Microstructure and electrical property of tantalum oxynitride thin films prepared using high-power impulse reactive magnetron sputtering

Abstract

Ta-N thin films were prepared on glass and Al2O3 substrates using high-power impulse reactive magnetron sputtering. A Ta target was used and sputtered using Ar/N2 two gasses mixture. The phase structures, microstructures and electrical properties of Ta-N thin film with different powers and annealing temperatures were investigated. The results showed that an amorphous structure existed in the as-deposited Ta-N films at 500 W, and some crystalline phases (TaN, Ta2N and β-Ta) were observed in as-deposited films at 1500 W and 2500 W. The crystallization phase did not change when the annealing temperature ranged from room temperature up to 500 °C. When the sputtering power increased to 2500 W, TaN, Ta2N and β-Ta crystalline phases coexisted in the as-deposited films. However, Ta-N films deposited at 2500 W and annealed at 500 °C in N2 exhibited resistivity of ∼460 μΩ-cm with −93 ppm °C−1 temperature coefficient of resistance.