不同栅结构的部分耗尽NMOSFET/SIMOX的总剂量辐照效应研究

Total-dose irradiation effect of partially-depleted NMOSFET/SIMOX with two different gate structures

摘要: 研究了在改性注氧隔离(SIMOX)材料上制备的具有环栅和H型栅结构的部分耗尽NMOS晶体管在三种不同偏置状态的总剂量辐照效应。实验表明在10keV的X-射线总剂量辐照下,器件的背栅、正栅阈值电压负向漂移和漏电流都控制在较小的水平;在2Mrad(SiO₂)的辐照下仍能正常工作。研究证实了无论哪种栅结构,对于背栅,PG均为最劣偏置,其次是OFF偏置,而ON偏置下器件受辐照的影响最小;而对于正栅,ON均为最劣偏置。通过拟合计算出了绝缘埋层(BOX,即埋氧)中的饱和净正电荷密度N_ot和空穴俘获分数α。

Abstract: Total-dose irradiation effect of partially-depleted NMOS transistors with gate-all-around and H-gate structures fabricated on modified SIMOX was studied.It is found experimentally that back and top gate threshold shifts and drain current is confined to a low level during irradiation.The transistors can work properly under the dose of 2 Mrad（SiO₂）.It is also confirmed that for the back gate of both gate-all-around and H gate,PG is the worst case;for the top gate,ON is the worst case.The saturated net positive charge density N_ot and the fraction of hole capture α in buried oxides are calculated by data fitting.