Influence of temperature on the threshold voltage and subthreshold slope of strained-Si/SiGe MOSFETs with polysilicon gates

In this paper, analytical models for threshold voltage V_t and subthreshold slope S for biaxially strained-Si channel nMOSFETs are proposed. Analytical approaches for predicting Vt and S are developed by considering the effect of strain on material and transport parameters, the effect of bandgap narrowing due to heavy channel doping, poly depletion effects and quantum mechanical effects for a wide temperature range 77 to 550 K. Accuracy of models have been verified by comparing analytical results obtained from the proposed model with the reported experimental data. Moreover, the model provides a physical insight for the variation of V_t and S for strained Si/ SiGe MOSFETs over a large temperature range.