Ferroelectric thin films of PbTiO₃ system prepared by sputtering deposition and their application to pyroelectric sensors

Abstract

Highly c-axis oriented PbTiO₃,Pb_1−x/4O₃(PLT), and tetragonal PbZr_xTi_1−xO₃(PZT) thin films were successfully grown with good epitaxy on (100)-cleaved MgO single crystal and [100]-oriented Pt thin films by rf-magnetron sputtering method. It was found that the thin films have large pyroelectric currents and high figures of merit for infrared (IR) sensors without a poling treatment. High sensitive pyroelectric infrared sensors (point and linear array type) were fabricated by using PLT thin films with x = 0.1 (PL10) which are the most suitable for pyroelectric material. The linear array sensors with reticulated PL10 have a remarkably high specific detectivity D* of 5 × 108 cm Hz^1/2/W and a very low thermal cross talk of 3% at 100 Hz.