Improvement of radiation hardness due to aging of fluorinated and chlorinated SiO/sub 2//Si MOS capacitors

Effect of ageing on x-ray induced dopant passivation in MOS capacitors

“…However, mechanism (i) may be less probable since Krauser et al [14,15] have reported that no change in the hydrogen distribution profile could be measured while storing oxidized Si wafers in a clean-room environment over a period of 5 months [15]. With respect to mechanism (ii), Wang et al [24] showed that the radiation hardness of MOS capacitors containing fluorinated or chlorinated oxides gradually improved on storing the capacitors at room temperature or at elevated temperatures. Shaneyfelt et al [1] also observed less radiation-induced interface trap buildup after storage at elevated temperatures.…”

“…Shaneyfelt et al [1] also observed less radiation-induced interface trap buildup after storage at elevated temperatures. Wang et al [24] have proposed that the improvement in radiation hardness could be due to reactions of fluorine species near the interface. These reactions could improve the radiation hardness in two ways: (a) replacement of Si-H bonds by stronger F-H bonds, and (b) gradual strain relaxation at the interface by conversion of low-fold member rings in the oxide into larger rings.…”