Carbon nitride films deposited by very high-fluence XeCl excimer-laser reactive ablation

We report the characteristics of CNx films deposited by excimer laser ablation of graphite targets in low pressure N-2 atmosphere. We used a XeCl laser(lambda = 308 nm, tau(FWHM) = 30 ns) at the fluence of 32 J/cm(2) (similar to 1 GW/cm(2)) and repetition rate of 10 Hz. Substrates were Si [111] single crystals at room temperature. Different diagnostic techniques [scanning electron microscopy (SEM), Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR)] were used to characterise the deposited films. Films are plane and adhesive to their substrates. Deposition rates vary from similar to 0.25 to similar to 0.025 Angstrom/pulse, decreasing with increasing N-2 ambient pressure (0.5-100 Pa), N/C atomic ratios vary from 0.2 to 0.45, as inferred from RES measurements: Raman spectroscopy evidences a prevalent amorphous structure of the films at low ambient pressures and a dominance of crystallites at high ambient pressures. XPS results show that N atoms are mainly bonded to C atoms in the sp(2) and sp(3) bonding states. (C) 2000 Elsevier Science B.V. All rights reserved.