We investigate the stability of boron dopants near the interface between crystalline Si and amorphous SiO2 through first-principles density functional calculations. An interstitial B is found to be more stable in amorphous SiO2 than in Si, so that B dopants tend to segregate to the interface. When defects exist in amorphous SiO2, the stability of B is greatly enhanced, especially around Si floating bond defects, while it is not significantly affected near Si-Si dimers, which are formed by O-vacancy defects. (C) 2011 Elsevier B.V. All rights reserved.