A comparison of random discrete dopant induced variability between Ge and Si junctionless p-FinFETs

Abstract

In this letter, the random discrete dopant (RDD) induced variability for a Ge junctionless (JL) p-FinFET is reported. A one-to-one comparison of the RDD-induced variability between Ge and Si JL FinFETs for varying device parameters and supply voltage is made using a 3-D numerical device simulator. Results indicate that the Ge JL FinFET shows higher immunity to RDD induced threshold voltage fluctuation than its Si counterpart, which is partially due to the higher dielectric constant of Ge than Si. Because of the lower band gap of Ge than Si, a higher variation in subthreshold swing due to RDD is, however, observed for Ge devices. Technology scaling is found to reduce σSS, although it has almost no effects on σVT for both types of devices. The difference in σSS between Ge and Si devices decreases with technology scaling, which makes Ge very attractive for scaled p-type JL FinFETs.