The influence of deposition time and testing temperature on mechanical proprieties of niobium nitride thin films

This paper is focused on studying the effects of testing temperature on the mechanical properties (hardness and modulus of elasticity) of niobium nitride thin (NbN) films. In this respect, NbN thin films were deposited on silicon substrate at room temperature by direct current magnetron sputtering using a niobium target of high purity. All the films were deposited on non-biased substrates. The deposition time was ranged between 10 and 40 minutes. Thus, we've obtained four types of samples deposited at different deposition times namely 10, 20, 30 and 40 minutes. The mechanical properties of these thin films such as the modulus of elasticity and hardness were investigated using the nanoindentation mode of the atomic force microscopy. The experimental tests were carried out by varying the testing temperature. The purpose of this analysis was to determine the change in mechanical characteristics of NbN films when the testing temperature was varied from room temperature up to 100 °C. The outcome of this investigation points out that the change in testing temperature has a significant influence on the mechanical properties of NbN thin films. The results also allowed us to determine the films characterized by the best mechanical behaviour.