Drain voltage dependent analytical model of tunnel field-effect transistors

Abstract

Tunnel field-effect transistors (TFETs) are potential successors of metal-oxide-semiconductor FETs because they promise superior input characteristics. However, the output characteristics of TFETs are poorly understood, and sometimes a superlinear onset, undesirable for circuit design, is observed. We present the first analytical model to include the impact of the drain voltage on the TFET performance. The model is developed for both a pure line-tunneling TFET and a pure point-tunneling TFET. Good agreement is observed with device simulations, especially for line-tunneling TFETs. Our model highlights and explains the superlinear onset of the output characteristics, thereby enabling an improved analysis of experimental data. Increasing the source doping level and switching to a smaller bandgap material can remove the undesired onset. We confirm this finding with our experimental data.