Multipurpose MEMS thermal sensor based on thermopiles

Abstract

This paper presents design, fabrication and experimental results of multipurpose thermopile based sensor which is compatible with technological processes already developed at IHTM-IMTM for fabrication of pressure sensors. Thermal isolation is assured using back etching of bulk silicon. Thermopiles have multilayer structure and sandwich membrane consists of layer of residual n-Si and sputtered oxide. Post-etching technique was developed and functional structures with membranes below 3 mu m were fabricated. Steady state and transient behaviour of fabricated structures were anticipated by applying two-zone 1D analytical model and FEA Comsol simulation. Sensors were tested as ac-dc transfer devices, gas flow meters and vacuum detectors.