polysilicon

# Polysilicon (Poly-Si)

Poly-Si is silicon containing many crystalline grains. Poly and PO can be local shorthand for its process or mask level.

## Connect the name to its role

Document whether this film is a target, mask, liner, electrode or temporary layer at the step being discussed. The same material can have different roles in different modules.

## Integration context

Doped polysilicon can act as a gate electrode or other conductive feature. Doping and grain structure can alter etch behavior. A replacement-metal-gate flow may use a temporary polysilicon gate rather than retain it in the final device. PO is not a universal abbreviation.

## What to verify

Identify whether the film is a permanent electrode or a dummy gate; verify sheet resistance, thickness and underlying dielectric.

Before selecting removal conditions, identify all exposed neighboring materials and the amount of loss each can tolerate. Verify the result using the measurements appropriate to the structure, then check that the surface is suitable for the next deposition, contact or clean step.

## Related terminology

polysilicon, Poly-Si, Poly, PO. Short abbreviations are local process vocabulary and can have other meanings; use the full module name when searching.

## Source and scope

[Fabrication and etch resources](https://www.cleanroom.byu.edu/processes). The diagram is an original teaching schematic. Layer choices and process families describe an example rather than a universal manufacturing recipe.