Chemical processing and dielectric properties of ferroelectric SrBi2Ta2O9 thin films

Ferroelectric SrBi2Ta2O9 (SET) thin alms were prepared on Pt/SiO2/Si substrates at 800 degrees C by MOD and sol-gel methods. SET thin films prepared by the MOD method using strontium 2-ethylhexanoate, bismuth 2-ethylhexanoate and tantalum ethoxide showed a fine-grained structure with grain sizes of about 130 nm. The SBT thin films with a thickness of 400 nm exhibited epsilon(r) of about 180, P-r of about 4.5 mu C/cm(2) and E(c) of 60 kV/cm. No fatigue was observed up to 10(9) switching cycles, On the other hand, in the sol-gel method, SET thin films crystallized with a high (105) diffraction intensity at 650 degrees C, but with a highly (00l) preferred ed orientation at 800 degrees C. The thin films showed grain structure with grain sizes of 100-300 nm. The sol-gel-derived 390 nm-thickSET films with random orientation exhibited epsilon(r) of about 100, P-r of about 2.8 mu/cm(2) and E(c) of 108 kV/cm.