Surface Modulation of SiGe by Hydrogen Plasma Process with Site Exchange Mechanism between Si and Ge

We present hydrogen plasma treatment at low temperature that modulates SiGe surface. In this study, we investigated the mechanism of SiGe surface modification after hydrogen plasma exposure, which produces a Si-rich surface. We reveal the mechanism of the surface modulation, which is induced by Si surface segregation (i.e., ion-energy induced site exchange between Si and Ge across different layers). We also propose an ion-energy localization model that drives the Si segregation. Ab-initio calculation also proves how energetically favorable the site exchange is.