Abstract: The present disclosure is directed to a method for manufacturing a micro-electro-mechanical device. The method includes the steps of forming, on a substrate, a first protection layer of crystallized aluminum oxide, impermeable to HF; forming, on the first protection layer, a sacrificial layer of silicon oxide removable with HF; forming, on the sacrificial layer, a second protection layer of crystallized aluminum oxide; exposing a sacrificial portion of the sacrificial layer; forming, on the sacrificial portion, a first membrane layer of a porous material, permeable to HF; forming a cavity by removing the sacrificial portion through the first membrane layer; and sealing pores of the first membrane layer by forming a second membrane layer on the first membrane layer.

Abstract: An electroacoustic MEMS transducer, having a substrate of semiconductor material; a through cavity in the substrate; a back plate carried by the substrate through a plate anchoring structure, the back plate having a surface facing the through cavity; a fixed electrode, extending over the surface of the back plate; a membrane of conductive material, having a central portion facing the fixed electrode and a peripheral portion fixed to the surface of the back plate through a membrane anchoring structure; and a chamber between the membrane and the back plate, peripherally delimited by the membrane anchoring structure.

Abstract: An electroacoustic MEMS transducer, having a substrate of semiconductor material; a through cavity in the substrate; a back plate carried by the substrate through a plate anchoring structure, the back plate having a surface facing the through cavity; a fixed electrode, extending over the surface of the back plate; a membrane of conductive material, having a central portion facing the fixed electrode and a peripheral portion fixed to the surface of the back plate through a membrane anchoring structure; and a chamber between the membrane and the back plate, peripherally delimited by the membrane anchoring structure.