Interface stability of electrode/Bi-containing relaxor ferroelectric oxide for high-temperature operational capacitor

Abstract

The interface stability between electrodes (Pt, TaC, TiC, and RuO2) and a Bi-containing relaxor ferroelectric oxide, BaTiO3–Bi(Mg2/3Nb1/3)O3 (BT–BMN), applied to a high-temperature operational capacitor was investigated by hard X-ray photoelectron spectroscopy. All the electrodes showed electron filling at the Fermi level after annealing at 400 °C. However, Pt and TaC indicated electrical property degradations due to the thick intermediate layer formation and defect formation of the BT–BMN layer relating to the Bi diffusion into the electrodes. In contrast, TiC inhibited the Bi diffusion and did not show any change in the band alignment after annealing. Furthermore, RuO2 eliminated the defect formation in BT–BMN and showed no change in the band alignment although the Bi diffusion was also observed. These results suggest that the TiC/RuO2/BT–BMN stack structure is a potential candidate for the high-temperature operational capacitor.

(Invited) Development of New High-Dielectric Constant Thin Films By Combinatorial Synthesis

“…To reduce the leakage current and improve the temperature stability of dielectric constant, Ta was doped. Ta is able to reduce oxygen vacancies owing to its low oxidization energy, and inhibit the Bi migration in the BT-BMN layer at high temperature on the basis of the thermal diffusion theory (17)(18)(19). To investigate the Ta doping effects, a Ta composition spread sample was fabricated by combinatorial method as shown in Fig.…”