Open AccessResearch on dark signal degradation in 60Co γ-ray-irradiated CMOS active pixel sensor
Author(s) -
Bo Wang,
Yudong Li,
Qi Guo,
Changju Liu,
Wen Wei Lin,
Ma Li Ya,
Jing Sun,
Wang Hai-Jiao,
Zhong-Chao Cong,
Wu Ma
Publication year - 2014
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.63.056102
Subject(s) - photodiode , dark current , cmos , shallow trench isolation , signal (programming language) , optoelectronics , irradiation , materials science , transistor , radiation hardening , radiation , physics , optics , photodetector , computer science , nanotechnology , layer (electronics) , voltage , trench , nuclear physics , programming language , quantum mechanics
A study of ionizing radiation effects is presented for CMOS active pixel sensors manufactured in a 0.5-μm CMOS (complementary metal oxide semiconductor)by n-well technology. The basic mechanisms that may cause failure are also presented. After exposure in γ-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.