Source material assessment of heterojunction DG-TFET for improved analog performance

In this work, the viability of different materials as the source region of a Double-Gate Tunnel FET (DG-TFETs) has been studied. The study essentially focuses on obtaining superior current switching ratio (I
_ON
/I
_OFF
), threshold voltage (V
_th
) and subthreshold swing (SS) in DG-TFETs. In this regard, a comparative analysis of electrical and analog parameters of DG-TFETs with Silicon (Si), Germanium (Ge) and Indium-Arsenide (InAs) sources has been carried out. Choice of materials has been made in such a way as to study the effects of both, elemental semiconductors from the 14
^th
group and binary compounds of elements from the 13
^th
and 15
^th
groups of the periodic table respectively. Such a change in the source material allows for the creation of a heterojunction at the source-channel interface, which significantly modifies the band bending in the device on application of gate bias. Using numerical simulation techniques based on the Non-local Band-to-Band Tunneling (BTBT) model, the strong correlation between the properties of the source and the characteristics of the device is examined. While both Ge and InAs source DG-TFETs show significant improvement over standard Si source DG-TFETs, it is assessed that Ge clearly outperforms InAs as a preferable source material.