Structure control of pulsed laser deposited ZrO2/Y2O3 films

Structure control in the laser ablation deposition of yttria stabilized zir conia (YSZ) films is explored. A focus was given to a low temperature growt h of tetragonal and cubic YSZ films with [001] growth orientation. using su rface ion bombardment. Unlike an ion-beam assisted pulsed laser deposition, the ion bombardment was achieved by the acceleration of zirconium ions fro m the ablation plumes themselves with a negative substrate bias. The large degree of zirconium ionization was obtained by using low pressure Ar backgr ounds. Correlation between substrate bias, film lattice parameters, orienta tion. surface microtopography, stress, and hardness are discussed. Film str uctural change from nearly amorphous and predominantly (111) oriented to di storted tetragonal and to cubic with (002) orientation were observed as the bias was increased from zero to -300 V in 0.2 Pa Ar environment. The techn ique was used to produce single-axis oriented YSZ films with a smooth (002) surface and 30 GPa hardness on a number of single and polycrystalline subs trates at 100 degreesC deposition temperature. (C) 2001 American Vacuum Soc iety.