EFFECT OF SURFACE ENERGY ON THE GROWTH OF DIAMOND-LIKE CARBON/AMORPHOUS SILICON FILMS ON VARIOUS SUBSTRATES

• Published in: Instrumentation science & technology 2013-05, Vol.41 (3), p.213-223
• Main Authors: Srisang, C., Asanithi, P., Limsuwan, S., Pokaipisit, A., Limsuwan, P.
• Format: Article
• Language: English
• Subjects: amorphous silicon; Applied sciences; Condensed matter: structure, mechanical and thermal properties; contact angle; Cross-disciplinary physics: materials science; rheology; DLC film; Electronics; Exact sciences and technology; Materials science; Mechanical and acoustical properties; Methods of deposition of films and coatings; film growth and epitaxy; Microelectronic fabrication (materials and surfaces technology); Physical properties of thin films, nonelectronic; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solid-fluid interfaces; Spray coating techniques; surface energy; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Wetting
• ISSN: 1073-9149; 1525-6030
• DOI: 10.1080/10739149.2012.751604

Diamond-like carbon/amorphous silicon bilayer films were deposited on SiO 2 , Ge, and Ta 2 O 5 substrates using a pulsed filtered cathodic arc (PFCA) system. Amorphous silicon (a-Si) layer was firstly deposited on three substrates using DC magnetron sputtering, then diamond-like carbon (DLC) film was deposited on a-Si layer via pulsed filtered cathodic arc. The thicknesses of a-Si layer and DLC film as monitored by in-situ ellipsometry during the film deposition were 7 and 10 nm, respectively. The surface energy of SiO 2 , Ge, and Ta 2 O 5 substrates was determined by measuring the contact angle of water on these substrates. It was found that the contact angles of water on SiO 2 , Ge, and Ta 2 O 5 substrates were 53°, 63°, and 75°, respectively. This result indicates that SiO 2 has the highest surface energy while Ta 2 O 5 has the lowest surface energy. The thickness of the a-Si layer and DLC film was determined from the cross-section transmission electron microscopy (TEM) images. The thinnest a-Si layer of 5.64 nm was obtained from SiO 2 substrate which has the highest surface energy. The thickest a-Si layer of 6.97 nm was obtained from Ta 2 O 5 corresponding to the lowest surface energy. This study shows that the thickness of the growth film strongly depends on the surface energy of the substrate. However, the DLC films deposited on each a-Si layer of three substrates have the same thickness approximately of 9.9 nm, because all of them were deposited on a-Si layers having the same surface energy.