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

2000; Elsevier BV; Volume: 154-155; Linguagem: Inglês

10.1016/s0169-4332(99)00376-1

1873-5584

S. Acquaviva, E. D’Anna, Maria Luisa De Giorgi, M. Fernández, G. Leggieri, A. Luches, A. Zocco, G. Majni,

High-pressure geophysics and materials

We report the characteristics of CNx films deposited by excimer laser ablation of graphite targets in low pressure N2 atmosphere. We used a XeCl laser (λ=308 nm, τFWHM=30 ns) at the fluence of 32 J/cm2 (∼1 GW/cm2) 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 ∼0.25 to ∼0.025 Å/pulse, decreasing with increasing N2 ambient pressure (0.5–100 Pa). N/C atomic ratios vary from 0.2 to 0.45, as inferred from RBS 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 sp2 and sp3 bonding states.