Characteristics of single crystal "thin film" capacitor structures made using a focused ion beam microscope

The focused ion beam microscope was used to isolate thin parallel-sided lamellae from single crystals of BaTiO3 and SrTiO3. Damage and ion-implantation on the faces of the lamellae were observed, but could be removed by thermal annealing. A series of lamellae ranging in thickness from similar to660 to similar to300 nm were made from a SrTiO3 single crystal, and after thermal annealing, gold electrodes were deposited on either side to form parallel-plate capacitor structures. The room temperature functional properties of these single crystal "thin film" capacitors were investigated. Although space-charge artifacts dominated the low frequency response, above 10 kHz, examination of the change in capacitance as a function of lamellar thickness allowed the room temperature relative dielectric constant to be meaningfully extracted. This was found to be similar to300, as is the case in bulk. For these single crystal lamellae there was therefore no evidence of a collapse in dielectric constant associated with thin film dimensions. (C) 2004 American Institute of Physics.