PURPOSE: To prevent a valley from being generated in the spectral sensitivity of an infrared photodetector by a method wherein the infrared incident surface of the photodetector is formed into a satin form to disperse the angle of incidence of infrared rays.
CONSTITUTION: Infrared rays 11 enter through the rear of an infrared photodetector. The infrared rays 11 are properly scattered by a satin-shaped incident surface 9 of the photodetector. The entering infrared rays 11 reach a platinum silicide layer 2. A part of the infrared rays are absorbed. The residual infrared rays are reflected by a reflective film 8. After that, the reflection of the rays 11 is repeated in an SiO2 film 7. However, no interference is generated by the action of the satin-shaped incident surface 9. Electrons out of generated carries are taken out via gas rings 4. In such a way, a valley in the spectral sensitivity of the infrared photodetector is dissolved. In the rear incidence type photodetector, a lapping process, a polishing process and the formation of an anti-reflection film have been hitherto executed to smoothen the rear of the photodetector, but the lapping process has only to be executed, the manufacturing time of the infrared photodetector is significantly shortened and the manufacturing cost of the photodetector can be also reduced.
KOMAI ATSUSHI
TOMOFUJI TETSUYA
