Effects of Substrates on Thin-Film Growth of Nickel Zinc Ferrite by Spin-Spray Deposition

In certain applications, such as on-chip integrated inductors, ferrite materials are highly desirable owing to their superior magnetic and insulation properties. Spin-spray deposition is a promising method for producing high-quality thin films of ferrite, as it does not require a vacuum and can operate at low temperatures. A comprehensive analysis was conducted to investigate the influence of the substrate on the microstructure and magnetic properties of the thin films, and the growth mechanism of this phenomenon was discussed. In addition, first-order reversal curve measurements were used to study the coercivity and grain size distribution. The results indicate that thermal conductivity played a significant role in determining the thin-film growth during spin spray deposition. Polyimide is considered a more suitable substrate under this process due to its appropriate thermal conductivity, which results in more uniform grain distribution and improved magnetic properties, with maximum permeability and a cutoff frequency reaching 55 and 485 MHz, respectively. Our results provide valuable insights into the mechanism of spin-spray deposition and offer an effective way to tune the performance of ferrite thin-film materials.