Integrity of Micro-Hotplates During High-Temperature Operation Monitored by Digital Holographic Microscopy

An investigation on the integrity of micro-hotplates using in situ digital holographic microscopy is reported. The surface topography and surface evolution of the devices during high-temperature operation (heating/cooling cycles) is measured with nanometer-scale resolution. A localized permanent out-of-plane surface deformation of 40% of the membrane thickness caused by the top measurement electrodes occurring after the first cycle is observed. The integrity-related issues caused by such a permanent deformation are discussed.