Oscillation of gate leakage current in double-gate metal-oxide-semiconductor field-effect transistors

Abstract

Using the nonequilibrium Green’s function method, gate current characteristics are investigated for nanometer-scaled double-gate metal-oxide-semiconductor field-effect transistor. The mode-space approximation is, at the first stage of the calculation, used to obtain self-consistently the potential profile and the charge distribution in the structure. This solution is then used to solve the two-dimensional transport equation to extract the desired quantities. In addition to the dependence of the gate-leakage current on the gate bias and on the oxide thickness, our calculation shows the oscillation behavior of the leakage current versus the drain voltage. It is explained as the result of the strong quantization of electronic states inside the device, giving a resonant-like character to the tunneling of charges from source and drain contacts to the gates. This effect is strongly dependent on the gate length.