A study of ionizing radiation effects is presented for CMOS active pixel sensors manufactured in a 0.5-mu m CMOS (complementary metal oxide semiconductor) by n-well technology. The basic mechanisms that may cause failure are also presented. After exposure in gamma-rays, the most sensitive parts to radiation-dark signals and dark signal non-uniformity are discussed, i.e. the physical mechanism of the degradation by irradiation. One can see from the experiment that the mean dark signals are dramatically increased with total dose for both operated and static devices. Static device seems more affected by irradiation than operated device. We find that most part of the total dark signal in a pixel comes from the depletion of the photodiode edge at the surface and the rest part is caused by the leakage of the source region of the reset transistor. Dark signal non-uniformity follows the dark current evolution with total dose. Further study of photodiode and LOCOS (local oxidation of silicon) isolation behaviors under irradiation should be done so as to correctly use this qualification techniques on MOS sensors manufactured in CMOS n-well technology process.
Chinese Acad Sci, Xinjiang Tech Inst Phys & Chem, Urumqi 830011, Peoples R China;Chinese Acad Sci, Key Lab Funct Mat & Devices Special Environm, Urumqi 830011, Peoples R China;Xinjiang Key Lab Elect Informat Mat & Devices, Urumqi 830011, Peoples R China;Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China;Chongqing Optoelect Res Inst, Chongqing 400060, Peoples R China
Wang Bo,Li Yu-Dong,Guo Qi,et al. Research on dark signal degradation in Co-60 gamma-ray-irradiated CMOS active pixel sensor[J]. ACTA PHYSICA SINICA,2014,63(5).