Deposition of silicon carbon nitride films by ion beam sputtering

Silicon carbon nitride films have been successfully synthesized at a temper ature below 100 degrees C from an adenine(C5N5H5)-silicon-mixed target sput tered by Ar ion beam. The effects of Ar ion sputtering voltage, area ratio of Si to adenine in the mixed target and nitrogen atom addition during depo sition on the film growth are investigated. XPS, XRD, and ellipsometry were employed to characterize the composition, chemical bonding, structure, and optical property of the films. The growth characteristic and film properti es of the silicon carbon nitride films are also compared with those of the carbon nitride films deposited from an adenine target to elucidate the effe ct of silicon incorporation. The silicon content of the resultant films inc reased significantly as the area ratio of Si to adenine increased, whereas a higher Ar ion voltage led to a lower level of silicon incorporation, pres umably due to differential sputtering yield of Si and adenine. XPS chemical stare analysis revealed multiple bonding structures for every element in t he SiCN films, of which possible implications are given. XRD studies showed that only amorphous films for Si-rich SiCN were obtained, while the films with low Si incorporation and deposited at high Ar ion beam voltage contain ed nanocrystallites. Furthermore, the: refractive index of the SiCN films i ncreased with increasing silicon content. The appearance of the nanocrystal line structure in the films led to a reduction in the refractive index. (C) 1999 Elsevier Science S.A. All rights reserved.