Effects of Oxygen Partial Pressure and Thermal Annealing on the Electrical Properties and High-Temperature Stability of Pt Thin-Film Resistors

The effects of oxygen partial pressure and annealing temperature on the microstructure, electrical properties, and film adhesion of Pt thin-film resistors with PtxOy as the adhesion layer were investigated. Pt/Pt(x)O(y )films were deposited on alumina substrates by radio frequency sputtering and annealed in a muffle furnace at temperatures in the range of 800-1000 degrees C. The microstructure and chemical composition of Pt thin-film resistors were examined by optical microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. The experimental results show that annealing will lead to the formation of bubbles on the surface of the film, and the film prepared at 20% oxygen partial pressure has the least bubbles. The Pt thin-film resistors with a PtxOy adhesion layer sputtered with 10% oxygen partial pressure had the highest TCR (temperature coefficient of resistance) of 3434 ppm/degrees C, and the TCR increased with increasing annealing temperature. Repeated experiments show that Pt thin-film resistors have better stability at annealing temperatures of 800 degrees C and 900 degrees C. Comprehensively considering the TCR and stability, the optimal adhesion layer of Pt thin-film resistors was prepared at an oxygen partial pressure of 10% and an annealing temperature of 900 degrees C.