Lag cancellation in CMOS image sensors

摘要

A pixel cell with improved lag characteristics without increased noise. The pixel cell according to embodiments of the invention includes a photo-conversion device and a floating diffusion region switchably coupled to the photo-conversion device. The pixel cell includes a reset transistor, which has a first terminal electrically connected to the floating diffusion region and a second terminal switchably coupled to first and second voltage sources. The first voltage source is higher than the second voltage source. The pixel cell operates by returning a potential on the photo-conversion device to a value approximately equal to a value of a potential barrier between the photo-conversion device and the floating diffusion region prior to generating charge in the photo-conversion device.