Al:ZnO top electrodes deposited with various oxygen pressures for ferroelectric (Pb,La)(Zr,Ti)O 3 capacitors

Abstract

Ferroelectric (Pb,La)(Zr,Ti)O3 capacitors were fabricated using chemical solution deposition with Al:ZnO (AZO) top electrodes that were deposited using pulsed laser deposition (PLD), where the oxygen pressure was varied systematically. The oxygen pressure during deposition of the AZO layer affected the surface morphology of the AZO top electrodes, as well as the ferroelectric properties of the capacitors. As the oxygen pressure increased, the AZO grains gradually appeared clearer in the SEM images, indicating less dense stacking, and the polarisation–voltage hysteresis loops expanded horizontally. The largest values of remnant polarisation and coercive voltage were obtained at 10 Pa. Appropriate ferroelectric properties were obtained for oxygen pressures in the range of 0.5–2.0 Pa. The hydrogen degradation resistance during annealing in 3% H2 200°C and 1 Torr was independent of oxygen pressure during PLD.