Fabrication of robust PbLa(Zr,Ti)O3 capacitor structures using insulating oxide encapsulation layers for FeRAM integration
Various encapsulation oxide thin films of 20 nm Al2O3, HfO2, Bi3Ti4O12 (bismuth titanate, BIT), ZrO2 and SiO2 on the Pt top electrodes and sol-gel derived ferroelectric PbLaZrTiOx (PLZT) capacitors were prepared, and then the hydrogen barrier characteristics were investigated by electrical properties measurements before and after in a 3% hydrogen atmosphere annealing. The Al2O3 film by pulse laser deposition and the SiO2 film by radio frequency sputtering are shown to be promising candidates as the hydrogen barrier layer and maintained 86 and 69% of an initial polarisation value even after 45 minutes of hydrogen annealing, respectively.