SEMICONDUCTOR LASER

PURPOSE:To obtain a laser which operates in high efficiency and up to high temperature in a striped semiconductor laser by forming a buried region which hardly becomes ON without forming a channel, thereby extremely reducing the leakage current. CONSTITUTION:A buried region such as an active layer 6 is formed on an N type InP substrate 1, and when the region is surrounded by a semiconductor layer, an N type InGaAsP layer 8 which is the same as or smaller in a forbidden band width than the layer 6 is grown on the substrate 1. Then, an N type InP layer 1a, an undoped InGaAsP active layer 6 and a P type InP layer 7 are laminated at the center on the surface of the layer 8, P type and N type layers 2, 3 for forming a reverse bias junction for blocking a current are laminated and grown while disposing the exposed side surface on the layer 8. Thereafter, a P type InP layer 4 and an InGaAsP cap layer 5 are laminated and grown on the entire surface including the surface of the exposed layer 7, and a P type region 9 which is intruded into the layer 4 corresponding to the layer 6 is diffused and formed.