This paper presents a sensitivity-enhanced gas sensor based on a film bulk acoustic\nresonator (FBAR). It was designed and fabricated with micro through-holes in its top electrode\nfor sensitivity enhancement. The sensor was driven by a Colpitts oscillator circuit, and the output\nsignal had characteristics of a power of âË?â??2.6 dBm@3 V and a phase noise of âË?â??90 dBc/Hz@100 kHz.\nIn order to test the performance of the sensor, it was used for the detection of relative humidity\n(RH) and ethanol. When the relative humidity ranged from 25% to 88%, the frequency shift of\nthe sensor was 733 kHz, which was 3.2 times higher than that of the existing FBAR sensor with a\ncomplete top electrode. Fitting results of the frequency shift and the relative humidity indicated that\nthe measurement error was within Ã?±0.8% RH. When the ethanol concentration ranged from 0 to\n0.2355 g/L, the frequency shift of the sensor was 365 kHz. The effect of the oscillator circuit on the\nadsorption reaction and temperature response of the FBAR sensor device was analyzed to optimize\nits detection application.
Loading....