Microstructural evolution of dense and porous pyroelectric Pb1-xCaxTiO3 thin films

Pb1-xCaxTiO3 thin films with x = 0-0.3 for pyroelectric applications were d eposited on platinized silicon wafers by chemical solution processing. Ca-s ubstitution for Pb in PbTio(3) results in a reduced cia ratio of the unit c ell, which, in turn, leads to better pyroelectric properties. Control of nu cleation and growth during rapid thermal annealing to 650 degrees C allowed the formation of either highly porous or dense (111) oriented films. The i nclusion of pores creates a matrix-void composite with the low permittivity desired for pyroelectric applications, resulting in a high figure of merit . The growth mechanisms for the microstructural evolution of both dense and porous films were analyzed by x-ray diffraction, transmission electron mic roscopy, scanning electron microscopy, and Rutherford backscattering spectr ometry and allowed establishment of microstructure/property relationships.