Nanocrystalline Bi4Ti3O12 thin film for pressure sensor

Nanocrystalline Bi4Ti3O12 (BTO) thin film pressure sensor was fabricated by sol gel method. The multiple Bi-Ti-O layers were spin coated over the TiO2 buffered Si/SiO2/RuO2 substrate, followed by heating of each layer at 300 degrees C for 15 mins. The nanocrystalline Bi4Ti3O12 film was formed after the sample was rapid thermal annealed at 450 degrees C in air for 60 s. The scanning electron microscope result showed that the film exhibited crack free, fine and uniform grain structure, where the grain size obtained was around 10 to 15 nm. For the sensor response measurement, Al film was deposited as top electrode and the sensor tested by pneumatic loading method. The nanocrystalline Bi4Ti3O12 (BTO) thin film demonstrated good repeatability for the pressure sensing. The sensor achieved a linear characteristic response between 17.5 psi and 65 psi with sensitivity of 0.3 mV/psi.