Fine frequency tuning in resonant sensors

To realize highly sensitive resonant IR sensors the control of mechanical properties of the p+ silicon film is essential. Microfocus Raman spectroscopy and secondary ion mass spectrometry were used to measure the stress and boron concentration profile in the p+ silicon film respectively. Measurements of bending in cantilevers, of transversal stress gradient and boron profile in the films were found as being consistent with each other. Prediction of mechanical properties of micromechanical structure can be realized by using these techniques. Fine tuning of the resonance frequency in the final, packaged device, was realized by using an electrostatically activated axial force.