Effects of Channel Scaling on Electron Transport Properties of Sb-based HEMTs

In order to improve cutoff frequency further, Sb-based material has attracted much interest as a channel due to smaller electron effective mass (
$\boldsymbol{m}^{\ast}$
) and higher electron mobility (
$\boldsymbol{\mu}$
). In this work, we investigate the suitability of the InSb and GaInSb channels for the channel scaling. In the GaInSb channel, the larger
$\boldsymbol{m}^{\ast}$
results in the lower
$\boldsymbol{\mu}$
, but in the larger sheet electron density also thanks to the larger conduction band discontinuity. Eventually, the GaInSb channel structure exhibits the smaller sheet resistance even when channel and spacer thickness decrease. These indicate the suitability of the GaInSb channel for the channel scaling.