JPH01215088A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To keep leak current from flowing into a bonding adhesive layer even if a laser diode is bonded on a heat sink or other equipment, by forming insulation areas in the depth to reach at least a clad layer on a semiconductor substrate side through a clad layer and an active layer, on both sides of a laser diode near the active layer. CONSTITUTION:On both sides 11 of a laser diode, insulation regions 16 are formed in the depth to reach the surface of a semiconductor substrate 1 from a second clad layer 4 through an active layer 3 and a first clad layer 2. The insulation areas 16 are formed by conducting selective ion implantation of boron, hydrogen or other material after formation of the clad layer 4 or the adhesive layer 5 in the manufacturing process of the laser diode. Even if the laser diode manufactured by such a method is bonded on a heat sink by solder 15 at a surface 12 near the active layer 3, leak current is not generated by the solder 15 when the solder 15 climbs up since there are the insulation regions 16 on both sides 11 of the laser diodes. Therefore, an operation failure of the semiconductor laser caused by generation of leak current can be avoided and an yield can also be increased.

Description

[Detailed description of the invention] The present invention will be described in the following order.

A, III Field of industrial application B0 Overview of the invention C0 Prior art [Figure 3] D0 Problem to be solved by the invention [Figure 4] E0 Means for solving the problem F0 Effect G, Examples [Figures 1 and 2] Effects of the H0 invention (A, industrial application field) The present invention is a novel semiconductor laser, especially a novel device that does not cause leakage current to flow through the bonding adhesive layer even when bonded to a heat sink or the like. This invention relates to a double heterostructure semiconductor laser.

(B. Summary of the invention) The present invention relates to a double heterostructure semiconductor laser.

In order to prevent the risk of leakage current flowing through the bonding adhesive layer even when bonding to a heat sink, etc., there is a layer on both sides that runs from the surface closest to the active layer, passes through the cladding layer, the active layer, and at least the semiconductor substrate side. An insulating region is formed with a depth that reaches the cladding layer.

(C, Prior Art) [Figure 3] Semiconductor lasers are often used as light sources for optical heads, etc.
Furthermore, it has the potential to be widely used in other fields, and active research is being conducted to improve its performance and reliability. The applicant company has also proposed a semiconductor laser, for example, in Japanese Utility Model Application No. 120756/1983.

Incidentally, a semiconductor laser generally has a double heterostructure as shown in FIG. In the drawings, 1 is the first
A conductive type semiconductor substrate 2 is a first cladding layer formed on the semiconductor substrate 1 by vapor phase growth, and is of a first conductive type. 3 is an active layer formed on the cladding layer 2 by vapor phase growth; conductivity type or second conductivity type. Reference numeral 4 denotes a second crat layer formed on the active layer 3 by using a vapor phase acid, and is of the second conductivity type. Reference numeral 5 denotes an insulating layer formed on the second cladding layer 4, and has a groove in the center extending straight from the laser beam emitting end face 8 to the opposite end face 9. 6
7 is an electrode film made of metal formed on the insulating layer 5; 7 is a current confinement portion of the electrode film 6 that enters inside the groove formed in the insulating film 5; A portion corresponding to the current confinement portion 7 becomes a portion where laser oscillation occurs.

Reference numeral 10 denotes a protective film made of, for example, silicon nitride Si3N4, which is formed on the surface of the laser beam emitting end face 8 and the surface of the end face 9 opposite thereto. The protective IIIi film 10 protects only the end faces 8 and 9, and both side faces 11 and 11 of the semiconductor laser remain diced. Therefore, the first cladding layer 2, the active layer 3, the second
The cladding layer 4 and the like remained exposed on its side surfaces 11 and 11. In addition, 12 is the front surface of the semiconductor laser,
Specifically, the surface closest to the active layer 4 is the surface 13, and the surface 13 is the opposite surface.

(D. Problem to be solved by the invention) [Figure 4] By the way, the conventional semiconductor laser as shown in Figure 3 is
Since the first cladding layer 2, the active layer 3, and the second cladding layer 4 were exposed on both side surfaces 11 and 11, the semiconductor laser was attached to the heat sink 14 by soldering, for example, as shown in FIG. 5, the solder 15 causes a short circuit between the second cladding layer 4 side and the first cladding layer 2 side, resulting in frequent failures in which the semiconductor laser does not operate. This is because semiconductor lasers are generally soldered to a heat sink 14 at the surface 12 closest to the active layer 3, as shown in FIG. 4, in order to improve heat dissipation.
Therefore, the height of the active layer 4 from the heat sink 14 is low, and depending on the soldering condition, the solder 15 is placed at a higher position than the active layer 3, which easily causes an accident in which the solder 15 causes a short circuit between the upper and lower electrodes. It is. In addition, there have been many accidents in which, although not short circuits, the leakage current is so large that laser oscillation cannot occur.

The present invention has been made to solve these problems, and an object of the present invention is to prevent leakage current from flowing through the bonding adhesive layer even when bonding to a heat sink or the like.

(E. Means for Solving the Problems) In order to solve the above-mentioned problems, the semiconductor laser of the present invention has a cladding layer on both sides from the surface near the active layer, and a cladding layer on at least the semiconductor substrate side through the active layer. It is characterized by forming an insulating region with a depth that reaches the depth of the layer.

(F. Effect) According to the semiconductor laser of the present invention, insulating regions are formed on both sides, and the first cladding layer, the active layer, and the second cladding layer are formed on both sides.
cladding layers cannot be exposed. Therefore, even if the semiconductor laser is bonded on the large surface near the active layer, there is no risk of short-circuiting between the two electrodes due to the bonding adhesive layer, and leakage current due to the bonding adhesive layer does not flow. Can be done.

(G. Embodiment) [FIGS. 1 and 2] The semiconductor laser of the present invention will be described in detail below according to the illustrated embodiment.

1 and 2 show an embodiment of the semiconductor laser of the present invention, with FIG. 1 being a perspective view and FIG. 2 being a sectional view showing the state after bonding.

This example differs from the semiconductor laser shown in FIGS. 3 and 4 in that insulating @ regions are formed on both side surfaces, but is similar in other respects. Since this has already been explained, the explanation thereof will be omitted, and only the different points will be explained in detail.

16.16 is a second
An insulating region having a depth extending from the surface of the cladding layer 4 through the active layer 3 and the first cladding layer 2 to the surface of the semiconductor substrate 1 after the second cladding layer 4 is formed in the semiconductor laser manufacturing process. It can be formed by selectively implanting ions of boron, hydrogen, etc., in the step 1 or in the step after forming the adhesive layer 5. According to such a semiconductor laser, as shown in FIG. 2, even if the heat sink 14 is bonded with solder 15 on the surface 12 near the active layer 3, there are insulating regions 16, 16 on both side surfaces 11, 11. Therefore, even if the solder 15 creeps up, no leakage current is generated due to the solder 15.

Therefore, it is possible to eliminate the inoperability of the semiconductor laser due to the occurrence of leakage current, and it is possible to improve the yield.

The depth of the insulating region 16.16 is preferably set so that the bottom 17 of the insulating region 16.16 is higher than the height at which the solder 15 creeps up during bonding.

Note that the first cladding layer 2, the active layer 3, and the second cladding layer 4 are exposed on the laser beam emitting end face 8 and the end face 9 on the opposite side thereof. Protective film (e.g. silicon nitride 5i3N4) 10.10
solder on the end face 8.9!
5, there is no risk of leakage current occurring.

(H, Effects of the Invention) As described above, in the semiconductor laser of the present invention, a first cladding layer is formed on the surface of a semiconductor substrate, an active layer is formed on the surface of the first cladding layer, and an active layer is formed on the surface of the first cladding layer. In a double heterostructure semiconductor laser in which a second cladding layer is formed on the surface of the active layer, a second cladding layer is provided on both side surfaces perpendicular to the surface of the semiconductor substrate and the laser beam emitting end surface that emits the laser beam. An insulating region is formed with a depth extending from the surface of the cladding layer side through the active layer to at least the first cladding layer.

Therefore, according to the semiconductor laser of the present invention, insulating regions are formed on both sides, and the first cladding layer, the active layer,
The junction by the second cladding layer cannot be exposed. Therefore,
Even if the semiconductor laser is bonded on the surface near the active layer, there is no risk of short-circuiting between the two electrodes due to the bonding adhesive layer, and by extension, leakage current due to the bonding adhesive layer will not flow. can do. Therefore, it is possible to eliminate the possibility that the semiconductor laser will become defective due to bonding.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the semiconductor laser of the present invention. FIG. 1 is a perspective view, FIG. 2 is a sectional view showing the state after bonding, and FIG. 3 is a conventional semiconductor laser. FIG. 4 is a perspective view showing an example, and a sectional view showing the problem to be solved by the invention. Explanation of symbols 1... Semiconductor substrate, 2... First cladding layer, 3... Active layer, 4...
Second cladding layer, 8... Laser light emitting end face, 9... End face,! l... Side surface, 12... Surface to be bonded, 16... Insulating region. Figure 2: Cross-sectional view of the bond after bonding

Claims (1)

[Claims] (1) A double heterostructure in which a first cladding layer is formed on the surface of a semiconductor substrate, an active layer is formed on the surface of the first cladding layer, and a second cladding layer is formed on the surface of the active layer. In the semiconductor laser, at least a first cladding layer is formed on both side surfaces perpendicular to each of the surface of the semiconductor substrate and the laser beam emitting end face that emits the laser beam, from the surface on the second cladding layer side through the active layer. A semiconductor laser characterized by forming an insulating region having a depth of