High-On/Off-Current-Ratio AlGaN/GaN HEMTs via Van Der Waals Epitaxy GaN With a BN Inset Layer

In nitride heteroepitaxy, lattice mismatch and thermal stress inevitably induce dislocation proliferation and defect formation, which critically degrade device reliability. In this letter, we demonstrate the high-quality epitaxial growth of nitride heterojunction structures on two-dimensional high-quality boron nitride (h-BN) materials via van der Waals epitaxy. Furthermore, BN also functions as a gate dielectric in the fabricated metal-insulator-semiconductor HEMT (MIS-HEMT), leveraging its ultrawide bandgap properties. The combined advantages of Buffer-assisted heterostructures and ultrawide-bandgap BN dielectric enabling a 10³-fold gate leakage reduction. Additionally, the proposed device exhibits an on/off current ratio of 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup>, with a maximum saturated output current density of 1550 mA/mm and 30% increase in transconductance. This shows the great potential of the proposed device for future power-electronics applications.