Synthesis and characterization of (0001)-textured wurtzite Al1-xBxN thin films

Al1-xBxN films of the wurtzite structure and a strong c-axis texture have been grown at room temperature by reactive sputter deposition with B concentrations of up to 10 at.%. The crystallographic structure of the films has been studied with XRD and HRTEM/SAED with stoichiometry and chemical bonding determined by XPS. Nanoindentation experiments show that the films have a hardness in excess of 30 GPa, which is retained after annealing for 1 h at 1000 °C. An amorphous phase is observed at the interface, the thickness of which increases with the B concentration in the film, while the film crystallinity is seen to improve with film thickness.

► Synthesis of c-textured wurtzite (Al,B)N thin films with varying boron concentration up to 12 at.%. ► All analysis indicate that the films are single phase. ► All boron containing films exhibit high hardness exceeding 30 GPa. ► Film hardness retained after annealing for 1 h at 1000 °C. ► Film texture generally improves with thickness.