Thermoelectric microsensor for heat flux measurement

We present a new microsensor for heat flux measurement. The sensor is prepared by using thin Bi_1-xSb_x films. which are patterned by photolithography. The films are deposited on 800 nm thin membranes of silicon oxide/silicon nitride. Which are structurized by micromachining (anisotropic etching of silicon wafers). The sensor consists of ten membranes with 889 thermocouples on each membrane. The high density of thermocouples on a small membrane size of 22 mm² enables the high sensitivity of 5,87 mV/(W/m²), whereas the sensitivity of conventional heat flux sensors is only 0.07 mV/(W/m²). This increase is achieved by the microlithographic design. The results of the sensor modelling and the design optimization are presented. The sensor can be calibrated absolutely by using an integrated thin-film heater, which generates a well-defined heat flux (self-calibration)