Synthesis of few-layer graphene films by controllable Cr4rFr8r plasma etching SiC

C₄F₈-based, inductively coupled plasma (ICP) combined with dual frequency capacitively coupled plasma (DFCCP) was used to etch 6H-SiC substrates for the synthesis of few-layer graphene-on-insulator (FLGOI) films. X-ray photoelectron spectroscopy and atomic force microscopy were extensively used to characterize the quality of the FLG surface. The Raman spectroscopy studies were useful in confirming the graphitic composition and measuring the thickness of the FLG samples. The combination of high frequency CCP and ICP modes can facilitate the tuning of the Cr₄rFr₈r discharge dissociation characteristics. By modulating the electron energy probability functions, the concentrations of F and fluorocarbon radicals are increased by the collisions of electron-neutrals, which depend on high-energy electrons, resulting in a high Si selectively etching rate and a low fluorocarbon film deposition rate. A balance is struck between etching and deposition, leaving an ultra-thin C-rich overlaying film on the surface. After the layer annealed at low temperature (920 °C), they can expel the F in them and reconstruct themselves to form an FLG film.