Characterisation of amorphous/nanocrystalline multilayer Si₃N₄–Si₃N₄/Si₂N₂O films prepared by alternately sputtering

Abstract

By using direct current (DC) and radio frequency (RF) co-sputtering deposition, multilayer Si₃N₄ films composed of alternately DC layer and RF layer were prepared. Phase composition, microstructure, and hardness/toughness of different Si₃N₄ films were studied. X-ray diffraction results showed that DC layer was amorphous Si₃N₄ film, while RF layer was nanocrystalline Si₃N₄ film. The hardness of amorphous Si₃N₄ film was higher than that of nanocrystalline Si₃N₄ film and the plasticity of nanocrystalline Si₃N₄ film was higher than that of amorphous Si₃N₄ film. Furthermore, the hardness/toughness of multilayer Si₃N₄ films was obviously higher than that of the single Si₃N₄ film and the plasticity was higher than that of single nanocrystalline Si₃N₄ film, which can be attributed to the fact that a large number of interface hindered the increasing of particles, thus, the fine particles and the interface strengthened the multilayer films, while the propagation of micro-crack was prevented by amorphous/nanocrystalline layer of multilayer Si₃N₄ film.

Keywords:

• Multilayer Si₃N₄–Si₃N₄/Si₂N₂O films
• Amorphous/nanocrystalline films
• Alternately sputtering
• High hardness/toughness

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors acknowledge the financial supports by the National Basic Research Program of China (973 Program) (Grant No. 2013CB632302), National Natural Science Foundation of China (Grant No. 51475449), and Ningbo Municipal Innovation Team (Grant No. 2011B81001).