Radio-frequency modeling of square-shaped extended source tunneling field-effect transistors

The radio-frequency (RF) performances and small-signal parameters of double-gate (DG) square-shaped extended source tunneling field-effect transistors (TFETs) with different gate lengths have been extracted and compared with those of conventional TFETs in terms of cut-off frequency, maximum oscillation frequency, current gain, unilateral power gain, gate-source capacitance, gate-drain capacitance, channel resistance, time constant and transconductance. The small-signal parameters have been extracted by using of a nonquasistatic radio-frequency model, which were verified up to 250 GHz. Because of the higher transconductance and current drivability and smaller gate capacitance of DG square-shaped extended source TFETs compared to conventional TFETs, DG square-shaped extended source TFETs have higher cut-off and maximum oscillation frequencies and smaller switching time. The impact of high-κ gate dielectric on RF figures of merit and device performance has also been investigated for extended source TFET. The results showed close agreement between the Y-parameters and the extracted parameters of modeling, SPICE simulation and device simulation for high frequency range up to the cut-off frequency.