INFLUENCE OF THE OXIDE CHARGE BUILDUP DURING FOWLER-NORDHEIM STRESS ON THE CURRENT-VOLTAGE CHARACTERISTICS OF METAL-OXIDE-SEMICONDUCTOR CAPACITORS

A study of the influence of the oxide charge build-up during Fowler-No rdheim is presented, emphasizing the current-voltage characteristics. In some cases, a diminution of the slope of current-voltage characteri stics was observed. It is shown that the slope variation is due to a c hange of the cathode field which is basically related on the location of the oxide charge. The proximity of this oxide charge (positive or n egative) to substrate-Si/SiO2 or gate/SiO2 interfaces modifies the sha pe of the tunneling barrier. From a qualitative analysis of the voltag e shifts of current-voltage and capacitance-voltage characteristics, t he origins of the oxide charge have been discussed and the degradation of the oxide is found to be consistent with both mechanisms of trap c reation and/or impact ionization.