超高总剂量辐射下SOI MOS器件特性研究

Total Dose Radiation Characteristics of SOI MOSFET

在超高总剂量辐射下,界面电荷的改变对MOS器件的阈值电压影响将越来越显著,甚至会引起NMOS的阈值电压增加,即所谓的"反弹"现象[1,2]。文章研究的SOINMOS的阈值电压并没有出现文献中所述的"反弹",原因可能和具体的工艺有关。另外,通过工艺器件仿真和辐射试验验证,SOI器件在超高总剂量辐射后的漏电不仅仅来自于阈值电压漂移所导致的背栅甚至前栅的漏电流,而是主要来自于前栅的界面态的影响。这样,单纯的对埋层SiO2进行加固来减少总剂量辐射后埋层SiO2中的陷阱正电荷,并不能有效提高SOIMOS器件的抗超高总剂量辐射性能。

Under ultra-large total dose X-ray or C60 radiation, The NMOS threshold voltage may increase, that is VT ＂rebound＂, due to interface charge changing. This phenomenon was not observed in our study, which perhaps is relative to actual process. Otherwise, the leakage of SOI NMOSFET mainly coming from contribution of the front-gate interface states was given by device simulation and radiation experiment. So, it is perhaps not effective to improve characteristics of SOI MOSFET under ultra-lager total dose radiation only by hardening buried SiO2.