Reliability and characteristics of magnetron sputter deposited tantalum nitride for thin film resistors

Abstract

Tantalum nitride (TaN) films were deposited onto SiO2/Si and multilayer ceramic (MLC) substrates with a reactive direct current magnetron sputtering method. After they were kept at different N-2 partial pressures and substrate temperatures, these were characterized for their electrical, structural, and mechanical properties for use as thin film resistors (TFRs). Results of X-ray diffraction analysis, observation of microstructure, sheet resistance measurement, and accelerated degradation tests highly indicated that TaN films with high crystalline phases, good surface roughness, stable deposition rates, appropriate sheet resistances, and high reliabilities could be obtained if N-2 partial pressure was maintained at around 20%. Adhesive strengths of TaN films grown on MLC substrates were increased with increasing substrate temperature up to 300 degrees C. A low resistance change was confirmed by temperature coefficient of resistance variation as a function of temperature, implying high reliability and durability. Results of this study suggest that TFRs described in this study are suitable for embedded passive resistors with practical applications, including controlled resistances for fabricated TaN based TFRs with different widths.