氧等离子气氛中NMOS器件的性能退化

Performance Degradation of NMOS Device in Oxide Plasma Ambience

文章描述了氧等离子干法剥离光刻胶中MOS器件的性能退化问题,并且制备了不同天线比AR(AntennaRatio),相同器件结构的NMOS器件来检测器件的退化。实验结果发现栅漏电流密度Jg和阈值电压Vt漂移会随着Al的天线面积的增加而非线性地增加,尤其表现在阈值电压漂移上。运用增加电流应力时间的测试来模拟器件在等离子反应腔中所受的实际应力,发现了与天线比增加时阈值电压变化趋势相同,表明在氧等离子气氛中器件受到了负电应力的影响。最后,基于此次实验的结果,在器件的设计,工艺参数的制定方面提出了一些减小干法剥离光刻胶工艺带来器件性能退化的建议。

Performance degradation problem of MOS devices in oxide plasma stripping is described in this paper and corresponding 0.8 μm NMOS devices with the same device structure and different antenna ratio （AR） were fabricated. Experiment results show that gate leakage current density Jg and threshold voltage shift increase non-linearly with the aluminum antenna ratio（AR） increasing, especially in the case of Vt shift. The test of increasing current stress time is developed to simulate the actual stress in plasma chamber and shows the same degradation trend as Vt shift with antenna ratio increasing, which convinces that the performance of NMOS devices in oxide plasma stripping is influenced by negative stress. At last, based on the experiment results, some suggests are provided in device design and process parameter setting to minimize the performance degradation in oxide plasma ambience.