Fabrication of a Micro-hotplate for Application as an Infrared Emitter

The aim of this research is to design, fabricate and characterize a micro-hotplate which is suitable for application as an infrared source. For the heater material, Nichrome Ni-Cr (80/20) % an alloy of Ni (nickel) and Cr (chromium) is used. Nichrome exhibits high resistivity, low TCR and is resistant to natural processes of oxidation and corrosion; these qualities make nichrome a suitable material for a micro-hotplate. The heater resistance versus applied voltage is measured, where the slope of the curve is related to the TCR of the material. TCR measurements are carried out using a SPA with the sample on a temperature controlled chuck. NiCr thin film TCR is measured using a four-point probe technique from room temperature to 180℃. NiCr structures integrated on micro-hotplates are simultaneously heated and the corresponding resistance is measured using a source-meter that applies bias voltage and measures current. The MHP resistance is found to be stable after it has been passed through several conditioning steps.