Process and fabrication of a lead zirconate titanate thin film pressure sensor

Lead zirconate titanate (PZT) ferroelectric material is highly attractive for sensor and actuator device applications. Static pressure sensor structures were fabricated using sol-gel deposited PZT spin coated onto Pt/SiO2/Si substrates, with the platinum layer forming the bottom electrode. A subsequent platinum layer deposited onto the PZT formed the device top electrode. The resultant Pt/PZT/Pt/SiO2/Si stacks were patterned with photoresist and defined by ion beam milling and reactive ion etching in a HC2ClF4 plasma to form electrical capacitor structures. Capacitance measurements were performed on 200 μmx200 μm and 300 μmx300 μm dimension structures over the frequency range 0.12-100 kHz. Capacitance remained relatively unchanged over this frequency range, with a magnitude corresponding to its predicted value along with a low dissipation factor (0.02), thus verifying the high quality of the device structures. The device is intended to measure pressure in the range of 10 000-100 000 psi