Patent ID: 9496312
Filing Date: 2016-11-15
CPC Classification: H01L

Claim Text:
1. An active pixel structure of CMOS type comprising: a P-type semiconductor substrate; at least one photoelectric conversion zone defined by N-doping in the substrate, accumulating an amount of charge during exposure to light and comprising a P-doped surface zone; at least one floating diffusion node defined by N-doping in the substrate; at least one readout circuit to read a variation in voltage on the floating diffusion node induced by the transferred charges; at least one transfer transistor of MOS type, the gate of said transfer transistor being electrically insulated from the substrate and controllable to transfer said charges from said photoelectric conversion zone to said floating diffusion node; wherein: the gate of said transfer transistor partly covers said P-doped surface zone; and said photoelectric conversion zone extends under said gate of said transfer transistor at least as far as the end of the P-doped surface zone covered by said gate of the transfer transistor, and wherein the structure comprises a well defined by N-doping in the substrate, the well being in contact with the floating diffusion node and with the photoelectric conversion zone and covering at least part of the extent of said photoelectric conversion zone to ensure transfer of charges in the bulk of the well.