Composition for forming Bi-based ferroelectric thin film, Bi-based ferroelectric thin film and method for producing the same

摘要

PROBLEM TO BE SOLVED: To attain high residual polarization and to reduce the fatigue of a film without producing a thermally harmful effect on a substrate by substituting Ba and/or Pb for a part of Sr in a compsn. for an Sr-Bi-Ta ferroelectric substance. SOLUTION: Metallic compds. are mixed in an org. solvent so that the molar ratio among the metals in the resultant soln. is represented by A:B:C=X:Y:Z (where A is Sr and Ba and/or Pb, B is Bi, C is Ta and/or Nb, 0.4=X1.0, 1.5=Y=3.5 and z=2) and the molar ratio among Sr, Ba and Pb is represented by Sr:Ba:Pb=a:b:c (where 0.7X=aX and 0b+c=0.3X). The resultant compsn. for a thin film of a Bi-contg. ferroelectric substance is applied on a substrate, dried and calcined. These processes are repeated several times until the desired film thickness is attained and the formed thin film is fired and crystallized to obtain the objective thin film of a Bi-contg. ferroelectric substance.