Electrical characteristics of the MOD-derived SrBi sub(2x)Ta sub(2)O sub(9) and SrBi sub(2.4)(Ta,Nb) sub(2)O sub(9) thin films

Ferroelectric and leakage current characteristics of the MOD-derived SrBi sub(2x)Ta sub(2)O sub(9) (0.8 less than or equal to x less than or equal to 1.6) and SrBi sub(2.4)(Ta sub(1-y)Nb sub(y)) sub(2)O sub(9) (0 less than or equal to y less than or equal to 1) thin films were investigated. The SBT and SBTN films were fully crystallized to Bi-layered perovskite structure by annealing at 800 degree C for 1 hour in oxygen atmosphere. The ferroelectric characteristics of the SBT films were optimized at the Bi/Ta mole ratio x of 1.2. The leakage current density of the Bi-excess SBT films decreased remarkably by the post-metallization annealing at 800 degree C for 10 minutes in oxygen ambient. The ferroelectric characteristics of the SBTN films were optimized with the SBN content y of 0.25. The SrBi sub(2.4)(Ta sub(0.75)Nb sub(0.25)) sub(2)O sub(9) film exhibited 2P sub(r) and E sub(c) of 19.04 mu C/cm super(2) and 24.94 kV/cm at plus or minus 5 V, which were superior to 2P sub(r) of 11.3 mu C/cm super(2) and E sub(c) of 39.6 kV/cm obtained for the SrBi sub(2.4)Ta sub(2)O sub(9) film after the post-metallization annealing. The MOD-derived SrBi sub(2.4)(Ta sub(0.75)Nb sub(0.25)) sub(2)O sub(9) film did not exhibit the polarization fatigue after 10 super(11) switching cycles at plus or minus 5 V.