Formation of hydrogenated carbon nitride films by reactive sputtering

Hydrogenated carbon nitride films have been grown on Si (100) substrates using magnetron sputtering. Reactive deposition is achieved using a graphite target in an argon/nitrogen/hydrogen plasma at room temperature. These films are characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. At lower-hydrogen fraction, the films include 10-20 nm beta-C3N4 crystal grains which are identified by TEM analysis. With a further increase in hydrogen fraction, the films change to be totally amorphous. AFM measurement indicates the hydrogenated carbon nitride films have low-surface roughness. From XPS data, the hydrogen promotes the C-H and N-H bonds. XPS spectra of the films typically shows three major peaks in the C 1s core-level spectrum (centered at 284.64, 285.96, and 287.45 eV) and three major peaks in the N 1s core-level spectrum (centered at 398.3, 399.1, and 400.2 eV). FTIR spectra showed five absorption bands in the range of 1000-3500 cm(-1). The absorption band between 3100 and 3500 cm(-1) can be assigned to the N-H bond. The absorption band between 2800 and 3000 cm(-1) can be assigned to the C-H bond. The absorption band around 2200 cm(-1) can be attributed to the C=N nitrile bond. The absorption bands around 1600 and 1080 cm(-1) demonstrate the existence of C=NH (sp(2)) and C-NH (sp(3)) bonds. The analysis of Raman spectrum further demonstrates the coexistence of these chemical bonds. (C) 2002 American Institute of Physics.