金属栅功函数变异对纳米MOSFET模拟/射频性能影响的统计分析

Title Statistical Analysis of Metal Gate Work-Function Variation on Analog/RF Performance for Nanometer MOSFETs

当集成电路技术进入到纳米尺度,金属栅极上分布的晶粒显著减少,功函数变异(WFV)对MOSFET器件和电路性能产生重要的影响.文中通过偏差反向传播(POV)方法将功函数变异解析为平带电压标准差,建立22nm NMOS器件模拟/射频性能的统计分析,这些性能参数包括栅电容、跨导、截止频率和跨导效率.经HSPICE仿真分析结果表明:上述参数均受WFV影响产生随机波动现象,且参数变化相对标准偏差对栅电压非常敏感;从统计分布看,模拟/射频性能参数受WFV影响均偏离正态分布,但其概率统计特性却各有差异.

As integrated circuit enters nanometer scale,the number of grains in the metal gate decreased significantly,and the work-function variability(WFV)has played an important role on the performance of the MOSFET devices.In this paper,the statistical analysis of analog/RF performance is carried out for 22 nm NMOS devices by transferring WFV effect into flat-band voltage variation based on propagation of variation methodology(POV)methodology.These investigated performance parameters include gate capacitance,trans-conductance,cutoff frequency and trans-conductance efficiency.The experimental results by HSPICE show that these parameters are all impacted by WFV,and their standard deviations are very sensitive to gate voltages.In addition,their statistical distributions differ from each other although they don’t follow normal distribution.