Characterization of Interface Characteristics of Hexagonal Boron Nitride with Different Thicknesses Using Scanning Microwave Microscopy

Hexagonal boron nitride (h-BN) holds significant application value in two-dimensional electronic devices due to its excellent dielectric properties. This study characterized the microwave response characteristics of h-BN with different thicknesses and interfaces covered on interdigital electrodes by using scanning microwave microscopy. We explain the microwave absorption effect and dielectric response of h-BN with different layer thicknesses. Experimental results indicated that the microwave response of h-BN exhibits a distinct thickness dependence. The thin-layer regions (less than 90 nm) exhibit significant changes in the dielectric response gradient at the interface. Due to the stronger dielectric shielding effect, the signal changes at both ends of the interface are significantly weakened in the thick-layer region (about 170 nm). Additionally, as the thickness of h-BN increases, microwave absorption also increases. This study not only provides important experimental evidence for the dielectric properties and thickness dependence of h-BN in the microwave frequency band at the microscale but also provides theoretical guidance and technical reference for the optimization design and performance control of two-dimensional materials in microwave devices.