Pt Heating Electrode for Microheater Based on Electrochemically Prepared Anodic Porous Alumina

摘要

Electrochemically prepared anodic aluminum oxide (AAO) was used as a supporting chip material fora microheater sensor, on which a patterned Pt electrode was deposited to generate resistive heat duringcurrent flow. Photolithography and a Pt/Ta sputtering process were conducted to prepare aninterdigited electrode on the AAO supporting material. For efficient heat management within theheating zone, an air-gap ring was created around the heating zone using a chemical etching process. Athermal infrared camera image revealed that the generated heat is isolated within the heating zone. Toachieve stable heating performance of the Pt layer, the Pt deposited on AAO was thermally annealedunder various conditions. With increasing annealing temperature, the grain size of the Pt planesincreased, leading to a highly stable Pt electrode on AAO. However, increasing the annealingtemperature to 650C resulted in the generation of pinholes, which led to degraded heating properties.A very small amount of heating power (50 mW) was consumed to maintain a heating zone temperatureof over 600C in the proposed AAO-based microheater.