Thermopile-based GaAs micromachined devices

International audienceGaAs based semiconductors are attractive materials for thermal sensors because of the transistor operation at high temperatures (resulting from the large bandgap), low thermal conductivity, high Seebeck coefficient and, of course, electronic compatibility. The feasibility and usefulness of GaAs-TiAu thermocouples using the PML D02AH process were extensively evaluated through analytical formulations, electrical circuit models and FEM simulations. Two potential applications were particularly studied. They are the infrared detector and the electro-thermal converter. This converter device can be efficiently used as a microwave power sensor in monolithic microwave integrated circuit design. On the other hand, the absence of a sensitive area (black layer) in the proposed thermopile structures resulted in low performance of infrared sensors. Thermocouple structures have been successfully fabricated and experimental measurements are in progress