A comparative study of surface quantization effects in Si and strained-Si MOS structures with ultrathin gate oxides

In this paper, a comparative study has been performed on the locations of charge centroid and quantized carrier distributions for conventional and strained-Si MOS capacitors. The induced channel strain has been observed to modify surface quantization effect significantly. The position of charge centroid and the relevant carrier distribution have been studied for the variation of gate dielectric layer thickness, substrate doping concentration, and induced strain in the epitaxial layer. Position of charge centroid and peak carrier density modifies the measured oxide thickness, leading to the extraction of erroneous device parametric values. Therefore, a correction factor for the measured thickness of ultra thin gate dielectric layer has also been developed for the MOS capacitors with quantized surface.