A Novel Characterization Scheme of $\hbox{Si/SiO}_{2}$ Interface Roughness for Surface Roughness Scattering-Limited Mobilities of Electrons and Holes in Unstrained- and Strained-Si MOSFETs

Abstract

In this paper, a novel method to directly determine the surface roughness scattering-limited mobilities (μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sr</sub> ) of electrons and holes in Si MOSFETs from the experimental data of MOS interface roughness is proposed and compared with the experimental μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sr</sub> of Si MOSFETs with and without biaxial tensile strain. This method includes the direct evaluation of the scattering potential from the power spectra of Si/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> interface roughness data, which are taken through high-resolution advanced transmission electron microscopy measurements, without assuming any autocorrelation function form of the interface roughness, like a Gaussian or exponential function. It is found, for the first time, that, by employing the present method, experimental electron and hole μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sr</sub> (both unstrained and strained Si) could be presented by a same model. As a result, the difference in strain dependence between electron and hole μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sr</sub> , which has experimentally been observed, is systematically explained by the change of power spectra of the interface roughness due to strain.