PURPOSE: To make it possible to obtain a semiconductor laser having a low threshold current and a high differential efficiency at a high yield by a method wherein in the semiconductor laser having a window type structure, crystal growths are all performed by an MOCVD method and a regrowth interface is treated with a sulfur-containing solution.
CONSTITUTION: A buffer layer 2 of the same conductivity type as that of an N-type or P-type GaAs substrate 1, an optical confinement layer 3, a light guide layer 4 and an active layer 5 are grown on the substrate 1 and the layer 5 at resonator end face parts is etched up to the layer 4. After the etching, a protective film is formed by performing a treatment using a sulfur-containing solution on the surface of the semiconductor layer and thereafter, a clad layer 6 of a conductivity type different from that of the substrate and a cap layer 7 are grown. Then, a ridge 9 is formed by etching, current constriction layers 10 of the same condictivity type as that of the substrate are buried-grown and moreover, current blocking layers 12 of the same conductivity type as that of the substrate are respectively formed at the end face parts, whereby current non-injection regions are respectively formed in the vicinities of the end faces. As all crystal growths are performed by an MOCVD method and the surface level density is reduced by forming the protective film on a regrowth interface, the semiconductor layer having a low threshold current and a high differential efficiency can be manufactured at a high yield.
NAITO HIROKI
SHIMIZU YUICHI
