Structural and electrical characterization of tantalum nitride thin film resistors deposited on AlN substrates for π-type attenuator applications

Tantalum nitride thin films were deposited on AlN substrates at room temperature with an nitrogen/argon flow ratio (N2/(N2 + Ar)) of 3% by dc-magnetron sputtering technique, and then were annealed at 525 °C in 6.7 × 10−4 Pa. The microstructural and electrical properties of the films were investigated as a function of film thickness. The crystallinity of the films decreased with decreasing film thickness and the sheet resistance of 50 nm-thick tantalum nitride films is approximately 80 Ω/□ suitable for 10 dB application in π-type attenuators. The TCR values increase positively with increasing the thickness and 50 nm thick films exhibit a near-zero TCR value of approximately −6 ppm/K.