Time-of-flight detection pixel
AssigneeSTMicroelectronics (Crolles 2) SAS
InventorFrancois Roy
Life of this patent
Estimating the term…
Abstract
A time-of-flight detection pixel includes a photosensitive area and at least two assemblies. Each assembly includes: a charge storage area; a transfer transistor configured to control charge transfer from the photosensitive area to the charge storage area; and readout circuit configured to non-destructively measure a quantity of charges stored in the charge storage area.
Claims28
A time-of-flight detection sensor comprising a plurality of pixels, wherein each pixel comprises a photosensitive area and at least two circuit assemblies, and wherein each circuit assembly comprises:
- a charge storage area;
- a transfer transistor configured to control charge transfers from the photosensitive area to the charge storage area;
- and
- a readout circuit configured to provide for non-destructively measuring a quantity of charge stored in the charge storage area;
- wherein the readout circuit comprises:
- a readout transistor having a source, a drain, a gate coupled to receive a control signal and a bulk, wherein the charge storage area provides the bulk of the readout transistor;
- a constant current source configured to power a source-drain path of the readout transistor;
- and
- a circuit for measuring a voltage across the readout transistor.
A time-of-flight detection sensor comprising a plurality of pixels, wherein each pixel comprises a photosensitive area and at least two circuit assemblies, and wherein each circuit assembly comprises:
- a charge storage area;
- a transfer transistor configured to control charge transfers from the photosensitive area to the charge storage area;
- and
- a readout circuit configured to provide for non-destructively measuring a quantity of charge stored in the charge storage area;
- wherein each pixel comprises:
- a semiconductor substrate including a first doped layer of a first conductivity type forming the photosensitive area;
- wherein the charge storage area extends from an edge of the photosensitive area, from a first portion of the first doped layer coated with a gate of the transfer transistor;
- wherein the charge storage area comprises a well of the first conductivity type more heavily doped than the first doped layer, and being laterally delimited by two vertical insulated conductive walls positioned parallel and opposite to each other;
- a ring-shaped gate coating a portion of said well and surrounding a heavily-doped area of a second conductivity type penetrating into the well and being coupled to a constant current source;
- and
- a second doped layer of the second conductivity type coating the charge storage area and the photosensitive area except for portions that are coated with the ring-shaped gate.
A time-of-flight detection pixel, comprising:
- a semiconductor substrate including a photosensitive area that comprises a first doped layer of a first conductivity type;
- a charge storage area extending from an edge of the photosensitive area from a first portion of the first doped layer coated with a gate of a transfer transistor, the charge storage area comprising a well of the first conductivity type more heavily doped than the first doped layer, and being laterally delimited by two vertical insulated conductive walls that are located parallel and opposite to each other;
- a ring-shaped gate coating a portion of said well and surrounding a heavily-doped area of a second conductivity type penetrating into the well and configured to receive a constant current;
- and
- a second doped layer of the second conductivity type coating the charge storage area and the photosensitive area except for portions coated with the ring-shaped gate.
Dependencies are inferred from the claim text.