MEMS device having a substrate of semiconductor material; a first structural layer of semiconductor material, on the substrate; a second structural layer of semiconductor material, on the first structural layer; an active portion, accommodating active structures formed in the first structural layer and/or in the second structural layer; a connection portion, accommodating a plurality of connection structures and arranged laterally to the active portion; and a plurality of conductive regions, arranged on the substrate and extending between the active portion and the connection portion. Each connection structure is formed by a first connection portion, in electrical contact with a respective conductive region and formed in the first structural layer, and by a second connection portion, on the first connection portion and in electrical continuity therewith, the second connection portion formed in the second structural layer. The first connection portion has a greater thickness than the second connection portion.

A MEMS microphone is provided. The MEMS microphone includes a substrate, a membrane, and a backplate. The substrate is with a cavity. The membrane is disposed on the substrate across the cavity. The backplate is disposed over the membrane and separated from the membrane by an air gap. The membrane has a corrugation. The backplate has a portion corresponding to and directly above the corrugation. A step height of the portion is equal to or less than 20% of a step height of the corrugation.