Low-noise wide dynamic range image sensor
AssigneeSTMicroelectronics (Crolles 2) SAS
InventorsFrancois Roy, Stephane Hulot, Andrej Suler, Nicolas Virollet
Life of this patent
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Abstract
A semiconductor image sensor includes a plurality of pixels. Each pixel of the sensor includes a semiconductor substrate having opposite front and back sides and laterally delimited by a first insulating wall including a first conductive core insulated from the substrate, electron-hole pairs being capable of forming in the substrate due to a back-side illumination. A circuit is configured to maintain, during a first phase in a first operating mode, the first conductive core at a first potential and to maintain, during at least a portion of the first phase in a second operating mode, the first conductive core at a second potential different from the first potential.
Claims20
A semiconductor image sensor, the image sensor including a plurality of pixels, each pixel of the image sensor comprising:
- a semiconductor substrate having opposite front and back sides, the semiconductor substrate is of P-type and has a first doping level;
- a first insulating wall penetrating into the semiconductor substrate from the front side of the semiconductor substrate, the first insulating wall including a first conductive core and laterally delimiting the semiconductor substrate, the first conductive core being insulated from the semiconductor substrate;
- and
- a second insulating wall penetrating into the semiconductor substrate from the front side of the semiconductor substrate, the second insulating wall being ring-shaped and delimiting a central region of the semiconductor substrate, the central region having a lower portion and an upper portion of P-type that has a second doping level greater than the first doping level, the second wall including a second conductive core insulated from the central region.
A pixel, comprising:
- a semiconductor substrate having an opposing front side and back side;
- a first insulating wall extending from the front side into the semiconductor substrate, the first insulating wall including a first conductive core insulated from the semiconductor substrate and laterally delimiting the semiconductor substrate;
- and
- a second insulating wall extending into the semiconductor substrate from the front side, the second insulating wall laterally delimiting a central region of the semiconductor substrate, the central region including a lower portion of P-type and a first doping level and an upper portion of P-type and a second doping level greater than the first doping level.
A method, comprising:
- forming first insulating wall penetrating into a P-type semiconductor substrate from a first surface of the semiconductor substrate, the first insulating wall laterally delimiting a first region of the semiconductor substrate within the first insulating wall, the first insulating wall including a first conductive core insulated from the semiconductor substrate;
- forming a second insulating wall penetrating into the first region of the semiconductor substrate from the first surface of the semiconductor substrate, the second insulating wall being ring-shaped and delimiting a central region including a lower portion continuing the semiconductor substrate and an upper portion of P-type and having a doping level greater than a doping level of the semiconductor substrate, the second wall including a second conductive core insulated from the central region.
Dependencies are inferred from the claim text.