title: Synthesis and characterization of hexagonal boron nitride film as a dielectric layer for graphene devices.
abstract: Hexagonal boron nitride (h-BN) is a promising material as a dielectric layer or substrate for two-dimensional electronic devices. In this work, we report the synthesis of large-area h-BN film using atmospheric pressure chemical vapor deposition on a copper foil, followed by Cu etching and transfer to a target substrate. The growth rate of h-BN film at a constant temperature is strongly affected by the concentration of borazine as a precursor and the ambient gas condition such as the ratio of hydrogen and nitrogen. h-BN films with different thicknesses can be achieved by controlling the growth time or tuning the growth conditions. Transmission electron microscope characterization reveals that these h-BN films are polycrystalline, and the c-axis of the crystallites points to different directions. The stoichiometry ratio of boron and nitrogen is close to 1:1, obtained by electron energy loss spectroscopy. The dielectric constant of h-BN film obtained by parallel capacitance measurements (25 μm(2) large areas) is 2-4. These CVD-grown h-BN films were integrated as a dielectric layer in top-gated CVD graphene devices, and the mobility of the CVD graphene device (in the few thousands cm(2)/(V·s) range) remains the same before and after device integration.
authors.affiliation: Department of Electrical Engineering and Computer Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Ki Kang
authors.initials: KK
authors.lastname: Kim
authors.forename: Allen
authors.initials: A
authors.lastname: Hsu
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Jia
authors.forename: Soo Min
authors.initials: SM
authors.lastname: Kim
authors.forename: Yumeng
authors.initials: Y
authors.lastname: Shi
authors.forename: Mildred
authors.initials: M
authors.lastname: Dresselhaus
authors.forename: Tomas
authors.initials: T
authors.lastname: Palacios
authors.forename: Jing
authors.initials: J
authors.lastname: Kong
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D017097:Electric Impedance; D006108:Graphite / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008567:Membranes, Artificial; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D001896:Boron Compounds; D046911:Macromolecular Substances; D008567:Membranes, Artificial; C017282:boron nitride; D006108:Graphite