In this paper, the total ionizing dose (TID) effects of the Sense-Switch pFLASH cell consisting of sense (T₁) and switch (T₂) co-floating gate pFLASH transistors fabricated with a $0.13\mu \text{m}$ eFLASH technology are studied. Firstly, the impact of TID effects on the programming/erasing state’s characteristics of T₁and T₂ transistors are mainly analyzed though Current-Voltage (I-V) and Transconductance-Voltage (G_m-V) curves. Secondly, the re-programming/erasing state’s characteristics of the pFLASH device after TID irradiation, and its threshold voltage, sub-threshold swing, maximum transconductance and other parameters are thoroughly investigated. Lastly, it can be concluded that the threshold voltage of T₁ and T₂ transistors is mainly determined by the changes of floating gate charge (i.e., programming state: electron emission and hole injection; erasing state: electron injection and hole emission), trap charge concentration in oxide layers around floating gate (N_ot) and trap charge concentration in the interface trap of tunnel oxide (N_it). Meanwhile, the absolute values of the programming and erasing threshold voltage of T₁ and T₂ transistors decrease linearly with the cumulative dose, and the change rates are about 2.25 mV/rad (Si) and 1.45 mV/rad (Si), respectively. In addition, the charge change of floating gate under the ionizing radiation can be compensated by re-programming and re-erasing, but the charge of N_it and N_ot will increase with the increase of cumulative dose.

中文翻译：

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抗辐射感应开关 pFLASH 单元的 TID 特性

在本文中，传感开关 pFLASH 单元的总电离剂量 (TID) 效应由传感 (T ₁ ) 和开关 (T ₂ ) 共浮栅 pFLASH 晶体管组成 $0.13\mu\text{m}$ eFLASH技术进行了研究。首先，主要通过电流-电压(IV)和跨导-电压(G _m -V)曲线分析TID效应对T ₁和T ₂晶体管的编程/擦除状态特性的影响。其次，深入研究了pFLASH器件在TID照射后的重编程/擦除状态特性，及其阈值电压、亚阈值摆幅、最大跨导等参数。最后，可以得出结论，T ₁和 T ₂的阈值电压晶体管主要由浮栅电荷（即编程状态：电子发射和空穴注入；擦除状态：电子注入和空穴发射）、浮栅周围氧化层中的陷阱电荷浓度（N _ot）和陷阱电荷浓度的变化决定在隧道氧化物（N _it）的界面陷阱中。同时，T ₁和T ₂晶体管的编程和擦除阈值电压的绝对值随累积剂量线性下降，变化率分别约为2.25 mV/rad (Si)和1.45 mV/rad (Si)。另外，电离辐射下浮动栅的电荷变化可以通过重新编程和重新擦除，但充N个被补偿_它和N _OT将与累积剂量的增加而增加。