Growth and thermal stability of Sc-doped BaZrO3 thin films deposited on single crystal substrates

Thin films of BaZr1-xScxO3-x/2, (0 <= x <= 0.64), well known as proton conducting solid electrolytes for interme-diate temperature solid oxide fuel cell, were deposited by magnetron sputtering. X-ray diffraction analysis of the as deposited films reveals the presence of single-phase perovskite structure. The films were deposited on four different substrates (c-Al2O3, LaAlO3100, LaAlO3110, LaAlO3111) yielding random, (110)-or (100)-ori-ented films. The stability of the as-deposited films was assessed by annealing in air at 600 degrees C for 2 h. The annealing treatment revealed instabilities of the perovskite structure for the (110) and randomly oriented films, but not for (100) oriented film. The instability of the coating under heat treatment was attributed to the low oxygen content in the film (understoichiometry) prior annealing combined with the surface energy and atomic layers stacking along the growth direction. An understoichiometric (100) oriented perovskite films showed higher stability of the structure under an annealing in air at 600 degrees C.