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Transconductance (gm) enhancement in n-type and p-type nanowire field-effect-transistors (nwFETs) is demonstrated by introducing controlled tensile strain into channel regions by pattern dependent oxidation (PADOX). Values of gm are enhanced relative to control devices by a factor of 1.5 in p-nwFETs and 3.0 in n-nwFETs. Strain distributions calculated by a three-dimensional molecular dynamics simulation reveal predominantly horizontal tensile stress in the nwFET channels. The Raman lines in the strain controlled devices display an increase in the full width at half maximum and a shift to lower wavenumber, confirming that gm enhancement is due to tensile stress introduced by the PADOX approach. [ABSTRACT FROM AUTHOR]

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/15 min, (B) 850 °C/1 h, and (C) 850 °C/1 h 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. [ABSTRACT FROM AUTHOR]