Preparation and properties of micro-hotplates for gas sensors based on GaAs

In this work, analysis of three different heating systems for two types of Pt micro-hotplate is reported: GaAs bulk structure (bulk GaAs), polyimide/GaAs bulk structure (PI-GaAs) and AlGaAs/GaAs suspended membrane structure (AlGaAs/GaAs). Complex electro-thermal characterization of prepared micro-hotplates was realized. Maximal reachable temperature of suspended membrane heating structure was 260degC with corresponding power 36 mW compared with the GaAs bulk structure with maximal temperature 220degC and corresponding power 1.5 W. At temperatures and powers above maximal limits, degradation and destruction of heating meanders occurred. Power consumption P_200degC of sample on GaAs bulk substrate was 850 mW, and on PI/GaAs bulk substrate 380 mW, whereas power consumption of sample prepared on AlGaAs/GaAs suspended membrane was significantly lower about 26 mW.