Amplifing Image Sensor with Buried Electrode

Abstract

The proposed structure allows opaque driving electrode to be removed from the cell surface, increasing high quantum efficiency and resulting in higher photo-sensitivity. Mode selection (such as reset, charge storage and readout) can be performed by driving electrodes buried in silicon substrate. Readout signal amplitude, which is the output of a source follower, is determined by the number of signal holes stored in each photodiode. Simulation of a device with 1000×1000 of these cells/cm² indicated that the sensor could be operated without image lag, blooming and low smear. The simulated photo-sensitivty, cell charge capacity and charge-to-voltage coversion factor were high enough for videocameras.