Impact of strained-silicon-on-insulator (sSOI) substrate on FinFET mobility

In this letter, it is shown that for fin widths down to < 20 nm, strain can be retained in patterned strained-silicon-on-insulator (sSOI) films and is correlated to mobility enhancements observed in FinFET devices. NMOS FinFET mobility is improved by 60% and 30% for [110]/<110> and (100)/<100> fin surface/direction, respectively. Although PMOS FinFET mobility is degraded by 35% for [110]/<110> fins, it is enhanced by up to 30% for (100)/<100> fins. These results can be qualitatively explained using the bulk-Si piezoresistance coefficients.