Fabrication and characterization of NiCr-based films with high resistivity and low temperature coefficient of resistance

As a metal alloy, NiCr films have a relatively high resistivity and low temperature coefficient of resistance (TCR) and are widely used in electronic components and sensors. However, the resistivity of pure NiCr is insufficient for high-resistance and highly stable film resistors. In this study, a quaternary NiCrAlSi target (47:33:10:10, wt. %) was successfully used to prepare resistor films with resistivities ranging from 1000 to 10 000 μΩ cm and TCR within ±100 ppm/K. An oxygen flow was introduced during the sputtering process. The films exhibit high-temperature stability at 450 °C. The films were analyzed using Auger electron spectroscopy, x-ray diffraction, time-of-flight secondary-ion mass spectrometry, and x-ray photoelectron spectroscopy. The results show that the difference in the oxide proportion of the films caused the differences in resistivity. The near-zero TCR values were considered to be due to the competition between silicon and other metals. This study provides new insights into the electrical properties of NiCr-based films containing Si, which will drive the manufacturing of resistors with high resistivity and zero TCR.