Tunneling current through ultra-thin silicon dioxide films formed by controlling preoxide in heating-up

With the down-scaling of metal-oxide-semiconductor field effect transistors (MOSFETs), the gate oxide thickness becomes extremely thin. Ultrathin silicon dioxide films with high electric insulating performance and high reliability are demanded in order to realize ultra-small MOSFETs for large scale integration (LSI) chips. The influence of a preoxide grown during silicon wafer heating up to thermal oxidation temperature on the dielectric performance cannot be neglected as the gate oxide becomes thin. Thick preoxides in ultrathin gate oxide films can induce degradation of the electric insulating performance. In this study, we have investigated the influence of the preoxide on the dielectric characteristics and have examined the characteristics of silicon dioxide films with thicknesses of 1-3 nm.