Narrowed Si0.7Ge0.3 Channel FinFET with Subthreshold Swing of 64mV/Dec Using a Cyclic Self-limited Oxidation and Removal Process

Abstract

Abstract In this work, a narrowed Si0.7Ge0.3 channel FinFET device using a precise cyclic wet treatment process is demonstrated in detail. Si0.7Ge0.3 fin/per side of 0.63nm can be accurately removed in each cycle by utilizing a self-limited oxidation with 40% HNO3 solution for 40 s and oxidation removal with 1% HF solution for 10 s. As a result, after the dummy gate removal, the fin width of Si0.7Ge0.3 can be narrowed from 20nm to 8nm by utilizing 10 cycles of this wet treatment process. Compared with the conventional Si0.7Ge0.3 FinFET under the similar process, the narrowed Si0.7Ge0.3 channel FinFET using this newly developed wet treatment process can realize a stronger gate control capability because its subthreshold slope can be reduced by 24%, improved from 87 to 64 mV/dec.