Preparation of biaxially aligned cubic zirconia films on pyrex glass substrates using ion-beam assisted deposition

Yttria stabilized zirconia films were deposited using ion-assisted, electron beam deposition (IBAD) on pyrex glass substrates heated to 600 °C. Films deposited under these conditions without IBAD exhibit fiber texture such that preferred (100) orientation exists perpendicular to the substrate. The orientation of the films has been studied as a function of ion bombardment angle, deposition rate, ion current density, and ion beam energy. Films deposited with IBAD at bombardment angles of less than 63° display strong (100) preferred orientation perpendicular to the substrate. Films having ion to atom ratios of 0.05 exhibit (220) biaxial alignment in the plane of the film. Best results were achieved for films with deposition rates of 2.4 Å/s, beam energies of 75 eV and ion fluences of 18 μA/cm2. Increasing the beam energy to 300 eV increases the concentration of wire texture in these films. Films deposited at higher ion/atom ratios (0.11 and 0.25) produce films with alignments highly dependent on the angle of ion bombardment. Processing conditions have been shown, therefore, to effect absolute orientation, and not just the quality of the pre-existing orientation. The microstructures of the biaxially aligned films have been studied and this has allowed for a clarification of the growth mechanism of these films. A growth instability of the differing orientations during ion bombardment is shown to cause in-plane alignment rather than preferential etching of misoriented nuclei.