Temperature Dependence of Off-Current in Bulk and Fully Depleted SOI MOSFETs

Re-examinations of the temperature dependence of off-current (Ioff) in metal oxide semiconductor field-effect transistors (MOSFETs) have been carried out, from 0.25 µm to 65 nm technology nodes comparing bulk MOSFETs to fully depleted silicon on insulator (FD SOI) MOSFETs. Analytical calculations and two-dimensional (2D) device simulations are performed, and the ratio of Ioff at a high temperature to that at room temperature has been focused on for discussion. The temperature dependence of Ioff consists of two components: subthreshold factor component (S component) and threshold voltage component (Vth component). It is found that the Vth component determines the relative merits of bulk and FD SOI MOSFETs, and originates from the difference in the temperature dependence of Vth. It is also found from the simulation that, although the advantage of FD SOI MOSFETs remains when the short-channel effect can be neglected, it diminishes when the short-channel effect is dominant as the technology node advances.