Mechanical and Chemical Properties of CBxNy and CSixNy Thin Films Grown by N*-Plasma Assisted Pulsed Laser Deposition

Abstract

ABSTRACTCarbon silicon nitride (CSixNy), and carbon boron nitride (CBxNy) thin films have been grown by pulsed laser deposition (PLD) of various carbon (silicon/boron) (nitride) targets using an additional nitrogen RF plasma source on [100] oriented silicon substrates without additional heating. The CSixNy and CBxNy thin films were amorphous and showed nano hardness up to 23 GPa compared to 14 GPa for silicon and maximum nitrogen content of 30 at%. The maximum nanohardness was achieved for 10% Si and 10% B content in the films. The lower hardness of this films compared to the nanohardness of 30-50 GPa of DLC films indicates a lower amount of covalent carbon-nitrogen bonding in the films. However, in contrast to DLC films, the CSixNy and CBxNy films can be grown to thickness above 3 μm due to lower internal compressive stress. XPS of CSixNy and CBxNy film surfaces shows clear correlation of binding energy and intensity of N ls, C ls, and Si 2p peaks to composition of the PLD-targets and to nitrogen flow through plasma source, indicating soft changes of binding structure due to variation of PLD parameters. The results demonstrate the capability of the plasma assisted PLD process to deposit hard amorphous CSixNy, and CBxNy thin films with adjustable properties.