We report new insight into the high-frequency operation potential of the tunnel emitter transistor, based on device measurements and on a detailed device model accurately predicting device behaviour. Using our model in combination with a simple hybrid-pi equivalent circuit we estimate the scaling properties of the unity-gain cutoff frequency We suggest device configurations which should provide an intrinsic f(T) in excess of 100 GHz without the need for aggressive geometrical scaling. (C) 2002 Published by Elsevier Science Ltd.