| 摘要 |
PURPOSE:To obtain a light-receiving element at multi-wavelengths by laminating N-type semiconductor layers onto a semi-insulating semiconductor substrate so that band gaps are increased in succession and attaching separated electrodes to each layer. CONSTITUTION:N-InGaAs layers 22, 23, 24 are superposed onto semi-insulating InP 21, and the compositions of several layer are adjusted and E1<E2<E3 holds from a lower section in band gaps E. When beams 28 of three kinds are projected, they are absorbed respectively in the layers 22-24, and isolated severally from electrode terminals 25, 26, 27 and extracted as electric signals. Multilayer semiconductor layers are laminated in the structure, but the multilayer semiconductor layers are isolated electrically, electric signals do not leak to other electric terminals, and the degree of isolation is improved and manufacture is simplified. The semiconductor layers 22-24 may take a P-type. |
