Ab-Initio Study of the Effect of Hydrogen and Point Defects on Arsenic Segregation at Si (100)/SiO2 Interfaces

The previously suggested segregation model for arsenic at Si/SiO$_{2}$ interfaces based on a combined trapping/pairing model [J. Dabrowski \textit{et al}., Phys. Rev. B \textbf{65}, 245305 (2002)] requires high binding energies for interface vacancies, which our results of $\approx $ 0.2 eV cannot confirm. As an alternative explanation, we present ab-initio results which show that As and hydrogen bond with an energy gain of 1.5-3 eV with their minimum-energy position at the interface, which creates additional trapping sites for As segregation. We also find a similar situation in case of boron segregation. The inclusion of hydrogen into the modeling might thus be able to explain the differences between the previous model and experiments.