Microstructure and Mechanical Property Investigation of TaSiN Thin Films Deposited by Reactive Magnetron Sputtering

Abstract

Tantalum silicon nitride (Ta–Si–N) films were synthesized on Si substrate via magnetron sputtering. The structure and properties of the Ta–Si–N films were investigated as a function of the N2 content in the N2/Ar gas mixture. Increasing the N2 percentage in the gas mixture from 7% to 20% changed the film structure from textured hexagonal (hex) Ta2N to nontextured hex Ta2N to a mixture of face-centered cubic (fcc) TaN and hex Ta2N, and finally to fcc TaN. X-ray photoelectron spectroscopy showed Ta–N and Si–N bonds in the films. The film microstructure was found to change from columnar morphology with visible amorphous boundaries (at 13% N2) to columnar morphology with absence of amorphous boundaries (at 15% N2). Increasing N2 content increased hardness in the films with those deposited with 13–15% N2 displaying the highest hardness of ~40 ± 2 GPa. In addition, the 13% N2 films showed a ratio of H/E* > 0.11, elastic recovery of ~60%, low coefficient of friction of 0.6, reduced wear rate (7.09 × 10−6 mm3/N·m), and remained thermally stable up to 800 °C. The results suggest that the Ta–Si–N films have high potential as hard tribological nanocomposite coatings.