Analytical relationship between subthreshold swing of thermionic and tunnelling currents

An analytical relationship between the subthreshold swing of the thermionic current and the tunnelling current is derived for double‐gate metal–oxide semiconductor field‐effect transistors (MOSFETs), based on the Wentzel‐Kramers‐Brillouin approximation. This formula allows predicting the behaviour of an ultimately scaled MOSFET in the subthreshold regime, as well as the performance of III–V devices.