Surface- and inner-microdefects in annealed silicon wafer containing oxygen

Surface- and inner-microdefects examined after a two-step annealing process are compared and related to the intrinsic gettering phenomenon. After the defects are characterized by means of transmission electron microscopy, the defect types (dislocations, precipitates, and stacking faults) and defect structures as well as nature are correlated with the annealing temperature. It is found from the observations that a surface-microdefect is a stacking fault extrinsic in nature possibly caused by a process-induced ’’heavy metal contamination’’ such as copper and that the type of Si-O complex precipitates generated strongly depends on annealing temperatures: <1050°C⋅⋅⋅ platelike cristobalite, 1100°C<⋅⋅⋅ regular octahedral amorphous SiO2. In addition, the mechanism for the formation of these defects is discussed based on electron microscope observations.