Measurements of low field mobility in ultra-thin SOI n- and p-MOSFETs

Abstract

Low-field electron and hole effective mobilities ( μ eff) of ultra-thin SOI n- and p-MOSFETs, down to a silicon thickness T Si of approximately 5 nm, have been measured at different temperatures using a special test structure able to circumvent parasitic resistance effects. At large inversion densities ( N inv), ultra-thin SOI exhibit higher mobility than heavily doped bulk MOS and a weak dependence of mobility on silicon thickness. However, at small N inv the mobility is clearly reduced for decreasing T Si, due to enhanced phonon scattering in the thin quantum well.