Impact of scaling silicon film thickness and channel width on SOI MOSFET with reoxidized MESA isolation

The characteristics of reoxidized MESA isolation for silicon-on-insulator (SOI) MOSFET have been studied in terms of the dependence of device performance on silicon film thickness and channel width scaling. For devices with silicon film thickness (T_si) smaller than a critical thickness, humps appear in subthreshold IV and negative threshold voltage shift is observed in narrow width devices. The width encroachment (AWO also increases rapidly with reducing T_Si. These observations can be explained by the formation of sharp beak and accelerated sidewall oxide growth in these devices. A simple guideline is given to optimize the reoxidation process for different T_Si.