Comparative study of reliability issues in La-doped bismuth titante thin films according to the bottom electrode materials

We have investigated the effects of bottom electrode materials on fatigue and hydrogen-induced degradation in La-doped bismuth titanate (Bi_3.25La_0.75Ti₃O₁₂; BLT) thin films. BLT thin films were deposited on SrRuO₃ (SRO) and platinum (Pt) electrodes by pulsed laser deposition. BLT films on both electrodes showed good crystallized structures and ferroelectric properties after post-deposition annealing. Also, it was observed that there is almost no fatigue degradation in both cases. However, substantially different hydrogen-induced degradation behavior was observed in the case of BLT-based capacitors according to the bottom electrode materials. When Pt was used as a bottom electrode, the hydrogen-induced degradation was found to be very severe, resulting in polarization failure even at 300°C. In contrast, BLT films on SRO electrodes were highly immune to hydrogen-induced degradation.