Backgate bias and stress level impact on giant piezoresistance effect in thin silicon films and nanowires

Top-down fabrication and electrical characterization of undoped p-type silicon nanowires with and without stress using a 4-point bending fixture are shown. Uniaxial tensile stress values of around 200 MPa are possible with the bending fixture. Giant piezoresistance is measured for wires of 50 nm-thick and widths from 25 nm to 1 ¿m. Nonlinear characteristics at high stress level and impact of backgate bias on piezoresistance coefficient are presented for the first time.