Effect of Thickness and Annealing on Stress in Tantalum and Tantalum Nitride Thin Film Hard Coatings

Abstract

AbstractAn understanding of the relationship between stress and the other properties of thin films is extremely useful in the design of hard coatings for long term performance. In our earlier study, sputtered Ta and Ta(N) films were found to exhibit promising hard coating properties. For example, nano hardness as high as 30 GPa was observed in the nitride (pN2 = 0.100 mTorr) films. In this work, we study the variation in the stress in these films with respect to film thickness and annealing. Films in six different thicknesses (50, 250, 350, 500, 750, and 1000 nm) were deposited on oxide coated Si (111) wafers. Stresses in the films in the as-deposited state and as a function of temperature (300°C) were determined using a thin film stress measuring unit.