Deposition of TiN/Al bilayers on a rotating substrate by reactive sputtering

A balanced dual-cathode reactive magnetron sputtering system has been developed. which allows the growth of TiN/AIN bilayers from pure titanium and aluminium targets in a mixture of argon and nitrogen gases. One important property of the TiN/AIN coatings is that they combine two important requirements for protective coatings: good adhesion properties of the TiN films and the chemical stability of the AlN films. The chemical composition of the grown layers has been studied by Auger electron spectroscopy (AES), elastic recoil detection analysis (ERDA) and Rutherford backscattering spectroscopy (RBS) techniques, and nitrogen incorporation in the nitrides has been correlated to the argon/nitrogen ratio in the sputtering gas. Structural properties have been studied by X-ray diffraction (XRD), and the results showed the presence of cubic TiN and hexagonal AIN phases in the grown bilayer. Mechanical properties have been extracted from nano-indentation measurements, giving hardness values for TiN/AIN bilayer in the range of the reported values for TiN coatings. (C) 2002 Elsevier Science B.V. All rights reserved.