Thin and hard ZrC/TiN multilayers grown by pulsed laser deposition

Abstract

ZrC, TiN, and ZrC/TiN multilayers thinner than 400 nm were grown on (100) Si substrates at 300 °C by the pulsed laser deposition (PLD) technique using a KrF excimer laser. X-ray reflectivity and X-ray diffraction investigations showed that films exhibited densities above 95% of the bulk values and were crystalline. The oxygen content, measured by Auger electron spectroscopy (AES), was below 2 at.% and 4 at.% in the ZrC and TiN layers, respectively. Nanoindentation investigations found hardness values between 35 and 38 GPa for the multilayers, higher than the 30–33 GPa values measured for ZrC and TiN films. High-resolution cross section transmission electron microscopy and energy dispersive spectroscopy studies of the nanoindentation sites showed that the adhesion and the structural and chemical integrity of the layers adjacent to the Si substrate were preserved even when the indent depth greatly exceeded 10% of the multilayer thickness. Moreover, no dislocations or other major structural defects were found in the underlying Si.