US Patent 7446056 Method for increasing polysilicon grain size

The present invention relates to a method for increasing the grain size of a polysilicon layer, which includes exposing a silicon oxide wafer in a deposition chamber to an amount, effective for the purpose, of nitrogen at a flow rate of at least about 240 standard liters per minute (slm). The instant invention further relates to a method for inhibiting the formation of a polysilicon seed in a furnace, which includes the treatment as noted above. The invention also relates to a method for forming a polysilicon layer, including: forming a silicon oxide layer on a substrate, the silicon oxide layer having a plurality of oxygen molecules therein; exposing the silicon oxide layer to a predetermined amount of nitrogen-containing gas in a furnace, whereby a plurality of nitrogen molecules in the nitrogen-containing gas replaces at least part of the oxygen molecules in the silicon oxide layer; and forming a polysilicon layer on the silicon oxide layer.