Parylene supported uncooled thermoelectric infrared detector with umbrella like absorber

Abstract

In this work a very small (20 μm x 20 μm) uncooled surfacemicromachined thermoelectric infrared detector is fabricated and tested. This TE detector features a P-doped polysilicon/Nichrome thermocouple embedded into a layer of Parylene-N to provide structural support. This sensor also features an umbrella-like IR absorber with the area of ∼19 μm x 19 μm resulting in a 90% fill factor. At room temperature, a responsivity of ∼150 V/W with a time constant of 1.3 ms is measured from the fabricated devices in vacuum when viewing a 500K blackbody without any concentrating optics. NEP and D∗ are calculated to be 2.6e-10 watt and 7.7e6 cm∗Hz^0.5/w, respectively.