Positive charging of buried SiO2 by hydrogenation

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Abstract
Simple hydrogen annealing of the buried oxide (BOX) of state‐of‐the‐art separation by implanted oxygen material in the range 450–700 °C was found to introduce net positive charge in the BOX with areal densities up to 5×1012 elem. charges cm−2, while H2 annealing in the range 700–1000 °C was observed to activate a neutral state. Both processes appeared reversible upon appropriate vacuum annealing. The positive charge in the BOX is detected using electron spin resonance of a positive BOX‐charge‐induced signal in Si. The results are interpreted in terms of a two‐state model which describes the trapping of hydrogen at a reactive site yielding an either positively charged (activation temperature TA≊450 °C) or neutral (TA≊715 °C) state, based on hydrogen incorporation into oxygen vacancies (Si—Si bonds).