Combined effect of mechanical stressors and channel orientation on mobility in FDSOI n and p MOSFETs

Abstract

We have calculated the combined effect of biaxial and uniaxial strain in FDSOI MOSFETs for different channel orientations using a comprehensive Monte Carlo simulator. Our results confirm that tensile uniaxial strain improves the electron mobility of sSOI channels, with low impact of channel orientation, or silicon thickness, i.e., biaxial and uniaxial strains have cumulative effects. In the case of holes, the effect of compressive uniaxial strain strongly depends on the channel orientation and on the Ge mole fraction of the sSOI channel: for low x <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ge</sub> , compressive uniaxial strain enhances the hole mobility (cumulative effects); for high x <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ge</sub> , compressive uniaxial strain cancels the mobility enhancement achieved by the biaxial strain.