Effect of substrate doping on the capacitance-Voltage characteristics of strained-silicon pMOSFETs

The effect of substrate doping on the capacitance-voltage characteristics of a surface-channel strained-silicon p-channel MOSFET has been studied to explain a measured anomalous behavior in which a "plateau" in the accumulation region was observed. It is found that this plateau is substrate doping dependent and it switches from a plateau on the inversion side to that on the accumulation side as the substrate doping increases. The physics behind this behavior has been explained by the one-dimensional Poisson solution and validated with numerical simulations and experimental data.