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.