Studies of electron energy loss near edge structure at the interface between Si and amorphous carbon films deposited by direct carbon ion beams

Using direct carbon ion beam deposition, in situ surface modification was p erformed by an energetic C- beam (400 and 500 eV) prior to amorphous carbon film growth to enhance adhesion of the film. It has been found from high-r esolution electron microscopy that the C and Si mixing layer at the interfa ce causes strong adhesion of the film. Electron energy loss spectroscopy wa s used to investigate chemical-states of the C and Si mixing layer at the i nterface. The carbon composition profile in silicon showed that the thickne ss of the mixing layer was about 30 nm for 500 eV modification (at 200 degr ees C). Silicon L-edge study at the C/Si interface found C-Si bond formatio n only at the surface of silicon over 2-3-nm-thick layers. The C-Si bond fo rmation is a function of C- ion impingement energy. The thickness of the bo nding layer decreased to less than 1 nm for 400 eV surface modification. Wh en the substrate was modified by a 500-eV C- beam at 800 degrees C, the thi ckness of the SiC layer was about 10 nm. C-Si bond formation was enhanced b y the supplemental thermal energy.