Effects of the ion-beam voltage on the properties of the diamond-like carbon thin film prepared by ion-beam sputtering deposition

Abstract

Diamond-like carbon (DLC) thin film is one of the most widely used optical thin films. The fraction of chemical bondings has a great influence on the properties of the DLC film. In this work, DLC thin films are prepared by ion-beam sputtering deposition in Ar and CH4 mixtures with graphite as the target. The influences of the ion-beam voltage on the surface morphology, chemical structure, mechanical and infrared optical properties of the DLC films are investigated by atomic force microscopy (AFM), Raman spectroscopy, nanoindentation, and Fourier transform infrared (FTIR) spectroscopy, respectively. The results show that the surface of the film is uniform and smooth. The film contains sp2 and sp3 hybridized carbon bondings. The film prepared by lower ion beam voltage has a higher sp3 bonding content. It is found that the hardness of DLC films increases with reducing ion-beam voltage, which can be attributed to an increase in the fraction of sp3 carbon bondings in the DLC film. The optical constants can be obtained by the whole infrared optical spectrum fitting with the transmittance spectrum. The refractive index increases with the decrease of the ion-beam voltage, while the extinction coefficient decreases.

Preparation and structural properties of thin carbon films by very-high-frequency magnetron sputtering

“…This shift of peak position to a lower wavenumber is indicative of the increase of the sp 3 content in the a-C films. [2,7] However, for the 13.56 MHz RF sputtering, a very weak peak centered at about 1590 cm −1 (peak 3), corresponding to the G peak, can be found. The weak peaks probed in these Raman spectra may be related to the visible excitation (514 nm) used here because the intensity and the exact peak position of the Raman spectrum depend on the wavelength of excitation.…”

“…Usually, the Raman spectra of carbon films have two main peaks, the D peak around 1350 cm −1 , corresponding to disorder-allowed phonon modes, and the G peak around 1560 cm −1 , corresponding to the E 2g symmetry of graphitic sp 2 bonded carbon. [2,7,16] The intensity ratio between the D peak and G peak as well as the position of the G peak are related to the sp 3 content in the carbon films. [2] In this work, peak 1 corresponds to the D peak, but peak 2 diverges from the position of a typical G peak and shifts to a lower wavenumber.…”

“…Amorphous carbon (a-C) and diamond-like carbon (DLC) films have attracted a great deal of attention for a long time because of their unique properties, such as high hardness, low friction, high wear resistance, chemical inertness, low magnetic susceptibility, and large optical band gap. [1][2][3][4][5][6][7][8][9][10][11] These properties are critical to many applications, such as magnetic storage devices and microelectromechanical systems. Recently, the thin (< 30 nm) [1] and ultrathin (< 2 nm) [2] a-C films are of particular interest as protective overcoats in several leading technologies.…”

Fabrication of broadband antireflection coatings using broadband optical monitoring mixed with time monitoring

“…The broadband AR coating was fabricated by dual ion beam sputtering (DIBS), [12][13][14][15] as shown in Fig. 1.…”

Structural Characteristics of Diamond-Like Carbon Films Synthesized by Different Methods

“…a-C and a-C:H films can be used as antireflective and protective coatings for IR-optics components [1], solar cells [2], and laser [3], mechanical [4], medical [5] and other systems [6]. There exist many factors affecting the hardness and optical properties of the coatings.…”