Preparation and use of mosaic target for the deposition of ferroelectric bismuth titanate thin films

Ion beam sputter deposition using a Kaufman source is a well-established technique for fabricating thin films. This method has the capability for yielding smooth surfaces and depositing uniform films over a large area. We have used this technique, in the past, with a 5 inches diameter target to deposit smooth ferroelectric bismuth titanate (Bi₄Ti₃O₁₂) films. One of the major obstacles was fabricating the large target with the desired composition. To reduce cost by simplifying the target preparation process we developed a `mosaic' target to deposit ferroelectric Bi₄Ti₃O₁₂ films. Films were deposited at different substrate temperatures. Measurements show that the post-annealing of the deposited films results in measurable ferroelectric properties and enhanced low field dielectric behavior in the films. The discussion will include the target fabrication, the observed properties of the resultant films, and the effect of the deposition and post-annealing temperatures on the film properties.