STUDY ON THE GROWTH OF BIAXIALLY ALIGNED YTTRIA-STABILIZED ZIRCONIA FILMS DURING ION-BEAM-ASSISTED DEPOSITION

(001)-oriented and in-plane aligned yttria-stabilized zirconia (YSZ) t hin films were synthesized on Ni-Cr alloy substrates by ion beam assis ted deposition. It was found that it is not the (111) axial channel bu t the {110} plane channel that will always follow the direction of the bombarding ion beam and will result in the in-plane aligned structure of the YSZ films. At 55 degrees incident angle, the bombarding ion be am is in the {110} plane channel and the (111) axial channel simultane ously; this produces the optimal biaxial alignment of YSZ films. On YS Z single crystalline substrates or textured YSZ layers, growth of YSZ films will not be controlled by the bombarding ion beam; rather, but t he films continue to grow along the lattice orientation of the substra te. The formation of the biaxial alignment is an evolutionally selecte d process by ion beam selective bombardment. YSZ grains of (001) orien tation are resputtered less than other oriented grains under ion beam bombardment, which causes the (001) orientation to emerge from initial random orientations evolutionally. About a 1000 Angstrom-M20 thicknes s is needed to develop the alignment. The roughness of the substrate h as no obvious influence on the alignment within several hundred ii. In creasing the substrate temperature tends to reduce the (001) orientati on and to promote the (111) orientation along the substrate normal. Po stannealing of the YSZ films fabricated at ambient temperature can imp rove the crystalline structure. (C) 1997 American Vacuum Society.