DEPOSITION OF HARD SILICON CARBONITRIDE COATINGS FROM HEXAMETHYLDISILAZANE (HMDS) AND HMDS+BENZENE VAPORS IN LASER PLASM
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DEPOSITION OF HARD SILICON CARBONITRIDE COATINGS FROM HEXAMETHYLDISILAZANE (HMDS) AND HMDS+BENZENE VAPORS IN LASER PLASMA V. N. Demin1*, T. P. Smirnova1, V. O. Borisov1, G. N. Grachev2, A. L. Smirnov2, and M. N. Khomyakov2
Hard silicon carbonitride coatings are prepared using Ar and Ar (10 vol.% He) laser plasma from hexamethyldisilazane (HMDS) [(CH3)3Si]2NH and HMDS+benzene vapors. The coatings are characterized by infrared (IR), Raman, and X-ray photoelectron spectroscopies, transmission electron microscopy, and atomic force microscopy. The obtained coatings are amorphous and uniform in composition and over the film thickness. The microhardness of coatings synthesized on steel from a HMDS+ benzene mixture increases from 12 GPa to 18 GPa provided that other parameters remain constant. DOI: 10.1134/S002247662009005X Keywords: laser plasma of a powerful optical discharge, silicon carbonitride, hard coatings.
INTRODUCTION Silicon carbonitride is a unique multifunctional material successfully combining the best properties of silicon carbide and nitride. One traditional process to obtain silicon carbonitride layers and coatings is plasma-enhanced chemical vapor deposition (PE CVD). Nitrogen containing volatile organosilicon compounds are widely used as precursors [1, 2]. The novel CVD laser-plasma process for the preparation of silicon carbonitride coatings from HMDS is based on the use of high-power optical pulsed discharge (OPD) laser plasma to activate the process. Such plasma is obtained in a gas using pulsed periodic irradiation of a CО2 laser (50-150 kHz) and the peak energy of laser pulsations of 500-1000 kW [3]. The OPD plasma is characterized by: – unprecedented (for plasma-chemical methods) specific energy release up to 5 GW/cm3 in the gas phase volume; – possibility to obtain locally equilibrium (exchange time ∼10 ns) plasma under pressures from 1 atm and higher; – high temperature (up to 20-30°⋅103 K) and concentration (1018-1021 cm–3) of particles; – high level of UV radiation exchange favoring dissociation, ionization, excitation of particles, and the activation of deposited nanoclusters and the substrate surface to intensify the synthesis of the coating. Along with physicochemical advantages of the laser plasma method, there are general advantages for the design of industrial nanotechnologies: the process can be carried out under pressures of P > 1 so that expensive vacuum systems and
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Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia; *[email protected]. 2Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia. Original article submitted March 10, 2020; revised April 13, 2020; accepted April 16, 2020. 1390
0022-4766/20/6109-1390 © 2020 by Pleiades Publishing, Ltd.
working chambers in many cases can be excluded from the technologies, whereas coatings can be deposited on bulky and complicatedly shaped objects. A novel type of powerful optical pulsed discharge was first reported in our work dedicated to l
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