Fabrication and annealing effect of c-axis orientated potassium lithium niobate thin film on glass substrate

Potassium lithum niobate (KLN; K3Li2Nb5O15) thin films were prepared by an rf-magnetron sputtering technique using a sintered K- and Li-excessed targe t. In this experiment the optimum sputtering conditions were an rf power of 100 W, working pressure of 150 mTorr, and substrate temperature of 600 deg rees C. When the KLN was grown on a Coming 1737 glass substrate at a temper ature of 600 degrees C with a sputtering pressure range of 50-200 mTorr the thin film KLN was (001) oriented. The (001) preferred orientation of a KLN thin film is due to the minimum surface energy of the (001) plane. The lat tice constant of an as-grown thin film has a slightly larger value than the tetragonal tungsten bronze structure range. The lattice constant and full width half maximum (FWHM) of the thermal-treated films were shrunk by the s tress relaxation of the thin film. When annealing at a temperature of 650 d egrees C the value of the lattice constant of the c-axis was in the middle of the tetragonal structure range. Accordingly, the use of a K- and Li-enri ched sintered KLN target enables the fabrication of c-axis-oriented ferroel ectrics directly onto an amorphous substrate.