Self-polarized pyroelectric LiTaO3 thin films

We present a characterization study to develop self-polarized, highly pyroelectric lithium tantalate thin films obtained by RF magnetron sputtering. A preliminary work is done on the bottom electrode to reduce short-term variations of the pyroelectric behavior. Then, the influence of pressure and of deposition temperature is studied to determine the best set of parameters as to obtain a large pyroelectric behavior. The crystalline structure modification as well as the influence on the pyroelectric coefficient have been studied in each case. An as-deposited pyroelectric coefficient as high as 32 μC.m^-2.K^-1 has been obtained for the optimal set of pressure (2 mTorr) and temperature (630 °C).