质子辐照对RADFETs的γ辐照剂量响应的影响研究

Study on the effect of proton irradiation on the dose response of RADFETs toγ-ray

针对辐射敏感晶体管(Radiation Sensitive Field-Effect Transistors,RADFETs)在地面标定使用(60)^Coγ射线源而实际空间应用时存在的质子电子辐射环境的差异性问题,进行了10 MeV质子和(60)^Coγ射线的对比辐照与协和辐照试验。采用中带电压法(Mid-gap Technique,MGT)和电荷泵法(Charge Pumping,CP)对器件辐照过程中的氧化物陷阱电荷和界面态陷阱电荷进行了分离,结合Geant4工具包仿真质子在氧化层中初级反冲原子(Primary Knock-on Atom,PKA)的产生过程,对RADFETs质子与(60)^Coγ辐射响应差异的微观机理进行了探讨。研究结果表明:RADFETs对质子的剂量响应较少,但质子辐照会在RADFETs中引入位移损伤,加剧其邻近界面处的陷阱电荷对测量结果的影响。因此RADFETs在空间应用时,有必要使用质子电子的通量模型对测量数据进行修正或设计特定的标定方案。

[Background]Radiation sensitive field-effect transistors(RADFETs)are calibrated on the ground using a(60)^Coγ-ray source that is different from the proton-electron radiation environment that exists in actual space applications.[Purpose]This study aims to explore the influence of space protons on the radiation response of RADFETs.[Methods]First of all,the comparative and combinative radiation experiments with 10 MeV proton and(60)^Coγradiation were carried out.Then,the oxide-trap charge and interface-trap charge were separated by mid-gap technique(MGT)and charge pump(CP)method,and the generation process of proton primary knock-on atom(PKA)in oxide was simulated by Geant4 toolkit.Finally,the microscopic mechanism of RADFETs radiation response difference between proton and(60)^Coγwas investigated.[Results]The results show that dose response of RADFETs to proton is insensitive in comparison withγ-ray,proton irradiation introduces certain displacement damage in RADFETs which will intensify the influence of trap charge near the interface on the measurement results.[Conclusions]It is necessary to use the proton and electron flux model to modify the measured data or carry out a specific calibration scheme for the RADFETs applied to space.