Monolithic complementary metal-oxide semiconductor (cmos) - integrated silicon microphone

A method, comprising:

• forming a diaphragm and a backplate between first and second dielectric layers arranged over a first substrate, wherein the first dielectric layer is formed between the diaphragm and the first substrate, wherein the backplate is formed between the diaphragm and the second dielectric layer, and wherein the diaphragm and the backplate are separated by a sacrificial layer;
• bonding the second dielectric layer to a third dielectric layer disposed over a second substrate, which includes at least one semiconductor device;
• removing the first substrate;
• forming a first recess extending from an upper surface of the first dielectric layer to an upper surface of the diaphragm;
• forming a second recess extending from a lower surface of the second substrate to a lower surface of the backplate;
• and
• removing the sacrificial layer to create an air gap between the diaphragm and the backplate, which joins the first and second recesses to form a cavity extending continuously from the lower surface of the second substrate to the upper surface of the third dielectric layer.

A sensor, comprising:

• a substrate including at least one semiconductor device;
• one or more dielectric layers arranged over an upper surface of the substrate;
• a cavity, which continuously extends from a lower surface of the substrate through an upper surface of the one or more dielectric layers facing away from the substrate;
• and
• a microelectromechanical system (MEMS) capacitor, comprising a conductive diaphragm arranged over the upper surface of the substrate, and a conductive backplate, which is arranged within the one or more dielectric layers between the conductive diaphragm and the substrate.