Abstract
Abstract This study reports a CMOS-MEMS condenser microphone implemented using the standard thin film stacking of 0.35 μm CMOS 3.3/5.0V logic process, and followed by post-CMOS micromachining steps without introducing any special materials. The corrugated diaphragm for the microphone is designed and implemented using the metal layer to reduce the influence of thin film residual stresses. We improved the acoustical sensitivity from design and process parameters, such as diaphragm thickness, diaphragm size, air gap distance, and vent hole ratio on back-plate, etc. Moreover, a silicon substrate is employed to increase the stiffness of the back-plate. Measurements show the sensitivity of microphone is ?42 ± 3 dBV/Pa at 1 kHz (the reference sound-level is 94 dB) under 6 V pumping voltage, the frequency response is 100 Hz–10 kHz, and the S/N ratio >55 dB. It also has low power consumption of less than 200 μA, and low distortion of less than 1% (referred to 100 dB). By the way, reliability concepts are potentially applicable in diaphragm vibration, and the issues of reliability and long-term survivability are crucial factors to yield a good performance in MEMS microphone.