Fluorine-vacancy complexes in ultrashallow B-implanted Si

摘要

Shallow fluorine-vacancy (FV) complexes in Si have been directly observed using variable-energy positron annihilation spectroscopy and secondary ion mass spectrometry. The FV complexes, introduced to combat the deactivation and transient-enhanced diffusion of ultrashallow boron, were observed in preamorphized Si wafers implanted with 0.5 keV B and 10 keV F ions at a dose of 10~(15) cm~(-2), and then annealed isothermally at 800℃ for times ranging from 1 to 2700 s. The results are in agreement with a model which predicts that the complexes are of the form F_(3n)V_n, with n most probably being 1 and/or 2.