The world's smallest MEMS chip—a tiny 700 square micron digital microphone—was fabricated recently by Bosch Sensortec GmbH for its subsidiary Akustica Inc. The CMOS die integrates a mechanical microphone diaphragm in a sea of mixed signal CMOS circuitry that culminates in a standard PDM (pulse density modulation) output.
Using Bosch's CMOS process, Akustica has shrunk the size of its die by 80 percent, yielding five-times as many chips per wafer.
The MEMS microphone market topped 695 million units in 2010, up more than 57 percent from the 441 million units shipped in 2009, according to IHS iSuppli (El Segundo, Calif.), which predicts that shipments will rise to more than 1.7 billion units, or $471 million, by 2014. Applications for MEMS microphones include mobile phones, touchscreen tablets, PCs, laptops, netbooks, video- and audio-recorders, Bluetooth headsets and camera modules.
Further Reading: http://bit.ly/NextGenLog-f3y9