Method of manufacturing a capacitor coupled contactless imager with high resolution and wide dynamic range

摘要

A capacitor coupled contactless imager structure and a method of manufacturing the structure results in a phototransistor that structure includes an N-type collector region formed in P-type semiconductor material. A P-type base region is formed in the collector region. An n-doped polysilicon emitter contact is formed in contact with the surface of the P-type base region such that an n+ epitaxial region is formed in the base region as the emitter of the phototransistor. Silicon dioxide separates the poly1 emitter content and exposed surfaces at the base region from a layer of poly2 about 3000-4000 ANGSTROM thick that partially covers the base region; the gates of the CMOS peripheral devices are also poly2. The poly2 over the base region serves as a base coupling capacitor and a row conductor for the imager structure. The thickness of the poly2 capacitor plate allows it to be doped utilizing conventional techniques and silicided to improve the RC constant.