Vertical thermal and PECVD (plasma enhanced chemical vapor deposition) polysilicon oxides, formed on polysilicon sidewalls, are investigated to demonstrate that the oxides on polysilicon sidewalls have much better electrical qualities than do conventional planar polysilicon oxides. For thermally grown vertical polysilicon oxides, the charges-to-breakdown were as high as 10 C/cm(2), values that are comparable to that of the single crystal oxide. This improvement is primarily due to the fewer number of grain boundaries in the vertical direction of the polysilicon.