Multi-megarad (Si) radiation-tolerant integrated CMOS imager

Abstract

The paper describes the design, operation, and performance of integrated CMOS imagers that withstand multi-megarad(Si) total dose of ionizing radiation. It reports test result from two imagers - one with on-chip integrated timing and control, and the other with a variety of pixel structures for parametrically investigating the effects of radiation ion imager performance. The CMOS Imager has been shown to response only to ionizing radiation, and is able to withstand high proton fluence. Minimal change in imager performance is observed after being subjected to a proton fluence of 1.2 X 10<SUP>12</SUP> protons/cm<SUP>2</SUP>. The imager also exhibits minimal change in optical response after being dosed with 1.5 Megarad(Si). The radiation-induced dark current ins small and is well-behaved over the entire dose range. No change in operation bias is needed either for operating the imager at low-temperature or after irradiation. The parametric test chip indicates that the LOCOS region plays a significant role in determining the total-side-hardness of the pixel. Based on test results, most promising pixel structures for imaging under high radiation environments have been identified.