Work-Function Variation Effects of Tunneling Field-Effect Transistors (TFETs)

The work-function variation (WFV) effects of tunneling field-effect transistors (TFETs) are discussed for the first time. According to the 3-D device simulation results, TFETs are less immune to the WFV than metal-oxide-semiconductor FETs (MOSFETs) in terms of subthreshold swing (S) and threshold voltage (V th ). TFETs show ~ 1.4× larger V th standard deviation (σV th ) and ~ 4.6× larger S standard deviation (σS) than MOSFETs at high drain voltage (VD). It is because TFET characteristics are mainly determined by WF values of metal grains near to the source region where band-to-band tunneling occurs.