Deposition of 60 nm thin Sr0.8Bi2.2Ta2O9 layers for application in scaled 1T1C and 1T FeRAM devices

Voltage scaling of 1T1C and 1T FeRAM devices requires the optimization of very thin ferroelectric layers. A current challenge is to deposit thin films on relevant substrates with minimized degradation of bulk ferroelectric properties. In this work, we characterize the microstructure of 60 nm thin SBT films deposited either by MOD or MOCVD on Pt, SiO2, Si3N4, and HfO2. We show that MOCVD is more suited than MOD to deposit layers with dense microstructure, and that the substrate dependence of the microstructure is strongly reduced for MOCVD layers. We discuss crystallization mechanisms for both techniques and we correlate them to the better ferroelectric properties of MOCVD films.