Optimization of Thin Film process to Fabricate Electrolyte Layers for Thin Film Solid Oxide Fuel Cell

Abstract

This work is dedicated to the investigation of highly uniform and crystalline thin films of YSZ that were produced by using Atomic Layer Deposition and Sputtering. Since these two are the most abundantly used methods of deposition, it seemed necessary for me as a researcher to investigate which one of them can be used according to the conditions deemed appropriate. The layers of same composition and thickness were analyzed. This allowed competitive measurements to be made and also aided in pinpointing the technological aspects of both methods. Binding energy of ALD YSZ layers was more than that of Sputtered YSZ showing more adhesion to the substrate. This shows that the ALD method must be adopted when it is necessary for the layers to hold upto any substrate, while sputtered layers can be adopted when it is not as much necessary to hold up the layers against the substrate. The growth rate per hour of Sputtered YSZ was faster than that of ALD YSZ. However the contol of the growth was more finer in case of ALD as compared to Sputtered YSZ. One of the main reasons of using YSZ as the electrolyte layer for Solid Oxide Fuel Cells is the advantage it has for conduction of oxygen ions. The conductivity of about 70nm YSZ films prepared by ALD was much more higher than Sputtered YSZ of same length. YSZ Sputtered layers showed comparable performance with thin film ALD YSZ layers only when the thickness was increased. ALD is therefore a far superior method to produce thin film electrolytes for Solid Oxide Fuel Cells