Method for forming hemispherical silicon grains on designated areas of silicon layer
AssigneeUnited Semiconductor Corp.
InventorsAnchor Chen, Shih-Ching Chen
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Abstract
A method for forming hemispherical silicon grains on selected surfaces of a silicon layer includes the steps of forming a doped polysilicon layer over a substrate, and then forming amorphous spacers on the sidewalls of the doped polysilicon layer. Thereafter, an ion implantation is carried out to transform the upper portion of the doped polysilicon into an amorphous silicon layer. Finally, hemispherical silicon grains are formed on the upper surface of the amorphous layer lying above the polysilicon layer and the exposed surface of the amorphous spacers.
Claims13
A method for forming hemispherical silicon grains on a silicon layer, comprising the steps of:
- providing a substrate, which has a dielectric layer on top, and has an opening in the dielectric layer to expose the substrate beneath the dielectric layer;
- forming a doped polysilicon layer over the substrate, wherein the doped polysilicon layer also fills the opening;
- patterning the doped polysilicon layer to remove an undesired portion;
- forming amorphous silicon spacers on sidewalls of the doped polysilicon layer;
- transforming an upper portion of the doped polysilicon layer into an amorphous silicon layer, wherein the amorphous silicon layer and the amorphous silicon spacer together cover the doped polysilicon layer;
- and
- forming hemispherical silicon grains on an exposed surface of the amorphous silicon spacers and an upper surface of the amorphous silicon layer lying above the doped polysilicon layer.
A method for forming a lower electrode of a capacitor, comprising the steps of:
- providing a substrate;
- forming a dielectric layer over the substrate, wherein a contact opening that exposes a portion of the substrate is also formed in the dielectric layer;
- forming a doped polysilicon layer that fills the contact opening and covers a portion of the dielectric layer;
- patterning the doped polysilicon by photolithography;
- forming amorphous silicon spacers on sidewalls of the doped polysilicon layer;
- performing an ion implantation to transform an upper portion of the doped polysilicon layer into an amorphous silicon layer;
- and
- forming hemispherical silicon grains on an exposed surface of the amorphous silicon spacers and an upper surface of the amorphous silicon layer lying above the doped polysilicon layer.
Dependencies are inferred from the claim text.