To easily enable selective etching of AlGaAs of the mirror surface with an HF system etchant.
An n-type AlGaAs clad layer of a first semiconductor laser 39 to be formed previously on an n-type GaAs buffer layer 22 is formed in the double-layer structure of the secondn-type AlxGa1-xAs (x = 0.500) clad layer 23 and the first n-type AlxGa1-xAs (x = 0.425) clad layer 24. At the time of removing the secondn-type clad layer 23 located in the side of the n-type GaAs buffer layer 22, since an Al crystal mixing ratio of the secondn-type clad layer 23 is set to 0.500 (x = 0.500), whitening does not occur and mirror surface etching can be realized. Moreover, since selection of GaAs is possible, the etching automatically stops at the n-type GaAs buffer layer 22. Even in this case, since the Al crystal mixing ratio x of the firstn-type clad layer 24 in the side of the AlGaAs multiple quantum well active layer 25 is equal to 0.425, the elliptical coefficient can be improved by setting the radiation angle θ in the vertical direction to 36°.
MORIMOTO TAIJI
MIYAZAKI KEISUKE
UEDA SADAAKI
TATSUMI MASAKI
Atsushi Maeda
Yukinori Nakakura