Abstract A capacitor coupled contactless imager structure and a method of manufacturing the structure results is 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 to 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 contact and exposed surfaces at the base region from a layer of poly2 about 3000-4000 Å 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.
A capacitor coupled contactless imager structure formed in the semiconductor substrate, the imager structure comprising: a collector region of N-type conductivity formed in the P-type semiconductor material; a base region of P-type conductivity formed in the collector region; an n-doped polysilicon emitter contact formed in contact with a surface of the base region such that an n+ epitaxial emitter region is formed in the base region beneath the polysilicon emitter contact; silicon dioxide formed over the polysilicon emitter contact and exposed surfaces of the base region; and a layer of second polysilicon about 3000-4000 Å which is formed on the silicon dioxide such that the layer of second polysilicon only partially covers the base region.
Claim 2
Dependent Claim
115 words
A capacitor coupled contactless imager structure formed in the semiconductor substrate, the imager structure comprising: a collector region of N-type conductivity formed in the P-type semiconductor material; a base region of P-type conductivity formed in the collector region; an n-doped polysilicon emitter contact formed in contact with a surface of the base region such that an n+ epitaxial emitter region is formed in the base region beneath the polysilicon emitter contact; silicon dioxide formed over the polysilicon emitter contact and exposed surfaces of the base region; and a layer of second polysilicon about 3000-4000 Å which is formed on the silicon dioxide such that the layer of second polysilicon only partially covers the base region.