The effect of remote Coulomb scattering on electron mobility in W/La 2 O 3 /Si gate stacked metal-oxide-semiconductor field-effect transistors (MOSFETs) was studied. Experimental results show that scattering caused by the Coulomb charges located near the W/La 2 O 3 interface becomes a dominant factor for the mobility of MOSFETs with an equivalent oxide thickness (EOT) of 1 nm or less.