Mutual promotion effect of crystal growth in TiN/SiC nanomultilayers

The mutual promotion effect of crystal growth in TiN/SiC nanomultilayers is described in this letter. TiN, SiC single layers and a series of TiN/SiC multilayers with different thickness of SiC and TiN layers were prepared using magnetron sputtering. Microstructure analysis shows that TiN and SiC single layers exist as nanocrystal and amorphous, respectively. However, in the alternately deposited nanomultilayers of TiN and SiC, due to the influence of crystal structure of TiN layer, SiC layer forms a B1-cubic phase when its thickness is less than 0.6 nm. At the same time, the formation of SiC crystal promotes the growth of TiN layer and greatly improves its integrity when the thickness of the TiN layer is less than 4.3 nm. Due to this effect, TiN/SiC multilayers form a coherent epitaxial grown superlattice within a certain thickness range of TiN and SiC layers. Correspondingly, the multilayers show a superhardness effect which presents an anomalous enhancement of hardness and elastic modulus. The highest hardness of TiN/SiC nanomultilayers reaches 60 GPa. (C) 2005 American Institute of Physics.