Experimental study on superior mobility in [110]-oriented UTB SOI pMOSFETs

The superior mobility in [110]-oriented ultrathin body (UTB) pMOSFETs with silicon-on-insulator (SOI) thickness (t/sub SOI/) ranging from 32 down to 2.3 nm is experimentally examined for the first time. It is shown that the mobility in [110] UTB pMOSFETs, which is much higher than the universal curve in conventional (100) pMOSFETs, is not degraded until t/sub SOI/ is thinned to 3 nm. Scattering mechanisms in [110] UTB pMOSFETs are discussed on the basis of the temperature dependence of the mobility. The high mobility in the UTB regime in [110] pMOSFET is attributed to subband modulation by carrier confinement and heavier hole effective mass normal to the channel surface.