Electron And Proton Irradiation Effects On CMOS Image Sensor

In this study,2×6MV EN-18tandem electrostatic accelerator and DD1.2high-frequency high-voltage electron accelerator were used to perform anexperiment of using11MeV proton and1MeV electron irradiation to thecommercial LUPA4000CMOS image sensors. After irradiation annealingexperiments were also carried out both at room temperature and hightemperature（100℃）. LUPA4000CMOS image sensor was evaluated underdifferent condition such as irradiation particles, irradiation fluence, bias voltage,annealing temperature. The performance variation and change rule of parameterof the CMOS image sensor was summarized after the test. This study discussedthe influence of bias voltage to the CMOS image sensor, analyzed the differencebetween proton and electron irradiation, and tried to explore the irradiationdamage mechanism of the CMOS image sensor. So that this study could providean experimental and data basis for establishing the space radiation effectsequivalent and simulation methods and exploring the image sensor protectionapproach.After1MeV electron irradiation, the performance parameter of CMOSimage sensor with bias voltage have obviously changed. Dark signal and readoutnoise is changing almost linearly, under the influence of1.1E12/cm², dark signalis3784mv.ms^-1, compare to43mv.ms^-1before irradiation, readout noise is0.9041mv, compare to0.7448mv before irradiation. PRNU and abnormal pixelis changing tiny under low irradiation fluence, and extremely fast under highirradiation fluence of5E11/cm²and9E11/cm². Compare to unbiased one, theparameter changing of biased one is heavier, it lose effectiveness under1.3E12/cm²fluence.After11MeV proton irradiation, the performance parameter of CMOS imagesensor unbiased is changing tiny under fluence1E10/cm²，and then is changingobviously with the grow of fluence. When the flence is3E11/cm², dark signaland readout noise reach7531mv.ms^-1and1.04511mv. When irradiation fluenceis low, the CMOS image sensor with biased voltage, the parameter changing issimilar with unbiased one. When irradiation fluence is high, changing of sensorwith biased voltage is higher, it lose effectiveness under3E11/cm².Anneal experiment is taken to CMOS image sensor with bias voltage after11MeV proton irradiation. The performance parameter is recovered on somelevel at the beginning of annealing at room temperature.Although CMOS image sensor recovered more annealing at100℃,it could not go back to the level beforeirradiation.After analyses for the irradiation damage mechanism of CMOS imagesensor, we could draw a conclusion that: to photosensitive diode, particles causeirradiation defect in N-semiconductor and interface state in SiO2-Si interface,which make dark singal increased. To MOS transistor, the irradiation damagecause increasement of readout noise, PRNU, and abnormal pixel. Protonirradiation cause both ionizing affect and displacement affect, ionizing affectfrom proton irradiation is weaker than ionizing affect from electron irradiation,so the parameter changing under proton irradiation is less obvious than electronirradiation. Displacement affect will play a leading role when irradiation fluenceincreases to a certain value, then the parameter will increase sharply.