JPS58137282A - Manufacture of laser diode - Google Patents

Abstract

PURPOSE:To improve the efficiency of assembly work by forming an electrode onto a grown layer in shape that is thick and is extended on both sides while dividing a chip through mesa etching and cleavage. CONSTITUTION:The grown layer 22, a diffusion preventive insulating film 23 and stripes 24 are formed onto a GaAs substrate 21. A Cr evaporated layer 25 and an Au evaporated layer 26 are formed onto the surface. The layer 26 is patterned in the direction that crosses at right angles with the stripes 24. A layer 27 is plated thickly with Au. An electrode metallic layer 29 is formed onto the back of the substrate 21, and beltlike metallic layers 30 are shaped through patterning. The substrate 21 and the layer 22 are mesa-etched while using the layers 30 as masks. Layers 25, 27, 28 are cut, and the rectangular laser diodes are formed. The layers 30, beltlike semiconductor layers 31 and the layer 25 are cloven between the layers 27, 28.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a laser diode.

llB151J indicates a conventional laser diode, (a
) is the plane -1a3) is positive -m-. This laser diode is manufactured as follows.

First, two layers of n-GaAtAa (2 t-1' to 2 fiIl, n-GaA
s activity 4310.5~lμwr, p-GamutA easy-to-understand level 4kl~2μwr.

Grow n-GaAs 11i15 k 1 to 211 m. Next, a diffusion prevention insulating film 6 is formed on the surface of the n-caAs layer 5.
II, PIII7tn-GaAmM by forming and then diffusing p-temperature impurities such as Zn.
5 and p-GaAjAa are formed in a stripe shape in 2 dots@4. After that, an n-side electrode [i8] is formed on the surface of the GaAA substrate, while diffusion is prevented completely! A pl electrode 9 is formed on the 6th surface connected to the p layer 7. With the above steps, wafer processing is first completed.

Next, the wafer after electrode formation is opened and divided into rectangular steps. As a result, a first afl laser diode is obtained.

In the laser diode manufactured in this way, heat generated during use is concentrated in the active layer 3 located directly below the 9W layer 7. Therefore, it is important to dissipate the heat from this area to a heat sink or package.

As shown in Figure 11!1, there is a method of soldering and fixing the chip (laser diode) to the heat sink or package using the upside down method, with the back side of the board facing up and the P proof layer 7 facing down. It is taken.

However, the conventional laser diode (chitsuf) described above has 0
．． It's small, about 25 to 0.5 bullet points, and it's small.

During the above assembly work, the conductor itself is handled by handling with a bottle set, etc., but the assembly work cannot be performed efficiently. Shi, and even PN
The electrode 9 is generally ren〈, and the active Nll3 is Pl1l
Since the active layer 3 is located close to K&9, soldering sometimes puts strain on the active layer 3, resulting in a high failure rate during assembly.

In addition, all conventional laser diodes are manufactured by chip division using arm opening.

Manufacturing was time-consuming and productivity was poor.

This invention was made in view of the above points, and it is possible to manufacture a laser diode that can be assembled efficiently and to reduce the defective rate during assembly, and also increases the productivity of the laser diode. It is an object of the present invention to provide a method for manufacturing a laser diode that can be manufactured using the following methods.

This invention will be explained in detail below, but please refer to @1■.

A laser diode manufactured according to an embodiment of the invention is shown in FIG. The second column (&) is a plan view, and FIG. 2(b) is an enlarged plan view.

11 In Fig. 2, 11 is a GaAs substrate.
On the bottom (2) of the decoy are an n-GaAtAs cladding layer 12, an n-GaAs5 active layer 13. p-GaAt
As-2-14* n-GaAs #15 is formed by a crystal growth method such as a liquid phase growth method. n-GaA
A diffusion prevention insulating film 16 is formed on the surface of the s-layer 150.

Then, by selectively diffusing PrMl impurities such as Zn as this diffusion prevention insulation III/6T-mask, the PA1 layer 17 (hereinafter referred to as a stripe) becomes an n-G
aAs layer 15 and p-GaAtA1 cladding 114
It is formed into stripes.

On the back surface (the top surface in the figure) of the n-caAs substrate 11, an n@electrode &18 is formed. On the other hand, a p11 electrode 19 is formed on the surface of the growth layer (consisting of layers 12 to 15) including the anti-diffusion insulation I116.

This platform, the pIlil electrode 19, is formed in a strip shape, and extends outward from the growth layer at both ends lII in a direction orthogonal to the stripe 17. 11p @ turtle @ 19H is formed thickly. Note that the GaAa substrate 11 and the growth layer 17m are formed on topography, but the A side, that is, the growth layer 2
The reason why it is perpendicular to f17 is because of the force
It is formed by On the other hand, %B [i to 9 strike f17
The end face parallel to is formed by mesa etching.

Figures 3 to 11 are diagrams showing embodiments of the present invention for manufacturing laser diodes using this method. An embodiment of the invention will be described below with reference to this figure.

W2B prisoner ((a) is a front view, (b) is a horizontal view).

21 is a GaAs substrate, and first, a grown layer 22 (consisting of @2-〇 layers 12 to 15) is formed on this substrate 21 by a crystal arrangement such as a liquid phase growth method, and a diffusion prevention insulating layer is formed on its surface. Form $23i. Do it.

By diffusing p-type impurities as a mask for the diffusion prevention insulating film 23t, several strands of holes 24t are formed parallel to the growth 11122.

Next, a thin layer of Cr--Out is vapor-deposited on the surface of the growth layer 22, called the diffusion-preventing insulating film 23t. The state of this vapor deposited layer is @4
In the figure, 25 indicates a Cr vapor deposition site as a base metal, and 26 indicates an Au vapor deposition site.

Next, the Au vapor deposited layer 26t is turned into a plurality of strips in a direction perpendicular to the stripes 24.

Do□'s condition after Nolly Jung is #! Figure 5 (lotus) is a plan view.

Φ) is shown at
& Indicates arrival RMt. The diameter of this band-shaped AuA deposited layer 27 is l
O~50μmml! Keep conversations as small as possible.

Next, by electrolytic gold plating, only each band-shaped Au vapor deposition layer 27 is plated with Au tML<(30 to 100 am, 1 m). In this case, all of the band-shaped Au vapor deposition 127 is C
Since it is connected to the stain by the r vapor deposition layer 25, full-thickness plating is formed on all the strip-shaped Au vapor deposition layers 27 by simply connecting a part of the entire band-shaped Au vapor deposition layer 27 to the plating turtle. . The state after this thick plating is shown in No. 6 ((1) is a plan view, and (2) is a plated surface), and in the figure, 28 indicates each of the belt-shaped thick plating layers.

Next, as shown in 1i71N, the back side of the substrate 21 - ○,
An electrode metal layer (made of Au--Go) 29 is formed at 5 to l/jsa8. Then, the upper electrode metal part 29fj is turned into a plurality of strips such that each of the stripes f24 is located in the center and the stripes are spaced from each other at a predetermined distance. The soft line after this mother turning is shown in Figure @8 ((a
30 in the figure indicates each strip 1IIL electrode metal Ff11.

Next, as each band-shaped electrode metal 30t mask, the substrate 21 and the growth layer 22 (also including the diffusion prevention insulating film 23) are turned into a corresponding multi-ohm band shape by t mesa etching. The state after this patterning is shown in Figure 9 (hull).
is shown in the positive 1lt1 diagram, and (b) is shown in the downward direction 1), and 31 in the % diagram is each band-shaped semiconductor layer consisting of the substrate 21 and the growth layer 22.

Next, in the middle of each band-shaped semiconductor layer 31, C.
r vapor deposition layer 25. Band-shaped Au vapor deposition layer 27 and rhino plating 11
28t-, cut with a utility knife or razor. By this cutting, a laser diode with a circular shape is created, one of which is t-@xOaiJ ((a) t! Positive 111i-1 伽)
is shown below.

Thereafter, a strip-shaped electrode gold Is layer 30 . Band-shaped cow conductor layer 3
1 and Cr 11 pigeons 25Ytg #flying.

As a result, Figure 11 of Hatake ((a) is a downward view)
As shown in the figure, the laser diode (chip f
) is completed.

According to this manufacturing method, the PN electrode is formed by rsCr vapor deposition, the Au deposition layer, and the thick plating layer so that the electrode has a p thickness and extends to both sides of the semiconductor layer. Therefore, when assembling, do not touch the conductor part p 11
Not only can you link the elements with 1m4k, but you can also solder them to the heat sink and package.
By pressing down on the extending part.

This is possible without touching the semiconductor, and no strain is applied to the active layer, reducing the failure rate during assembly. In addition, the difference in thermal expansion coefficients of the heat sink and package is absorbed by the thin PAL electrode before being applied to the semiconductor layer.
The reliability of the element is improved.

Furthermore, the handling is easy and the efficiency of the 91 assembly work is improved.

Further, in the above manufacturing method, the end face perpendicular to the resonator end face, that is, the OB face in FIG. 2 is formed by mesa etching. Therefore, compared to a method in which the entire surface is formed by pressing and opening, manufacturing is easier and productivity is improved. However, the curve A in the resonator end face 982 is formed by pressing and opening. Therefore, the laser diode can be operated without increasing the threshold current of the oscillation.

In the above embodiments, the method of using a laser diode with a GaAa-pulled heterostripe structure was explained, but this method can be applied to a laser diode with a stripe structure made of other materials and structures.

First, in the above embodiment, the
) is formed by diffusion to form a striped waveguide. Therefore, the growth layer has 24 stripes.
The point of forming the (pg layer) can be said to be that the waveguide is formed in a stripe shape.

As described in detail above, according to the method of manufacturing a laser diode of the present invention, the crack is formed thickly on the growth layer and extends in both directions on the electrode, and the chip is divided by mesa etching and gI opening. As a result, it is possible to improve the efficiency of assembly work, reduce the defective rate during assembly, and improve reliability.In addition to being able to manufacture laser diodes, it is also possible to increase the productivity of the laser diode. .

[Brief explanation of drawings]

1- is a diagram showing a conventional laser diode, 2- is a diagram showing a laser diode manufactured according to an embodiment of the present invention, and FIGS. 3-11 are embodiments of the method for manufacturing a laser diode of this invention FIG. 11 ・n-GaAs substrate, 12 ・-n-GaAj
As 2 Rad layer s l 3 ・n-GaAg active layer, 1
4- p -GaAjAg clad Nts l 5
・n-Gaps @s l 6...Diffusion prevention film, 17...p knitting (stripe), 18 ・n@electrode, l 9-・-p 1ll-pole, 21 ・GaAs
Substrate, 22...Growth layer, 23...Diffusion prevention insulating film,
24...strike f, 25...Cr vapor deposition layer, 26.
... Au vapor deposition theory, 27... Band-shaped Au vapor deposition layer, 28...
・Thick plating layer. 29... Electrode gold ll4Nk, 30... Band-shaped electrode metal layer, 31... Band-shaped semiconductor layer. Patent issuer: Oki Electric Industry Co., Ltd. t1 Figure 2 Figure J4-6 Figure 7 Leap, 4

Claims (1)

[Claims] A step of growing a crystal on a substrate and forming a plurality of waveguides in the form of stripes on the grown layer, and depositing a base metal and Au on the surface of the grown layer.
A step of turning the deposited layer into a plurality of strips in a direction perpendicular to the stripes, a step of applying thick (Au plating) to the turned Au vapor deposited layer, and a step of applying an electrode to the back surface of the substrate. a step of forming a metal layer; and a step of forming the electrode metal layer Yr/leaning into a plurality of strips such that each piece of the waveguide is located at the center and separated from each other by a predetermined width.The substrate and the growth layer. Semiconductor layer t, consisting of the above) turned electrodes Gold II & FIIIt as a mask. A process of mesa etching/turning into a plurality of corresponding strip-shaped semiconductor layers, and a thick plating layer t@cutting of the previous underlying metal-Au vapor deposited layer and mu U at the middle of each of the strip-shaped semiconductor layers. A laser diode comprising a step of interfacing a wL metal layer and an iron-like semiconductor field and a base metal IIA layer between the band-shaped Au evaporation and thick plating layers. Production method.