Effects of Silicon Source Gas and Substrate Bias on the Film Properties of Si-Incorporated Diamond-Like Carbon by Radio-Frequency Plasma-Enhanced Chemical Vapor Deposition

Abstract

We have deposited Si-incorporated diamond-like carbon (DLC) films by radio-frequency plasma-enhanced chemical vapor deposition using methane, argon, and organosilanes, and investigated the effects of Si source gas (monomethylsilane, dimethylsilane) and substrate bias (negative dc bias, negative pulse bias) on the structure and the mechanical and tribological properties of the films. The Si-DLC films deposited using monomethylsilane as a Si source gas tended to have a higher Si atomic fraction ratio [Si=ðSi þ CÞ] than the films deposited using dimethylsilane. Friction coefficient and internal stress decreased by the incorporation of Si into the films. However, many particles composed mainly of Si were observed on the film surfaces when deposition using a dc bias was carried out at higher monomethylsilane or dimethylsilane flow ratios. It was found that for both the Si source gases, the use of a pulse bias was effective in suppressing the formation of particles and further decreasing friction coefficient and internal stress. Additionally, the pulse-biased Si-DLC films were found to have a higher wear resistance than the dc-biased Si-DLC films.

Deposition of silicon-doped diamond-like carbon films by plasma-enhanced chemical vapor deposition using an intermittent supply of organosilane

“…The specific wear rate monotonically increases with increasing Si content. Similar trend of the wear rate has been reported in the previous literatures [8,23]. The increase in wear rate is mainly due to the decrease in the hardness of the films with an increase in the Si content in the films [9][10][11].…”

“…The substrates used were Si and GaAs wafers. The GaAs wafer was used as a substrate for electron probe microanalysis Diamond & Related Materials 51 (2015) [7][8][9][10][11][12][13] (EPMA) measurements. The substrate was mounted on the other electrode (anode).…”

“…However, its drawback is that wear protection and hardness were reduced by the Si doping [7][8][9][10][11][12]. It has been reported that the wear protection or hardness of Si-DLC films decreased with increasing Si content in the films [7][8][9][10][11][12]. It is, therefore, strongly required to provide highly adhesive Si-DLC films with high wear resistance as well as low friction.…”

Fabrication of hydrogenated amorphous silicon carbide films by decomposition of hexamethyldisilane with microwave discharge flow of Ar

“…As potential candidates for the mechanical, electronic, and biomedical applications, thin films of amorphous carbon and related materials have attracted much attention. 1,2) Among them, amorphous silicon carbides (a-SiC x ) and hydrogenated a-SiC x (a-SiC x :H) have been expected for the applications of protective coatings, [3][4][5][6][7] solar cells, 8,9) low frictions, 4,10,11) and biocompatibilities. 12) Recently, the standardizations of amorphous carbon and related materials including a-SiC x (:H) have been promoted in Japan for the industrial applications of these materials.…”