Alumina as a Hydrogen Barrier Layer for FeRAM Devices

Alumina ("AlOx") thin films are evaluated as a hydrogen diffusion barrier for ferroelectric memory devices. Ferroelectric capacitors (FeCAP) covered with the barrier is used in this study. The capacitor is annealed in a deuterated forming gas (DFG) ambient according to back-end-of-line (BEOL) thermal budget. The deuterium profile inside the stack structure is analyzed by Secondary Ion Mass Spectrometry (SIMS) to characterize the performance of alumina as a hydrogen barrier. The electrical performance of the FeCAP structure with alumina barrier is measured before and after the DFG anneal. Pulse saturation curves and P-V curves and electrical characteristics associated switched polarization, remnant polarization and saturation polarization are discussed as a performance of the FeCAPs. These parameters are compared before and after the annealing to examine any degradation due to deuterium diffusion.