Modifications of reactively sputtered titanium nitride films by argon and vanadium ion implantation: Microstructural and opto-electric properties

Abstract

Polycrystalline titanium nitride (TiN) layers of 240nm thickness and columnar microstructure were deposited at 150°C by d.c. reactive sputtering on Si(100) wafers and then irradiated at room temperature with either 80keV V+ ions (at fluences of up to 2×1017ions/cm2) or 200keV Ar+ ions (at fluences of 5×1015–2×1016ions/cm2). Rutherford backscattering spectroscopy, cross-sectional (high-resolution) transmission electron microscopy and X-ray diffraction were used to characterize ion-induced changes in the structural properties of the films. Their optical and electric properties were analyzed by infrared reflectance (IR) and electric resistivity measurements. After deposition, the stoichiometric TiN films had a (111) texture. Ion implantation generated a damaged surface layer of nanocrystalline structure, which extended beyond the implantation profile, but left an undamaged bottom zone of (111) orientation. This layer geometry determined from transmission electron microscopy was inferred in the analysis of IR reflectance data using the Drude model, and the variation of the electric and optical resistivity with the irradiation was deduced. The results were compared to those recently gained for ion-implanted reactively sputtered chromium nitride films.