JPS61248584A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To arrange many semiconductor lasers, which can be independently driven, on the same semiconductor substrate, by forming grooves in a current block layer on an active layer, and forming isolating grooves reaching the current block layer from the surface of a crystal. CONSTITUTION:On an n-type GaAs substrate 1, an n-type Al0.4Ga0.6As layer 2, an n-type Al0.11Ga0.89As layer 3 that is to become an active layer, a p-type Al0.4Ga0.6As layer 4 and an n-type GaAs layer 5 that is to become a current block layer are sequentially formed. Thereafter, a groove 9' is formed from the surface of a crystal to the layer 4. Then, a p-type AlGaAs layer 6 and a p-type GaAs layer 7 are sequentially formed on the entire surface of the crystal. Thereafter, a p-type ohmic electrode 8, an isolating groove 9 reaching the layer 5 from the crystal surface and an n-type ohmic electrode 10 are formed. Thus, semiconductor lasers A and B can be driven electrically independently. Since the bottom of the groove 9 is positioned on the upper surface of the layer 5 and sufficiently separated from the layer 3, occurrence of transversal irregular streaks on the layer 5, when the crystal is cleaved, can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor radar used as a light source for optical information processing of optical discs and the like.

[Conventional technology]

Semiconductor radars have just begun to be used as light sources for optical communication, optical disks, and other optical information processing, and semiconductor radars with each pole structure have been proposed. In particular, a radar that has a plurality of semiconductor radars on a semiconductor substrate, each of which can operate independently, can perform simultaneous processing of writing and reading information to and from an optical disk, etc., and can read signals in parallel from written tracks. can be expected. FIG. 4 shows an example of a conventional semiconductor radar. FIG. 4 shows an n-type GaAs substrate 1
On top of the n-type At (L 4G & (L 6A 8 layers 2,
n-type AzB, I G, a 11 B to be the active layer?
AIl f'd 3, p-type AL (14G!L 16A
After sequentially forming the 11 layer 4 and the n-type GaAa layer 5, the p-type impurity diffusion region 12 such as Zn, the p-type ohmic electrode 8, and the
An example is shown in which a type ohmic electrode 10 and a separation groove 9 are formed to form semiconductor radars A and B that can be driven independently.

[Problem that the invention seeks to solve]

In this example, in order to eliminate the current 13 flowing between them, an n-type kA capacitor is used. It is necessary to dig the separation trench 9 deeply until it reaches the Ga-6As layer 2, and for this reason, the unevenness of the resonator surface is removed from the bottom of the separation trench 9 or the crystal interface between the folds of the crystal that forms the resonator surface. ->14 etc. are generated across the n-type At (111G & a139Am layer 3) which becomes the light emitting region, scattering the Raded oscillation mode, making the beam emission direction unstable, or causing the oscillation threshold current to decrease. It is not possible to avoid disadvantages such as increase in

The purpose of the present invention is to eliminate such drawbacks of conventional semiconductor radars, to enable simultaneous processing of information writing and reading on optical disks, etc., and to read recorded signals on multiple tracks in parallel, thereby making it possible to perform optical An object of the present invention is to provide a semiconductor radar excellent as a light source for information processing.

[Means for solving problems]

The present invention includes a crystal laminate on a semiconductor substrate in which a semiconductor layer serving as a light emitting region is sandwiched between semiconductor layers having a larger forbidden band width, and a striped groove is provided adjacent to the crystal laminate. The semiconductor laser is characterized in that it includes at least a semiconductor layer having the same conductivity as the semiconductor substrate, and has grooves extending from the crystal surface to the semiconductor layer to form a plurality of light emitting regions.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a diagram explaining the invention in detail, Figure 2 (4)
, (B) are diagrams for explaining the manufacturing process of the present invention, and FIG. 3 is a diagram for explaining another embodiment of the present invention.

First, as shown in FIG. 2 (4), as a first crystal growth step, an n-type A of about 1 micron thickness is grown on an n-type GaAs substrate 1.
La 4Ga a 6A 1 layer 2, about 0.05-0.0
n-type AzOL11 that becomes the active layer with a thickness of 8 microns
After sequentially forming Ga CL B g A 11 layer 3, p-type ALIIL4Gal16A8 layer 4 with a thickness of about 0.1 micron, and n-type GaAs layer 5 with a thickness of about 0.8 micron, p-type AZ14G Ik (L bA8 Groove 9 with a groove width of approximately 3 microns and a groove spacing of approximately 50 microns up to layer 4.
' is formed by a chemical etching process. Next, after cleaning the crystal surface, a second
As part of the crystal growth process, p-type At[L4c'16'' with a thickness of about 1 micron is grown so as to cover the entire crystal surface shouldering groove 9'.
If 6, a p-type GaAs layer 7 having a thickness of about 1 micron is sequentially formed. Thereafter, as shown in FIG. 1, a p-type ohmic electrode 8, a separation trench 9, and an n-type ohmic electrode 10 are formed to complete the semiconductor laser according to the present invention. In this embodiment, an example is shown in which semiconductor radars A and B have light emitting regions spaced apart by about 50 microns.

In this structure, an n-type GaA layer having stripe-like grooves with a groove width of approximately 3 microns is formed on the p-type At, 4Gm, and 6As layer 4.
By arranging the s-layer 5, the current path can be limited by this groove width, and furthermore, the separation groove 9 is formed from the crystal surface to this n-
By forming it until it reaches the type GaAs layer 5, the laser A
and radar B can be electrically driven independently, and furthermore, the bottom of the separation trench 9 is a rounded, conventional type which is located on the upper surface of the n-type GaAs layer 5 and is sufficiently far away from the active layer 3. It was possible to avoid the occurrence of irregularities that cross the active layer 5 during crystal opening, which was a problem when forming a semiconductor radar.

Since semiconductor lasers A and B can each be driven independently, it has become possible to write to semiconductor laser A and read the recorded data to semiconductor laser B.

In addition, both semiconductor radars A and B can perform parallel simultaneous write or read operations on different tracks), and the recording and read speeds can be increased by the number of elements.

Furthermore, another embodiment of the present invention is shown in FIG.

In FIG. 3, this embodiment differs from the previous embodiment only in that the number of semiconductor radar elements is increased to three (A, B, and C shown in the figure), and the rest is the same as that shown in FIG. 2. It is. Identical components are given the same numbers and their explanations will be omitted. By separating the semiconductor lasers into three elements, and driving the semiconductor lasers A, B, and C independently, parallel operations such as erasing, recording, and reading operations are possible. It is possible to provide an excellent semiconductor radar.

Further, according to the above structure, by handling one semiconductor substrate once, the electrical characteristics and optical characteristics of the semiconductor laser A e B e C, etc. can be examined continuously and independently, and then, Along the cutting line 11 located in the separation groove 9,
It can also be applied to cases where each independent element is separated and classified according to quality of characteristics.

Note that in this structure, n-type GaAa is used as the current blocking layer.
Although a layer is used here, it goes without saying that an AZxGa 1 ++xA' layer or a multilayer laminate may also be used.

[Invention effect]

As described above, according to the present invention, it is possible to arrange a large number of semiconductor radars that can be driven independently on the same semiconductor substrate, and it is suitable as a light source for speeding up recording, reading, erasing, etc. on optical disks, etc. It is not only a simple device that can construct a semiconductor radar, but also allows a large number of devices to be investigated and classified in one operation, and has the advantage of being applicable to mass production processes.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing one embodiment of the semiconductor radar according to the present invention, Fig. 2) and ■) are cross-sectional views showing the manufacturing process of the present invention in order of process, and Fig. 3 is another embodiment of the present invention. FIG. 4 is a cross-sectional view of a conventional semiconductor radar. 1: n-type GaAs substrate, 2: n-type At, 4Gm, 6As
Layer 3: n-type 1tCL4. Ga CLB tAs layer, 4
:p-type At, 100m, 6As layer, 5:n-type GaAm
Layer, 6: p-type At, 4GaF, 6As layer, 7: p-type Ga
As layer, 8: p-type ohmic electrode, 9: separation groove, 10:
n-type ohmic electrode, 11: cutting line, 12: p-type impurity diffusion region, 13: current flowing between them, 14: streak causing unevenness on the resonator surface.

Claims (1)

[Claims] (1) A crystal laminate is provided on a semiconductor substrate, in which a semiconductor layer serving as a light emitting region is sandwiched between semiconductor layers having a wider forbidden band width, and a striped groove is provided adjacent to the crystal laminate, and A semiconductor laser comprising at least a semiconductor layer having the same conductivity as the semiconductor substrate, and having grooves extending from the crystal surface to the semiconductor layer to form a plurality of light emitting regions.