Methods of forming polysilicon-comprising plugs and methods of forming FLASH memory circuitry

A method of forming a polysilicon-comprising plug, comprising:

• providing a substrate comprising an opening formed therein;
• forming polysilicon within the opening to less than fill the opening and comprise a crevice therein;
• exposing the polysilicon within the opening to an H2-comprising atmosphere and a temperature of at least 500° C. effective to remove the crevice;
• and
• after the exposing, forming metal within the opening over the polysilicon.

A method of forming FLASH memory circuitry, comprising:

• forming a line of floating gates over a semiconductor substrate, and defining source areas on one side of the line proximate the floating gates and drain areas on another side of the line proximate the floating gates;
• forming insulative material over the line of floating gates, the source areas, and the drain areas;
• forming contact openings through the insulative material to the drain areas;
• forming polysilicon within the contact openings to less than fill the contact openings;
• exposing the polysilicon within the contact openings to an H2-comprising atmosphere and a temperature of at least 500° C.;
• and
• after the exposing, forming metal within the contact openings over the polysilicon.