Design, analysis, and modelling of a MEMS capacitive microphone for integration into CMOS circuits

Author

Ahmadnejad, Javad ; Ganji, Bahram Azizollah ; Nemati, Ali

Author_Institution

Electr. & Comput. Eng. Dept., Babol Noshirvani Univ. of Technol., Babol, Iran

fYear

2013

fDate

19-21 Dec. 2013

Firstpage

186

Lastpage

190

Abstract

A MEMS capacitive microphone with high mechanical sensitivity is presented. The microphone has a diaphragm thickness of 1 μm, 0.5 × 0.5 mm² dimension, and an air gap of 1.0 μm. Using the results from analysis and simulation, important features of MEMS capacitive microphone such as pull-in voltage, sensitivity and resonance frequency are respectively obtained as 3.8v, -43dbv/Pa, and 74 kHz. A model for this MEMS capacitive microphone is provided by using the relationship between capacitance of microphone and exerted pressure of acoustic wave. To study the accuracy of model, it is simulated in an RC circuit. The results from the simulations show that the proposed model has similar functions as a variable capacitor structure. Simulations show that voltage signal in steady state operates according to exerted pressure and has swing around the bias point of microphone (2.3 V).

Keywords

CMOS integrated circuits; capacitive sensors; micromechanical devices; microphones; CMOS circuits; MEMS capacitive microphone; RC circuit; acoustic wave; air gap; frequency 74 kHz; mechanical sensitivity; pull-in voltage; resonance frequency; size 1 mum; variable capacitor structure; voltage 2.3 V; voltage signal; Capacitance; Integrated circuit modeling; Micromechanical devices; Microphones; Resonant frequency; Semiconductor device modeling; Sensitivity; CMOS circuit; Capacitive microphone; Micro electromechanichal system (MEMS); mechanical sensivity; pull-in voltage; resonance frequency;

fLanguage

English

Publisher

ieee

Conference_Titel

Microelectronics and Electronics (PrimeAsia), 2013 IEEE Asia Pacific Conference on Postgraduate Research in

Conference_Location

Visakhapatnam

Print_ISBN

978-1-4799-2750-0

Type

conf

DOI

10.1109/PrimeAsia.2013.6731202

Filename

6731202