Pulverisation method for active layer coating on microsystems

By means of the pulverisation of a solution of indium oxide nanoparticles, sensitive layers for gas detection were deposited in silicon micromachined sensors in order to define layers with a thickness range covering thin and thick technologies. Influence of electrodes geometry, interdigited and parallel, was studied and better sensor response was found in interdigited sensors. Continuously heated and temperature-pulsed working modes were also compared, showing that pulsed mode improve the sensor response. As an example, sensor response to low concentrations of NO2 in humid air has been studied and results confirmed the viability of this technique to obtain micromachined gas sensors.