A COMPARATIVE-STUDY OF TUNABLE BA1-XSRXTIO3 THIN-FILM CAPACITORS PREPARED BY RF-SPUTTERING AND LIQUID-PHASE DEPOSITION

Ba1-xSrxTiO3 thin film capacitors have been successfully prepared usin g rf-sputtering and a metal organic deposition (MOD) method. The struc ture, microstructure and composition of the BSTO films are presented. Films grown on lanthanum aluminate LAO(100) showed c-axis preferred gr owth orientation. Broad paraelectric-to-ferroelectric transitions were observed in films prepared by both methods. The tunability of the cap acitance by means of an appplied electric field is examined using vari ous capacitor geometries. A decrease in the capacitance exceeding 75% at 77 K was obtained from the MOD deposited films under an electric fi eld strength of 0.3 MV/cm. On the other hand, the tunability of the ca pacitance in the rf-sputtered films ranged from 5 to 10% at 77 K and a t 20 kV/cm, while it exceeds 50% in some films. The results are compar ed with the predictions of Devonshire's phenomenological theory.