Submicrometer Process and RF Operation of InAs Quantum Hot-Electron Transistors

The fabrication process of a hot-electron unipolar transistor with vertical transport based on InAs material is reported. Devices with an emitter width of 0.3
$\mu\hbox{m}$
are fabricated and characterized. This submicrometer geometry allowed suppressing parasitic resistances and achieving high-current densities required for high-frequency operation. For the first time, for a hot-electron transistor, RF performances were achieved at room temperature. Cutoff frequencies of
$f_{t} = \hbox{75}\ \hbox{GHz}$
and
$f_{\max} = \hbox{88}\ \hbox{GHz}$
were obtained on devices transferred on an insulating substrate.