A patterning technique of lead zirconate titanate thin film by ultraviolet-light

Abstract

The patterning technique of PZT thin film is an essential process in device fabrication processes for application in microsensors and microactuators. Chemical etching and physical etching processes are two of the most commonly used techniques to pattern PZT thin film. However, the difference in etching yields of Pb, Zr, and Ti leads to undesired residues on PZT films in chemical etching process. The poor selectivity of PZT over photoresist mask and platinum electrodes causes unsatisfactory PZT pattern. This thesis developed a PZT pattern technique by photolysis processes PZT thin films were first spin coated on the substrate and exposed by UV light for photolysis step. The UV photolysis step defined exposed and unexposed area by mask, and the pattern will be transferred to PZT thin film. After photolysis, PZT films were placed in non-ionic surfactant to remove unexposed area. Finally, PZT films were sintered at 650°C in the furnace for crystallization. Experimental results showed that remnant polarization of PZT film by UV photolysis was 21.4(µc/cm2), which was compared to 17.24(µc/cm2) by hot plate prolysis. Coercive fields were 45 and 104 kV/cm by UV photolysis and hot plate prolysis, respectively. Dielectric loss was 0.027 by UV photolysis which was much smaller than 0.043 by hot plate prolysis. PZT thin films patterned by UV photolysis showed satisfactory geometries.