PURPOSE: To eliminate the need for selective diffusion by forming a P-type layer having high impurity concentration into an N-type buried layer and inverting a conductive type of one part of the buried layer through the diffusion of impurities by heat treatment.

CONSTITUTION: An N-type InP layer 13, an undoped In0.65Ga0.35As0.78P0.22 active layer 14, a P-type In0.82Ga0.18As0.42P0.52 layer 15 and a P-type InP layer 16 are grown successively onto an N-type InP substrate 12. A striped SiO2 film 23 is formed, and the layers 15, 16 are etched using the film 23 as a mask. The SiO2 film 23 is removed, and the N-type InP layer 17, the P+ type InP layer 18 to which Zn is doped, and the N-type InP layer 19 are grown in order. The conductive type of a section corresponding to an upper section of a mesa- shaped section of the InP layers 17, 19 is inverted through the diffusion of impurities by heat treatment at that time.