Macroscopic and microstructural properties of CSixNy thin films deposited by RF nitrogen-plasma-assisted pulsed laser deposition

Carbon silicon nitride (CSixNy) thin films have been grown by pulsed laser deposition (PLD) of various [C(1-z)(Si3N4)(z)]-targets using an additional nitrogen RF plasma source on [1 0 0] oriented silicon substrates without ad ditional heating. At the beginning of the deposition the resulting microstr ucture is amorphous with some embedded microcrystals of approximate to 30 n m diameter, which induce increasing internal stress. After less than 200 nm thickness the growth of the films is changing, resulting in an amorphous m icrostructure with textured nanocrystallites. In this growth-mode the inter nal stress is decreasing. Due to the resulting low internal stress, CSixNy films can be grown to a thickness above 3 mum, in contrast to DLC films. Th e microstructure of the films is found as textured graphitic planes of smal l size connected to each other by fullerene-like three-dimensional CNx-stru ctures. This three-dimensional bonding network leads to high nanohardness o f up to 20 GPa. Most of the silicon is bonded to carbon, which results in a nisotropic hardness properties. (C) 2001 Elsevier Science BN. All rights re served.