Structure of micro-electro-mechanical-system microphone and method for fabricating the same

A method for fabricating micro-electro-mechanical-system (MEMS) microphone, comprising:

• providing a preliminary structure, including:
• a silicon substrate of semiconductor, having a first opening in the silicon substrate;
• a dielectric layer disposed on the silicon substrate, having a portion exposed by the first opening, wherein a diaphragm is formed in the dielectric layer, wherein the diaphragm is configured to have an embedded part surrounding the first opening and an exposed part within the embedded part corresponding to the first opening, wherein the exposed part has a junction peripheral region, a buffer peripheral region and a central region, wherein the junction region has an elastic structure with slits, the buffer peripheral region includes a plurality of holes and is disposed between the junction peripheral region and the central region;
• a backplate disposed on the dielectric layer, wherein the backplate includes venting holes distributed at a region corresponding to the central part of the diaphragm;
• and
• performing an isotropic etching process to etch the dielectric layer through the first opening of the silicon substrate and the venting holes of the backplate, so as to form a second opening in the dielectric layer to expose the exposed part of the diaphragm and the backplate,
• wherein the holes and the slits of the diaphragm allow an etchant to flow through to etch a dielectric material of the dielectric layer,
• wherein the buffer peripheral region of the diaphragm provides a space gap between slits and the venting hole to reduce a low frequency decay from the slits.