Novel method for thermal characterization of MEMS
The use of thermal modulation techniques provides powerful tools to enhance and influence the selectivity and sensitivity of metal oxide based functional layers in gas sensing applications. However, when using micromachined, low-power consuming, so-called hotplate devices, the determination of the absolute temperature of the sensitive layer still presents a challenge. In this contribution, a novel method based on a phase transition in thermally sensitive materials is applied to determine the absolute temperature with high accuracy. The technique relies on depositing small, well-defined amounts of various materials with high spatial resolution using an inkjet printer and then establishing the relation between the heater's resistivity and the absolute temperature when the phase transition occurs. With this approach, the spatial distribution of the absolute temperature of microelectromechanical systems can be achieved. Due to the flexibility of inkjet printing, the presented method may be applied to a wide range of scenarios.