Residual stress formation in multilayered TiN/TaN_x coatings during reactive magnetron sputter deposition

Multilayered physical vapor deposited TiN/TaN_x coatings were deposited on cemented carbide substrates using a dual target magnetron sputtering system. The coatings were investigated with respect to the influence of nitrogen partial pressure during deposition on the residual stress developed in the coatings. Furthermore, the fracture strength of the material, i.e., the magnitude of the tensile stress that the coating can support without cracking, was evaluated. It was found that, by increasing the nitrogen partial pressure, it is possible to change the stress from compressive to tensile. The highest tensile stress was about 3.6 GPa. Despite this high stress, the coating displayed no cracking. This implies that it is possible to grow TiN/TaN_x multilayered coatings with high tensile fracture strength using dual magnetron sputtering and a high deposition temperature (about 680 °C). © 2000 American Vacuum Society.