Impact of Quantum Confinement on Gate Threshold Voltage and Subthreshold Swings in Double-Gate Tunnel FETs

We investigate how the inclusion of quantum confinement in double-gate tunneling field-effect transistors (DG-TFETs) modifies the conventional behavior of electrical parameters of utmost importance in these devices, such as subthreshold swings (point and average) and the gate threshold voltage. We make use of a simple approach that allows us to incorporate a quantum-mechanical description in which the discreteness of subband energy levels causes a significant reduction in the band-to-band tunneling probabilities. The inclusion of quantum confinement along with a nonlocal band-to-band model for tunneling is shown to greatly affect the aforementioned parameters as key issues for the characterization of these novel devices.