Microstructural and Nanomechanical Properties of Aluminium Nitride (AlN) Thin Films Deposited by RF Magnetron Sputtering

Abstract

Aluminium nitride (AlN) thin films were deposited on AISI-1018 low carbon steel substrates at different substrate temperature (Room temperature −600 °C) using RF magnetron sputtering technique. The microstructural, mechanical and corrosion properties were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), nanoindentation and salt spray test respectively. The microstructural and properties were investigated as a function of substrate temperature. The XRD analysis of the AlN thin films prepared at RT and 200 °C indicated the poor crystallinity of the films, while the films prepared in the temperature 400–600 °C range indicated the increased crystallinity with hexagonal (0002) and cubic (002) structure. The AFM analysis showed the average roughness of 7 nm, 5.5 nm and 16 nm for room temperature, 200 °C and 500 °C temperature respectively. The hardness of the AlN thin films were found to be 11.99 GPa, 13.05 GPa, 12.29 GPa, 23.0 GPa and 11.12 GPa at room temperature, 200 °C, 400 °C, 500 °C and 600 °C, respectively. The salt spray analysis indicated no corrosion on low carbon steel substrates for 12 hours.