Random Dopant-Induced Variability in Si-InAs Nanowire Tunnel FETs: A Quantum Transport Simulation Study

In this letter, we report a quantum transport simulation study of the impact of random discrete dopants (RDDs) on Si-InAs nanowire p-type Tunnel FETs. The band-to-band tunneling is simulated using the non-equilibrium Green's function formalism in effective mass approximation, implementing a two-band model of the imaginary dispersion. We have found that RDDs induce strong variability not only in the OFF-state but also in the ON-state current of the TFETs. Contrary to the nearly normal distribution of the RDD-induced ON-current variations in conventional CMOS transistors, the TFET's ON-currents variations are described by a logarithmic distribution. The distributions of other figures of merit (FoM) such as threshold voltage and subthreshold swing are also reported. The variability in the FoM is analyzed by studying the correlation between the number and the position of the dopants.