JPS63120426A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To eliminate the irregularity of etching as well as to vertically form both opposing surface of the side wall of a groove vertical by a method wherein a stepping, having an inclined side wall in forward direction, is formed by performing chemical etching on the surface of a semiconductor, and said inclination of the side wall is made steep by performing dry etching. CONSTITUTION:After a stepping having the side wall inclined in forward direction has been formed on the surface of a semiconductor 6 by performing chemical etching, said inclination of side wall is made steep by conducting dry etching. For example, TiO2 1 is formed by performing a sputtering method on the epitaxial wafer of double-hetero structure by successively liquid-phase growing N-InP 5, InGaAsP 4, P-InP 3, P-InGaAsP 2 on the N-InP substrate 6, and a patterning operation is performed using a photolithographic method. Then, when chemical etching is performed as deep as to the N-InP substrate 6 with a Br2-CH3OH solution using TiO2 1 as a mask, a taper is formed in the forward direction on the etching surface of plane (111). Then, when RIE (reactive ion etching) is performed using CCl4 gas under the above-mentioned state, the degree of verticality can be improved remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a reflecting mirror of a semiconductor laser device by etching.

Conventional technology Reactive ion etching (RIE) method (d) is suitable and widely used for forming mirrors in semiconductor lasers because its etching characteristics do not depend on crystal orientation.However, when the selectivity with the mask material is small or the mask edge If the mirror is not sufficiently perpendicular, a phenomenon called mask recession effect occurs, which deteriorates the perpendicularity of the mirror.The perpendicularity of the mirror directly affects the threshold current and differential quantum efficiency, which are important parameters of semiconductor lasers. It is important to form a mirror with sufficient verticality.

Until now, in order to ensure the verticality of the mirror, for example, the Institute of Electronics and Communication Engineers Technical Research Report 5SD85-47 (Vol.

85 & 110) as shown in
The IE method has been devised. FIG. 2 is a cross-sectional view for explaining the oblique R2H, and sample 7 is made of TiO on InP10.
It is patterned using 29 as a mask, and 8 is a diagonal jig. Sample 7 is attached to susceptor 1 using diagonal jig 8.
It is placed 6 in the chamber of the RIM device at an angle of 3 to 0. The equipment used is a normal parallel plate type RIE setup, and when performing RIE using, for example, C12 gas, the accelerating electric field is perpendicular to the sample 7 (since it is generated obliquely by 0). The active species of CI are incident 1-1 on the sample at an angle of incidence of 20. As a result, an etched shape as shown in FIG. 3 is obtained.

The problem that the invention is trying to solve! - The above-mentioned Eel Manufacturing 5 has the disadvantage that the etching rate differs depending on the location in FIG. For this reason, this method was unsuitable for the process of semiconductor rays using large-area wafers.Furthermore, as shown in Fig. 3, the perpendicularity of the mirror surface 11 is improved, but the opposing mirror surface 12 is inverted. Since the perpendicularity deteriorates, when manufacturing a semiconductor laser using the method described above, is it necessary to separately manufacture the lance on one side by a method such as cleaving?
is.

Means for Solving the Problems The present invention provides stripe-like mesh (
The present invention provides a method of forming a mirror with good 11- and 1'-inch characteristics using the iRIE method on the side wall surface of a meza of 1-, 1'''.

January 1: When forming a meza by chemical etching, the slope in the forward direction was created on the side wall surface by diagonal RIE.
The same effect as the method can be expected, and the wafer can also be soaked in water.
f (can be arranged, it is possible to eliminate variations in etching, and furthermore, it is possible to make both of the opposing side walls of the groove part heavier.

Embodiment FIG. 1 shows a cross section of an embodiment of the present invention, in which samples t1 and (n-I nP substrate 6, n-
InF3. InGaAsP5. P-InF3. PInG
Sequential liquid phase growth of aAsp2 to create fC double/Zoro structure 1
A No. 5 J Vitaki Zoyal wafer is used. Figure 1a
The above-mentioned Evitaginyaruru. - Ti by sputtering method
The state in which O21 was formed and patterned by ordinary photolithography is shown in i~. Figure 1 shows a Ti
Br2-CH30H (2% by weight) using O21 as a mask
This figure shows a state where an n-InP substrate 61 is chemically etched using a liquid. Therefore, the etched surface is (111) and has a forward taper. When etching was performed in this state by RIE using c7?4 gas, the verticality was significantly improved as shown in Figure 1C.0 Effects of the Invention According to the present invention, etching is performed with the wafer placed horizontally. Etched mirrors can be used on both end faces of the semiconductor laser because the etching variation within the wafer is small, allowing the use of large-area wafers, and the perpendicularity of all sidewall surfaces is improved. That is, the mass productivity of semiconductor lasers is dramatically improved, and the industrial value of the present invention is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a process to explain a method according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of a process to explain a conventionally used diagonal 6/-7 RIE method, and Fig. 3 is a process cross-sectional view of a diagonal RIE method.
FIG. 3 is a sectional view showing a J-notching shape according to the method. 1---- T i O2,2=...P, -1:nG
aAsP, 3. ------P-InF14----
--1nCzhAsP, ts---n-1:nP. 6...n-InP substrate. Name of agent: Patent attorney Toshio Nakao and 1 other person/
---Ti0z 2--- F -In Cr0LAs /) Figure 1
3-F-1nF 4---1? 1.6cLA S P 5-77-1 Arrow P (0-) /)-n -17LP board (b) 7-Trial folding ε -m-Needle J La white tool Q ---Ti0z Fig. 3 // ,/total - mirror surface (C)

Claims (4)

[Claims] (1) A method for manufacturing a semiconductor device, comprising the steps of: forming a gap having forward-sloping sidewalls on a semiconductor surface by chemical etching; and making the slope of the sidewall steeper by dry etching. (2) The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor includes at least InP. (3) The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor includes at least GaAs. (4) The method for manufacturing a semiconductor device according to claim 1, wherein the dry etching is reactive ion etching using a gas containing Cl or Br as a component element.