Selective chemical bath deposition of iridium oxide on thin film flexible substrates

Abstract

A flexible thin film metal oxide electrode fabrication methods and devices are provided and illustrated with thin film polyimide electrode formation and IrOx chemical bath deposition. Growth factors of the deposited film such as film thickness, deposition rate and quality of crystallites can be controlled by varying the solution pH, temperature and component concentrations of the bath. The methods allow for selective deposition of IrOx on a flexible substrate (e.g. polyimide electrode) where the IrOx will only coat onto an exposed metal area but not the entire device surface. This feature enables the bath process to coat the IrOx onto every individual electrode in one batch, and to ensure electrical isolation between channels. The ability to perform selective deposition, pads for external connections will not have IrOx coverage that would otherwise interfere with a soldering/bumping process.