Lateral cantilever beam in BESOI technology

In this work a novel MEMS device will be presented; it consists of a cantilever beam, also named here “foil”, that deforms along the die surface directions and not, as usual, transversely to the die surface. The device has been analytically and numerically studied and it has been realized in Bulk and Etch Silicon-On-Insulator (BESOI) technology; it exploits the thickness of the wafer for its “width” dimension in order to save space on die surface. The cantilever deflection will therefore be along the “lateral” direction instead of the traditional “vertical” one. This micro-structure is coupled with two integrated silicon interdigitated capacitors both for reading and for actuation. The solution proposed here gives access to several interesting applications such as MEMS switches, or controlled optical waveguide or dual axes “in-plane” cantilever accelerometer on single die.