Development of high frequency SAW devices devoted for pressure sensing

The paper presents a successful demonstration of 0-level packaged SAW pressure sensors developed on GaN/Si thin membranes (1.3 μ m/ 10 μ m) with a backside Mo metallization (30 nm). FEM simulations were performed in order to predict the mechanical behavior of the membrane and of the package. One-port SAW devices having IDTs of 120 nm width were fabricated bye-beam nanolithography. High values of the sensitivity (1102 kHz/Bar) and of the pressure coefficient of frequency (126 ppm/Bar) have been obtained due to the very high frequency operation (8.7 GHz) of the SAW. An insignificant dropping of these values was obtained after the bonding of the capsule.