High temperature nitrogen annealing induced interstitial oxygen precipitation in silicon epitaxial layer on heavily arsenic-doped silicon wafer

High temperature nitrogen annealing induced interstitial oxygen (Oi) precipitation has been investigated in silicon epitaxial layers (epilayers) grown on heavily arsenic-doped Czochralski silicon wafers. Both transmission electron microscopy and secondary ion mass spectrometry data indicate a strong Oi precipitation and/or segregation in the subsurface of epilayers annealed in N2 at 1200 deg. C. The Oi precipitates have needlelike morphology with {111} habit planes along <110> directions. This precipitation is facilitated by thermal nitridation-produced vacancies or nitrogen-vacancy complexes and is sensitive to annealing conditions. Annealing in Ar or in N2 at temperature <1125 deg. C results in no epilayer subsurface Oi precipitation