Structure and fabrication method of a high performance MEMS thermopile IR detector

摘要

The invention involves structure and fabrication method of a high performance IR detector. The structure comprises a substrate; a releasing barrier band on the substrate; a thermal isolation chamber constructed by the releasing barrier band; a black silicon-based IR absorber located right above the thermal isolation chamber and the black silicon-based IR absorber is set on the releasing barrier band; a number of thermocouples are set around the lateral sides of the black silicon-based IR absorber. The thermopiles around the black silicon-based IR absorber are electrically connected in series. The cold junctions of the thermopile are connected to the substrate through the first thermal-conductive-electrical-isolated structures as well as the heat conductor under the first thermal-conductive-electrical-isolated structures. The hot junctions of the thermopile are in contact with the IR absorber through the second thermal-conductive-electrical-isolated structures, and the second thermal-conductive-electrical-isolated structures are located above the releasing barrier band. The structure of such detector is simple, and it is easy to implement and can also be monolithicly integrated. Such detector has high responsivity and detection rate, and is CMOS-compatible, thus can be used widely in a safe and reliable manner.

主权项

1. A high performance MEMS thermopile infrared (IR) detector, comprising:
a substrate, wherein: a releasing barrier band formed on the substrate; a thermal isolation chamber formed in the releasing barrier band; a black silicon-based IR absorber disposed above the thermal isolation chamber; the black silicon-based IR absorber set on the releasing barrier band; a number of thermocouples set around lateral sides of the black silicon-based IR absorber; the thermocouples around the black silicon-based IR absorber are electrically connected in series to form a thermopile; metallic electrodes are set beside the thermopile to output electrical signals; one-side terminals of the thermopile adjacent to the IR absorber form the hot junctions and the other-side terminals far away from the IR absorber form the cold junctions; the cold junctions of the thermopile are connected to the substrate through the first thermal-conductive-electrical-isolated structures as well as the heat conductor under the first thermal-conductive-electrical-isolated structures; the heat conductor is located outside the thermal isolation chamber but between the releasing barrier band and the substrate; the first thermal-conductive-electrical-isolated structures are embedded in the releasing barrier band; the hot junctions of the thermopile are in contact with the IR absorber through the second thermal-conductive-electrical-isolated structures; and the second thermal-conductive-electrical-isolated structures are located above the releasing barrier band.