Presentazioni e Articoli Tecnici

Monitoring of indoor CO₂ concentration is of particular interest to detect room occupancy in order to optimise power consumptions of building. One technological approach is to use optical detection using specific absorption lines of CO₂ molecules in the infrared domain close to 4.2 μm. Key features for a wider use in public and private buildings are power consumption and price. Such optical sensors include a detector, typically a micro-bolometer, an IR source – such as a hot filament – and a filter to select the interesting band in the black body spectrum of the emitter. All these components can be made in well known planar Si technology using MEMS approach. To fabricate a free-standing microhotplate, we chose Si₃N₄/SiO₂ as supporting layer and TiN/Pt/TiN for heater layer.