Semiconductor laser device and the manufacturing method thereof

Abstract

A gain waveguide type semiconductor laser oscillating visible light has an N type GaAs substrate of, and a double-heterostructure provided above the substrate to include an InGap active layer, and first and second cladding layers sandwiching the active layer. The first cladding layer consists of N type InGaAlP, whereas the second cladding layer consists of P type InGaAlP. A P type InGaP layer is formed as an intermediate band-gap layer on the second cladding layer. An N type GaAs current-blocking layer is formed on the intermediate band-gap layer, and has an elongated waveguide opening. A P type GaAs contact layer is formed to cover the current-blocking layer and the opening. The intermediate band-gap layer has a carrier concentration, in a layer portion being in contact with the opening, high enough to cause a current injected in the oscillation mode to concentrate on the layer portion and has a carrier density, in the remaining layer portion, low enough to suppress or prevent the injected current from spreading thereinto. The layer portion may be formed by additionally doping a selected impurity into the intermediate gap layer by using a presently available impurity diffusion/injection technique.