MOS Capacitor Deep Trench Isolation for CMOS image sensors

Abstract

This paper proposes the integration of MOS Capacitor Deep Trench Isolation (CDTI) as a solution to boost image sensors' pixels performances. We have investigated CDTI and compared it to oxide-filled Deep Trench Isolation (DTI) configurations, on silicon samples, with a fabrication based on TCAD simulations. The experiment measurements evaluated on CDTI without Sidewall Implantation (SWI) exhibit very low dark current (~1aA at 60°C for a 1.4μm pixel), high full-well capacity (~12000e-), and it shows quantum efficiency improvement compared to DTI configuration. Pixels with optimized CDTI gate oxide thickness have demonstrated comparable angular response to oxide-filled DTI counterparts.