Intrinsic gettering in nitrogen doped Czochralski crystal silicon

The intrinsic gettering processes of nitrogen-doped Czochralski (NCZ) silicon has been investigated. The NCZ silicon samples were annealed in different high-low-high thermal cycles, which were designed by orthonormal test. The denuded zone of the NCZ silicon wafers was checked by a Scanning Electron Microscope. In comparison, the conventional Czochralski (CZ) silicon treated by the same intrinsic gettering processes has been also studied. It was found in the NCZ silicon the good denuded zone in the near surface and the high density of intrinsic gettering sites in the bulk could be achieved, if suitable thermal cycles, which were different from CZ silicon, were chosen. It is believed that the time and temperature in the second step annealing are the most important facts for the effective intrinsic gettering. The optimization of intrinsic gettering process for NCZ silicon was discussed.