CMOS有源像素图像传感器的电子辐照损伤效应研究

对某国产CMOS图像传感器进行了两种不同能量的电子辐照试验,在辐照前后及退火过程中采用离线测量方法,考察了暗信号、饱和电压、光谱响应特性等参数,分析了器件的电子辐照效应损伤机理。结果表明:暗信号和暗信号非均匀性都随着辐照剂量的增加及高温退火时间的延长而增大;饱和电压在两种能量电子辐照下均出现较大幅度的减小,并在高温退火过程中有所恢复;光谱响应特性无特别明显变化。经分析,暗电流、饱和电压的变化主要由辐照诱发的氧化物陷阱电荷导致的光敏二极管耗尽层展宽和界面陷阱电荷密度增大导致产生-复合中心的增加所引起。

Electron Beam Radiation Effects on CMOS Active Pixel Sensor

Electron beam irradiation experiments were taken on the domestic CMOS image sensors,the irradiation effect and damage mechanism of the devices were analyzed.By using off-line measuring method before and after irradiation and in the process of annealing,the parameters such as dark signal,saturated voltage,spectral response characteristics were measured.The experiment results show that the non-uniformity of dark signal and dark current increase with the increase of irradiation dose and high temperature annealing time.The saturation voltages reduce significantly under the electron beam irradiation and recover in the process of high temperature annealing.There is no significant change for spectral response characteristics before and after the irradiation.The changes of the dark current,saturation voltage are due to the broadening of the photodiode depletion layer caused by irradiation-induced oxide trapped charge and the increase of recombination centers caused by irradiation-induced interface states.