基于FDSOI的TFET和MOSFET总剂量效应仿真

对基于全耗尽绝缘体上硅(FDSOI)的隧穿场效应晶体管(TFET)器件和金属氧化物半导体场效应晶体管(MOSFET)器件进行了总剂量(TID)效应仿真,基于两种器件不同的工作原理,研究了总剂量效应对两种器件造成的电学影响,分析了辐照前后TFET和MOSFET的能带结构、载流子密度等关键因素的变化。仿真结果表明:两种器件在受到较大辐射剂量时(1 Mrad (Si)),TFET受辐射引起的固定电荷影响较小,仍能保持较好的开关特性、稳定的阈值电压;而MOSFET则受固定电荷的影响较大,出现了背部导电沟道,其关态电流增加了几个数量级,开关特性发生了严重退化,阈值电压也严重地向负电压偏移。此外,TFET的开态电流会随着辐照剂量的增加而减小,这与MOSFET的表现恰好相反。因此TFET比MOSFET有更好的抗总剂量效应能力。

Simulation of Total Ionizing Dose Effect in Tunneling- FET and MOSFET Based on FDSOI

Total ionizing dose(TID) effects in both tunneling field effect transistor(TFET) and metal oxide semiconductor field effect transistor(MOSFET) based on fully depleted silicon-on-insulator(FDSOI) were simulated. Based on the different working mechanisms of the devices, the electrical effects of TID on the two devices were investigated, and changes of the key factors such as the energy band structure and carrier density of the two devices before and after radiation were analyzed. The simulation results show that when the two devices were subjected to a large dose of radiation(1 Mrad(Si)), the TFET is less affected by fixed charges caused by radiation and maintains good switching characteristics and stable threshold voltage. On the other hand, the MOSFET is greatly affected by fixed charges, a back conductive channel appears in the MOSFET and the off-state current increases by several orders, thus the switching characteristics seriously degrade and the threshold voltage greatly shifts to the negative direction. In addition, the on-state current of the TFET decreases with the increase of the radiation dose, that is contrary to the performance of the MOSFET. Therefore TFETs have better immunity to the TID compared to MOSFETs.