Comparative Analysis of Electrical Characteristics of Si and Ge-Si Double-Gate Tfets

The TFET is an emerging electronic component with the potential to offer ultra-low power operations by overcoming the conventional 60mV/dec thermal limit of subthreshold swing achievable through MOSFET devices. In this paper, a comparative study between Ge/Si heterostructure double-gate TFET and Si double-gate TFET will be performed based on simulations conducted using the Synopsys Sentaurus TCAD software. The electrical properties of interest include transfer characteristics, threshold voltage, subthreshold swing, ION/IOFF ratio, transconductance, gate capacitance, cut-off frequency, and gain bandwidth product. Simulations show that the heterostructure TFET possesses improved ON-current compared to its conventional counterpart because of Ge having a smaller bandgap, hence resulting in lower tunneling barrier height at the source-channel interfaces. Therefore, the Ge/Si DG-TFET outperforms the Si TFET in DC and RF operation with respect to its superior electrical properties, making it an ideal device for VLSI applications.