Crystallizing Process of Amorphous Thick Films of Ferroelectric Lead Germanate Family

Real-time investigation of crystallizing processes of amorphous thick films of ferroelectric lead germanate (PGO) and silicon-doped PGO (PGSO) is carried out using a high-temperature X-ray diffraction system. Two irreversible phase transitions took place near 370° C and 530° C on heating: the first is the crystallization from the amorphous to a metastable crystal state, and the second is from the metastable to a ferroelectric stable state of Pb 5 Ge 3 O 11 . Both transitions were completed very quickly, i.e., within approximately 7 and 58 min, respectively. The optimum heat-treatment conditions for fabricating well-oriented polycrystalline films were discussed together with the results of quick heating and quenching experiments.