Radiation Effects in Thin Film Hexagonal Boron Nitride

The radiation response of 2 nm and 12 nm hexagonal boron nitride (hBN) thin film insulators was studied using metal insulator semiconductor (MIS) devices. Current-voltage, capacitance-voltage, and impedance spectroscopy measurements were compared to quantify changes in hBN resistance due to radiation damage. MIS devices exposed to a gamma total dose deposition of 3.1 Mrad(Si) from a Co- 60 source exhibited a small increase in hBN resistance and no observable C-V shift associated with charge trapping. MIS devices irradiated with 4.5 MeV silicon ions showed no significant resistivity decrease to a threshold fluence of 1 ×1012 for the 2 nm sample and 5 ×1012 ions/cm2 for the 12 nm sample, beyond which both devices exhibited hard dielectric breakdown. This result suggests a correlation between threshold ion fluence and a thickness dependent critical density of displacement defects. Conduction mechanism fitting showed a transition from electrode limited conduction to bulk limited conduction mechanisms at threshold ion fluence in both the 2 nm and 12 nm hBN samples, however, this result is inconclusive and requires further research