Foundry-compatible process for a mems audio device

A Micro-Electromechanical System (MEMS) audio device comprising:

• a first wafer characterized by a first surface comprising a first cavity and a second surface having at least a first vent hole formed through the first wafer and coupled to the first cavity, wherein the first surface comprises a first plurality of electrical contacts;
• a second wafer disposed upon the first surface of the first wafer, wherein the second wafer is characterized by a flexible material layer, wherein a portion of the flexible material layer is disposed above the first cavity of the first wafer;
• a third wafer coupled to the second wafer using an insulating material, wherein the third wafer includes a second cavity, and having at least a second vent hole formed through the third wafer and coupled to the second cavity;
• wherein the first portion of the flexible material forms a diaphragm for the MEMS audio device.

A micro-speaker device comprising:

• a movable diaphragm device composed of one or more sequentially deposited thin films from a first group consisting of:
• silicon, polysilicon, silicon nitride, or graphene material, and comprising a total thickness of 0.1 nm to ten microns, and configured spatially within a cavity region, the movable diaphragm device having a first surface and a second surface opposite of the first surface, wherein the movable diaphragm is coupled to at least two flexible supports selected from a second group consisting of:
• cantilever and springs, wherein each flexible support is coupled between a peripheral region of the movable diaphragm device and a portion of a frame disposed adjacent to the movable diaphragm device;
• a substrate device coupled to the frame, wherein a first electrode is configured using the substrate or an electrically conductive material deposited on the substrate to provide an electrostatic force relative to the movable diaphragm, wherein movement of the movable diaphragm in response thereto is configured to generate acoustic signals;
• the substrate device includes a first vent and a first cavity configured to allow back pressure to flow therethrough;
• and
• a cap electrode is coupled to the frame with an insulating material selected from a third group consisting of:
• epoxy, a polymer, and an adhesive, wherein the cap electrode includes a second vent and a second cavity region is formed between the cap electrode and the movable diaphragm device, wherein a height of the second cavity is determined in response to a thickness of the insulating material, and wherein the cap electrode includes an electrode on a top surface of the cap electrode;
• wherein the cap electrode is configured to provide an electrostatic force relative to the movable diaphragm, wherein movement of the movable diaphragm in response thereto is configured to generate acoustic signals from the first vent or the second vent.