EPITAXIAL WAFER, PRODUCTION THEREOF AND LIGHT EMITTING DIODE

摘要

PURPOSE: To increase the carrier concentration only in the vicinity of the surface of a p-type clad layer while specifying the concentration of the p-type barrier in the vicinity of the surface of a p-type GaAlAs clad layer. CONSTITUTION: The concentration of a p-type carrier is set in the range of 0.7×10<18> -2×10<18> cm<-3> in the vicinity of the surface of a p-type GaAlAs clad layer. The p-type GaAlAs clad layer 2 has AlAs mixed crystal rate of 0.65 and the carrier concentration is set at about 5×10<17> cm<-3> in the vicinity of the interface with a p-type GaAlAs active layer. The p-type GaAlAs active layer 3 has AlAs mixed crystal rate of about 0.35 and the carrier concentration is set at about 1×10<18> cm<-3> . An n-type GaAlAs clad layer 4 has AlAs mixed crystal ratio of about 0.65 and the carrier concentration is set at about 1.5×10<18> cm<-3> in the vicinity of the surface. The concentration of p-type carrier in the p-type clad layer peaks in the vicinity of the surface and then drops abruptly. Subsequently, a constant level is kept up to the interface of p-type active layer and a high concentration appears in the following p-type active layer. The concentration then increases linearly in the n-type clad layer because of the high segregation coefficient of Te. Consequently, the carrier concentration can be increased only in the vicinity of the surface.