Optimization of passivation layers for corrosion protection of silicon-based microelectrode arrays

The protectivity of passivation layers decides on the lifetime of silicon-based sensor chips in liquid and corrosive media. In this study the barrier effect of different organic (spin-coated) and inorganic (PECVD) thin films in brine was investigated using a microelectrode array as a microsensor model. The corrosion resistance of the microelectrode array was optimized by using buried conducting tracks and duplex (SiO2/Si3N4) or triplex (SiO2/Si3N4/SiO2) layers instead of inorganic monolayers. The failure mechanisms were investigated with respect to physical and mechanical effects, and corrosive attack.