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

Abstract

Abstract 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°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 μm structure have been demonstrated. After annealing at 800°C, 140 nm thick films showed remanent polarizations of 2Pr = 25 μC/cm2 @ 5V and leakage currents between 10-8-10-9 A/cm2 @ 3 V. Endurance after 2x1011 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).