The kinetics of the oxide charge trapping and breakdown in ultrathin silicon dioxide

The kinetics of carrier trapping and breakdown in oxides of less than 5 nm was studied. It was found that electron trapping was negligible, but hole trapping was relatively high. An effective oxide trap density due to tunnel annealing was proposed. The rate equation of carrier trapping in the bulk oxide was presented in connection with the generated hole injection by anode surface plasmons. The voltage variation during a constant current test was analyzed using the hole trapping model and capacitance-voltage measured interface trap generation, and approximate values for the capture cross section and hole generation rate were extracted. The gate voltage shift rebounded after 30-100 C/cm² electron fluence due to interface trap generation. In ultrathin oxides hole trapping causes breakdown, and that trapping is mainly developed in localized weak areas. Using the weak area breakdown model we found that the ratio of weak to robust area is about 5%.