Tantalum nitride thin films (TaNx) are mechanically hard, self-passivated and corrosion - resistive layers, often used for precise thin film resistors. In order to investigate the behavior at high current densities, a DC- and a pulsed measurement technique was applied to the film resistive structures. The analysis is made on TaNx thin film resistors on silicon substrates, with applied DC- and pulsed stress, showing the behavior before, during and after stressing. Permanent Changes or destruction of the resistive layer can occur.