Rapid Thermal Annealing of Ta-N Thin Films and Its Effects on Phase Transition and Electrical Behaviors

Ta-N thin films were prepared using magnetron DC reactive sputtering deposition with a fixed argon flow rate and various nitrogen flow rates. After deposition, rapid thermal processing was applied to anneal the films at 400°C for 2, 4, and 8 minutes, respectively. The microstructures and electrical properties of these thin films were then characterized to observe the influences caused by the variation of nitrogen flow-rate and annealing time. The results show that the stoichiometric Ta-N phase can be formed only when N2 flow rate is 8 sccm. A higher N2 flow rate results in a higher resistivity and a more negative TCR and vice versa. Besides, according to the analyses of X-ray diffraction and X-ray photoelectron spectroscopy, the annealing time has little effect on the microstructures of Ta-N thin films. Although rapid thermal annealing could result in higher resistivity and more negative TCR, its effect becomes insignificant when the annealing time is longer than 2 minutes.