Analysis of TID Process, Geometry, and Bias Condition Dependence in 14-nm FinFETs and Implications for RF and SRAM Performance
Analysis of TID Process, Geometry, and Bias Condition Dependence in 14-nm FinFETs and Implications for RF and SRAM Performance
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DOI：
10.1109/tns.2016.2634538
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发表时间：
2017-01-01
影响因子：
1.8
通讯作者：
Massengill, L. W.
中科院分区：
文献类型：
--
作者：
King, M. P.;Wu, X.;Massengill, L. W.
提供了总电离剂量结果，显示了 14 nm FinFET 的不同阈值调整注入工艺和辐照偏置条件的影响。观察到各种晶体管类型之间由辐射引起的阈值电压偏移最小。 nMOSFET 晶体管的断态漏电流表现出强烈的栅极偏压依赖性，这表明子鳍区的静电栅极控制和相应的寄生传导路径是 FinFET 技术中抗辐射性最大的问题。高 V-th 晶体管在所有偏置条件下都表现出最佳的辐照性能，显示出断态漏电流和 V-th 的相当小的变化，而低 V-th 晶体管则表现出较大的断态漏电流变化。静态随机存取存储器中的下拉和传输门 nMOSFET 在照射期间的“最坏情况”偏置条件被确定为导通状态 (V-gs = V-dd)。我们发现，由于晶体管几何结构和沟道掺杂差异，SRAM 位单元的 nMOSFET 下拉和传输门晶体管表现出比低 V 晶体管更少的辐射引起的退化。近阈值操作是一种减少辐射引起的断态器件漏电流增加的方法。在 14 nm FinFET 技术中，建模表明具有高通道截止掺杂的器件对 TID 表现出最稳健的响应，从而允许环形振荡器和 SRAM 位单元稳定运行，同时关键运行特性的变化最小。
Total ionizing dose results are provided, showing the effects of different threshold adjust implant processes and irradiation bias conditions of 14-nm FinFETs. Minimal radiation-induced threshold voltage shift across a variety of transistor types is observed. Off-state leakage current of nMOSFET transistors exhibits a strong gate bias dependence, indicating electrostatic gate control of the sub-fin region and the corresponding parasitic conduction path are the largest concern for radiation hardness in FinFET technology. The high-V-th transistors exhibit the best irradiation performance across all bias conditions, showing a reasonably small change in off-state leakage current and V-th, while the low-V-th transistors exhibit a larger change in off-state leakage current. The "worst-case" bias condition during irradiation for both pull-down and pass-gate nMOSFETs in static random access memory is determined to be the on-state (V-gs = V-dd). We find the nMOSFET pull-down and pass-gate transistors of the SRAM bit-cell show less radiation-induced degradation due to transistor geometry and channel doping differences than the low-V-th transistor. Near-threshold operation is presented as a methodology for reducing radiation-induced increases in off-state device leakage current. In a 14-nm FinFET technology, the modeling indicates devices with high channel stop doping show the most robust response to TID allowing stable operation of ring oscillators and the SRAM bit-cell with minimal shift in critical operating characteristics.