Design, fabrication, and characterization of BESOI-accelerometer based on photonic band gap effect

This paper reports numerical and experimental investigation on a (bulk and etch silicon on insulator) BESOI optoelectromechanical system, realized using a multilayer, metal-dielectric photonic band gap (PBG) structure. Variations in the reflectance spectrum are related to the displacement of the proof mass induced by an external acceleration. The properties of PBG transparent metals allow to obtain a sharp change in the output signal even for very small changes of the air gap and therefore of the relative positions of the proof mass, due to the high refractive difference of indexes. The MEMS is represented by a suspended squared shape mass supported by a four crab-leg beams and the central part is used as active optical area to normally focus the light beam. The advantages of silicon micromachining combined with PBG properties have been addressed and compared with our previously work. The sensor proposed here has been first analytically and numerically studied by using CoventorWare, then the device has been fabricated and an experimental campaign has been performed.