Design and characterization of microfabricated piezoresistive floating element-based shear stress sensors

作者：Barlian A Alvin^*; Park Sung Jin; Mukundan Vikram; Pruitt Beth L

来源：Sensors and Actuators A: Physical , 2007, 134(1): 77-87.

DOI：10.1016/j.sna.2006.04.035

• shear stress sensor
• in-plane force
• out-of-plane force
• piezoresistors
• piezoresistive
• ion implantation
• oblique-implant
• underwater
• floating element
• MEMS
• micromachined

This paper presents the design, fabrication, and characterization of unique piezoresistive microfabricated shear stress sensors for direct measurements of shear stress underwater. Sidewall-implanted piezoresistors measure lateral force (integrated shear stress) and traditional top-implanted piezoresistors detect normal forces. In addition to the oblique-implant technique, the fabrication process includes a hydrogen anneal step to smooth scalloped silicon sidewalls left by the deep reactive ion etch (DRIE) process. This step was found to reduce the 1/f noise level by almost an order of magnitude for the sidewal I-implanted piezoresistors. Lateral sensitivity was characterized using a microfabricated silicon cantilever force sensor. Out-of-plane sensitivity was evaluated by laser Doppler vibrometry and resonance of the plate element. In-plane sensitivity and out-of-plane crosstalk were characterized, as well as hysteresis and repeatability of the measurements. TSUPREM-4 simulations were used to investigate the discrepancies between the theoretical and experimental values of sidewall-implanted piezoresistor sensitivity. The sensors are designed to be used underwater for studies of hydrodynamic flows.

• 出版日期2007-2-28