TFET-based Well Capacity Adjustment in Active Pixel Sensor for Enhanced High Dynamic Range

We present a Tunnel Field-Effect Transistor (TFET)-based pixel circuit for well capacity adjustment that does not require subthreshold operation on the part of the reset transistor. In CMOS, this subthreshold operation leads to temporal noise, distortion and Fixed Pattern Noise (FPN), becoming a primary limiting performance factor. In the proposed circuit, we exploit the asymmetric conduction associated with TFETs. This property, arising from the inherent physical structure of the device, provides the selective well adjustments during photo-integration which are demanded for achieving High Dynamic Range (HDR). A GaNbased heterojunction TFET has been designed according to the specific requirements for this application