Variability in the Characteristics of InGaAsSb/InAs Tunnel FETs Caused by Dopant-induced Traps

In this paper, an attempt is made to understand the dopant-induced traps near the hetero-interface as a source of variability in InGaAsSb/InAs Tunnel FETs (TFETs). Comparing simulated and measured variability data suggests that a characteristic energy η=50 meV of the induced density-of-states (DOS) tail yields the best match with the experimental distribution of the sub-threshold swing (SS). Density Functional Theory (DFT) calculations of alloy supercells containing a randomly placed dopant confirm that alloy randomness indeed gives rise to band tails with a significantly larger η compared to that in pure semiconductors.