Effects of film thickness and process parameters on the properties of SrBi2Ta2O9 ferroelectric capacitors for non-volatile memory applications

Effects of processing parameters and thickness on the properties of spin-on SrBi₂Ta₂O₇ (SET) films were investigated. Film crystallinity was improved with heat treatment but surface roughness also increased significantly above 400°C. Capacitor polarization was found to be a function of electric field, based on the results of the films in the thickness range of 0.11-0.44 μm. Thinner films saturate at a lower voltage but result in a higher leakage current and lower capacitor yield. According to an interfacial layer model, the thickness-independence dielectric constant, coercive field, and breakdown field for the spin-on SET films were calculated to be 282, 2.5 V/μm, and 28.1 V/μm, respectively. The electrical data indicate films of 0.19 μm thick should be used for integration with the current processing parameters