Title :
A polymer condenser microphone on silicon with on-chip CMOS amplifier
Author :
Pedersen, Michael ; Olthuis, Wouter ; Bergveld, Piet
Author_Institution :
MESA Res. Inst., Twente Univ., Enschede, Netherlands
Abstract :
In this paper the development of a capacitive microphone with integrated preamplifier is described. The condenser microphone is made by micromachining of polyimide on silicon, and is compatible with CMOS technology. Therefore, the structure can be realised by post processing on substrates containing integrated circuits, independently of the IC process. Microphones with a required DC bias voltage of 4 V have been realised on a CMOS substrate containing PMOS buffer preamplifiers. From the measurements on these structures, it is illustrated how an immediate improvement of 4.8 dB of the microphone sensitivity and noise level can be obtained by using the integrated preamplifier. The measured sensitivity of the integrated condenser microphone was 2.5 mV/Pa and the equivalent noise level (ENL) was 29.5 dB(A) SPL
Keywords :
CMOS analogue integrated circuits; frequency response; integrated circuit measurement; integrated circuit noise; micromachining; microphones; microsensors; polymer films; preamplifiers; 4 V; CMOS technology compatibility; DC bias voltage; PMOS buffer preamplifiers; Si; capacitive microphone; equivalent noise level; frequency response; integrated preamplifier; micromachining; microphone sensitivity; on-chip CMOS amplifier; polyimide; polymer condenser microphone; post processing; twin-well CMOS process; CMOS technology; Integrated circuit technology; Micromachining; Microphones; Noise level; Noise measurement; Polyimides; Polymers; Preamplifiers; Silicon;
Conference_Titel :
Solid State Sensors and Actuators, 1997. TRANSDUCERS '97 Chicago., 1997 International Conference on
Conference_Location :
Chicago, IL
Print_ISBN :
0-7803-3829-4
DOI :
10.1109/SENSOR.1997.613681
