A SOI-MEMS Based Resonant Barometric Pressure Sensor with Differential Output

This paper presents a laterally driven resonant barometric pressure sensor fabricated using SOI-MEMS technology. In this device, pressure under measurement causes a deflection of a pressure-sensitive silicon square diaphragm, which is further translated to stress build up in "H" style doubly-clamped micro beams, leading to resonant frequency shift. In device fabrication, SOI-MEMS fabrication processes were utilized, where a new modified buffered hydrofluoric acid (BHF) solution was used to remove the buried oxide layer and release the suspended resonant beams. Experimental results recorded a device resolution of 10Pa, a nonlinearity of 0.04% and a temperature coefficient of -0.04% F.S/degrees C in the range of -40 degrees C to 30 degrees C. The long-term stability error of the proposed device was quantified as 0.05% F.S over the past 3 months.