Patent ID: 6965102

Claim:
A low-leakage, high-dynamic range active pixel sensor comprising: a p-type semiconductor substrate; a photodiode cathode n-type region disposed within said semiconductor substrate forming a pn junction with said semiconductor substrate; an n-well disposed in said semiconductor substrate and in electrical contact with said photodiode cathode n-type region; an annular p-well in said semiconductor substrate disposed around and spaced apart from said n-well; an annular polysilicon gate region forming a gate for a reset transistor disposed over a thick gate dielectric on the surface of said semiconductor substrate; an annular n-type region disposed within and inward from an inner periphery of said annular p-well and having inner edges substantially aligned with an outer periphery of said annular polysilicon gate region, said annular n-type region forming a drain for said reset transistor; a surface n-type region disposed in said n-well at the surface of said semiconductor substrate, said surface n-type region having outer edges substantially aligned with an inner periphery of said annular polysilicon gate region, said surface n-type region forming a source for said reset transistor; a sense transistor having a gate coupled to said surface n-type region, a drain coupled to a drain supply potential, and a source, said sense transistor having a thick gate dielectric; an output transistor having a drain coupled to the source of said sense transistor, a gate coupled to a row-select line, and a source coupled to a column output line.