Optimization of Deposition Conditions of SrBi2Ta2O9 Thin Films in Radio-Frequency Magnetron Sputtering

SrBi2Ta2O9 thin films were fabricated on Pt/Ti/SiO2/Si substrates at various sputtering pressure and target-to-substrate distance using radio-frequency magnetron sputtering in this study. The compositions of the deposited films significantly vary with sputtering pressure and target-to-substrate distance. Both strontium and bismuth contents decrease with increasing the process pressure; however, only bismuth content increases with the target-to-substrate distance. The sputtering pressure and target-to-substrate distance also affect the electrical properties. The leakage current of prepared films increases not only with an increase in the target-to-substrate distance, but also with a decrease in the sputtering pressure. The remanent polarization value (2Pr) of SBT films deposited under 100 mtorr at the target-to-substrate distances of 3 cm is 5.3 µC/cm2, and no significant fatigue is found after 109 switching cycles.