JPS60107881A - 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 Application of the Invention] The present invention relates to a method of manufacturing a high-output semiconductor laser.

[Background of the invention]

Many semiconductor lasers have been studied that have a structure in which a so-called optical guide layer is provided in contact with the active layer, but it is necessary to control the active layer width to be smaller than the optical guide layer width and with good reproducibility. It has been difficult to satisfy these requirements using the manufacturing methods up to now.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a manufacturing method that can easily manufacture a high-output semiconductor laser with stabilized transverse mode at a high yield.

[Summary of the invention]

The characteristics Fi of a high-power semiconductor laser provided with an optical guide layer are greatly influenced by the following two points. The first is to control the width of the active layer, and the second is to ensure that the width of the light guide layer is sufficiently wide relative to the width of the active layer.

With conventional manufacturing methods, it has been a national problem to satisfy the above two points. The present invention is characterized in that it can be controlled with good reproducibility up to just above the active layer by material selection and anisotropic etching, and the width of the active layer can be easily controlled by making the sides of the mesa stripe perpendicular to the substrate. be. For vertical processing of mesas, various methods can be considered, such as chemical etching using semiconductor materials and dry etching using reactive gases. For example, for %ZnP, a hydrochloric acid based etching solution is effective, and for %G a A of 8, dry etching using CC12Fm gas is effective.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a cross-sectional view sequentially showing the manufacturing steps of a semiconductor laser device according to the present invention. Note that each figure is a cross-sectional view taken on a plane perpendicular to the laser beam. As shown in Figure 1(a), n
-I n P (100) An n-' np buffer layer (thickness 0.5
~24m) 2,n In1-! G axAst-yPy
Light guide layer (x=0.25.y=0.55: thickness 1~
2 μm) 3, undoped In1-x G axA81-
y Py active layer (x=0.3. y=0.4: thickness 0.15 μm) 4, p-I n P cladding layer 5% pI
'1-110 azA81-y Py cap layer (x
=0.2. y = 0.6; thickness 0.15 μm) 6
grow sequentially. The cap layer is a quaternary layer intended to facilitate ohmic contact. Next, as shown in FIG. 1(b), after forming the etching protection film 7 in a stripe shape, a material selective etching solution of InGaAsp, HO80a:HlO:HO0! +:! The cap layer 6 is removed at a ratio of 4:1:1. Thereafter, as shown in FIG. 1(C), HCl: HsPOa = 4:1, which has material selectivity for InPIC.
The cladding layer is removed. At this time, since the HCl-based etching solution has anisotropy in which the side surfaces of the mesa are (1103 planes), it is possible to create a mesa shape that is perpendicular to just above the active layer.
By removing the light guide layer and exposing the light guide layer, a mesa shape as shown in FIG. 1(d) can be obtained. At this time, the width of the active layer is the same as the width of the etching protection film 7, and the width of the active layer can be precisely controlled by the width of the etching protection film 7. Next, liquid phase epitaxial growth! ＞'s p Inp layer 8゜n
-InP layer 9% pInl-tGaxA! 11
-y Py layer (X = 0.2. y = 0.6) 10 was embedded (Fig. 1 (e)).
This is to reduce leakage current and improve ohmic contact.

〔Effect of the invention〕

According to the present invention, it is possible to suppress the control accuracy of the active layer width within ±0.5 μm in a semicircular laser with a light guide layer, and the light guide layer width 5 can be made sufficiently wider than the active layer width, so that ^Elements with characteristics in which the small power transverse mode is stabilized can be manufactured with a high yield.

Moreover, not only the composition shown in the example (0(x(1°0<y
Applicable within the range <1. In addition to InGaAsP, for example, QaAtAs which is a ■-■ group compound semiconductor
It can also be applied to other semiconductor lasers.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(e) are process explanatory diagrams of a method for manufacturing a laser device according to the present invention. −

Claims (1)

[Claims] 1. A first . Second. The third and fourth semiconductor layers have at least a light trapping region in which they are in contact with each other, the first and fourth semiconductor layers are smaller in refractive index than the second and third semiconductor layers, and the third semiconductor layer is smaller in refractive index than the third semiconductor layer. the refractive index of the second semiconductor layer is larger than that of the second semiconductor layer, and the forbidden band width of the second and fourth semiconductor layers IVI is larger than that of the third semiconductor layer, and at least the first and fourth semiconductor layers correspond to each other. The confinement region is formed in a mesa stripe shape, and the sidewalls of the mesa stripe are buried with a fifth semiconductor layer, and the confinement region has a cross section perpendicular to the traveling direction of the laser beam. In forming a mesa stripe of a semiconductor laser device in which the width of the second semiconductor in the direction parallel to the junction plane existing in the light confinement region is wider than that of the third semiconductor layer, the width of the second semiconductor layer is selected for the fourth layer. A step of forming a mesa stripe on the entire side surface perpendicular to the substrate by selective and anisotropic etching, and exposing the third layer in the area outside the stripe, and removing the third layer in the area outside the mesa stripe to form the second layer. 1. A method for manufacturing a semiconductor laser device, which comprises a step of exposing a semiconductor laser device.