Spatial resistivity profiling of multilayer capacitors as a function of furnace atmosphere

The research preformed was designed to discover what specific aspects of furnace control or sintering atmospheres cause a multilayer capacitor (MLC) to degrade and fail under typical usage conditions and typical HALT conditions. Reliability problems were assumed to relate to furnace atmosphere and burn-in testing. MgTiO₃ and commercial X7R BaTiO₃ MLCs were used in this study. These samples were initially examined in their as received state using a semiconductor probing station adapted for use as a DC high resistivity profiling device. The samples were then annealed in various partial pressures of oxygen (PO₂) in an effort to alter oxygen vacancy concentration and change the density of charge carriers in the samples. Using DC profiling, it was found that there was a decrease in the insulation resistance of the dielectric material as samples were reduced in low PO₂ atmospheres. This was thought to be a possible source of life test failure. After reduction the BaTiO₃ MLCs were re-oxidized in air for varying lengths of time and then profiled before HALT tested.