Double-channel AlGaN/GaN Schottky barrier diode with AlN super back barrier on SiC substrate

Abstract

In this work, high-performance double-channel AlGaN/GaN Schottky barrier diodes with AlN super back barrier are demonstrated, and the corresponding current transport mechanisms at various anode bias voltages are studied. Benefiting from the electric field-modulated GaN double channel via polarized charge, high output current of 339 mA/mm and high breakdown voltage of 2.18 kV are obtained. The initial leakage current is dominated by thermionic emission, when the anode is biased at a small voltage. With the increase in anode voltage, electrons in the GaN channel are partly depleted, and two-dimensional variable-range hopping, through high-density trap states in the GaN-based material, dominates the total leakage current. When the anode reverse bias is large enough to fully deplete electrons in channel, the temperature-dependent leakage current shows little dependence on the applied anode voltage, and the trap-assisted tunneling model satisfies.