Lead zirconate titanate MEMS accelerometer using interdigitated electrodes

Piezoelectric bulk micromachined accelerometers have been designed and fabricated using silicon micromachining techniques. These devices use interdigitated (IDT) electrodes to exploit a combination of the d₃₃ and d₃₁ piezoelectric responses of lead zirconate titanate (PZT) thin films. A simple fabrication process involving only three photomasks and two deep-trench reactive ion-etching (DRIE) steps has been developed. Frequency response measurement has been used to measure the sensitivity of the devices as well as the bandwidth. Voltage sensitivities in the range of 1.3-7.86 mV/g with corresponding resonance frequencies in the range of 23-12 kHz have been obtained for these accelerometers. The voltage sensitivity mode of the interdigitated electrode accelerometer results in a higher acceleration sensitivity than that for a through-the-thickness poled PZT accelerometers with identical device structure.