Total dose responses and reliability issues of 65 nm NMOSFETs

In this paper, total dose responses and reliability issues of MOSFETs fabricated by 65 nm CMOS technology were examined. "Radiation-induced narrow channel effect" is observed in a narrow channel device. Similar to total dose responses of NMOSFETs, narrow channel NMOSFEs have larger hot-carrier-induced degradation than wide channel devices. Step Time-Dependent Dielectric Breakdown (TDDB) stresses are applied, and narrow channel devices have higher breakdown voltage than wide channel devices, which agree with "weakest link" theory of TDDB. Experimental results show that linear current, transconductance, saturated drain current and subthreshold swing are superposed degenerated by total dose irradiation and reliability issues, which may result in different lifetime from that considering total dose irradiation reliability issues separately.     

体效应对超深亚微米SOI器件总剂量效应的影响

研究体偏置效应对超深亚微米绝缘体上硅（SOI,Silicon-on-insulator）器件总剂量效应的影响.在TG偏置下,辐照130nm PD（部分耗尽,partially depleted）SOI NMOSFET（N型金属-氧化物半导体场效应晶体管,n-type Metal-Oxide-Semiconductor Field-Effect Transistor）器件,监测辐照前后在不同体偏压下器件的电学参数.短沟道器件受到总剂量辐照影响更敏感,且宽长比越大,辐射导致的器件损伤亦更大.在辐射一定剂量后,部分耗尽器件将转变为全耗尽器件,并且可以观察到辐射诱导的耦合效应.对于10μm/0.35μm的器件,辐照后出现了明显的阈值电压漂移和大的泄漏电流.辐照前体偏压为负时的转移特性曲线相比于体电压为零时发生了正向漂移.当体电压Vb=-1.1V时部分耗尽器件变为全耗尽器件,|Vb|的继续增加无法导致耗尽区宽度的继续增加,说明体区负偏压已经无法实现耗尽区宽度的调制,因此器件的转移特性曲线也没有出现类似辐照前的正向漂移.     

Double humps and radiation effects of SOI NMOSFET

Radiation experiments have been carried out with a SOI NMOSFET.The behavior of double humps was studied under irradiation.The characterization of the hump was demonstrated.The results have shown that the shape of the hump changed along with the total dose and the reason for this was analyzed.In addition,the coupling effect of the back-gate transistor was more important for the main transistor than the parasitic transistor.     

重离子成角度入射导致的锗硅异质结双极晶体管单粒子效应三维数值仿真

针对国产锗硅异质结双极晶体管(SiGe HBTs),采用TCAD仿真,建立SiGe HBT单粒子效应三维损伤模型,研究重离子成角度入射SiGe HBT时单粒子效应电荷收集的关键因素。选择几个典型入射位置和不同入射角度进行数值仿真,通过分析器件结构和仿真结构来研究电荷收集机制。结果表明,无论是离子入射位置如何,只要离子径迹穿过器件的灵敏体积,就会引起大量电荷收集。电荷收集量不仅与离子径迹在SiGe HBT敏感体积内的长度有关,同时也受到浅槽隔离以及离子径迹和电极之间的距离的影响。此项工作对SiGe HBT空间实际应用,并进一步提出加固方案提供了理论依据。