| 摘要 |
PURPOSE:To decrease the sensitivity of an infrared area and to suppress blooming, etc., by forming a semiconductor layer of the 2nd conduction type under a semiconductor layer. CONSTITUTION:An N type semiconductor substrate is used as a substrate 8, a P type area 9 is formed on the N type semiconductor substrate 8, and N type diffusion layers 2 and 4 are formed in the P type area 9. When light incident between the N type semiconductor substrate 8 and P type area 9 while a bias voltage 10 is applied, a photoelectron generated in the depletion layer 11 formed of the substrate 8 and P type area 9 flows toward the substrate 8 and an effective signal is only a photoelectron generated more adjacently to the surface than the diffusion layers 2 and 4. Consequently, the sensitivity becomes small in the infrared area. The width of the depletion layer 11 is varied freely with the bias 10, so desired sensititivity is set.
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