All-epitaxial Al/AlGaN/GaN low-barrier Schottky diodes

Abstract

All-epitaxial Al/AlxGa1−xN/GaN low-barrier Schottky diodes with different x compositions were fabricated in the single process of molecular-beam epitaxy. A decrease in the effective barrier height is achieved by polarization-induced δ-doping of the AlxGa1−xN/GaN heterojunction. At zero bias, the diodes have high values of ampere-watt sensitivity (7 A/W) with a low specific value of differential resistance (5 × 10−4 Ω⋅cm2) and retain non-linear properties when the resistance decreases to 10−4 Ω⋅cm2. The fundamental importance of the absence of impurities, oxides, and structural defects at the metal–semiconductor interface for effective control of the transport properties of diodes is demonstrated.