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Title: Giant secondary grain growth in Cu films on sapphire

Single crystal metal films on insulating substrates are attractive for microelectronics and other applications, but they are difficult to achieve on macroscopic length scales. The conventional approach to obtaining such films is epitaxial growth at high temperature using slow deposition in ultrahigh vacuum conditions. Here we describe a different approach that is both simpler to implement and produces superior results: sputter deposition at modest temperatures followed by annealing to induce secondary grain growth. We show that polycrystalline as-deposited Cu on α-Al{sub 2}O{sub 3}(0001) can be transformed into Cu(111) with centimeter-sized grains. Employing optical microscopy, x-ray diffraction, and electron backscatter diffraction to characterize the films before and after annealing, we find a particular as-deposited grain structure that promotes the growth of giant grains upon annealing. To demonstrate one potential application of such films, we grow graphene by chemical vapor deposition on wafers of annealed Cu and obtain epitaxial graphene grains of 0.2 mm diameter.
Authors:
; ; ; ; ;  [1]
  1. National Institute of Standards and Technology, Boulder, CO 80305 (United States)
Publication Date:
OSTI Identifier:
22220458
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 3; Journal Issue: 8; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM OXIDES; ANNEALING; BACKSCATTERING; CHEMICAL VAPOR DEPOSITION; COPPER; DEPOSITS; ELECTRON DIFFRACTION; EPITAXY; GRAIN GROWTH; GRAPHENE; LAYERS; MICROELECTRONICS; MONOCRYSTALS; OPTICAL MICROSCOPY; POLYCRYSTALS; SAPPHIRE; SUBSTRATES; THIN FILMS; X-RAY DIFFRACTION