| 摘要 |
PURPOSE:To obtain an excellent outer differential quantum efficiency using a low injection current by a method wherein, in the semiconductor laser having a groove on a semiconductor, the first semiconductor layer on the upper part of the groove, an active layer, the second semiconductor layer and a part of a diffusion layer are formed in mesa shape, and a low resistance layer wherein a semiconductor material is buried in the mesa-shaped part is formed. CONSTITUTION:An N type Ga1-xAlxAs waveguide layer 12, a GaAs active layer 13 and a P type Ga1-xAlxAs layer 14 are successively formed on an N type GaAs substrate 11 having a groove by performing a liquid-phase epitaxial method. Then, after the above layers have been left in mesa shape which is a little wider than the groove on the substrate by performing a selective etching, an N type GaAs layer 15 is buried by performing a liquid-phase epitaxial method. A P type diffusion layer 16 is formed by diffusing An as far as the point in the midway of the layers 14 and 15. Both faces of electrodes 17 and 18 are vapor- deposited, and a semiconductor laser element is obtained. An active layer is placed in the mesa-shaped part, a groove-shaped waveguide layer is positioned under the active layer, an unnecessary active layer is removed, loss is reduced, and a groove-shaped waveguide is obtained, thereby enabling to increase the photo output using a low current. |
