Effect of energetic particles on pulsed magnetron sputtering of hard nanocrystalline MBCN (M = Ti, Zr, Hf) films with high electrical conductivity.

Nanocrystalline MBCN (M = Ti, Zr, Hf) films were deposited onto Si substrates using pulsed magnetron co-sputtering of a single B 4 C-M target (at a fixed 45% fraction of M in the target erosion area) with a repetition frequency of 10 kHz, voltage pulse duration of 85 μs and a fixed target power. The substrate temperature was adjusted to 450 °C during the depositions on the substrates at a floating potential. The total pressure of 95% Ar + 5% N 2 gas mixture was 0.5 Pa for TiBCN and ZrBCN, but it had to be increased up to 1.7 Pa for HfBCN to decrease very high compressive stress in the films resulting in their delamination from the substrate. Energy-resolved mass spectroscopy was used to correlate the energy of Ar+ ions bombarding the growing films with high positive voltage overshoots after the negative voltage pulses. Monte-Carlo simulations were carried out to estimate the energy and flux of sputtered M atoms and backscattered Ar atoms at the substrate. It was found that the energy and flux of the backscattered Ar atoms increase significantly with the mass of the M atoms in the target. The MBCN films with 41–46 at.% of M, 25–31 at.% of B, 7–10 at.% of C and 14–22 at.% of N exhibit a high hardness (18–37 GPa), high elastic recovery (69–85%), high H/E⁎ ratio (0.10–0.14) and low electrical resistivity (1.7–2.7 μΩm) at a low internal stress (less than 0.8 GPa). • Pulsed magnetron sputtering of hard conductive MBCN (M = Ti, Zr, Hf) films. • Voltage overshoot leads to bombardment by energetic ions. • Metal-dependent backscattering leads to bombardment by energetic Ar atoms. • Low compressive stress achieved by metal-dependent working pressure. • Relationships between metal-dependent bombardment and film characteristics. [ABSTRACT FROM AUTHOR]