Session 2A-3

Comprehensive Understanding
of Surface Roughness Limited Mobility
in Unstrained- and Strained-Si MOSFETs
by Novel Characterization Scheme
of Si/SiO2 Interface Roughness

 

Abstract

In this paper, a novel method to determine the surface roughness-limited mobilities (μsr) of electrons and holes in MOSFETs directly from experimental data of MOS interface roughness is proposed and compared with experimental É sr with and without bi-axial tensile strain. This method includes the direct evaluation of the scattering potential from the power spectra of Si/SiO2 interface roughness data, which are taken through high resolution advanced TEM measurements, without assuming any autocorrelation function form like Gaussian or exponential. It is found, for the first time, that, by employing the present method, the amount of the calculated electron and hole É sr and the strain dependencies are in a systematic agreement with the experimental ones. As a result, the difference in the strain dependence between electrons and holes is found to be attributed to the change in spatial waveform of the roughness by oxidizing Si surfaces with tensile strain.