JPS61168282A - Semiconductor device - Google Patents

Abstract

PURPOSE:To enable to utilize the cleaved surface of a semiconductor as a mirror of a resonator by disposing the resonator of a laser and a photodetector in parallel. CONSTITUTION:Most of light enclosed in an active layer 6 is propagated and emitted to a resonator direction (direction 10), but part is propagated to both sides of the resonator. The propagation to the photodiode is arrived at a photodiode without any failure to generate electron and hole pairs, and a feedback signal of a laser light is generated. The lights of the photodiode and reverse direction are enclosed by a lower clad layer 7, and a GaAs substrate 8 having large refractive index for enclosing the light. Accordingly, most of the light propagated to the vertical direction to the resonator arrives at the photodiode.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semiconductor laser device (hereinafter referred to as a laser section).
and a semiconductor device in which a photodetector for feedback control is monolithically formed.

[Conventional technology]

Conventionally, when a laser section having a Fabry-Perot resonator and a photodetector for feedback control are formed monolithically, the photodetector is provided in the direction of the resonator of the laser section. Since it cannot be provided with open folds, it cannot be produced by wet etching or dry etching.

However, when creating a resonator by wet etching or dry etching, a surface having sufficient reflectance cannot be obtained with good reproducibility, so there is a problem that the efficiency of the originally important laser section is reduced.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a semiconductor device in which a laser section and a photodetector are monolithically formed, and the arm opening of the laser section can be used to create a mirror constituting a resonator.

[Means for solving problems]

In the present invention, the resonator of the laser section and the photodetector are arranged in parallel.

Therefore, according to the present invention, the arm opening of the laser section can be used to create a mirror.

〔Example〕

The present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of an embodiment of the semiconductor device of the present invention. In this example, n-type gallium arsenide (hereinafter referred to as GaAs)
n-type aluminum plate with a thickness of 2 tiles is placed on the substrate 8 of the
A lower cladding layer 7 of gallium arsenide (hereinafter referred to as A1GaSb), an active layer 6 of GaAs with a thickness of 0.1u+, an upper cladding layer 5 of semi-insulating AJI GaAs with a thickness of 2IL11, a thickness of 0.5u A cap layer 4 of semi-insulating GaAs is sequentially laminated, a p-type electrode extraction layer 3 is formed by diffusion of zinc, and finally a metal electrode 1.2.9 of a light emitting part and a light detection part (photodiode) is formed. is formed. Here, the resonator of the laser section having the electrode 1 is formed between the open planes of the active layer 6 in the direction of the electrode 1 (light beam direction 10), and a photodetector is arranged in parallel with the resonator.

At this time, since the electrodes 1.2 must be electrically insulated from each other, the upper cladding layer 5 and the cap layer 4 must be semi-insulating. The distance between the zinc diffusion flon h3a and the active layer 6 is 0.1u1 or less, but it is not necessary to make it this close in the photodiode part, and it is possible to increase the distance by increasing the withstand voltage and lowering the sensitivity by -L. It is possible. The width of the suirive electrodes 1.2 in the laser section and the photodiode section is approximately 101 LI11, and the distance between each electrode 1 and 2 is preferably as small as possible, but considering the lateral spread due to zinc diffusion, the width is approximately 10 LI11. There is.

FIG. 2 is an equivalent circuit of this embodiment. A current 12 is injected into the laser section 13 by the current source 11, a portion 14 of the laser light is propagated, and a current 16 flows through the photodiode 15 biased by the constant voltage power supply 17. As described above, most of the light generated in the laser section 13 is emitted in the direction of the resonator 10, but a portion of the laser light 14 is propagated in a direction parallel to the active layer 6 and perpendicular to the resonator. . A portion 14 of the laser beam reaching this photodiode 15 generates pairs of electrons and holes, and a current 1B flows. This current 16 reflects the strength of the laser beam, so it is
Can be used for link control.

In this example, Al is used as the material for the laser section and photodetector.
Although the case where GaAs/GaAs is used has been explained, Kono et al.
ArSb, InAsP.

Systems using ternary mixed crystals such as InGaAs and InGaSb, AfiGaAsSb, InGaAs! 1li
A system using a quaternary mixed crystal such as b can be used to monolithically fabricate a laser section and a photodetector.

FIGS. 3 and 4 show a semiconductor device according to another embodiment of the present invention in which optical confinement is performed in the lateral direction of the laser section (parallel to the active layer and perpendicular to the cavity direction).

FIG. 3(a) is a perspective view of a semiconductor device having a stepped substrate, FIG. 3(b) is a perspective view of the stepped substrate, and FIG. 3(C)
is a sectional view of FIG. 3(a). In FIG. 3(c), most of the light confined in the active layer 6 is directed toward the cavity (
It is propagated and emitted in the direction 10), but a portion is propagated to both sides of the resonator. Of these, the propagation in the direction of the photodiode reaches the photodiode without any hindrance, generates electron-hole pairs, and generates a feedback signal of the laser beam. On the other hand, the light traveling in the opposite direction from the photodiode section is not propagated because the lower clarification layer 7 for confining the light is thin and the GaAs substrate 8 with a high refractive index is present nearby. It is difficult to achieve optical confinement in this direction. Therefore, most of the light propagating in the direction perpendicular to the resonator reaches the photodiode.

4(a) is a perspective view of a semiconductor device having a substrate with a T-shaped groove, FIG. 4(b) is a perspective view of a substrate with a T-shaped groove, and FIG. 4(C) is a perspective view of a semiconductor device having a substrate with a T-shaped groove. It is a sectional view of (a). In Fig. 4(c), the lateral optical confinement of the resonator is
Since the lower cladding layer 7 is thin on both sides, both directions are realized. Therefore, the lateral light directed from the laser section toward the photodiode reaches the photodiode through the optical waveguide formed by the single-shaped groove.

〔Effect of the invention〕

As explained above, the present invention provides the following advantages: When the laser section and the photodetector for feedback control are monolithically formed, the photodetector is provided in parallel with the resonator of the laser section.
By using the semiconductor arm opening as a mirror of the resonator, it becomes possible to monitor the laser light for feedback control without deteriorating the laser characteristics.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the semiconductor of the present invention, FIG. 2 is an equivalent circuit of the embodiment of FIG. 1, and FIGS. Perspective views of an embodiment using a substrate with shaped grooves, FIG. 3(b) and FIG. 4(b)
is a perspective view with a stepped base plate and a T-shaped groove, FIG.
c) and FIG. 4(c) are cross-sectional views of FIG. 3(a) and FIG. 4(a), respectively. 1.2.9-m-electrode, 3-m-electrode extraction layer, 4-m-cap layer, 5.
7--Clad layer, 6--Active layer, 8--Substrate. 3a 3a Figure 1 Figure 2 (a) (b) (C) #ORη (a) (b) (C) Figure 4 procedural amendment (voluntary) April 15, 1980

Claims (1)

[Claims] A semiconductor device in which a semiconductor laser device and a photodetector for feedback control are monolithically formed, characterized in that a resonator of the semiconductor laser device and the detector are arranged in parallel. Semiconductor equipment.