Abstract: A semiconductor laser device in which the thickness and position of an active layer grown in a groove are made more controllable. The inventive device includes a buffer layer of a first conductivity type formed on a semiconductor substrate of the same conductivity type, a first current blocking layer of a second conductivity type formed over the first buffer layer, the aforementioned groove being formed through the first and current blocking layer to the buffer layer, the active layer buried in the groove, and mesas formed on both side of the groove. With this structure, during crystal growth of the active layer, atoms which would otherwise diffuse into the groove and make it difficult to control the thickness and position of the active layer diffuse into portions outside the mesas and grow thereon.

Abstract: In order to prevent the output characteristic of a semiconductor laser from being saturated at higher temperatures due to the thyristor effect of a combination of the semiconductor layers thereof, an intermediate layer of a conductivity type the same as that of the substrate and opposite that of the first semiconductor layer is provided between the substrate and the first layer. Due to the relatively low carrier density of the intermediate layer, oscillation can be stably carried out even at higher temperatures without triggering the thyristor structure.

Abstract: A p type GaAlAs layer is disposed on an n type substrate and then n type GaAlAs, GaAs and GaAlAs layers are successively grown on the p type GaAlAs layer. Zn is diffused into predetermined portions of those n type layers to a depth reaching the GaAlAs layer to form pn junctions between the original n type regions of the layers and their regions converted to the p form the n type conductivity. The pn junction formed in the GaAs layer serves as a light emitting region.