Effect of modulation structure on the growth behavior and mechanical properties of TiN/ZrN multilayers

TiN/ZrN multilayers were deposited on Si(111) substrates at 550 °C by using reactive radio frequency magnetron sputtering. The multilayers were designed to have different modulation periods and characterized using X-ray diffraction analysis, transmission electron microscopy and energy dispersive X-ray spectrum. It is found that the modulation structure can induce the growth behavior change. The TiN and ZrN layers have the growth rates much different from the single-layers. The preferred orientation of the multilayers can be changed from (100) to (111) with the decrease of Λdesign from 56 to 8 nm. The nano-indentation measurement shows the hardness values of the multilayers have a dependence on the modulation period similar to the elastic modulus. The hardness and elastic modulus of the multilayer reaches their minimums when Λexp is about 8 nm. The mechanical behavior of the multilayers is discussed with an interlayer model.