Densification of glassy carbon by fluorine ion implantation

A study has been made of the surface layer modification of glassy carbon (GC) by fluorine (F) ion implantation. F⁺-ion implantation into GC was performed at an energy of 150 keV with doses ranging from 5 × 10¹⁴ to 5 × 10¹⁶ ions/cm² near room temperature. The changes in structure, composition and surface morphology of implanted specimens were examined by means of Raman spectroscopy (Raman), secondary ion mass spectrometry (SIMS) and atomic force microscopy (AFM), respectively. The Raman spectra for high fluences indicate the formation of amorphous carbon. The SIMS depth profiles of F-atoms are Gaussian-like distributions, and the peaks shift toward the surface as the fluence increases. The AFM measurements show that a step height of approximately 108 nm is observed at a fluence of 5 × 10¹⁶ ions/cm². From the results of peak shifts and step heights, it is concluded that F-ion implantation into GC induces a densification of the surface layer.