DARK CURRENT REDUCTION IN IMAGE SENSORS VIA DYNAMIC ELECTRICAL BIASING

摘要

Image sensors and methods of using image sensors are disclosed. In an embodiment, the image sensor includes pixel regions having optically sensitive material (OSM). A bias voltage is provided to the OSM via a bias electrode for each pixel region. A pixel circuit (PC) for each pixel region includes a read out circuit and a charge store (CS) coupled to the OSM of the respective pixel region. The PC resets voltage on the CS to a reset voltage during a reset period, integrates charge from the OSM to the CS during an integration period, and reads out a signal from the CS during a read out period. The PC includes a reference voltage node coupled to the CS during the reset period and the read out circuit during the read out period, a reference voltage is applied to the reference voltage node and is varied during operation of the PC.

主权项

1. An image sensor, comprising:
a semiconductor substrate; a plurality of pixel regions, each pixel region comprising an optically sensitive material over the substrate, the optically sensitive material positioned to receive light; a bias electrode for each pixel region, the bias electrode configured to provide a bias voltage to the optically sensitive material of the respective pixel region; a pixel circuit for each pixel region, each pixel circuit comprising a charge store formed on the semiconductor substrate and a read out circuit, the charge store being in electrical communication with the optically sensitive material of the respective pixel region, the pixel circuit being configured to reset the voltage on the charge store to a reset voltage during a reset period, the pixel circuit being further configured to integrate charge from the optically sensitive material to the charge store during an integration period, the pixel circuit being further configured to read out a signal from the charge store during a read out period, pixel circuit further including a reference voltage node configured to be coupled to the charge store during the reset period and the read out circuit during the read out period, wherein a reference voltage being applied to the reference voltage node is configured to be varied during the operation of the pixel circuit.