A mechanism for formation of a surface reoxidation layer in surface boundary layer capacitor (SBLC) have been studied. SBLC were prepared by reduction of $BaTiO_3$ doped with $Bi_2O_3$ and metallizing of silver paste containing $Bi_2O_3$. The apparent dielectric constant were order of $10^5$ and the insulation resistance larger than $10^6Ω$. It may be expected that $Bi_2O_3$ dopant in $BaTiO_3$ plays role of inhibition of grain growth and decreasing the resistivity of $BaTiO_3$.
To confirm the forming process of surface reoxidation layer, the effects of atmosphere and annealing time in electrode sintering were investigated.
Equivalent circuit of SBLC was studied from I-V, C-V characteristics. This circuit can be explained by rectifying junction model. According to this model, it can be suggested that in metallizing, the bismuth ion in silver paste creates holes by substitution with titanium ion in barium titanate.
