Patent ID: 11961868
Assignee: STMICROELECTRONICS (CROLLES 2) SAS
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for acquiring a light flux using a pixel of an image sensor illuminated via a back side of a semiconductor substrate incorporating said pixel, the back side being opposite a front side of the semiconductor substrate, wherein said pixel comprises a first and second doped photosensitive regions that are superposed vertically in the semiconductor substrate between the back side and the front side, an upper portion of the first doped photosensitive region being laterally framed by a vertical annular transfer gate, said first doped photosensitive region being laterally framed by a first vertical annular gate that annularly surrounds the vertical annular transfer gate, said second doped photosensitive region being laterally framed by a second vertical annular gate that annularly surrounds the first vertical annular gate, the method comprising:
performing an integration phase during which said back side is illuminated with said light flux; and
biasing the vertical annular transfer gate and the first and second vertical annular gates during the integration phase so as to generate an electrostatic potential providing potential wells in a central portion of a volume of each doped photosensitive region and a potential barrier at each interface between two neighboring doped photosensitive regions.