| 摘要 |
PROBLEM TO BE SOLVED: To make thin single crystal semiconductor regions, including a light- absorbing layer and raise the light intensity at this light-absorbing layer by sandwiching the upper and lower sides of a first single crystal semiconductor region to be the light-absorbing layer between insulating films through second single crystal semiconductor regions. SOLUTION: A semiconductor photodetector comprises an n-type Si layer 3 on an SOI substrate 1, having an Si oxide film 2 buried in an insulation plate 1a. In a trench 10 at the center of the Si layer 3 a light-absorbing layer 4 and P-type Si layer 5 are grown epitaxially, and the absorptive layer 4 is sandwiched between the oxide film 2 buried in the SOI substrate 1 and Si oxide film 7 covering the photodetector top. This can raise the light intensity of a core, even if a waveguide is made thin, since the refractive index of the Si oxide film is considerably low, compared with that of Si. |
