Deposition of protective coatings in rf organosilicon discharges

Abstract

The paper discusses the deposition of protective coatings ranging from organosilicon plasma polymers to SiO 2 -like films and hard diamond-like carbon/silicon oxide (DLC : SiO x ) coatings in radio frequency capacitively coupled discharges using hexamethyldisiloxane (HMDSO). As a result of the optimization of the deposition conditions it was possible to obtain high performance protective coatings. In the HMDSO/O 2 mixture, it was shown that rather than the SiO 2 -like film a hard cross-linked SiO x C y H z polymer film can be used as a protective coating for polycarbonate. The optimum conditions for the deposition of an almost stress-free film were 17% of HMDSO and dc bias voltage of −240 V. The film hardness and elastic modulus were 10 GPa and 75 GPa, respectively. The refractive index at 600 nm was 1.5 and the extinction coefficient decreased from 0.02 at 240 nm down to zero at 600 nm. The films deposited from HMDSO/CH 4 and HMDSO/CH 4 /H 2 mixtures exhibited the attractive properties of DLC films with the partial elimination of some of their drawbacks, such as absorption in the visible and a high intrinsic stress. The optimum concentration of the HMDSO was approximately 21%. Under these conditions the concentration of SiO x in the films was approximately 9 at.%. The film hardness and elastic modulus were above 22 GPa and 120 GPa, respectively.

Deposition of hard thin films from HMDSO in atmospheric pressure dielectric barrier discharge

“…The Martens hardness of the film/polycarbonate system for the deposition temperature of 120 • C was several times higher than this of bare polycarbonate at small indentation depths. The deposition rate decreased with increasing temperature from 5 nm min −1 at 25 • C to 2.8 nm min −1 at 150 • C. However, the chemical structure, optical and mechanical properties of the films deposited at 150 • C approached those of SiO 2 films deposited in low pressure discharges [12,48]. …”

“…HMDSO is already widely used for SiO x thin film deposition in different discharge types [11,12,13,14]. In a previous study it was possible to deposit thin films from HMDSO in nitrogen APTD [15].…”

Plasma Enhanced CVD of Organosilicon Thin Films on Electrospun Polymer Nanofibers

“…Biocompatible hydrophobic coatings can be prepared from organosilicon monomers, for example hexamethyldisiloxane (HMDSO). Thanks to hybrid character of HMDSO the films can be deposited in different forms, polydimethylsiloxane (PDMS)‐like or SiO 2 ‐like, depending on the plasma parameters . The coatings have been used for change of surface wettability, corrosion protection, gas barrier, or gas sensing …”

Study of thin Film Formation From Silicon‐Containing Precursors Produced by an RF Non‐Thermal Plasma Jet at Atmospheric Pressure

“…Various experimental investigations have been reported in the literature [9,[15][16][17] to evaluate the reactions of HMDSO with active particles and subsequent reactions of the precursor fragments. One of the possible reactions is the dissociative ionisation of HMDSO in collisions with electrons, which leads to different products [18,19]. Subsequent reactions of the fragments are reported in [18].…”