High Stability of Epitaxial Graphene on a SiC Substrate

The effects of strong-acid treatment on an epitaxial graphene film on a SiC substrate are investigated to confirm its stability and compatibility with conventional semiconductor device fabrication processes. An epitaxial graphene film is treated with a strong acid in the form of piranha solution (H2O2 + H2SO4), which is conventionally used in washing processes for the silicon-based technology. Raman spectroscopy, Hall measurements, and contact angle measurements are carried out before and after piranha treatment. Raman mapping results show no drastic changes before and after piranha treatment. In particular, the D band is not observed after the piranha treatment. From Hall measurements, the electron mobility slightly increases from 920 to 1420 cm(2) V-1 s(-1) after five piranha treatments. The contact angle is almost constant before (72.8 degrees) and after five piranha treatments (75.2 degrees). These results indicate that the epitaxial graphene film is quite stable under piranha treatment.