Impact of electron velocity on the ION of n-TFETs

This paper presents a simulation study concerning the impact of the channel transport on the ON current, I_ON, of n-channel tunnel FETs. We show that, when the tunneling generation rate is enhanced to reach I_ON values approximately few μA/μm, then the I_ON becomes sensitive to the electron velocity in the channel. This is because, at large tunneling rates, the charge due to the generated electrons tends to modify the potential in the channel in such a way that limits the generation rate at the source. Such an electrostatic feedback is smaller the larger is the electron velocity, so that higher tunneling rates and I_ON values are observed when increasing the electron velocity.