The integrity of tetraethylorthosilicate (TEOS) polyoxide using chemical mechanical polishing (CMP) plus a high temperature rapid thermal annealing (RTA) step was studied in this work. The surface morphology of polysilicon is improved after a CMP process. Polyoxides deposited by low pressure chemical vapor deposition (LPCVD) TEOS in conjunction with CMP and RTA N-2/N2O annealing exhibit a better current-electric field (J-E) curve, higher charge to breakdown ratio, and lower electron trapping rate. In addition, the composite bilayer (TEOS deposited and thermally grown by RTA) polyoxide film introduces an asymmetry of electrical leakage current, trapping characterization, and charge to breakdown, with respect to the injection of different polarity (+V-g and -V-g)