Method of fabricating a wide-based box- structured capacitor containing hemi-spherical grains

A method of fabricating a wide-based, box-structured capacitor containing hemi-spherical grains, wherein a substrate is provided with a source/drain and a dielectric layer is formed on the substrate with a node contact opening that exposes the source/drain, the method comprising:

• forming a doped polysilicon layer on the substrate;
• forming a doped amorphous silicon layer on the doped polysilicon layer;
• performing an etching step, wherein flow speeds of chlorine and of hydrogen bromide are adjusted to etch the doped amorphous silicon layer and the doped polysilicon layer and a wide-based lower electrode is formed thereon in the node contact opening and on the surrounding first dielectric layer;
• and
• forming hemi-spherical silicon grains on a surface of the doped amorphous silicon layer in the lower electrode.

A structure of a wide-based, box-structured capacitor containing hemi-spherical grains, comprising:

• a substrate containing a source/drain;
• a first dielectric layer formed on the substrate with a node contact opening that exposes the source/drain;
• a boxed-structured lower electrode containing hemi-spherical silicon grains, sequentially formed by a doped polysilicon layer and a doped amorphous silicon layer, wherein the doped polysilicon layer fills the node contact opening and has a height higher than that of the first dielectric layer as well as a width wider than that of the doped amorphous silicon layer;
• a second dielectric layer on a surface of the lower electrode;
• and
• an upper electrode on the second dielectric layer.