An Analysis of the NBTI-Induced Threshold Voltage Shift Evaluated by Different Techniques
An Analysis of the NBTI-Induced Threshold Voltage Shift Evaluated by Different Techniques
复制标题
通过不同技术评估 NBTI 引起的阈值电压漂移的分析
DOI：
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发表时间：
2009
影响因子：
3.1
通讯作者：
G. Groeseneken
中科院分区：
文献类型：
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作者：
Z. Ji;J. Zhang;M. Chang;B. Kaczer;G. Groeseneken
负偏压温度不稳定性 (NBTI) 限制了 pMOSFET 的寿命，通常通过阈值电压 DeltaV<sub>t</sub> 的变化来监控。人们已经开发出不同的技术来提取 DeltaV<sub>t</sub>，包括准直流传输特性 <i>I</i> <sub>d</sub> ~<i>V</i> <sub>g</sub> 的传统外推法和最新的超快脉冲 <i>I</i> <sub>d</sub> ~<i>V</i> <sub>g</sub> 外推法以及应力偏置下的动态评估。在相同的应力下，这些技术可以产生高达一个数量级的 DeltaV<sub>t</sub> 差异。对于这种巨大差异的解释仍然存在争议。本文的目的是弥合从这些技术提取的 DeltaV<sub>t</sub> 值之间的差距。测量期间的退化和恢复、测量和截断误差以及跨导的计算都被检查。考虑到这些因素后，DeltaV<sub>t</sub> 中的间隙仍然无法填补，因此，现在必须考虑感测 V<sub>g</sub> 对 DeltaV<sub>t</sub> 的影响。结果发现| DeltaV<sub>t</sub> |随着传感的增加| V<sub>g</sub> |，因此，DeltaV<sub>t</sub> 独立于感测 V<sub>g</sub> 的流行假设是无效的。考虑到感测 V<sub>g</sub> 和恢复的影响后，|DeltaV<sub>t</sub>| 的差距桥接成功。探讨了感测V<sub>g</sub>效果与恢复效果之间的差异，结果表明它们是两种不同的现象。本文为测试工程师提供了一种确定给定工作电压下最坏情况 DeltaV<sub>t</sub> 的方法。
Negative bias temperature instability (NBTI) is limiting the lifetime of pMOSFETs, and it is often monitored by the shift of threshold voltage DeltaV<sub>t</sub>. Different techniques have been developed to extract DeltaV<sub>t</sub>, including the conventional extrapolation of the quasi-dc transfer characteristic <i>I</i> <sub>d</sub> ~<i>V</i> <sub>g</sub> and the more recent extrapolation of ultrafast pulse <i>I</i> <sub>d</sub> ~<i>V</i> <sub>g</sub> and the on-the-fly evaluation at stress bias. After the same stress, these techniques can produce a DeltaV<sub>t</sub> difference of up to one order of magnitude. The interpretation of this large difference is still controversial. The objective of this paper is to bridge the gap between the DeltaV<sub>t</sub> values extracted from these techniques. Degradation and recovery during measurement, measurement and truncation errors, and calculation of transconductance are all examined. After taking these factors into account, the gap in DeltaV<sub>t</sub> still cannot be filled, and hence, the effect of sensing V<sub>g</sub> on DeltaV<sub>t</sub> must now be considered. It is found that | DeltaV<sub>t</sub> | increases with sensing | V<sub>g</sub> |, and therefore, the popular assumption of DeltaV<sub>t</sub> being independent of sensing V<sub>g</sub> is invalid. After taking both the effect of sensing V<sub>g</sub> and recovery into account, the gap in |DeltaV<sub>t</sub>| is successfully bridged. The difference between the effect of sensing V<sub>g</sub> and recovery is explored, and the results show that they are two different phenomena. This paper provides test engineers a method for determining the worst case DeltaV<sub>t</sub> under a given operation voltage.