2DEg-heated AlGaN/GaN micro-hotplates for high-temperature chemical sensing microsystems

Abstract

Fully-suspended AlGaN/GaN micro-hotplates that leverage self-heating of the two-dimensional electron gas (2DEG) have been modeled, micro-fabricated, and characterized at elevated ambient temperatures (from 25°C to 600°C in air). An input power of ~75 mW heated the micro-hotplates to approximately 270°C from 25°C ambient conditions. In addition, finite element analysis (FEA) showed high-temperature uniformity across the micro-hotplate (<1% variation) and fast transient response times (~2 ms rise and fall times). These results support the use of the AlGaN/GaN-on-Si platform for high-temperature activation of chemical sensing catalysts and in-situ chemical sensing within high-temperature environments (e.g., combustion exhaust, industrial process, and downhole).