Patent ID: 8847289

Claim:
A complementary metal oxide semiconductor (CMOS) compatible microelectromechanical systems (MEMS) microphone, comprising: a silicon-on-insulator (SOI) substrate, wherein a CMOS circuitry is accommodated on its silicon device layer; a microphone diaphragm formed with a part of the silicon device layer, wherein the microphone diaphragm is doped to become conductive; a microphone backplate including CMOS passivation layers with a metal layer sandwiched and a plurality of through holes, provided above the silicon device layer, wherein the plurality of through holes are formed in the portion thereof opposite to the microphone diaphragm, and the metal layer forms an electrode plate of the backplate; a plurality of dimples protruding from the lower surface of the microphone backplate opposite to the diaphragm; and an air gap provided between the diaphragm and the microphone backplate, wherein a spacer forming a boundary of the air gap is provided outside of the diaphragm or on the edge of the diaphragm, wherein a back hole is formed to be open in the substrate underneath the diaphragm so as to allow sound pass through, and the microphone diaphragm is used as an electrode plate to form a variable capacitive sensing element with the electrode plate of the microphone backplate.