Performance of $n$ -Type InSb and InAs Nanowire Field-Effect Transistors

The electronic structure of highly scaled InSb and InAs nanowire (NW) field-effect transistors (FETs) is calculated with an eight-band kmiddotp model. Cross sections of 4 nm or less result in bandgaps of 0.8 eV or more. For these cross sections, all devices are single moded and operate in the quantum capacitance limit. Analytical expressions for the transconductance, cutoff frequency, and gate delay time are presented and compared to numerical results. The dependence of the intrinsic cutoff frequency on drive current is weak, scaling as radic{ID} with values in the 4-7 THz range that are good for RF applications. The gate delay times strongly depend on the drive current, scaling as I_D ^-3/2 with values ranging from 25 to 132 fs which are competitive for digital applications.