Entirely gate-surrounded MOS capacitor to study the intrinsic oxide quality

The intrinsic dielectric strength of gate oxides is investigated by MOS capacitors which are designed so that the gate poly does not cross the field oxide edge. Using the charge to breakdown in the high-injection regime as a sensitive indicator, it is shown that poly-surrounded capacitors are required to measure the intrinsic oxide quality, whereas conventional devices may be sensitive to process variations in the MOS isolation sequence and oxide thinning at the field oxide edge