Diamond-like carbon films from CO source gas by RF plasma CVD method

Abstract

Diamond-like carbon (DLC) films were fabricated by RF CO plasma chemical vapor deposition (CVD) to avoid hydrogen incorporation into the deposited films. Broadband optical emissions confirmed a hydrogen-free process without atomic hydrogen emissions. The fabricated films were characterized by Raman scattering spectroscopy, Rutherford backscattering spectrometry (RBS) with elastic recoil detection analysis (ERDA) methods, and FT-IR spectroscopy with comparison to conventional DLC films fabricated from C 2 H 2 gas. The hydrogen concentration in the DLC films was reduced to 4 at. % using a CO source while the conventional DLC films prepared from C 2 H 2 contained 27 at. %. The DLC films made from CO gas contained a large amount of oxygen, approximately 20 at. %, a larger number of graphite structures than the conventional DLC film, and characteristic triple bonds (C¸C) of carbon atoms in the FT-IR spectrum.

Development of gas-injected pulsed plasma CVD method using Ar/C2H2 mixed gas for ultra-high-rate diamond-like carbon deposition

“…Under the condition of constant discharge power and frequency, the deposition rate of DLC increases as the process pressure increases. 17,30,31) Thus, in the gas velocity range from 0.3 to 1.0 m s −1 , an increase in the flux of the DLC-precursor neutral particles reaching the substrate owing to the gas flow is considered a factor in increasing the DLC deposition rate. It was assumed that the effect of the gas flow on the ions was small because a negative bias voltage was applied to the substrate.…”

“…The nanoindentation hardness of the a-C:H films having less hardness than the ta-C films are 10-30 GPa. [14][15][16][17] The a-C:H films are prepared by a high deposition rate of several hundred nm/min using the plasma CVD method. [14][15][16][17] DLC films with low nanoindentation hardness also have low wear resistance.…”

“…[14][15][16][17] The a-C:H films are prepared by a high deposition rate of several hundred nm/min using the plasma CVD method. [14][15][16][17] DLC films with low nanoindentation hardness also have low wear resistance. [18][19][20][21] Thus, to attain surface protection properties similar to those of ta-C films, the a-C:H films must be considerably thicker than the ta-C films.…”

Ultra-high-rate deposition of diamond-like carbon films using Ar/C2H2 plasma jet CVD in combination with substrate-stage discharge

“…However, the deposition rate of the ta-C films is very slow at several tens nm min −1 . 9,[11][12][13] a-C:H films with the nanoindentation hardness of approximately 10-30 GPa are mainly fabricated using plasma chemical vapor deposition (CVD) [14][15][16][17] or plasma based ion implantation. 18) The DLC deposition rate in the plasma CVD methods is several hundred nm min −1 , approximately 10 times faster than that in the ta-C film deposition.…”

“…18) The DLC deposition rate in the plasma CVD methods is several hundred nm min −1 , approximately 10 times faster than that in the ta-C film deposition. [14][15][16][17] Therefore, the a-C:H films that can be easily prepared using the plasma CVD methods are the widely used DLC films.…”