JPS6453485A - Manufacture of semiconductor laser - Google Patents

Abstract

PURPOSE:To diffuse impurity in a specified region of an optical waveguide layer with good controllability and to acquire a semiconductor of an optimum devices structure by forming and then heat-treating an impurity diffusion source on the optical waveguide layer of superlattice structure. CONSTITUTION:An n-type clad layer 2, an active layer 3, a p-type optical waveguide layer 4 and a p-type superlattice optical waveguide layer 5 are formed on a substrate 1 one by one. Then an Si3N4 film 6 is formed onto the waveguide layer 5 of p-type superlattice and patterning is conducted at specified width and pitch. In the stripe region, a GaAs layer 7 which is Si-doped to high density is grown selectively and an Si3N4 film 8 is grown on the GaAs layer 7 and the Si3N4 film 6. Then heat treatment is conducted using Si as a cap allowing Si to diffuse from the GaAs layer 7 to a region (a region not covered with the Si3N4 film 6) excepting the stripe region of the optical waveguide layer 5. A superlattice disordered n-type AlyGa1-yAs layer 5A is thereby formed and refraction factor waveguide mechanism and current constriction mechanism in this case are formed.