Reliability improvement of suspended platinum-based micro-heating elements

Micro-hotplates consisting of a platinum-based heating element embedded in two low-stress silicon nitride layers were fabricated. In this communication, we report on the composition of the heater and its influence on both the micro-hotplate's life expectancy and the highest reachable operating power. These factors were characterized by measuring the deformation of the membrane, by ramping up the power until breakdown and by performing accelerated aging tests. Finally, the failure mechanisms were investigated using optical and SEM observations. The type of material used as adhesion layer has a strong influence on the heating element's performances. Addition of iridium significantly improved the lifetime of the device.