Elimination of hydrogen-related instabilities in Si/SiO2 structures by fluorine implantation

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Abstract
In this study we have investigated the effect of fluorination on the electrical properties of the Si/SiO2/Al system, including their degradation. Fluorine was introduced by ion implantation into the gate oxide with doses ranging from 109–1015 cm−2. Study of the electron and hole trapping properties of the as‐fabricated system showed that water‐related electron traps and hole traps with small cross section are removed after introduction of fluorine. Hole traps with large cross section related to oxygen vacancies are not affected. Fluorination also suppresses generation of donor‐type interface states and of oxide electron traps generated by vacuum ultraviolet irradiation. The data indicate that the involvement of fluorine is mostly of a catalytic nature. It is proposed that the post‐metallization anneal in the presence of fluorine promotes the elimination of hydrogen available for radiolysis.