Low Temperature Hydrogen Induced Degradation of (Ba,Sr)TiO3 Thin Film Capacitors

Abstract

AbstractWe have used electrical characterization and secondary ion mass spectroscopy (SIMS) to investigate the influence of hydrogen or deuterium (H/D) on the degradation of the electrical properties of metal/Ba0.7Sr0.3TiO3/metal (M/BSTO/M) thin film capacitors after forming gas annealing (FGA). Leakage and dielectric relaxation currents increase after FGA at temperatures as low as 23C. SIMS profiling shows that at 23C H/D diffuses through thin film metal electrodes and accumulates at electrode interfaces. The location (top or bottom electrode interface) of H/D accumulation is dependent on the type of electrodes and capacitor structure. The resulting asymmetric distribution of H/D leads to large voltage offsets in the C-V characteristic, asymmetric leakage currents, and increased dielectric relaxation currents. Possible mechanisms for increased leakage and relaxation currents after FGA are discussed.