High temperature hydrogen anneal of silicon wafers supported on a silicon fixture

摘要

A process for hydrogen annealing silicon wafers that have been cut from an ingot and polished on both sides, thereby removing crystal originated pits (COPs) in their surface. The wafers are then stacked in a tower having at least support surfaces made from virgin polysilicon, that is, polysilicon form by chemical vapor deposition, preferably from monosilane. The tower may include four virgin polysilicon legs have support teeth slotted along the legs and fixed at their opposed ends to bases. The wafers are supported at four equally distributed points at 0.707 of the wafer radius. The wafers so supported on the virgin polysilicon towers are annealed in a hydrogen ambient at 1250° C. for 12 hours.