Air-based deposition of titanium‑aluminum oxynitride thin films by reactive magnetron sputtering

Abstract

Quaternary titanium‑aluminum oxynitride (Ti,Al)NxOy films with various nitrogen and oxygen compositions can be applied to many interesting mechanical and technological applications. Conventionally, pure nitrogen and oxygen were required as reactive gases for producing the films by sputtering under a high vacuum environment. In this work, air was employed as a reactive gas instead. Thus, a low vacuum environment was sufficient, which could save a tremendous amount of processing time and cost. (Ti,Al)NxOy films were produced by dc magnetron sputtering at a high base pressure. By merely varying the air/Ar flow ratio in a suitable processing window, X-ray diffraction patterns show that obtained films could turn from a crystalline rock-salt structure to an amorphous phase. X-ray photoelectron spectroscopy revealed the compositions that could be tailored from N-rich to O-rich (Ti,Al)NxOy thin films. With increasing O/N ratios, as-deposited (Ti,Al)NxOy films could turn from metallic-like, semi-conductive, to dielectric-like behaviors. Moreover, the hardness and reduced Young's modulus of obtained (Ti,Al)NxOy films could also be tailored and achieved as high as 39.1 GPa and 331 GPa, respectively. This may be due to solid solution hardening effects.