| 摘要 |
PURPOSE:To obtain a buried semiconductor laser capable of operating at high power and high temperature with extremely small leakage current by forming semiconductor layers having a forbidden band width smaller than that of a current block layer at both sides of an active layer. CONSTITUTION:A lower clad layer 31, an active layer 32, an upper clad layer 33 and a cap layer 34 are formed by a liquid phase epitaxial technique on an N type InP substrate 30. Then, the layers 34, 33, 32 are striped by photoetching with an SiO2 film or the like as a mask. Thereafter, an InGaAsP layer 35, a current block layer 36, a buried layer 37 and an N type InGaAsP layer 38 are formed by a liquid phase epitaxial technique. Since the layer 35 has a forbidden band width narrower than a current block layer (P type InP) 36, the gain of an N-P-N transistor 43 is lowered. Accordingly, even if a gate current IG flows, the P-N-P-N structure is not turned ON, and the leakage current IL can be set substantially to zero. |
