The extent to shich crystal originated defect pits called COPs will enhance capacitor B-mode failures has been examined as a function of substrate carrier type and dopant concentration under accumulation and inversion bias modes. In heavily antimony doped samples, the COP density increases with the dopant concentration. However, an unexpected immunity to COPs has been found for n-type capacitors biased into accumulation. This could be readily explained by invoking FowlerNordheim tunneling and the morphology of the capacitor electrodes, as revealed by cross-sectional TEm on simulated COPs formed by KOH anisotropic etching. It is concluded that for wafers with COPs, an enhanced electric field due to small gate electrode curvature contributes to the capacitor breakdown below 8 MV.cm~(-1).
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