Control of Defect Concentrations within a Semiconductor through Adsorption

Abstract

The technologically useful properties of a crystalline solid depend upon the concentration of defects it contains. Here we show that defect concentrations as deep as 0.5 microm within a semiconductor can be profoundly influenced by gas adsorption. Self-diffusion rates within silicon show that nitrogen atoms adsorbed at less than 1% of a monolayer lead to defect concentrations that vary controllably over several orders of magnitude. The results show that previous measurements of diffusion and defect thermodynamics in semiconductors may have suffered from neglect of adsorption effects.

Reversible oxygen scavenging at room temperature using electrochemically reduced titanium oxide nanotubes

“…Such a fast oxygen uptake at a remarkably low temperature suggests a non-typical mechanistic pathway for the re-oxidation of TiO 2−x . Modelling the diffusion of oxygen, we show that a likely pathway involves 'exceptionally mobile' interstitial oxygen 8-10 produced by the oxygen adsorption and decomposition dynamics, recently observed on the surface of anatase 6 .The limiting step for oxygen uptake in metal oxides is often hypothesized to be the thermally activated diffusion of bulk oxygen vacancies (V O ) to the surface, where the V O are annihilated by adsorbed oxygen [10][11][12][13][14] . Materials that depend on this mechanism are useful only at high temperatures, or have a low oxygen uptake capacity that is limited by the sites available for surface absorption or adsorption.…”

“…Such a fast oxygen uptake at a remarkably low temperature suggests a non-typical mechanistic pathway for the re-oxidation of TiO 2−x . Modelling the diffusion of oxygen, we show that a likely pathway involves 'exceptionally mobile' interstitial oxygen [8][9][10] produced by the oxygen adsorption and decomposition dynamics, recently observed on the surface of anatase 6 .…”

“…The limiting step for oxygen uptake in metal oxides is often hypothesized to be the thermally activated diffusion of bulk oxygen vacancies (V O ) to the surface, where the V O are annihilated by adsorbed oxygen [10][11][12][13][14] . Materials that depend on this mechanism are useful only at high temperatures, or have a low oxygen uptake capacity that is limited by the sites available for surface absorption or adsorption.…”

Mechanistic benefits of millisecond annealing for diffusion and activation of boron in silicon

“…7 Table I summarizes the a priori estimates and the associated standard deviations. This a priori parameter set has proven capable of accurately simulating profiles for soak and spike annealing, 5 as Fig.…”

“…Corresponding rate parameters are estimated through Bayesian statistics. For example, descriptions have emerged 5 that incorporate a more accurate description of interstitials via surface dangling bonds 6,7 and the effects of near-surface band bending. 8 The present work employs such an approach for boron.…”