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

作者：Liu Bernard Haochih^*; Liao Fang Yi; Chen Jian Hong

来源：Thin Solid Films, 2013, 537: 263-268.

DOI：10.1016/j.tsf.2013.04.136

• Electroless plating
• Nickel-phosphorus
• Resistivity
• Microelectromechanical systems
• Microheater

In this work electroless nickel-phosphorous coatings were used as the micro heaters for scanning thermal microscopy. The deposition of Ni-P alloys not only simplified the microelectromechanical system fabrication steps but also provided flexibility in the tuning of the resistance of the heating elements. %26lt;br%26gt;Ni-P films were plated on patterned silicon substrates and silicon with a silicon nitride film. The pre-deposition reactive ion etch (RIE) treatment caused a change in surface roughness that enhanced the adhesion of Ni-P coatings. Optimization of RIE parameters and pH values could achieve selective deposition of Ni-P, thus helped the lift-off of a serpentine circuit pattern. %26lt;br%26gt;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) Omega 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.

• 出版日期2013-6-30