Giant Secondary Grain Growth in Cu Films on Sapphire
David L. Miller, Mark W. Keller, Justin M. Shaw, Katherine P. Rice, Robert R. Keller, Kyle M. Diederichsen
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: sputter deposition at modest temperatures followed by annealing to induce giant secondary grain growth. We show that crystalline as-deposited Cu on α-Al2O3(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 50 mm wafers of annealed Cu and obtain epitaxial graphene grains of 0.2 mm diameter.
, Keller, M.
, Shaw, J.
, Rice, K.
, Keller, R.
and Diederichsen, K.
Giant Secondary Grain Growth in Cu Films on Sapphire, AIP Advances, [online], https://doi.org/10.1063/1.4817829
(Accessed April 18, 2021)