Deposition of titanium dioxide nanoparticles on the membrane of a CMOS-MEMS resonator

Abstract

A CMOS-MEMS resonator is optimized as a highly sensitive gas sensor. The principle of detection is based on change in resonant frequency of the resonator due to adsorption/absorption of trace gases onto the active material on the resonator membrane. The resonator was successfully fabricated using 0.35 μm CMOS technology and post-CMOS micromachining process. The post-CMOS process is used to etch the silicon substrate and silicon oxide to release the suspended structures of the devices. Preliminary trials of nanocrystalline Titania paste (TiO2) was screen-printed on three aluminum plates of sizes 2mm × 2 mm. One of the samples was analysed as prepared while the other two samples were sintered at 300°C and 550°C, respectively. Physical observation indicated a change of the color for heated samples as compared to the unheated one. EDX results indicates a carbon (C) peak with average weight % of 18.816 in the as prepared sample and absence of the peaks for the samples sintered at 300°C and 550°C. EDX results also show that the TiO2 used consists of a uniform distribution of spherical shaped nanoparticles with a diameter of about 13.49 to 48.42 nm. Finally, the Titania paste was successfully deposit on the membrane of the CMOS-MEMS resonator for use as the gas sensitive membrane of the sensor.