title: Formation of ultrasharp vertically aligned Cu-Si nanocones by a DC plasma process.
abstract: We report an effective method for the production of ultrasharp vertically oriented silicon nanocones with tip radii as small as 5 nm. These silicon nanostructures were shaped by a high-temperature acetylene and ammonia dc plasma reactive ion etch (RIE) process. Thin-film copper deposited onto Si substrates forms a copper silicide (Cu3Si) during plasma processing, which subsequently acts as a seed material masking the single-crystal cones while the exposed silicon areas are reactive ion etched. In this process, the cone angle is sharpened continually as the structure becomes taller. Furthermore, by lithographically defining the seed material as well as employing an etch barrier material such as titanium, the cone location and substrate topography can be controlled effectively.
authors.affiliation: Molecular-Scale Engineering and Nanoscale Technologies Research Group, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6006, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Klein
authors.forename: A V
authors.initials: AV
authors.lastname: Melechko
authors.forename: J D
authors.initials: JD
authors.lastname: Fowlkes
authors.forename: P D
authors.initials: PD
authors.lastname: Rack
authors.forename: D K
authors.initials: DK
authors.lastname: Hensley
authors.forename: H M
authors.initials: HM
authors.lastname: Meyer
authors.forename: L F
authors.initials: LF
authors.lastname: Allard
authors.forename: T E
authors.initials: TE
authors.lastname: McKnight
authors.forename: M L
authors.initials: ML
authors.lastname: Simpson
mesh_terms: D000114:Acetylene / Q000737:chemistry; D000641:Ammonia / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D012825:Silicon / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000641:Ammonia; D003300:Copper; D000114:Acetylene; D012825:Silicon