SEMICONDUCTOR PHOTOSENSITIVE ELEMENT AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To realize high amplification factor and enable driving at a low voltage in a semiconductor photosensitive element wherein a thin film semiconductor is used. SOLUTION: In a semiconductor photosensitive element having an optical absorption layer 4 which generates photocarrier on sensing light and an amplification layer 3 which amplifies photocarrier generated in the optical absorption layer 4 between a lower electrode 2 and an upper electrode 5, the amplification layer 3 comprises a well layer 3a which causes avalanche phenomenon and a barrier layer 3b having a band gap which is larger than the optical absorption layer 4. The well layer 3a is formed of a crystal body wherein an energy value of a conduction band of the photocarrier in the well layer 3a is lower than an energy value of a conduction band of the photocarrier in the barrier layer 3b in an interface with the barrier layer 3b, and a difference between an energy value of the conduction band in the well layer 3a and an energy value of the conduction band in the barrier layer 3b is larger than a band gap between a valence band and a conduction band in the well layer 3a.