摘要:
应用负偏置温度不稳定性（negative bias temperature instability, NBTI）, 退化氢分子的漂移扩散模型, 与器件二维数值模拟软件结合在一起进行计算, 并利用已有的实验数据和基本器件物理和规律, 分析直流应力NBTI效应随器件沟道长度、栅氧层厚度和掺杂浓度等基本参数的变化规律, 是研究NBTI可靠性问题发生和发展机理变化的一种有效方法. 分析结果显示, NBTI效应不受器件沟道长度变化的影响, 而主要受到栅氧化层厚度变化的影响; 栅氧化层厚度的减薄和栅氧化层电场增强的影响是一致的, 决定了器件退化按指数规律变化; 当沟道掺杂浓度提高, NBTI效应将减弱, 这是因为器件沟道表面空穴浓度降低引起的; 然而当掺杂浓度提高到器件的源漏泄漏电流很小时（小泄露电流器件）, NBTI效应有明显的增强. 这些结论对认识NBTI效应的发展规律以及对高性能器件的设计具有重要的指导意义.
Abstract:
To analyze the dependence of the DC stress negative bias temperature instability (NBTI) effect on basic device paraments, such as the channel length, the gate oxide thickness, the doping concentration, we solve the hydrogen molecule drift-diffusion model of NBTI together with the semiconductor device equations. The results are compared with the existing experimental data and the basic laws and physics of devices, which is necessary for reliability studies of NBTI. The analysis results show that NBTI effect is not affected by the channel length change, but maily by the thickness of the gate oxide layer. Gate oxide thickness thinning and gate oxide layer electric field enhancement effect are consistent, which determines the device degradation in the manner of exponential law. With channel doping concentration increasing, NBTI effect will be reduced, which is because the device channel surface hole concentration is reduced, however with the doping concentration increases to such a value that the device source drain leakage current is very low (low leakage device), the MBTI effect is obviously enhanced. These are helpful for understanding NBTI and designing the high performance device.
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