TaN/TiN和NbN/TiN纳米结构多层膜超硬效应及超硬机理研究

采用射频磁控溅射方法制备单层TaN，NbN和TiN薄膜和不同调制周期的TaN/TiN和NbN/TiN纳米多层膜.薄膜采用X射线衍射仪、高分辨率透射电子显微镜和显微硬度仪进行表征.结果表明TaN/TiN和NbN/TiN纳米多层膜在一定的调制周期范围内均呈共格界面，相应地均出现了超硬效应，且最大硬度值接近.分析了TaN/TiN与NbN/TiN纳米多层膜的超硬机理，TaN/TiN的晶格错配度与NbN/TiN的接近，但TaN/TiN的弹性模量差与NbN/TiN的有一定的差别，表明由于晶格错配使共格外延生长在界面处 关键词： TaN/TiN纳米多层膜 NbN/TiN纳米多层膜 外延生长 超硬效应

Superhardness effect of TaN/TiN and NbN/TiN nanostructure multilayers and its mechanism

Monolithic TaN，NbN, TiN films and TaN/TiN, NbN/TiN multilayers with different modulation periods were prepared by reactive magnetic sputtering. The films were characterized by X-ray diffraction, high-resolution transmission electron microscopy and nanoindentation. Results showed that there are coherent interfaces between the layers of TaN and TiN in TaN/TiN multilayers and the layers of NbN and TiN in NbN/TiN multilayers within a modulation period. The superhardness effect happened and the maximum hardness values of the two multilayers are nearly equal. The superhardness mechanism was discussed. The lattices mismatch between NbN/TiN and TaN/TiN multilayers is similar, but the difference in modulus of NbN/TiN multilayers is larger than that of TaN/TiN multilayers. It shows that stress field induced by coherent epitaxial growth is the main reason of superhardness effect.