表面Ge沟道pMOSFET阈值电压模型

Threshold voltage model of the surface Ge channel pMOSFET

基于MOS器件的短沟道效应和漏致势垒降低效应理论,通过求解泊松方程,建立了表面Ge沟道pMOSFET的阈值电压模型.基于该模型对表面Ge沟道MOSFET器件的沟道长度、栅氧化层厚度、衬底掺杂浓度、SiGe虚拟衬底中的Ge含量等结构参数以及漏源电压对阈值电压的影响进行了模型模拟分析.模拟结果表明,当沟道长度小于200nm时,短沟道效应和漏致势垒降低效应对阈值电压影响较大,而当沟道长度超过500nm时,短沟道效应和漏致势垒降低效应对阈值电压的影响可以忽略.模型计算结果与实验结果吻合较好.

An analytical model of the threshold voltage of the Ge channel pMOSFET is developed by solving Poisson＇s equation for the first time. The short channel effect（SCE） and drain induced barrier lower （DIBL） are in eorporated into the model. Simulated results show satisfactory agreement with experimental data. Simulated results also show that the channel length, Ge content, substrate doping concentration, and gate oxide thickness affect the threshold voltage greatly. Simulation results show that, when the channel length is less than 200 nm, the SCE and DIBL affect to threshold voltage greatly, and when the channel length is more than 500 nm, the effect of the SCE and DIBL on the threshold voltage can be ignored.