Semiconductor device such as semiconductor laser device and manufacturing method therefor, and optical transmission module and optical disk unit employing the semiconductor laser device

摘要

After a p-type cladding layer, an etching rate reducing layer and a p-type contact layer are formed in order on an n-type substrate, an etching mask is formed. Then, by using the etching mask, the p-type contact layer, the etching rate reducing layer and the p-type cladding layer are partially etched in the region outside the etching mask with an etchant. At this time, the etching rate of the layers by the etchant is slower in the etching rate reducing layer than in the p-type cladding layer and the p-type contact layer. Then, a metal thin film is formed such that the film continuously coats an upper surface and side surfaces of a ridge consisting of the above layers left after the etching step. A normal vector at a surface coated with the thin film has an upward component.