Nb:SrTiO_(3)阻变单元及1T1R复合结构的电离辐射总剂量效应研究

Investigation on Total Ionizing Dose Effect of Nb∶SrTiO_(3) Resistive Switching Cells and 1T1R Structures

开展了Nb∶SrTiO_(3)阻变单元及1T1R复合结构的X射线总剂量效应实验研究。结果表明,Nb∶SrTiO_(3)阻变单元在累积剂量达到10 Mrad(Si)时依然能够保持良好的阻变特性,高、低阻态未发生逻辑混乱。1T1R复合结构中的NMOS选通晶体管对电离辐射较为敏感,在栅氧化层中辐射感生氧化物陷阱电荷的作用下,NMOS器件阈值电压逐渐向负方向漂移,泄漏电流逐渐增加,进一步导致关态条件下(V_(G)=0 V)对阻变存储单元的错误读写。通过选用抗辐射加固NMOS选通晶体管,可显著提升1T1R复合结构的抗总剂量能力。

The total ionizing dose(TID)effect of Nb∶SrTiO_(3)resistive switching cells and 1T1R structures were investigated by using X-rays.The experimental results show that the Nb∶SrTiO_(3)cells exhibit superior radiation tolerance exceeding 10 Mrad(Si)after which the resistive switching properties sustain well and the resistance states do not flip.However,the 1T1R structure is much more susceptible to ionizing radiation due to the performance degradation of NMOS access transistor.The radiation-induced positive oxide-trapped charges can result in the negative threshold shift and increase the leakage current of NMOS transistors,which leads to the unexpected read/write operation of the Nb∶SrTiO3cell at“off”state(V_(G)=0 V).Therefore,the radiation tolerance of 1T1R structure can be improved significantly by using hardened NMOS transistors.