Accelerated testing of anodically bonded glass-silicon packages in salt water

This paper reports long-term accelerated test results of glass-silicon packages in aqueous solutions including phosphate buffered saline (PBS) and de-ionized water. An analysis of the dominant failure mode and the long term biocompatibility of the packages is also performed. Using the accelerated data at 85 and 95°C in saline with an Arrhenius model we calculate an activation energy of 1.26 eV and an expected lifetime of 177 years at 37°C in saline. After an analysis of the failed samples, we find that the main failure mechanism is the dissolution of the polysilicon layer at elevated temperatures in saline, which causes premature failure of the package. In animal models the package is consistently found to be biocompatible and robust after implantation periods of up to a year