Patent ID: 7456040

Claim:
A method for producing a semiconductor optical device, comprising steps of: growing a series of semiconductor layers on a primary surface with (100) surface orientation of a first III-V compound semiconductor substrate with a first conduction type, the semiconductor layers including a lower cladding layer made of a second III-V compound semiconductor material with the first conduction type, an active region, an upper cladding layer made of a third III-V compound semiconductor material with a second conduction type, and a cap layer made of a fourth III-V compound semiconductor material; forming a mask on the cap layer, the mask extending along [011] orientation; selectively etching the cap layer with respect to the upper cladding layer such that both sides of the cap layer show (−11-1) and (−1-11)crystal planes, respectively; selectively etching the upper cladding layer, the active region, the lower cladding layer and a portion of the semiconductor substrate with respect to the cap layer to form a mesa structure such that a side of the lower cladding layer and the portion of the semiconductor substrate show planes with (11-1) and (1-11) planes, respectively, and both sides of the upper cladding layer showing planes varying from (−11-1) to (11-1) and (−1-11) to (1-11), respectively; thermally treating the mesa structure at a first temperature in an atmosphere including group V elements to form both side surfaces of the upper cladding layer with (01-1) and the (0-11) planes, respectively, by causing a mass transportation; and growing a burying region at a second temperature in both sides of the mesa structure to bury the mesa structure.