Preparation of CNx-phases using plasma-assisted and hot filament chemical vapour deposition

Abstract

Results are reported from a systematical investigation of deposition of binary CN-phases in a wide substrate temperature range. The experiments are carried out in a r.f. assisted chemical vapour deposition (CVD)-apparatus. A hot filament is positioned between the electrodes to support the generation of activated species and a negative bias is applied to the substrate to increase their energy. The deposition temperature ranged from 200°C without up to 1000°C using hot filament. Different carbon-precursors and Ar/H2 gas ratios were tested.The results can be summarized as follows. The films deposited at temperatures up to 250°C have mostly an amorphous polymer structure. Paracyan-like coatings grow preferably in the temperature range 600–650°C. At temperatures higher than 650°C using a hot filament technique with r.f.-plasma and bias enhancement the deposition rate decreased strongly. However, crystalline objects could be observed on the silicon substrate. Some of the X-ray diffraction peaks of those samples coincide with reflections of covalent C3N4 phases, but reflections from α- or β-Si3N4 are recorded additionally. Deposition experiments on inert substrates, for example nickel, but no CNx phases could be produced until now.