DEPENDENCE OF ELECTRICAL-PROPERTIES ON FILM THICKNESS IN PB(ZRXTI1-X)O3 THIN-FILMS PRODUCED BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

Strongly c-axis oriented Pb (ZrxTi1-x)O3 (PZT) thin films with tetrago nal perovskite structure (0.45 < x < 0.52) were epitaxially grown on ( 100)Pt/(100) MgO substrates using metalorganic chemical vapor depositi on. Film thickness could be varied by altering the growth time. The el ectrical properties of PZT thin films sharply change below a thickness of 0.5 mum: the dielectric constant and remanent polarization decreas e while the coercive field increases. These phenomena are explained by a model in which a layer with low dielectric constant exists in serie s with the normal PZT layer. The origins of this layer are systematica lly studied and found to be the intrinsic stress produced by the coale scence of crystal grains.