화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.159, No.1, H57-H60, 2012
Effect of Sample Thickness on SiO2/Si Interface Roughness Characterization through Transmission Electron Microscope Measurements in Strained-Si MOSFETs
In this study, we experimentally extract Si/SiO2 interface roughness of biaxially-tensile strained Si (s-Si) MOSFETs through high-resolution transmission electron microscopy (TEM) measurements with the different TEM sample thicknesses. The roughness-scattering-limited mobilities (mu(sr)) of electrons and holes are calculated by using the digitalized SiO2/Si interface roughness data and applying the autoregressive (AR) model to the extraction of the power spectral density, S(q), of the interface roughness from the digitalization data. It is found that the roughness height, Delta, of the SiO2/Si interface, directly determined from the digitalized interface data, decreases with an increase in the TEM sample thickness due to the projection effect in the TEM image formation. As a result, the S(q) is underestimated and mu(sr) is overestimated with an increase in the TEM sample thickness. The effectiveness of the linear S(q) correction is shown to be effective in representing the mu(sr) values, which is verified by the simulation of the projection effect on the interface roughness observed in a TEM sample with an finite thickness. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.055201jes].