Mechanical deformation of PZT thin films for MEMS applications

The mechanical properties of solution deposited lead zirconate titanate (PZ T) thin films; including the hardness, modulus, and fracture behavior, have been studied using continuous indentation methods. Comparisons are made be tween the behavior of the thin films and a bulk PZT ceramic. The thin films exhibit a hardness between 5 and 8 Gpa, slightly lower than the hardness m easured in a bulk PZT, approximate to 9 Gpa. The increased grain boundary a rea in the thin films, which have 100 nm grain sizes, may act to accommodat e plastic deformation. Fracture caused by indentations appears to be constr ained to the sub-surface regions of the film, and no evidence of indentatio n induced delamination was observed. Traditional indentation analysis canno t accurately determine the elastic modulus of thin film PZT materials due t o non-linear elastic behavior. The apparent modulus of the thin film PZT is insensitive to processing methods that alter the electrical properties of the film. (C) 1999 Elsevier Science S.A. All rights reserved.