Abstract. A new hypothesis regarding the role of rare earth dopants in improving the lifetime of
multilayer capacitors with base metal electrodes is presented. The hypothesis is based on the
experimental findings, which have shown that the site occupancy of the important dopants is a
function of the overall A/B ratio in the perovskite dielectric material. The main assumption is
that deviation from A/B stoichiometry significantly controls the mobility of oxygen vacancies
along the grain boundaries.