A miniaturized self-calibrated pyrometer microsystem

Abstract

paper describes the design, modeling and optimization of a miniaturized self-calibrated pyrometer to detect infrared radiation (in 5-20 µm range of wavelengths) in order to measure the real temperature of objects without contact. The microsystem consists of a thermally insulated absorbing area and two thermopiles with the hot junctions in the absorbing area and the cold junctions on a heat sink (i.e. the silicon bulk). The complete microsystem is in silicon planar technology and each thermopile has a different reference temperature, biased by a Peltier microstructure near to the cold junction of the thermopile. A silicon die passivated with a silicon nitride membrane is the ground floor of all microsystem. The absorbing area, a black gold strip on the silicon nitride membrane is obtained by anisotropic etching of the bulk silicon from the back of the wafer. The pyrometer microsystem is composed by: the IR optical filter on the top, the electronic system built in CMOS technology added by Multi-Chip-Module (MCM) techniques and the pyrometer. Application of a network of pyrometers in textile industry is the final goal.