| 摘要 |
PURPOSE:To reduce a leakage current due to a pinhole of an SiO2 protective film by a p-n junction formed by a buffer layer of the same conductive type as that of a semiconductor substrate and a current limiting layer of reverse conductive type to that of the substrate by sequentially forming the buffer layer and the limiting layer on the lower part of an external waveguide layer. CONSTITUTION:A cutout 1a is formed on the upper right part of a substrate 1, and a current limiting layer 12 is liquid-phase grown on the upper surface. Then, the left upper surface of the substrate 1 and the upper surface of the layer 12 are formed in the same plane by a meltback treatment, and a buffer layer 11, an active waveguide layer 2, a clad layer 3 and a cap layer 4 are sequentially liquid-phase grown on the upper surface. Then, the layers 2-4 are removed by etching, an external waveguide layer 5 and a clad layer 6 are sequentially grown, and a diffraction grating 7 is formed by etching on the upper surface of the layer 6. Then, after a stripe etching protective film is formed, it is etched to the depth of the layer 11, then p-InP first buried layer 14 and an n-InP second buried layer 15 are sequentially grown to bury the layers 2 and 5. |
