N-channel metal-oxide-semiconductor field effect transistors (MOSFETs) using barium strontium titanate (Ba0.5,Sr0.5)TiO3 (BST) as the gate dielectric are successfully fabricated. The BST films are deposited by RF magnetron sputtering. The IDS-VDS and IDS-VGS characteristics are measured. The electron mobility is about 206.6 cm2/Vs. The subthreshold swing is about 136.7 mV/dec. The interface trapped charge density Dit, the surface recombination velocity, and the minority carrier lifetime in the field-induced depletion region measured from gated diodes are 4.87 ?1014 cm-2eV-1, 3.96 ?104 cm/s, and 1.2 ?10-8 s, respectively.