High-temperature interstitial oxygen diffusion retardation in epitaxial-layered heavily arsenic- or boron-doped Czochralski silicon wafers

Abstract

Interstitial oxygen (Oi) diffusivity was examined in epitaxial-layered silicon substrates of various types (heavily doped arsenic and heavily doped boron) in varying annealing conditions. When a heavily doped arsenic substrate was annealed at up to 1125°C, the Oi diffusion slowed by 28% compared to that in the epilayer or a lightly doped boron substrate. When a heavily doped arsenic substrate is annealed at 1200°C in N2, Oi accumulates in the epilayer subsurface. A heavily doped boron substrate annealed at 1200°C shows both significantly reduced Oi outdiffusion in the substrate and Oi segregation at the epilayer-substrate interface due to misfit dislocation.