Material properties of a ZrNx film on silicon prepared by ion-assisted deposition method

Abstract

The resistivity, chemical composition, and crystalline quality of ZrNx films deposited on Si(100) substrates by an ion-assisted deposition (IAD) method were investigated as a function of deposition parameters. By this method, metallic Zr is deposited by electron-beam evaporation while simultaneously bombarding the film with nitrogen ions having energies of 400–700 eV. It was found that the crystalline quality of the film was improved by increasing the substrate temperature Ts to 820 °C and decreasing the ion energy. When Ts was 850 °C, zirconium silicide was formed easily near the interface between the film and the Si substrate. At Ts=820 °C, the chemical composition ratio of the film was hardly influenced by the arrival rate ratio N/Zr, Ra, in the range of 1.5 to 3.0 and the deposited ZrN film was almost stoichiometric. However, when Ra was more than 1.9, the film quality was degraded by radiation damage due to excess nitrogen ions in the growing film. When Ra was less than 1.5, the surface of the film was roughened and looked cloudy, probably because the nonstoichiometric film reacted with the Si substrate. Therefore, the optimum arrival rate ratio was found to be in the range of 1.5–1.9. With optimum fabrication conditions, a (100) oriented and almost stoichiometric ZrN film could be obtained with resistivity as low as 17.8 μΩ cm.