JPS61187288A - Manufacture of striped type semiconductor laser - Google Patents

Abstract

PURPOSE:To prevent the generation of an air gap in a striped section and the generation of leakage due to the adhesion of a metal for joining by exposing a peripheral section on a metallic electrode layer, selectively forming an Au electrode layer and interposing and joining thin-film-shaped Sn between a heat sink and the Au electrode layer. CONSTITUTION:An electric insulating layer 7 laminated on a laser wafer 14 is etched to a striped shape in predetermined width and the surface of the laser wafer 14 is exposed to shape stripes 8, and an ohmic electrode layer 9 with recessed sections 15 is formed. A metallic layer 16 consisting of a thick-film for bonding is laminated on the electrode layer 9, cleaving sections X, Y surrounding the prescribed length sections of the stripes 8 are exposed, a large number of rectangular independent layers are shaped while the recessed sections 15 are buried densely and the surface is flattened, and the laser wafer 14 is cloven and cut off, thus manufacturing chips 1. The chips are mounted onto a heat sink 11 through the metallic layer 16 and a thin- film composed of tin through thermo-compression bonding. Accordingly, an adhesion onto the end surface of the semiconductor laser 1 of a metal for joining can be prevented, and the formation of air gaps between the heat sink 11 and the semiconductor laser 1 is obviated, thus eliminating the lowering of the efficiency of removal of heat.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a method for manufacturing a semiconductor laser, and in particular to a method for manufacturing a striped semiconductor laser having striped windows in an electrically insulating layer.

"Prior Art" Conventionally, as an example of a semiconductor laser, a striped semiconductor laser as shown in FIG. 2 has been known.

The semiconductor laser 1 has an n-type GRAB substrate 2 and an n-type GRAB substrate 2.
aA/As layer 3, p@GaAF3 layer 4C active region)
, p-type GaAlAs layer 5 and p-type G6. AB layers 6 are epitaxially laminated in sequence, and the uppermost p-type QaA R layer 6
An electrically insulating layer 7fNNt made of SiO2 or 813N4 is formed on the electrically insulating layer 7f by etching to form a stripe 8f orthogonal to the cleavage plane F, and then a top layer is formed on the electrically insulating layer 7 through the stripe 8f. Uniform thickness of Au4S in contact with the surface of p-type QeAs #6
It has a structure in which an electrode layer 9 such as 100.n is laminated, and an Au'Go electrode layer 10 is laminated on the back surface of the substrate 2.

Incidentally, in order to maintain stable operation of a semiconductor laser over a long period of time, it is necessary to effectively remove Joule heat generated at the main KPN junction.

Therefore, in the striped semiconductor laser 1 described above, as shown in FIG.
When a metal foil 13 for bonding such as tin is placed on top, the stripe 8 of the semiconductor laser 1 is formed on the metal foil 13.
is brought into contact with the surface f on which the metal foil 1 is formed, and then the metal foil 1
3F By melting and solidifying by thermocompression bonding, the semiconductor laser 1 is mounted on a heat sink 11, so that the Joule heat generated in the semiconductor laser 1 is removed via the heat sink 11.

"Problems to be Solved by the Invention" The present invention attempts to solve all of the following problems in the prior art described above.

That is, when a striped semiconductor laser 1 is mounted on a heat sink 11 by the conventional method described above, the molten metal foil 13 does not fully penetrate into the stripes 8, and after solidification, the stripes 8 are not formed as shown in FIG.
Due to the problems that voids g are formed within the semiconductor laser 1 and the nuclear void Hg acts as a heat insulating layer and inhibits heat removal from the semiconductor laser 1, and the laser element is extremely small,
If the workability is very poor and the alignment between the semiconductor laser 1 and the metal foil 13 is inaccurate, the metal foil 13 will protrude to the side of the semiconductor laser 1 as shown in FIG. This causes problems such as adhesion to the end face C (cleavage part) of the l, causing defects such as leakage.

"Means for Solving the Problems" The present invention aims to provide a method for providing a striped semiconductor laser that can effectively solve all of the above-mentioned problems.
A striped window that exposes the surface of the semiconductor layer in the electrically insulating layer on the laser wafer and is perpendicular to the cleavage plane? After forming, the stripes are buried in the electrically insulating layer and deposited on the laser wafer. A thin electrode layer is deposited on almost the entire surface of the electrode layer with the opening exposed, and with the recess filled and the laser wafer cleaved, the peripheral edge is deposited until the surface of the bonding metal layer 4 becomes roughly flat. The laser wafer described in III is then broken along the cleavage portion and made into chips, and a thin film metal such as tin is inserted between the laser wafer and the heat sink, and they are bonded by thermocompression bonding. ``Function'' According to the present invention, when forming the entire pole layer of a striped semiconductor laser, a bonding metal f is added within the stripe.
Fill it completely so that the bonding surface of the semiconductor laser is almost flat.
'l and also the electrode layer? By forming the cleavage fg with it exposed and separating it from the cleavage to form a chip, a stepped portion is formed at the periphery of the bonding surface. In addition, even if the molten metal for bonding (C bonding) protrudes to the side of the semiconductor laser, the stepped portion completely prevents the molten metal from adhering to the end #F of the semiconductor laser. In addition, "Example" in which a striped semiconductor laser wafer with good adhesion at the bonding part is manufactured. ! An example will be explained in detail based on FIG. In the following description, parts common to those in FIGS. 2 and 2 to 4 will be designated by the same reference numerals, and the description will be simplified.

First, an n-type GaAs substrate 2 is formed into a rectangular shape as shown in FIG. A p-type QaAa layer 4, a p-type GaAtAs layer 5, and a p-type QaAs layer 6 are sequentially laminated by liquid phase epitaxy to form a laser wafer 14e as shown in FIG. 1(B).

Next, KSiO□ or 813 on the laser wafer 14
When the electrical insulating layer 7 is formed by laminating N4 or the like by vapor deposition or the like, the electrical insulating layer 7f is etched in stripes with a predetermined width to expose the surface f of the laser wafer 14 to form the stripes 8. Then, metal plating is performed on the electrical insulating layer 7 by vacuum evaporation to form an ohmic electrode layer 9f having a concave m15f along the stripe 8 (see FIG. 2(c)). The stripe 8 is formed perpendicular to the cleavage ff1F, and its width and pitch when forming a large number of stripes are determined based on the size of the laser wafer 14, the desired size of the semiconductor laser 1, etc.

After forming the entire electrode N49 on the laser wafer 14 in this way, %! lJ! A thick metal layer 16 for bonding is laminated on the pole layer 9. The metal layer 16 is formed independently in a large number in a rectangular shape by a selective plating method or the like so that the cleavage portions X and Yf surrounding the stripe 8 are exposed as shown in FIG. At the same time, the recess 15'f is formed so as to be densely filled and have a smooth surface.

After that, openings X and Y are opened to the laser wafer 14f.
Cleave and cut along K,
), it is possible to form a striped semiconductor laser 1f by making it into a chip.

The striped semiconductor laser 1 thus formed is mounted on a heat sink II by thermocompression bonding via a thin film of gold, the laminated layer 16, and tin (not shown). When mounting the metal semiconductor laser 1, depending on the thickness of the metal layer 16 for bonding.
Therefore, the occurrence of defects due to current leakage, etc. can be suppressed as much as possible.

Furthermore, since the recesses 15 of the electrode layer 9 are densely filled in at the stage of forming the metal 1 m 16, it is completely possible to prevent a gap from being formed between the heat sink 11 and the semiconductor laser 1 when the semiconductor laser 1 is mounted. , it is possible to prevent a decrease in heat removal efficiency.

Note that the compositions and forming methods of the laser wafer 14 and other components shown in the above-mentioned actual winding example are merely examples, and can be variously modified.

"Effects of the Invention" As explained above, according to the present invention, when mounting on a heat sink, it is possible to completely prevent the generation of voids in the stripe S, thereby preventing a decrease in heat removal efficiency, and also to prevent a decrease in heat removal efficiency when mounting on a heat sink. Does it prevent leaks due to uplinks and provide stable operation over a long period of time? A striped semiconductor laser wafer can be produced. Furthermore, since a large number of semiconductor lasers are prepared at the same time, it simplifies the laborious work, makes the quality uniform, and keeps the various conditions as constant as possible when mounting on the heat sink. It is possible to manufacture a stripe-type semiconductor laser that can stably perform six operations in a mounted state, and it also has excellent effects such as significantly improving the yield.

[Brief explanation of drawings]

Fig. 1 is a process diagram showing an embodiment of the present invention, Fig. 2 is an external perspective view showing an example of the structure of a conventional semiconductor laser, and Fig. 3 shows the semiconductor laser shown in Fig. 2 mounted on a heat sink. FIG. 4 is an enlarged sectional view of a main part of the semiconductor laser shown in FIG. 3 mounted on a heat sink. 1...[Stripe type] semiconductor laser 2...
...n-type QB, As substrate 3 ・----n-type GL! At4s layer 4...
p-type QaAF 3-layer C active region) 5... p-type GA
A1. As layer 6...p-type G5As layer, 7...electrical insulating layer 8...stripe 9...@pole layer F...cleavage Part 14... Laser wafer 15... Concavity] 6... Metal layer.

Claims (1)

[Claims] 1. A plurality of semiconductor layers are stacked on one main surface of a semiconductor substrate, an insulating layer having striped windows is formed on the top layer of the semiconductor layer, and a metal electrode layer is further formed on almost the entire surface including the insulating layer. In the striped semiconductor laser in which Au is formed, Au is selectively applied to expose the peripheral edge on the metal electrode layer.
A method for manufacturing a striped semiconductor laser, characterized in that after forming an electrode layer, a thin film of Sn is inserted between a heat sink and the Au electrode layer to bond the laser element and the heat sink.