JPS59121989A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To prevent a damaging by tweezers to P-N junction sections on both side surface adjacent to a reflection plane, the adhesion of moisture and fouling and the like and the deterioration of characteristics by coating the P-N junction sections on both side surfaces adjacent to the reflection plane with a surface protective film. CONSTITUTION:Diffusion sections 9 as current paths are formed to a semiconductor wafer consisting of four layers on an N type substrate 4. The central sections of the diffusion sections and the diffusion sections are etched up to the substrate. The whole surface of the wafer is coated with the surface protective film 11. The P-N junction sections on both side surfaces adjacent to the reflection planes are coated completely with the surface protective film 11 in the process. A film such as an SiO2 film is used as the surface protective film 11, and the structure formed through a CVD method can be realized easily. Lastly, the surface protective films 11 of the diffusion sections are removed, the surface is coated with an electrode 12, and the whole is separated into pellets by cutting or cleavage or the like at positions shown by broken lines 13.

Description

[Detailed description of the invention] The present invention relates to semiconductor laser pellets.

A conventional semiconductor laser pellet has a groove structure in which pn junctions are exposed on both adjacent side surfaces of opposing reflecting surfaces.

Therefore, when fusing this semiconductor laser pellet to a heat sink using solder, the pn junction, which is the laser operating part, may be damaged by pinching both sides adjacent to the reflective surface with a bottle set, or there may be moisture or dirt. In addition, there was a drawback that the solder force used for fusion could get stuck in the Zpn joint, causing a short circuit in the pn junction and deteriorating the characteristics.Especially In order to improve the temperature characteristics of a semiconductor laser, the active layer side is bonded to a heat sink, so-called "above-side down assembly".
The n-junction is located at a distance of approximately 10 μm from the solder bonding surface, and in this case, the influence of the solder's curvature becomes significant.

An object of the present invention is to provide a semiconductor laser that can solve these conventional drawbacks.

The present invention provides a semiconductor characterized in that pn junctions on both sides adjacent to a reflective surface are covered with a surface protective film.

-It is the.

The details of the invention will be explained with reference to the drawings.

FIG. 1 is a perspective view of a conventional planar strike life type semiconductor laser pellet. The reflective surface 1 may be protected with an anti-reflection film. 5. Both side surfaces 2 adjacent to the reflective surface 1
, the pn junction 3 is exposed. In the present invention, a surface protective film is formed on the side surface of such a semiconductor laser. An example of a method for forming a surface protective film will be described below.

First, as shown in FIG. 2, a diffusion portion 9 serving as a current path is formed in a semiconductor wafer consisting of four layers on an n-type substrate 4. Next, as shown in FIG. 3, the central portions of the sales promotion section and the diffusion section are etched until the substrate is reached.

Next, as shown in FIG. 4, a surface protective film 11 is applied over the entire surface of the wax. In this step, the pn junctions on both sides adjacent to the reflective surface are completely covered with the surface protection film 11. For example, this structure can be easily realized by using a 5i02 film as the surface protection film 11 and forming it by CVD.

Finally, after removing the surface protective film 11 of the diffusion part and coating it with a capacitor 12, if the position shown by the broken line 13 in FIG. 5 is separated into pellets by cutting or cleaving, as shown in FIG. It is possible to realize a semiconductor laser pellet in which the pn junction portions on both side surfaces adjacent to the reflective surface are covered with a surface protective film.

That is, according to the present invention, p on both side surfaces adjacent to the reflective surface
The drawback is that the n-junction may be damaged with a bottle set, or moisture or dirt may adhere to it, degrading its characteristics. It is possible to prevent defects that cause short circuits and deteriorate characteristics.

Although the above explanation is about a planar stripe type semiconductor laser with an n-substrate, it can also be applied to semiconductor lasers using a p-substrate or other structures.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a conventional planar stripe type semiconductor laser pellet. FIG. 2 is a cross-sectional view showing the process of forming a diffusion section. FIG. 3 is a sectional view showing the etching process. FIG. 4 is a cross-sectional view showing the process of forming a surface protective film. FIG. 5 is a cross-sectional view showing the process of forming electrodes after removing the surface protective film of the diffusion section. FIG. 6 is a perspective view of a semiconductor laser pellet showing an embodiment of the present invention, in which the pn junctions on both side surfaces adjacent to the reflective surface are covered with a surface protective film. Here, 1... reflective surface, 2... both side surfaces adjacent to the reflective surface, 3... pn junction, 4...
...n substrate, 5...first layer (n-type cladding layer), 6...second no (active layer), 7...
・Third layer (n-type cladding layer) 8...84 layers (
cap layer), 9...diffusion section, 10...
・Part removed by etching, 11...
Surface protective film, 12...Metal electric strength % 13...
...Position related to cutting or separation. Half 1 illustration therapy 2I ¥1 3rd Zo ¥40 Type left rotation skewer

Claims (1)

[Claims] A semiconductor laser characterized in that pn junctions on both sides of a semiconductor laser pellet adjacent to opposing reflecting surfaces are covered with a surface protective film.