Title :
Micro-machined resonant out-of-plane accelerometer with a differential structure fabricated by silicon-on-insulator–MEMS technology
Author :
Junbo Wang ; Yanlong Shang ; Jian Chen ; Zhenguo Sun ; Deyong Chen
Author_Institution :
State Key Lab. of Transducer Technol., Inst. of Electron., Beijing, China
fDate :
12/1/2012 12:00:00 AM
Abstract :
A new micro-machined resonant accelerometer with a differential structure enabling the detection of out-of-plane acceleration is described. The microaccelerometer consists of two sensitive structures composed of seismic masses, flexural hinges and double-clamped resonant beams. Owing to thickness differences and neutral axis variations among these three components, in response to an out-of-plane acceleration, the movements of the seismic masses lead to stress build up in flexural hinges, further translated as axial forces applied on resonant beams. In this differential design, under acceleration, one resonant beam is under a tensile stress, whereas the other one is under a compressive stress, producing a differential resonant frequency output. The microaccelerometer was fabricated by a silicon-direct-bonding silicon-on-insulator wafer with MEMS fabrication and a low-stress packaging method was also developed. Based on a closed-loop control circuit for resonant beam excitation and detection, device characterisation was conducted, producing a quality factor of 436 in air and a differential sensitivity of 813 Hz/g.
Keywords :
Q-factor; accelerometers; compressive strength; elemental semiconductors; hinges; micromachining; microsensors; seismology; silicon-on-insulator; stress analysis; tensile strength; MEMS fabrication; axial force translation; clamped resonant beam; closed loop control circuit; compressive stress; differential resonant frequency; differential sensitivity; differential structure; flexural hinge; microaccelerometer; micromachined resonant accelerometer; neutral axis variation; out-of-plane acceleration detection; packaging method; quality factor; resonant beam detection; resonant beam excitation; seismic mass; silicon direct bonding; silicon-on-insulator; tensile stress;
Journal_Title :
Micro & Nano Letters, IET
DOI :
10.1049/mnl.2012.0536