IMAGE SENSORS, METHODS, AND PIXELS WITH TRI-LEVEL BIASED TRANSFER GATES

An image sensor includes at least one pixel with a transfer gate that is controllable among at least three biasing conditions, including a first biasing condition in which electrons are transferable from a photodiode to a potential well under the transfer gate, a second biasing condition in which the electrons are confined in the potential well under the transfer gate, and a third biasing condition in which the electrons are transferable out of the potential well under the transfer gate. The pixel includes a p+ type doped barrier implant located at least partially under a portion of the transfer gate, and a pinned charge transfer barrier located on the opposite side of the transfer gate from the photodiode that includes a p+ type doped region and an n-type doped region. The image sensor can operate in a global shutter mode and/or a rolling shutter mode.