Experimental evidence of increased deformation potential at MOS interface and its impact on characteristics of ETSOI FETs

Abstract

Deformation potential (D <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ac</sub> ), which determines the strength of electron-phonon scattering, is one of the most important physical parameters of Si. A longstanding unresolved question in D <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ac</sub> is that D <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ac</sub> for MOSFETs is considered to be much greater than D <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ac</sub> for bulk Si. In this work, we have demonstrated for the first time that D <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ac</sub> increases sharply at MOS interfaces within several-nm range. Because of the enhanced D <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ac</sub> at MOS interface, D <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ac</sub> for nanoscale SOI channel is expected to be increased owing to the high surface-to-volume ratio, which is verified by electron mobility calculations in extremely-thin SOI (ETSOI) MOSFETs and experimental stress-induced mobility enhancement in nanoscale SOI.