Thermionic electron emission enhancement of PZT thin films sputter deposition

Abstract

In this study, PZT thin films are deposited using a novel dual-target (PZT/PbO) RF magnetron sputtering system coupled with plasma enhancement by hot filament thermionic electron emission. The plasma enhancement is expected to allow the deposition temperature to be decreased while retaining the desired properties of the PZT thin films. The influence of the intensified plasma to the structure of the deposited PZT films is investigated and correlated to its ferroelectric properties. The results show that with thermionic enhancement, high remnant and saturation polarization values of 31 μC/cm 2 and 76 μC/cm 2, respectively, are obtained at a deposition temperature of 550 °C if the higher PZT to PbO target power ratio is used; polarization behavior is not observed for the same deposition temperature without thermionic support. For the lower PZT to PbO target power ratio, improved polarization behavior is observed for the coating deposited at 580 °C with thermionic support. Moreover, film growth rate at this power ratio is increased on average by a factor of 1.7 with thermionic enhancement. This study presents the possibility of utilizing a thermionically enhanced plasma to aid in the deposition of ferroelectric PZT thin films by allowing either the deposition time or temperature to be reduced.