Patent ID: 7112503

Claim:
A capacitor fabrication method comprising: forming an opening in an insulative layer over a substrate, the opening having sides and a bottom; forming a layer of polysilicon over the sides and bottom of the opening; removing the polysilicon layer from over the bottom of the opening; converting at least some of the polysilicon layer to undoped hemispherical grain polysilicon; conformally forming a first capacitor electrode on and in contact with the hemispherical grain polysilicon, the first electrode being sufficiently thin that the first electrode has an outermost surface area per unit area greater than an outer surface area per unit area of the substrate underlying the first electrode and the outermost surface of the first electrode comprising a surface of the first electrode that is lastly formed; forming a capacitor dielectric layer on the first electrode and over the hemispherical grain polysilicon; and forming a second capacitor electrode over the dielectric layer and over the hemispherical grain polysilicon.