Image Number 2 for United States Patent #5010375.
A semiconductor laser device include a Si substrate, a current confinement layer having an aperture disposed on the substrate, compound semiconductor layers disposed on the current confinement layer and on the Si substrate at the aperture of the current confinement layer, and a buffer layer for relieving the stress caused by the difference in lattice constants disposed between the Si substrate and the compound semiconductor layers. The Si substrate is of a first conductivity type and the current confinement layer is of a second conductivity type, or the current confinement layer comprises a compound semiconductor while the substrate comprises Si. The aperture of the current confinement layer is produced by anodic oxidation and selective etching of the current confinement layer. Therefore, a good re-growth interface at the substrate is obtained. There are no problems from residual oxides at the surface of the substrate, of Si or p type impurities diffusing out of the surface of the substrate, or of non-uniform thermal etching during the subsequent crystal growth processes.