Fabrication of poly-germanium based thermopiles on plastic

Fabrication of germanium-based thermocouple on PET plastic and rubber-coated glass substrates is reported. The amorphous Ge film, deposited using electron beam evaporation, is post-treated for it to form a polycrystalline film. The annealing process has been performed at temperatures ranging from 120 to 175°C and study of physical characteristics of Ge films using XRD and SEM confirms its crystallinity. A value of 100μ V/°C is extracted for the Ge-Al junctions. The thermocouple fabrication and their response to flow are reported. A novel approach is described to perform the micro-machining on PET substrates for the formation of membranes. An average etch rate of 10μm/hr is achieved in the presence of 35mW/cm² of 360nm UV at ambient temperatures.