Fabrication and characterization of a thin film capacitor using Al anodizing and Ni electroless plating

We propose a thin film capacitor fabricated using anodized Al as the dielectric layer and electroless-deposited Ni as the electrode. For high capacitance, tunnel pits on Al were formed by electrochemical etching. The tunnels were 20 μm in length and 3.5 μm in width. The electrical properties showed a high capacitance of 46 nF cm−2 and a higher resonance frequency of 1.7 MHz, a lower dissipation factor of 0.68% and a lower equivalent series resistance than those of conventional electrolytic capacitors.