Study of MEMS technology and development of condenser microphone

This paper presents brief study of MEMS technology and development of condenser microphone with no holes in back plate. In general silicon materials are used in MEMs. MEMS devices can be fabricated by using bulk micromachining and surface micromachining. Microphone is designed by using a thin silicon crystalline material as flexible diaphragm and gold material as back plate. The aim of this paper is to study MEMS technology and development of microphone with more capacitance and sensitivity at low fabrication cost. With the help of equivalent circuit model, we have calculated pull-in voltage, resonant frequency, capacitance and sensitivity. Condenser Microphone has a diaphragm thickness of 20 μm, of square shaped diaphragm of area of 5mm × 5mm, air gap of 10 μm and back plate thickness of 20 μm. A 3V bias voltage is applied to the microphone. The sensitivity is 3.98 μV/Pa of microphone having no holes in back plate.