Dielectric permittivity, conductivity and breakdown field of hexagonal boron nitride
cond-mat.mtrl-sci
/ Authors
A. Pierret, D. Mele, H. Graef, J. Palomo, T. Taniguchi, K. Watanabe, Y. Li, B. Toury, C. Journet, P. Steyer
and 9 more authors
V. Garnier, A. Loiseau, J-M. Berroir, E. Bocquillon, G. Fève, C. Voisin, E. Baudin, M. Rosticher, B. Plaçais
/ Abstract
In view of the extensive use of hexagonal boron nitride (hBN) in 2D material electronics, it becomes important to refine its dielectric characterization in terms of low-field permittivity and high-field strength and conductivity up to the breakdown voltage. The present study aims at filling this gap using DC and RF transport in two Au-hBN-Au capacitor series of variable thickness in the 10--100 nm range, made of large high-pressure, high-temperature (HPHT) crystals and a polymer derivative ceramics (PDC) crystals. We deduce an out-of-plane low field dielectric constant $ε_\parallel=3.4\pm0.2$ consistent with the theoretical prediction of Ohba et al., that narrows down the generally accepted window $ε_\parallel=3$--$4$. The DC-current leakage at high-field is found to obey the Frenkel-Pool law for thermally-activated trap-assisted electron transport with a dynamic dielectric constant $ε_\parallel\simeq3.1$ and a trap energy $Φ_B\simeq1.3\;\mathrm{eV}$, that is comparable with standard technologically relevant dielectrics.