Impurity scattering effects on electron transport in short GaAs channels

Publisher Website
Google Scholar
Abstract
As high-speed requirements for field-effect transistors (FETs) force the active channel regions to become shorter, the doping in the channel is expected to be increased to maintain a high aspect ratio and gate voltage control in the device. In this paper we have examined electron transport in submicron GaAs FET channels with varying degrees of doping. We find that impurity scattering has a strong effect on electron transport, not only at low electric fields but also at high fields when the channel length is less than a micron. These results are different from those in long channels where at high fields (≥4 kV/cm) impurity scattering is relatively unimportant. We find, for example, that for a 0.25 μm channel, the peak velocity decreases from 4.9×107 cm sec−1 for undoped channel to 3.7×107 cm sec−1 for a doping of 8×1017 cm−3. Results are presented for 0.25- and 0.5-μm channels and compared to those for a 2-μm channel.