DEUTERIUM INTERACTIONS WITH ION-IMPLANTED SIO2 LAYERS IN SILICON

The interactions of deuterium gas (D2) with implantation-formed Si-SiO2-Si structures were investigated in the temperature range 500-1000-degrees-C using nuclear-reaction analysis. At 600-degrees-C and above there is substantial permeation of D through the overlying Si layer, and this D becomes stably bound within the buried SiO2. The reactions within the implantation-formed oxide differ significantly from those in thermal oxides and are characterized by two distinct time regimes. In the first regime there is a rapid transient reaction which, at least at 600-degrees-C, is controlled by permeation through the Si overlayer. After the initial transient there is a much slower reaction within the oxide, prominent at 700-degrees-C and higher, which is controlled by a reaction barrier. The results indicate that the implantation-formed oxides contain more numerous hydrogen-reactive sites than do silica or thermal oxides on Si, and further that the number of these sites is substantially increased by Si epitaxial deposition. Deuterium permeation through the Si overlayer was used to determine the permeability of hydrogen in Si at 600-degrees-C for the first time.