Patent ID: 6501109
Filing Date: 2002-12-31
Classification: H01L

Abstract:
A new active pixel sensor cell formed in a semiconductor substrate comprising:an n-type region in the substrate extending to a surface of said substrate, two p+ regions formed in said n-type region both extending to the surface of said substrate, covering almost all the active area of the new active pixel sensor cell, and with one of the p+ regions forming the p+ node of the photodiode having a substantially larger surface area than the other p+ region forming the p+ node of the output diode; isolation regions formed over those portions of the new active pixel cell periphery that will not be adjacent to other new active pixel sensor cells; a first dielectric layer over the surface of said n-type region; a first polysilicon layer over the first dielectric layer to form a floating gate that overlaps portions of both the said p+ regions, the floating gate is connected to said photodiode p+ region by a conducting region passing through the first dielectric layer; a second blanket dielectric layer disposed over said first polysilicon layer, said first dielectric layer and said isolation regions; a second polysilicon layer to form a control gate that is disposed over the photodiode p+ region and over said floating gate; a third blanket dielectric layer disposed over said second polysilicon layer and said second dielectric layer; a metal layer, disposed over the third dielectric layer, is connected to the output diode p+ region by a conductive region passing through the dielectric layers.