To improve MOS transistors operating characteristics, such as the switching speed and power consumption, the dimensions of integrated devices are continuously decreased, amongst other advances. One of the main drawbacks of geometry scaling is the increased variability of the threshold voltage between nominally identical devices. The origin for this lies in defects located inside the oxide and at the interfacial layer between the oxide and the semiconductor. At the same time, the number of defects becomes a countable quantity in devices approaching the tens of nanometer scale. Furthermore, their impact on the device performance significantly increases, in a way that charge transitions from single defects can be observed directly from electrical measurements. To describe the degradation of the devices caused by single defects, one has to investigate the distribution of their impact on the $\mathbf {V_{\mathrm {th}}}$ shift. For SiON technologies, uni-modal exponential distributions of step heights of single defects have been reported in the literature. However, our results reveal that the step heights are more likely bi-modal exponential distributed. These findings are essential for the accurate evaluation of the tail of the distribution, i.e., the defects showing an enormous impact on $\mathbf {\Delta V_{\mathrm {th}}}$ . Such defects can give rise to an immediate failure of devices and circuits. In this study, the statistical distributions of the effect of single defects are created and analyzed. We compare the results to values calculated using the commonly applied charge sheet approximation (CSA) and show that the CSA significantly underestimates the real impact of the defects for the studied technology. Finally, we use the obtained distributions and analyze their effect on the variability of measure-stress-measure simulations using our compact physical modeling framework.

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关于SiON晶体管中单缺陷阈值电压漂移的分布

为了改善 MOS 晶体管的操作特性，例如开关速度和功耗，集成器件的尺寸不断减小，以及其他进步。几何缩放的主要缺点之一是名义上相同的器件之间阈值电压的可变性增加。其根源在于位于氧化物内部以及氧化物与半导体之间的界面层处的缺陷。同时，在接近几十纳米尺度的器件中，缺陷的数量成为一个可计数的数量。此外，它们对器件性能的影响显着增加，可以直接从电测量中观察到单个缺陷的电荷转变。为了描述单个缺陷引起的器件退化， $\mathbf {V_{\mathrm {th}}}$ 转移。对于SiON 技术，文献中已经报道了单个缺陷台阶高度的单峰指数分布。然而，我们的结果表明台阶高度更可能是双峰指数分布的。这些发现对于准确评估分布的尾部至关重要，即显示出对分布的巨大影响的缺陷 $\mathbf {\Delta V_{\mathrm {th}}}$ . 此类缺陷会导致设备和电路立即发生故障。在这项研究中，创建和分析了单个缺陷影响的统计分布。我们将结果与使用常用电荷表近似 (CSA) 计算的值进行比较，并表明 CSA 显着低估了缺陷对所研究技术的实际影响。最后，我们使用获得的分布并使用我们紧凑的物理建模框架分析它们对测量-压力-测量模拟的可变性的影响。