Properties of SrBi2Ta2O9 thin films grown by MOCVD for high density FeRAM applications

A novel low temperature MOCVD process for SrBi2Ta2O9 (SBT) thin films is described. The process, which uses Bi(thd)(3) as the Bi source, allows deposition temperatures down to 300 degrees C enabling to maintain the integrity of the Pt bottom electrode. Excellent run-to-run repeatability and a step coverage > 90% on a 0.5 mu m structure have been demonstrated. After annealing at 800 degrees C, 140 nm thick films showed remanent polarizations of 2P(r) = 25 mu C/cm(2) @ 5V and leakage currents between 10(-8) - 10(-9) A/cm(2) @ 3 V. Endurance after 2x10(11) cycles was 90% using a 1.8 V, 1MHz square pulse signal. This manufacturable CVD process removes a further obstacle for production of high density ferroelectric memories (16M and above).