Manufacturing method of optical semiconductor device

Abstract

It is an objective to control the occurrence of the disorder of a far-field pattern and of an optical axial shift. A manufacturing method of a semiconductor laser device has the step for preparing a semiconductor substrate which has growth of a multi-layer including an active layer, the step for forming a mask over the growth of a multi-layer, and a step for forming a stripe-shaped ridge by dry etching and wet etching. A structure stacking a p-type AlGaInP layer, an etch-stop layer, a p-type AlGaInP layer, a p-type AlGaInP layer, a p-type GaAs layer, in order, over the active layer is taken in order to make the tailing part created in the dry etching process smaller by wet etching. The tailing part is composed of a p-type AlGaInP layer including a high mixed crystal ratio of aluminum. Therefore, the p-type AlGaInP layer is etched faster than the p-type AlGaInP layer during wet etching, so that the tailing part becomes smaller, the far-field pattern of the semiconductor laser device is not disordered, and the optical axis shift does not occur.