Prevention of degradation of (Ba,Sr)TiO3 during forming gas anneal by a SiO2 capped (Ba,Sr) RuO3 electrode

Degradation of (Ba,Sr)TiO3 during a forming gas anneal was examined and the effect of a SiO2 capped (Ba,Sr)RuO3 electrode was studied. All the samples were prepared by a rf magnetron sputtering technique and the forming gas 10% H-2 + 90% N-2) anneal was carried out at 400 degreesC for 30 min. The (Ba,Sr)RuO3 film directly exposed to H-2 ambient was damaged severely, which resulted in the reduction and phase separation into BaO and Ru. On the other hand, the SiO2 capped (Ba,Sr)RuO3 film was not damaged during H-2 annealing. By adopting the SiO2 capped (Ba,Sr)RuO3 as an electrode of (Ba,Sr)TiO3, the degradation of (Ba,Sr)TiO3 could be inhibited. SiO2 capping also decreased the extent of the reduction of a Pt/(Ba,Sr)TiO3/Pt Structured capacitor, which is known to degrade dramatically. It is believed that the major cause of the tolerance to the forming gas anneal Is the blocking capability Of SiO2 against the diffusion of reaction products such as H2O. (C) 2003 American Institute of Physics.