Effect of crystallization ambient on orientation selection in sol-gel derived Pb(Zr,Ti)O3 thin films on Pt electrode layers

Studies are presented on the role Of pO(2) in orientation selection during crystallization annealing of sol-gel derived PZT films on Pt electrode layers. Residual organics, left in the film after a short (10 s) pyrolysis step at 350C, result in a sharp (111) PZT fiber texture in the crystallized films. Meanwhile, longer pyrolysis times, resulting in complete removal of all oxidizable carbon from the film, result in mixed (111)/(100) oriented films. These results suggest that a reduced pO(2) at the PZT/Pt interface, caused by residual organic burnoff during the crystallization step, plays an essential role in the nucleation of (111) grains. Very thin (< 100 nm) films crystallized in air are fully (100) oriented, presumably because due to the greater transparency of these films to ambient O-2, nucleation of (111) grains is entirely suppressed. By performing the crystallization in N-2, the sharp (111) orientation could be recovered, confirming pO(2) as the key factor controlling orientation selection in very thin films.