CHARACTERIZATION OF LITHIUM TANTALATE THIN-FILMS SPUTTER-DEPOSITED ONTO RUO2 SI SUBSTRATES/

Lithium tantalate thin films have been prepared by reactive rf sputter ing from a ceramic target. The films deposited on RuO2-coated silicon at room temperature are initially amorphous. The films were crystalliz ed by annealing in an oxygen flow at various temperatures using two pr ocesses. In the first process, the samples were annealed for one hour and in the second they were subjected to rapid thermal annealing (RTA) for 45 seconds. X-ray diffraction shows that in both cases, crystalli zation starts above 500 degrees C. Transmission electron microscopy re veals that films subjected to RTA contain significant amounts of inter - and intragrain porosity as 8 nm bubbles. The composition depth profi le of the films has been determined by secondary ion mass spectrometry . The influences of deposition and annealing parameters on the film mi crostructure and composition are discussed.