JPH0294682A - Manufacture of semiconductor laser device - Google Patents

Abstract

PURPOSE:To make manufacture easy by a method wherein a mesa stripe is formed on a (100) substrate surface on an inclination of 15 deg. or more from the <011> and <011> directions, an active layer is buried, the end surface of the mesa stripe is etched substantially at right angles to the stripe direction, and a laser resonance surface is formed. CONSTITUTION:An SiO2 stripe 15 is formed on a p-GaInAsP cap layer 14 on an inclination of 15 deg. or more from the <011> and <011> directions using a normal photolithography method. Next, it is etched in a mesa form using dry etching. Next, a bury layer 16 is grown with the SiO2 film stripe 15 as a selective growth mask by means of a MOCVP method. Then, a mask for dry etching is formed and a laser resonance end surface is formed vertically on the SiO2 stripe 15 by reactive ion beam etching. Thus, a semiconductor laser device having a planar, buried shape can be manufactured with a simple process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a buried semiconductor laser device.

(Prior Art) In recent years, the MOCVD method, which uses an organometallic compound and a hydrogen compound as source gases, has attracted attention as a crystal growth technique for compound semiconductor devices such as semiconductor lasers.
This is because the MOCVD method can form a uniform crystal film over a large area with good controllability, and is therefore excellent as a mass production technology for compound semiconductor devices.

In a buried semiconductor laser device, after forming a -degree double heterojunction, a stripe region is formed by mesa etching, and another crystal is grown on both sides of the stripe to bury the stripe region. By the way, M.O.C.
It has been found that when crystal growth is performed on a mesa stripe by the VD method, the appearance of the crystal growth differs depending on the crystal direction of the mesa stripe. That is, when the direction of the mesa stripe is <ITO> or <ito>, protruding crystal growth occurs at both ends of the mesa stripe, and the direction of <100
> direction and directions shifted from the <ITO> and <110> directions by 15'' or more, flat crystal growth occurs without protrusions.

Therefore, the present invention attempts to manufacture a semiconductor laser element having a flat buried shape by utilizing the above-mentioned properties without requiring multiple etching steps.

[Problem to be solved by the invention]

Conventionally, for stripes in the <1.10> direction, a cleavage plane consisting of a (110) plane is used as a reflective surface. However, if the stripe direction is <100> direction,
Alternatively, if the direction is shifted by 15 degrees or more from the <ITO> or <110> directions, a problem arises in that the cleavage plane cannot be used as a reflective surface.

[Means to solve the problem]

The present invention has been made in view of the above points.
The purpose is to provide a method for manufacturing a buried type semiconductor laser device in which a flat buried shape can be obtained by the MOCVD method.The gist thereof is to form a mesa stripe including an active layer on a substrate, and In the manufacturing method of a buried semiconductor laser device, the mesa stripe is embedded with a semiconductor layer having a refractive index smaller than that of the active layer.
Then, the active layer is buried by metal organic chemical vapor deposition (MOCVD), and then the end face of the mesa stripe is etched approximately perpendicular to the stripe direction by dry etching, and then laser etched. This is a method of manufacturing a semiconductor laser device characterized by forming a resonant surface.

[Effect]

In the method for manufacturing a semiconductor laser device as described above, the buried surface of the mesa stripe can be formed flat and at the same level as the mesa stripe surface. In addition, since dry etching can be performed without depending on the crystal orientation, it is possible to form a smooth laser resonant surface perpendicular to the mesa stripe direction, regardless of the crystal orientation of the mesa stripe. can.

〔Example〕

The present invention will be described below based on embodiments shown in the drawings.

FIGS. 1(a) to 1(e) are process explanatory diagrams of a method for manufacturing a semiconductor laser device according to the present invention. (a) First, as shown in FIG. 1(a), an InP substrate is nInP cladding layer (II), non-doped Ga1nAsP active layer 0 on the (100) plane of
, P-1nP cladding layer side and p-Ga1nAsP
The cap layer 04 is sequentially grown in layers.

) Next, as shown in Figure 1), p-Ga1nAs
A SiO strip θω with a width of 2 to 5 Ina is formed on the P cap layer 0 using a normal photolithography method.
011> and <OIT> directions at an angle of 15° or more (shaded area in FIG. 2).

c) Next, as shown in FIG. 1(C), the film is etched into a mesa shape using dry etching using C12 gas or using a Br--CH,011 solution.

(e) Next, as shown in FIG. 1(d), a buried layer 00 is grown by MOCVD using the Sing film strut 0ω as a mask for selective growth at a growth pressure cuff of 6 Torr and a growth temperature of 650'.

e) Next, as shown in FIG. 1(e), a dry etching mask made of AZ photoresist/SiOz/AZ photoresist is formed, and the laser resonant end face is etched by reactive ion beam etching using C2□ gas. is formed perpendicular to the stripe θω.

) Finally, on the surface of the n-InP substrate 0, an n-side electrode, S
An n-side electrode is formed on the p-Ga1nAsP cap layer 04 excluding the iO stripe 00.

〔Effect of the invention〕

As explained above, according to the present invention, mesa stripes are formed on the (100) substrate surface at an angle of 15° or more from the <011> and <01st> directions, and then the active layer is buried by the MOCVD method. Next, the end faces of the mesa stripes are etched substantially perpendicularly to the stripe direction by dry etching, and the MOCVD method is used to form the resonance surfaces.

It is effective to manufacture a semiconductor laser element having a flat buried shape through a simple process and the excellent effect of q(7-kiru).

[Brief explanation of the drawing]

FIGS. 1(a) to 1(e) are process explanatory diagrams of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the striping direction in an embodiment of the present invention. 10-1 nP substrate, 1l-n-1nP cladding layer, 12... non-doped Ga1nAsP active layer,
13-p-1n P cladding layer, 14.p-
GaTnAsP cap layer, 15...SiO□ stripe, 16...buried layer.

Claims (1)

[Claims] A method for manufacturing a buried type semiconductor laser device, in which a mesa stripe including an active layer is formed on a substrate, and the active layer is embedded with a semiconductor layer having a refractive index lower than that of the active layer, wherein the mesa stripe is formed on a (100) substrate surface. is formed at an angle of 15° or more from the <011> and <01@1@> directions,
Next, an active layer is embedded by a metal organic chemical vapor deposition (MOCVD) method, and then the end face of the mesa stripe is etched substantially perpendicular to the stripe direction by dry etching to form a laser resonant surface. A method of manufacturing a laser element.