MANUFACTURE OF SEMICONDUCTOR LASER

PURPOSE:To realize current constriction with good reproducibility and to enable stable basic transverse mode oscillation and low threshold current oscillation by irradiating ion beam having a uniform direction to dry-etch a contact layer of a gain waveguide region and by exposing a substrate in an oxygen atmosphere. CONSTITUTION:A lamination wafer is etched to a middle of a second clad layer 105 to a shape of a rib etching mask 107 to form a rib. A single crystal ZnSXSe1-X layer 109 is formed on a second clad layer in the outside of the rib. A single crystal ZnSXSe1-X layer 110 is formed on a rib-etching mask 107 above the rib. Polycrystal ZnSXSe1-X layer above the rib is selectively etched and removed. Then, a p-type contact layer 106 is etched and removed to remain in stripe and a part of a gain waveguide part is exposed. The exposed contact layer is removed by reactive ion etching using chlorine. Then, it is exposed in an ozone atmosphere as it is.