Effect of Poly(vinylpyrrolidone) As a Stress-Relaxing Additive in Fabrication of PbZrxTi1-xO3 Thin Films Using Sol–Gel Route

We investigated how poly(vinylpyrrolidone) (PVP) suppresses crack generation during fabrication. It was confirmed that PVP plays the role of a stress-relaxing agent by in situ stress development measurement at temperatures from 200 to 300 °C. We found that PVP in the film was removed in two steps and that the residual PVP-decomposition product can be the cause of void generation. It was revealed that Young's modulus of the lead zirconate titanate (PZT) film prepared from PZT–PVP-sol was lower at temperatures from 300 °C to less than that from 400 °C than from PZT-sol during fabrication despite the fact that the each values at 450 °C are almost the same. It implies that PVP suppress crack formation by degrading Young's modulus of the film before crystallization. We obtained a 2-µm-thick PZT film with only 10 coatings and its electrical properties is equivalent to previously reported values obtained using the sol–gel route.