Incorporation of sulfur into hydrogenated amorphous carbon films

• Published in: Diamond and related materials Vol. 13; no. 4; pp. 1377 - 1384
• Main Authors: Filik, J., Lane, I.M., May, P.W., Pearce, S.R.J., Hallam, K.R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2004; Elsevier
• Subjects: Adsorbed layers and thin films; Amorphous alloys; Amorphous hydrogenated carbon; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Diamond-like carbon; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties; Photoemission and photoelectron spectra; Physics; Amorphous hydrogenated carbon; Diamond-like carbon; Amorphous alloys; Optical properties; Raman spectra; Spectroscopic ellipsometry; Films; Refractive index; Experimental study; Carbon; CVD; Growth from vapor; Secondary ion mass spectra; Diamond lattices; Sulfidation; Amorphous hydrogenated material; Preparation; Chemical composition; PECVD; Radiofrequency sputtering; X-ray photoelectron spectra
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2003.08.026

Amorphous hydrogenated carbon–sulfur thin films (a-C:H:S) were deposited from CH 4/H 2S gas mixtures by capacitively-coupled radio-frequency PECVD. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) were used to probe the composition of the films. XPS showed that the sulfur atomic percentage within a film was proportional to the fraction of H 2S in the H 2S/CH 4 gas mixture, and that films had been deposited with a sulfur content of up to 27 at.%. SIMS showed that the distribution of C and S was homogeneous throughout the films. Ex situ variable angle spectroscopic ellipsometry was used to evaluate the band gap energy variation by three different methods. Values of the E04 band gap for these films were between 1.5 and 2.5 eV, with refractive index values of between 1.8 and 2.1. Laser Raman spectroscopy (514.5 nm) suggested that the addition of sulfur increases the clustering of aromatic six-membered rings.