An infra-red lamp-annealing technique was employed for postannealing Si ion-implanted InP substrates. The effective electron mobility (μeff) of SiO2-InP metal-insulator-semiconductor field-effect transistors fabricated using infrared lamp annealing is remarkably temperature-dependent. The maximum μeff is ̃ 11000 cm2/Vs at 75 K and 1500–2500 cm2/Vs at room temperature.