Effect of deposition temperature of TiO_2 on the piezoelectric property of PbTiO_3 film grown by PbO gas phase reaction sputtering

摘要

A 17 nm thick PbTiO_3 (PTO) films were fabricated via PbO gas phase reaction with TiO_2 starting layer in a sputtering chamber. The influence of deposition temperature of TiO_2 on the piezoelectric properties of PTO thin films was investigated. The remnant piezoresponse of PTO films nonlinearly increased as a function of TiO_2 deposition temperature, which is correlated with the increase in average grain diameter of PTO film. As grain size increases, the restriction on remnant piezoresponse imposed by the grain boundary via coupling between local strain and polarization becomes less pronounced, which results in the increase in remnant piezoresponse. Furthermore, we found that the vertical shift in piezoresponse hysteresis loops is closely related to the residual stress state. A strong correlation between the negative vertical shift and the residual tensile stress reveals that residual stress on the resulting PTO film contributed to the asymmetric piezoelectric property.