Design, fabrication, and characterization of electroless Ni-P alloy films for micro heating devices

The chemical composition and microstructure of Ni-P films affect the electrical properties of micro heaters. Energy-dispersive X-ray spectroscopy identified the Ni-P composition and confirmed its insignificant level of oxidation. The high-temperature X-ray diffraction indicated that the as-deposited film was crystalline Ni, which later transformed into Ni3P at higher temperature. The resistivity of Ni-P films was tailored between 10− 5 and 10− 7 Ω m via a post-deposition annealing, which also obtained a stable temperature coefficient of resistance. Consequently, the performance of micro heaters could be designed with a high degree of flexibility.