Study of Direct Tunneling and Dielectric Breakdown in Molecular Beam Epitaxial Hexagonal Boron Nitride Monolayers Using Metal–Insulator–Metal Devices

Direct tunneling and dielectric breakdown in molecular beam epitaxial hexagonal boron nitride (h-BN) monolayers were studied based on Ni/h-BN/Ni metal–insulator–metal (MIM) device structures. Effective tunneling areas are orders of magnitude smaller than physical areas of the devices. Statistical Weibull analysis of the breakdown characteristics shows that the breakdown area-scaling law applies to effective areas rather than physical areas of the devices. The h-BN monolayer MIM devices can sustain repeated dc voltage sweeping stresses up to 85 times under an extremely high compliance current of 100 mA, and the critical electric field is determined to be at least 11.8 MV/cm, demonstrating high dielectric strength and reliability of these h-BN monolayers. The mechanism of breakdown and recovery of the h-BN monolayer MIM devices is also discussed.