Characterization of piezoresistive coefficients in silicon nanowire transistors

This paper presents an experimental study of the piezoresistive (PR) coefficients in silicon nanowire (NW) transistors as a function of NW width down to 10 nm. We have evidenced the variation of these coefficients as the width shrinks from wide SOI down to nanowire transistors, for both NMOS and PMOS. Below a critical width W_crit ≈ 100 nm, the longitudinal PR coefficient is improved for electrons, whereas it is reduced for holes. Our results are explained by the modification of the Si NW´s bandstructure with narrow dimensions.