Deposition of diamond-like carbon thin films by the high power impulse magnetron sputtering method

The goal of the conducted experiments was to evaluate if the increased density of the plasma ill High Power Impulse Magnetron Sputtering (HiPIMS) argon discharge would give the possibility of obtaining diamond-like films with high sp(3) fraction content at room temperature. The magnetron tathode was driven by the self-designed supply. It consisted of high voltage supply, tank capacitors and a set of switches. The tarik capacitors and the inductances of connecting wires formed an LC resonant circuit. As a result, each sputtering pulse (duration of 20 ps, peak current of 1500-2200 A) was followed by the inverse pulse (duration of 25 ps, peak current of 400-700 A), both having a sinusoidal shape. The repetition time was 3 s. The Silicon substrates were placed 8 cm above the target surface. The sputtering processes of 99.99% pure graphite target were conducted in argon atmosphere at a pressure of 6-8 x 10(-3) hPa. The carbon filrris obtained after 400 deposition pulses had a thickness of 35 nm. The surface RMS roughness, measured using an optical profiler, was about 2 nm. The refractive index was estimated by means of ellipsometric studies to be 2.45 and 23 at 400 and 800 nm, respectively. The sp(3) hybridization fraction content of about 70-80% was calculated based on the analysis of Raman Scattering spectra. (C) 2017 Elsevier B.V. All rights reserved.