Transconductance enhancement of nanowire field-effect transistors by built-up stress induced during thermal oxidation

Abstract

The authors report the enhancement of transconductance in nanowire field effect transistors due to build-up tensile stress during thermal oxidation. To evaluate the effect of stress, nanowires were thermally oxidized at (A) 900°C∕15min, (B) 850°C∕1h, and (C) 850°C∕1h with a subsequent 1000°C annealing. The transconductance of sample B is enhanced 2.6 times compared to sample A. No enhancement of transconductance is observed in sample C. The Raman spectra indicate tensile stress in sample B and compressive stress in sample C. This establishes that gm enhancement is due to the build-up tensile stress in nanowires, but is diminished by viscoelastic relaxation.