface 16.
It is best to make it parallel to.

Next, this embodiment will be explained in more detail based on FIGS. 2(a) and 2(b). Figure 2(a).

(b) shows that the oblique end has two types of angles θ1. Although an example is shown in which processing is performed with an inclination of θ2, the principle is exactly the same as that in FIG. 1. below.

Explain the manufacturing process.

First, a 14 m thick n-type GaAs layer 22 is formed on an n-type GaAs substrate 21 by molecular beam epitaxy.

The n-type AlGaAs layer 23 is made of 2 pm, /7 doped GaAs.
The layer 24 is 0.1 gm, and the P-type AlGaAs layer 25 is Igm.
m, P+GaAs layers 26 were sequentially grown to a thickness of 0.15 pm.

Next, Si 3 N 4 was added at 120% by plasma CVD.
After forming 0 people, in order to form the current injection part 2o, P”
GaAs layer 26 (17) S i 3N4 was etched. Furthermore, Cr-Au is deposited as an ohmic electrode 28, and etched for separation as shown in FIG. 2(a). After that, the resonant surface R having the angles Ql and Q2 is vertically processed by reactive ion etching. The etching depth was set to the middle of the n-type GaAs layer 22.

Table 1 shows the conditions for reactive ion etching.

Table 1 Next, the other resonant surface R' was created using the normal power chi method, and in order to protect the end face and increase the reflectance, a-3i, St
02(7)R electric multilayer reflective coating 45 was applied to give a reflectance of 80%.

As for the dimensions of each part, the cavity length LC is 300pm,
LCθ1: 310pm, LCθ2: 301.6gm, pitch l 50gm, inclination angle θ1=7°, θ2=3
．． The 5° length W is approximately 20Ii,m. The respective light emission directions were all polarized as if they were emitted from one point PO.

FIG. 3 shows a modification of the present invention, and the feature of this example is that the area of the current injection region 30 is the same, and for lasers other than θ-〇, the area between the emission end face and the electrode is a non-injection region. That's a thing.

Next, an example of a method for manufacturing a semiconductor device having such a structure (particularly the device shown in FIG. 1) will be described.

First, as shown in FIG. 4, a laser wafer 40-L having a double heterostructure is coated with Si3N4 44
Deposit an insulating film. Next, using photolithography technology, this S
A window with a width of about several pLm is opened in the i 3 N 4 film 44. Thereafter, after Cr:Au electrodes are deposited, wet etching of the electrodes is performed to separate the elements. Table 2 shows the etching solution.

Au KI+I2+H20=l:1=100Cr H3
PO4+H2O2+Zn This state is shown in FIG. 5(b). In the figure (51a,
51b, 51c), (52a, 52b, 52c), (5
3a, 53b, 53c)... create an array laser including a plurality of light emitting parts. Next, a part of the mask is shown in FIG. 6(a). Using this mask 60, the portions of the electrode Φ insulating film that are not necessary for the laser are etched and removed. Further, a dry etching process is performed as shown in FIG. 6(b). In FIG. 6(b), 61 is 60 after patterning FIG. 6(a) on the laser wafer 40.
indicates a mask. 63 indicates the direction of ion incidence. Finally, cut out the rear end and complete.

Next, a modification of the present invention will be explained.

(1) In the above-mentioned embodiment, a device that emits light in three directions was shown, but the number of light emitting directions is arbitrary. For example, the seventh
By doing as shown in the figure, light can be emitted in five directions. In this example, the slanted end 78 is processed into a concave shape. In addition, 71 to 75 are light emitting parts, 76 is an array laser,
Reference numeral 77 indicates a multilayer reflective layer, and 71a to 75a indicate directions in which light is emitted from the light emitting sections 71 to 75, respectively.

(2) In the above embodiment, the beveled end was machined into a concave shape, but the same effect can be obtained by machining it into a convex shape or other shapes as shown in FIGS. 8(a) and (b). It will be done. In addition, 8
1 to 83 are light emitting parts, 84 is an array laser, 85 is a multilayer reflective layer, 86a and 86b are oblique ends, and 81a to 83a.

81b to 83b indicate light emission directions.

(3) In the embodiment described above, although beams are emitted in a plurality of directions, there is only one beam in each direction. However, it is also possible to create a laser that emits multiple beams in each direction as follows. This increases the power of the emitted beam per direction. For example, a slanted end 110 as shown in FIG. 10 is formed.

(4) The array laser is not a semiconductor laser, but may be a solid-state laser, for example.

(5) There is no need for the shape of the slanted end to have a step; for example, the same effect can be obtained even if the shape is continuously and gradually changed as shown in FIG. In addition, 91 to 93 are light emitting parts, 94
is an array laser, 95 is a multilayer reflective layer, 96 is a slanted end,
91a to 93a indicate light emission directions.

(6) When forming the surface opposite to the slanted end, the Bekki method was used, but the surface can still be formed in this state as shown in FIG. 6(b). (Double-sided etching cavity laser) (7) FIG. 11 is an example in which the shape of the oblique end is changed so that the resonator length of each laser does not change.

(8) Also in FIGS. 7-11, variations in the injection current can be suppressed by keeping the electrode area constant as in FIG. 3.

Note that the value of the angle φ (degrees) of the different light emission directions from each laser (light emitting element) depends on the spacing between the arrays (1 mm) and the focal length of the optical system used. m In the case of m, l≦φ／Ki≦
Around 50 is appropriate. For example, in the prototype example shown in FIG. 14, u=io.

Good results were obtained with pm, Po=13 mm, and φ=1.2 degrees.

Furthermore, it goes without saying that the optical scanning method need not be limited to a system using a deflection reflecting surface 123 as shown in FIG. For example, it is also possible to install something like a diffraction grating behind the imaging lens 124 to deflect the light.

Furthermore, the preset angle φ of the light emission direction is generally shifted by a constant value; for example, φl
, φ2. φ3. You may take different values as necessary, such as...

It goes without saying that such array lasers with different light emission directions are not only applicable to devices having a scanning optical system.

Moreover, the material is not limited to GaAs, but also other m-v,
It may be n-■ system. Furthermore, the growth method is not limited to MBH, but may also be LPE, MOCVD, or the like. Etching is not limited to reactive ion etching, but may also be wet etching or reactive ion beam etching.

That is, the array laser in the semiconductor device according to the present invention is extremely advantageous for operations in which lasers from different light emitting points are collimated in substantially the same direction using a single lens.

Although the above 1-1 embodiments and modifications have mainly been described using an array laser as an example, similar effects are expected for other semiconductor light emitting devices such as LEDs.

〔Effect of the invention〕

As described in the following, the present invention provides an angle between a resonant surface and a resonant direction so that when a plurality of semiconductor light emitting devices are formed on a single substrate, the directions of light emitted from each of the semiconductor light emitting devices are different. An optical device that facilitates collimation of laser beams from multiple points by making it easy to collimate laser beams from multiple points, and images and scans the medium using a scanning optical system. This has the effect of being extremely effective as a light source for a laser beam printer (for example, a laser beam printer, etc.).

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing an embodiment of a semiconductor device according to the present invention, and FIGS. 2(a) and 2(b) are diagrams showing more details, respectively. Viewed cross-sectional view, 3rd
The figure shows a modification example corresponding to FIG. 2(a), FIG.
5(a), (b), FIG. 6(a), (b) are diagrams showing an example of a method for manufacturing a semiconductor device according to the present invention, FIG. 7, FIG. 8(a), ( b). 9, 10, and 11 are diagrams showing other modified examples of the present invention, FIG. 12 is a diagram showing a conventional example in which lasers are arranged in a hybrid manner, and FIG. 13 is a diagram showing a 7-ray laser with a constant emission direction. FIG. 14 is a diagram showing a conventional example in which a prism is combined with a prism to have different emission directions, and FIG. 14 is a diagram showing a conventional example in which an array laser whose emission direction is constant is corrected by an optical system. 14.44,76.84゜94.104・・・・・・・・・・・・・・・・・・
...Array laser 17.47, 78, 86a. 86b, 96, 106・・・・・・・・・・・・・・・
...Beveled end 11a N15a. 71a-75a. 81a N83a. 81b-83b. 91a N93a.

Claims (1)

[Claims] In a semiconductor device in which a plurality of semiconductor light emitting elements are monolithically formed, the semiconductor light emitting elements are configured such that the angles formed between the resonance plane and the resonance direction are different, and the angles formed between the resonance planes are different, and 1. A semiconductor device characterized in that at least a resonant surface on the emission side is formed by etching, and the respective light emission directions are different at the time when the light from each of the semiconductor light emitting elements is emitted from the emission end face.