RADIATION-INDUCED NEUTRAL ELECTRON TRAP GENERATION IN ELECTRICALLY BIASED INSULATED GATE FIELD-EFFECT TRANSISTOR GATE INSULATORS

Optically assisted electron injection was employed to quantify neutral electron trap and fixed positive charge concentrations in the gate oxides of electrically biased n-channel insulated gate field effect transistors exposed to 10 keV x-rays. This is the first known work to study the effects of an applied gate oxide field during x-ray irradiation on neutral electron trap generation. Surprisingly, the results show that neutral electron trap generation is dependent upon the gate bias, and the oxide thickness in a similar manner as positive charge buildup during irradiation. This possibly suggests an association between the two defect types. A neutral electron trap generation model is proposed in which the E'-gamma trapped hole center transforms into a dipolar neutral electron trapping site via electron compensation by an electron.