Effects of scattering direction of hot electrons in the drain of ballistic n+-i-n+ diode

Ionized impurity scattering has a weak influence on hot electron transport at low doping concentrations owing to the fact that ionized impurity scattering is an anisotropic scattering with a high preference for forward scattering and most hot electrons are absorbed in the drain after undergoing ionized impurity scattering. On the other hand, ionized impurity scattering approaches isotropic characteristics at sufficiently high doping concentrations and enhances the scattering of hot electrons in the backward direction and severely degrades the peak of the mean velocity of electrons in the channel and the steady-state current. We conclude that the scattering direction is an important factor for hot electron transport in the drain region of semiconductor devices. (C) 2011 The Japan Society of Applied Physics