JPS6465868A - Solid-state image sensor - Google Patents

Abstract

PURPOSE:To obtain a solid-state image sensor capable of being micronized which has functions such as an internal amplification, a nondestructive read, and a light signal memory function by a method wherein a gate insulating film of a gate storage type MOS photo FET is made to have a charge trap effect. CONSTITUTION:An N-type epitaxial layer 2 is made to overlap a P-type substrate 1, and a source 3 and a drain 4 both of N-type are diffused. A gate insulating film 7 composed of two layers, a SiO2 film 5 20-50Angstrom in thickness and a Si3N4 film 6 about 500Angstrom in thickness, is formed on a channel region. Al electrodes 8 and 9 are provided to the N<+> layers 3 and 4, and a transparent electrode 10 formed of SnO2 or the like is provided to the gate insulating film 7. By this structure, it can be provided with an internal amplification function the same as a conventional gate storage type POS photo FRT, light generating charges are stored just under a gate for a certain period as a gate electrode is kept in an invertedly biased state, and then when an inverted bias which makes light generating charges tunnel through the gate insulating film is applied, the light generating charges can be injected into a gate film and trapped there, and thus optical signals can be memorized. And, a transfer gate for light generating charges storage can be dispensed with and the sensor can be micronized.