Verfahren zur Herstellung einer piezoelektrischen Dünnschicht

摘要

A piezoelectric thin film having good properties, for example, a high dielectric constant and a high piezoelectric strain constant is disclosed. Further, a method for producing the same which does not suffer from cracks at the time of annealing is also disclosed. The piezoelectric thin film according to the present invention comprises a thin film with the average grain area of crystal grains observed on the surface of the thin film being not less than 0.1 mu m<2>, the thin film having no multilayer structure in its cross section. The method for producing the piezoelectric thin film is based on a sol-gel process and comprises the steps of: coating a substrate with a sol composition comprising a sol, of a metal component for constituting a piezoelectric film, and a polymer compound and then drying the coating to form a film; pre-sintering the film to form a porous thin film of gel comprising an amorphous metal oxide; pre-annealing the porous thin film of gel to convert the film to a film of a crystalline metal oxide; repeating the steps at least once to form laminated films of a crystalline metal oxide; and annealing the films thus prepared to grow crystal grains of perovskite type in the film into a larger size.