Abstract
The system (20) has a base (21) i.e. silicon substrate, comprising a rear chamber arranged on the base. A rear plate (24) made of polycrystalline silicon is arranged on the base, and comprises air holes (25) fixed with the rear chamber. An anchoring or fastening element (23) is located on the base, and comprises a supporting portion. A central portion of a membrane (22) i.e. flexible or rigid membrane, is supported by the supporting portion, so that the membrane is arranged parallel to the rear plate, in order to derive residual stress of the membrane outwardly from the supporting portion.