Radially non-uniform interaction of nitrogen with silicon wafers

Reproducible and pronounced ring-like structures have been revealed on both sides of commercial grade wafers after certain regimes of annealing in pure nitrogen atmosphere at 1200 °C. To minimize residual oxygen concentration during the annealing procedure, a furnace with a Si3N4 coated SiC reactor tube and high purity N2 flow were employed. Single-side polished Cz–Si wafers with a diameter of 200 mm, used in the experiments, were manufactured from silicon crystals free of oxidation-induced stacking fault rings.