PURPOSE: To obtain a desired structure with epitaxial growth processes performed twice by effecting selective crystal growth on areas except for a ridge and burning the ridge part, utilizing the surface orientation dependency and singularity of an epitaxial growth without the use of a selective deposition mask.

CONSTITUTION: Only a part of a p-type GaAs cap layer 5 is selectively removed, so that a ridge is formed in the shape of a quasi mesa with an exposed face (111) A. Only an uncovered cladding layer 4 on a p-type AlGaAs is selectively removed so that the cladding layer with a thickness d can remain, thereby forming a ridge in the form of a mesa with an exposed surface (111) B. The epitaxial growth of an n-type GaAs block layer 7 is effected under the conditions which inhibit a growth on the face (111) A. Lastly, a p-type GaAs contact layer 8 is caused to epitaxially grow over the entire surface under the conditions which permit a growth on the face (111) A. Thereby, a mask becomes unnecessary during a selective growth, and it is possible to form a ridge type semiconductor laser diode by carrying out epitaxial growth processes twice.