Preparation and characterization of Al-doped tantalum nitride thin films: Effect of dopant content and film thickness

Current research addresses the electrical, mechanical, and tribological characteristics of sputter-deposited un-doped and Al-doped tantalum nitride thin films that can be used for the development of thin-film resistors (TFRs). Ta and TaAl alloy targets were used to deposit the samples with different Al contents and film thicknesses on the unheated Si and SiO₂/Si substrates. X-ray diffraction technique was employed to characterize the crystallographic structure while the resistivity was measured using a four-point probe instrument. Indentation and scratch tests were used to consider the mechanical and tribological properties. Different characteristics of the samples showed a strong dependence on Al content and film thickness. The samples with the lowest thickness (80 nm) showed the highest resistivity values, the best resistance to plastic deformation and abrasion damage, and a near-zero temperature coefficient of resistance (TCR). An increase in Al content also developed the compressive strain in the film structure and improved the mechanical and tribological characteristics of the samples. (author)