RF performance enhancement in multi-fin TFETs by scaling inter fin separation

This paper deals with the extraction of RF metrics of multi-fin Tunnel FET (TFET) with the inter fin separation (IFS) scaled up to 1 nm. The structure of multi-fin TFET is designed by varying the number of fins (N) from 1 to 5. As the number of fins increases, the drive current (ID) gets multiplied and the maximum ID of 76 µA can be achieved for N = 5. Higher ID is obtained without compromising the leakage current (IOFF) which is in the range of femto amperes. For the various values of IFS, RF metrics such as intrinsic gain (A0), unity gain cut-off frequency (ft), maximum oscillation frequency (fmax), and admittance (Y) parameters are extracted for multi-fin TFETs. The results show for lesser values of IFS, higher intrinsic gain is obtained and the value does not affect as N increases. The maximum value of ft and fmax is obtained because of the electrostatic coupling between the two adjacent fins. The Y parameters are extracted at an operating frequency of 10 GHz. It can be seen that Y parameters offer better values as the number of fins and IFS increases. This is due to the larger value of gate to drain capacitance (Cgd) which occurs because of the parasitic effect for higher values of IFS.