Two experimental observations are reported concerning the degradation of the Sindash;SiO2interface during electron injection in metalhyphen;oxidehyphen;semiconductor structures. First, the generation of the interfacial positive charge during avalanche injection can be strongly inhibited by employing magnesium, instead of aluminum, as gate metal, or enhanced by employing gold. This correlates with the different work functions of the metals. Second, during negative bias highhyphen;field injection in Alhyphen;gate capacitors with thin oxides (lsim;100 Aring;), a threshold in gate voltage, of 7ndash;8 V, is found for the generation of the positive charge. Both observations are consistent with a model which assumes that holes generated in the anode by hot electrons, via emission of surface plasmons, are injected into the SiO2and are subsequently trapped at the Sindash;SiO2interface. Other possible mechanisms are also discussed.
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