Electrical insulation characteristics of metal-insulator-metal structures using boron nitride dielectric films deposited with low-energy ion impact

Sp²-bonded boron nitride (BN) films are deposited on Ni and Si substrates with mean ion impact energies between a few eV and around 100 eV by surface-wave plasma enhanced chemical vapor deposition and their electrical insulation characteristics are examined for temperatures up to 300 °C. The overall crystallinity and order of sp² structure in the films increase with decreasing ion energy, while the mass density becomes as high as sintered hexagonal BN only when the ion energy is above ∼50 eV. For a given temperature, the electrical resistivity of the films measured for metal-BN-metal structures increases with decreasing ion energy, and hence increasing crystallinity and order of sp² structure, almost independent of mass density. A decrease in resistivity with temperature is small below 150 °C, then becomes large above 150 °C with a drastic increase in apparent activation energy for carriers, which is attributed to generation and transport of the carriers that get over higher barrier heights associated with stronger ion impact.