JPH02230785A - Manufacture of semiconductor laser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor laser in which deterioration of a resonator end face is suppressed.

[Conventional technology]

Conventionally, semiconductor lasers with an end-face LOC structure that suppresses the deterioration of the cavity end face have been published in the 49th Academic Conference of the Japan Society of Applied Physics, Autumn 1988, Proceedings, Volume 3, P856, 5a-
It looked like a ZC-8.

Its main sectional view is shown in FIG. (401) n-type substrate, (402) n-type cladding layer, (4 0 3) active layer, (
After the 404) P-type cladding layer and the (405) P-type cap layer are epitaxially grown using the MOCVD method, the vicinity of the resonator edge is etched to the middle of the (404) P-type cladding layer, and then the (406) P-type cladding layer is grown again using the MOCVD method. An n-type optical guide layer and a (407) n-type cladding layer are grown. Then, a (408) P-type electrode and a (409) n-type electrode are deposited, and folds are opened for each chip to obtain a semiconductor laser having an end face LOC structure.

[Problem to be solved by the invention]

However, with the conventional technology, growth by MOCVD must be performed twice, and when etching near the cavity end face, the remaining thickness of the P-cladding layer is an important factor in determining the effective refractive index. Although precise control is required, the etching thickness is extremely difficult to control, requiring difficult processes and resulting in poor yields.

The present invention has been made to solve these problems, and an object thereof is to provide a method for manufacturing a semiconductor laser having an end face LOC structure through simple steps and with high yield.

[Means to solve the problem]

In order to solve the above problems, a method for manufacturing a semiconductor laser according to the present invention provides a method for manufacturing a semiconductor laser having an end-face LOC structure having an optical guide layer only near the cavity end face, in which, during epitaxial growth of the optical guide layer, The method is characterized in that it includes a step of irradiating light onto a region other than the vicinity of the resonator end face.

〔Example〕

FIG. 1 shows a main cross-sectional view of a semiconductor laser according to an embodiment of the present invention. (101) n-type GaAs substrate, (102
) n-type AΩ0. 45c ao. 55A s cladding layer, (1 0 3) AN O. 1,GaO,B
5A s active layer, (106) P type A (l 0.35G
a 0. 69A S light guide layer, (107) P type A
No, Gao, As cladding layer, (105) P-type Ga
As cap layers are sequentially grown epitaxially by MOCVD. (106) P-type Ag0. 35G ao
．． When growing the 55A s optical guide layer, light is irradiated to the area other than the vicinity of the cavity end face, and Aj7 of the MOCVD method is grown.
It promotes the decomposition efficiency of the raw material TMA and increases the A,9 composition. By light irradiation, the (104) light irradiation layer becomes (10
7) P-type AD o, Ga with the same composition as the P-type cladding layer
o, 5A s layer. After epitaxial growth by MOCVD method, (108) P type electrode, (109
) Vapor deposit an n-type electrode, open the arm for each chip, and then LOC
Obtain a semiconductor laser structure.

Since the obtained semiconductor laser has an LOC structure near the cavity end face, the optical density of the active layer at the end of the cavity is reduced, suppressing the deterioration of the end face, and the optical density does not decrease in areas other than the end face. Therefore, it is possible to suppress an increase in the threshold current as would be the case when the entire structure is made of L O C tfI structure. Therefore, high output oscillation is possible.

FIG. 2 shows a main configuration diagram of a semiconductor laser manufacturing apparatus in an embodiment of the present invention. The raw material gas is introduced into the reaction tube (2 1 0) from the raw material gas introduction system (209) (211
) to grow a compound semiconductor thin film. During the growth of the light guide layer, the ultraviolet light from the excimer laser (201) is shaped by the cylindrical lens (202) and reflected by the mirror (203).
), a synthetic quartz lens (2 0 5) is used to create a parallel beam, which is then passed through a mask (206) and focused on the substrate using a reduction lens (207) to form a region other than the vicinity of the cavity end face of the semiconductor laser. irradiate with light.

FIG. 3 shows a main cross-sectional view of a semiconductor laser according to another embodiment of the present invention. (301) n-type GaAS substrate, (3
02) n-type Af) 0. 45G a 0. 55A
S cladding layer, (3 0 3) AN 0. 15G
ao. s5A s active layer, (307) P type AN o. s
Gao,,, As cladding layer, (306) P type AN
0. 35G ao65A s light guide layer, (305
) A P-type GaAs cap layer is sequentially grown epitaxially by MOCVD.

(306) P-type Ag0. 39G a O. 65A
When growing the S light guide layer, light is irradiated to the area other than the vicinity of the cavity end face, and the AΩ material of the MOCVD method is grown.
Promote the decomposition efficiency of A (1-limethylaluminum),
Increase Ag composition. By light irradiation, the (304) light irradiation layer becomes P-type A having the same composition as the (307) P-type cladding layer.
(l 0.9 Ga o, 5 A S layer.

After epitaxial growth by MOCVD method, (30
8) A P-type electrode and a (309)n-type electrode are deposited, and the arms are opened for each chip to obtain a semiconductor laser with an end face LOC structure.

In the obtained semiconductor laser, the effective refractive index of the P-type cladding layer near the cavity end facets becomes small, so light leaks into the P-type cladding layer at the cavity facets, reducing the optical density of the active layer and causing deterioration of the facets. is suppressed.

In addition, since the difference in refractive index between the active layer and the P-type cladding layer is large in the region other than the vicinity of the end face, the optical density of the active layer does not decrease, and the threshold current does not increase as in the case where the entire LOG structure is used.

In this embodiment, a gain waveguide type semiconductor laser has been described, but it can of course be applied to a refractive index waveguide type semiconductor laser.

In addition, even if the Group Ⅰ organic metal is an Ag raw material other than TMA, the composition of the light irradiation area can be modulated by appropriately selecting the intensity, wavelength, etc. of the irradiation light.

〔Effect of the invention〕

As described above, according to the present invention, the following effects can be obtained.

(1) Since the conventionally necessary etching process after epitaxial growth is no longer necessary, the accompanying photo process and the like can also be omitted.

(2) No regrowth process is required. In order to perform re-growth of a semiconductor layer with good reproducibility, there are major constraints on conditions such as cleaning the substrate and optimizing growth conditions, so being able to omit the re-growth step can greatly simplify the process.

(3) By omitting the steps described above, the degree of freedom in the process increases, making it possible to apply it to more complex device structures.

(4) Furthermore, the manufacturing cost is reduced due to the significant improvement in yield, and semiconductor lasers capable of high output operation can be supplied at low cost.

[Brief explanation of the drawing]

FIG. 1 is a main cross-sectional view of a semiconductor laser in an embodiment of the present invention. FIG. 2 is a main configuration diagram of a semiconductor laser manufacturing apparatus in an embodiment of the present invention. FIG. 3 is a main cross-sectional view of a semiconductor laser in another embodiment of the present invention. FIG. 4 is a main cross-sectional view of a conventional semiconductor laser. (108), (109). N-type GaAs substrate P-type GaAs cap layer, P-type electrode, n-type electrode, n-type substrate, P-type cap layer, cylindrical force lens (101), (301) ・ ・ (105),
(305) Mirror Synthetic quartz concave lens Synthetic quartz convex lens High frequency oscillator Raw material gas introduction system Reaction tube exhaust system Applicant Seiko Epson Corporation Agent Patent attorney Kisaburo Suzuki (and 1 other person) ,←゛1/et1t
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Claims (1)

[Claims] A method for manufacturing a semiconductor laser having an end-face LOC structure having a light guide layer only in the vicinity of the cavity end face, characterized by including a step of irradiating light to a region other than the vicinity of the cavity facet during epitaxial growth of the light guide layer. A method of manufacturing a semiconductor laser.