JPS6476790A - Manufacture of semiconductor laser - Google Patents

Abstract

PURPOSE:To automatically control a distance between a buried first layer of the same conductivity type with that of a substrate and a current blocking layer of the same conductivity type with that of the substrate at the side faces of a mesa, by utilizing difference in etching rate for constructing a mesa with a double hetero junction such that the width of the uppermost layer is larger than that of the Iowermost layer. CONSTITUTION:A buffer layer 20, an active layer 30 and a clad layer 40 are deposited on a semiconductor substrate 10 to form DH crystals. Photoresist 51 is then selectively applied only on the central region to provide a mask for mesa etching the structure with an etching solution of BCK. The photoresist 51 is peeled off, and a buried first layer 61 of the first conductivity type identical with that of the substrate, a current block layer 71 of the second conductivity type, a current block layer 81 of the first conductivity type, a buried fourth layer 91 of the second conductivity type and a cap layer 101 are dehosited one over another. Thereby, a step is defined between the clad layer 40 and the active layer 30 of DH crystals, and a distance between of the buried first layer 61 and the current block layer 81 both having the same conductivity type with that of the substrate can be controlled at the side faces of the mesa top by a thickness of the clad layer.