The conduction and breakdown properties of thermally grown SiO 2 films on amorphous-deposited n+polycrystalline silicon (polysilicon) are evaluated using ramped current-voltage ( I-V ) measurements. It is shown that the inferior insulating properties of oxides on polysilicon (polyoxides), when compared to SiO 2 on bulk silicon, can be directly attributed to oxidation-induced interface roughness leading to localized enhancement of the oxide electric field. For example, 16.7-nm-thick polyoxides approach bulk SiO 2 properties since a breakdown field E BD of approximately 9.5 MV . cm-1and an effective barrier height for Fowler-Nordheim tunneling, φ Beff as high as 2.78 eV were measured. Both of these parameters are progressively degraded by increasing polyoxide thickness D OX such that for 165-nm-thick polyoxides E_{BD} \simeq 2.5 MV . cm-1and φ Beff is reduced to as low as 0.83 eV. The measured I-V curves are found to become more polarity dependent with increasing D OX due to a comparatively higher degree of oxidation-induced surface roughening at the lower interface, which renders it more conductive, with regard to Fowler-Nordheim electron injection, than the upper oxide-polysilicon interface. Certain specific device applications require a relatively conductive polyoxide capable of carrying high current densities before failure. Consequently, a polysilicon procedure was developed that has the effect of decreasing φ Beff , increasing breakdown current J BD , and eliminating the polarity dependence of I-V curves for any subsequently formed thin polyoxide. The particular process entails growing a predetermined thickness of texturing oxide D teox , and removal prior to formation of the device polyoxide of approximately 25-nm thickness. As D teox is increased from zero to 103 nm, the resultant J BD is found to increase by more than an order of magnitude for both polarities of bias. The corresponding decrease in φ Beff is from 1.7 and 2.4 eV for positive and negative gate bias, respectively, to a polarity-independent value of approximately 1.3 eV.