Electrical transport and capacitance characteristics of metal-insulator-metal structures using hexagonal and cubic boron nitride films as dielectrics

Metal-insulator-metal capacitor structures using thick hexagonal and cubic boron nitride (hBN and cBN) films as dielectrics are produced by plasma jet-enhanced chemical vapor deposition, and their electrical transport and capacitance characteristics are studied in a temperature range of 298 to 473 K. The resistivity of the cBN film is of the order of 10(7) Omega cm at 298 K, which is lower than that of the hBN film by two orders of magnitude, while it becomes the same order as the hBN film above similar to 423 K. The dominant current transport mechanism at high fields (>= 1 x 10(4) V cm(-1)) is described by the Frenkel-Poole emission and thermionic emission models for the hBN and cBN films, respectively. The capacitance of the hBN film remains stable for a change in alternating-current frequency and temperature, while that of the cBN film has variations of at most 18%. The dissipation factor as a measure of energy loss is satisfactorily low (<= 5%) for both films. The origin of leakage current and capacitance variation is attributed to a high defect density in the film and a transition interlayer between the substrate and the film, respectively. This suggests that cBN films with higher crystallinity, stoichiometry, and phase purity are potentially applicable for dielectrics like hBN films. Published by AIP Publishing.