Mechanical properties of ultra-thin W-N films for reducing the thickness after thermal treatment

In this research, we deposited a W-N thin film for a diffusion barrier layer on a Si (100) substrate to reduce the thickness from 100 to 30 nm by rf magnetron sputtering at a nitrogen flow rates of 0, and 0.5 sccm at a 600 °C annealing temperature. The crystalline structures and the nano-surface properties, such as the hardness, and the elastic modulus of the W or the W-N thin films, were determined using X-ray diffraction and Nano-indenter (Hysitron Corp.: TriboIndenter) systems, respectively. The Nanoindenter system has been established as a powerful method to characterize the mechanical properties of the nano-surface in W-N thin films. For the measurements, we convert theWeibull distribution and quantitatively define the thin-film stability. The hardness and the RMS surface roughness of the W-N thin film after annealing at 600 °C changed from 2.75 to 7.91 GPa and from 2 to 1.13 nm, respectively, as the thickness was reduced from 100 to 30 nm at a N2 gas flow of 0.5 sccm.