MICROSTRUCTURE AND EPITAXIAL CHARACTERISTICS OF PBTIO3 FERROELECTRIC THIN-FILM ON NACL BY MOCVD

Ferroelectric PbTiO3 thin films have been epitaxially grown on (100) N aCl cleavage surface by MOCVD using tetraethyllead and titanium isopro poxide as precursors. The microstructures and epitaxial characteristic s of as-grown thin films were investigated by means of transmission el ectron microscopy. TEM studies have shown that the epitaxial thin film was highly [001] oriented and even near single-crystal epitaxy if wit hout a small volume of 45 degrees rotated grains, the average grain si ze is around 1000 A. Low-angle grain boundary formed universally when islands coalesced during the early stage of epitaxial growth. A possib le growth mechanism has been given to explain this epitaxial phenomeno n by consideration of two-dimensional coincidence superlattice. 90 deg rees ferroelectric domains were also observed both in the large matrix grains and small 45 degrees rotated grains.