JPS61115366A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To reduce defectives due to electrical short circuits, which have been generated in an assembly process in the conventional method, largely by constituting p-n junction sections exposed to side surfaces except the end surface of a resonator for a semiconductor laser under the state in which the p-n junction sections are indented to the substrate side more than an internal p-n junction section. CONSTITUTION:p-n junction sections in the vicinity of side surfaces except the end surface of a resonator take constitution in which the p-n junction sections are formed recessed to the substrate side more than internal p-n junction sections. A proper protective film for preventing the deterioration of the end surface of the resonator is shaped onto the end surface. When a semiconductor laser is prepared by a cutting such as cleavage according to the constitution, sections made to be contained in the end surface of the resonator in the end sections of p-n junctions exposed in all directions are insulated electrically by the protective film, and the ends of the p-n junctions in side surfaces approximately vertical to these sections made to be contained in the end surface of the resonator are separated from the surface, and formed on the side nearer to a substrate. Consequently, when the laser is bonded by using a solder material while the surface is directed downward, electrical short circuit due to the creeping, etc. of the solder material can be prevented.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a semiconductor laser device.

(Conventional structure and its problems) Semiconductor lasers have many advantages such as being small, highly efficient, and can be directly modulated by drive current, and are useful as light sources for optical communications, optical information processing, etc. It is promising and is being put into practical use.

In order to use the semiconductor laser chip for these purposes, it is necessary to bond the surface of the semiconductor laser chip close to the oscillation region to a heat sink that also serves as an electrode using a solder material.

Figure 1 shows a cross section of a conventional striped double heterostructure semiconductor laser perpendicular to the direction of light propagation. In Figure 1, 1 is an n-GaAs substrate, 2 is an n-Ga
Ams layer, 3 is n-GaAtAs layer, 4 is p-GaAt
5 is an n-GaAs layer, 6 is a p-side electrode, 7 is an n-side electrode, and 8 is a Zn diffusion region. As shown in FIG. 2, such a semiconductor laser is usually fused to a heat sink 9 made of copper or the like using In or Sn solder 10 with the p-side electrode 6 facing down. At this time, in the conventional structure shown in FIG. 1, the pn junction exposed on the side surface is 2 to 4
Since the distance is only about μm, as shown in FIG. 2, the swelling of the solder material 10 used for fusion
There is a problem in that the n-side portion of the n-junction is likely to come into contact with the n-side portion, resulting in an electrical short circuit.

(Object of the Invention) In view of the above drawbacks, an object of the present invention is to provide a semiconductor laser device in which electrical short circuits due to solder material are less likely to occur even when the device is attached to a heat sink with the pn junction facing down. do.

(Structure of the Invention) In order to achieve this object, the semiconductor laser device of the present invention has a pn junction near the side surface other than the cavity end face.
It has a configuration in which it is recessed closer to the substrate than the n-junction. A suitable protective film is formed on the resonator end face to prevent deterioration of the end face.

With this configuration, when a semiconductor laser is manufactured by cutting such as cleavage, among the ends of the pn junction that are exposed on all sides, the part included in the cavity end face is electrically insulated by the protective film, and is almost insulated from these ends. The end of the pn junction on the vertical side is formed farther away from the surface and closer to the substrate, so when soldering is done with the surface facing down, there is no electricity caused by the solder material wrapping around. can prevent short circuits.

(Description of Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows the structure of a semiconductor laser device according to an embodiment of the present invention, and shows a cross section perpendicular to the direction in which light travels. A semiconductor laser chip with such a structure
7' Id, as shown in FIG. 4, a groove is formed on the semiconductor substrate 1, a double heterostructure including an active layer is formed on this, and the structure is separated at the center of the substrate groove. can do. The laser chip manufactured in this way has an insulating film such as Az2O3 attached to the two cross sections forming the resonator, which are parallel to the cross section shown in FIG. 3, to prevent deterioration due to end face oxidation, etc. Can be electrically insulated.

On the other hand, when the side surfaces that are substantially perpendicular to these end surfaces are bonded as shown in FIG. 5, they are located at a distance from the surface fused by the solder, so that electrical short circuits are less likely to occur.

(Effects of the Invention) As described above, the present invention provides the following effects by configuring the pn junction portion exposed on the side surface other than the cavity end face of the semiconductor laser to be recessed toward the substrate side than the internal pn junction portion. It is possible to significantly reduce defects caused by electrical short circuits that conventionally occur in the assembly process, and the industrial effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional semiconductor laser chip, FIG. 2 is a diagram showing a denting state of a conventional semiconductor laser chip, and FIG. 3 is a cross-sectional view of a semiconductor laser chip according to an embodiment of the present invention. , Fig. 4, Fig. 9 of the same issue, Fig. 3-1, and Fig. 5 are diagrams showing the bending state of the semiconductor laser chip. 1---- n-GaAs substrate, 2- n-GaAtAs
, 3-n-GaAlAs, 4... p-GaAtA
s, 5...n-GaAs, 6-p side electrode, 7...
・N-side electrode, 8... Zn diffusion region, 9... heat sink,
10...Solder material. Figure 1 Figure 2

Claims (1)

[Claims] 1. A semiconductor laser device characterized in that, among pn junctions formed on a semiconductor substrate, a pn junction near a side surface other than a resonator end face is recessed toward the substrate than other pn junctions.