Recovery process of degraded ferroelectric properties in the forming-gas-annealed Pt/Bi4-xLaxTi3O12/Pt capacitor

The recovery of ferroelectric properties in the forming-gas-annealed Pt/Bi4-xLaxTi3O12/Pt (Pt/BLT/Pt) capacitor was studied by examining changes in ferroelectric responses, phase evolution, and spatial distributions of relevant species during the recovery annealing. The degraded ferroelectric properties were practically restored to their original values after the recovery annealing at 600 degreesC for 10 min in an O-2 atmosphere. The following recovery process has been delineated from the present study: (i) the removal of impregnated protons from the degraded capacitor due to the chemical potential difference of protons between the forming-gas-annealed capacitor and the contacting atmosphere, and (ii) the restoration of perovskite BLT phase with the help of replenishment of the Bi and oxygen losses via diffusion from the neighboring intact region to the Bi-depleted columnar region located beneath the top Pt electrode. (C) 2003 American Institute of Physics.