| 摘要 |
PURPOSE:To allow a current to scarcely flow to the oblique face of a bump and to improve controllability by selecting a surface of a plane (001) as the main face of a semiconductor substrate, and so selecting that the longitudinal direction of the bump becomes an axis of a plane (110) in case of forming the bump, thereby forming an active region in a bump state. CONSTITUTION:A resist is formed along an axis of a plane (110) on a GaAs substrate 21. The substrate 21 is so etched as to retain a section corresponding to the resist. Thereafter, when the resist is exfoliated, a bump 103 of inverted trapezoidal shape called 'reverse mesa' is formed. When it is further etched, it is formed in a bump 104. A GaAs buffer layer 22, a clad layer 23, an active layer 24 and an upper clad layer 25 are sequentially formed on the n-type substrate 21. A current injecting window is formed by forming an SiO2 film of an insulating layer 27 and removing only the top of the bump. When a current flows in such a configuration, since the current flowing in the film laminated on the oblique face scarcely flow due to larger resistance than that of the flat part, the injected current is effectively narrowed to a laser oscillation region, thereby reducing its threshold value. |
