THERMAL STABILITY OF HARD TANTALUM BORIDE FILMS

The article reports on physical and mechanical properties of the understoichiometic tantalum boride (TaBx < 2) films prepared by magnetron sputtering. The films were grown from a TaB2 target. It is shown that the stoichiometry x of the TaBx film is strongly influenced by its ion bombardment controlled by negative substrate bias Us. It was found that the understoichiometric TaBx < 2 films are hard and flexible X-ray amorphous films with a high H/E* ratio and an enhanced resistance to cracking; here H and E* is the hardness and the effective Young’s modulus, respectively. The conditions under which such films are created are given. The thermal stability and oxidation resistance of the sputtered TaBx films thermally annealed in the air are also reported.