On the modeling and design of Schottky field-effect transistors

A short-channel threshold-voltage model and an Airy function transfer-matrix tunneling model have been adopted and modified to result in a one-dimensional Schottky field-effect transistor (SFET) model. Model calculations were performed in MATLAB 7, and the results suggest that, for small Schottky barrier (SB) heights, the tunneling current does not play a dominant role in the total ON-state current. Instead, increases in current at the gate biases beyond the source-body flat band voltage (V_sbfb) are due mostly to the increases in thermal current from SB lowering (SBL), not tunneling current modulation. Also, the inclusion of SBL in this model suggests that barrier heights on the order of 0.25 eV can indeed support greater than 1-mA/μm drive current density for both n-channel and p-channel SFETs for 25-nm CMOS.