Electrical characterization of GaN/SiC n-p heterojunction diodes

GaN/SiC heterojunction diodes have been fabricated and characterized. Epitaxial n-type GaN films were grown using metalorganic chemical vapor deposition (MOCVD) and electron cyclotron resonance assisted molecular beam epitaxy (ECR-MBE) on p-type Si-face 6H-SiC wafers. The I-V characteristics have diode ideality factors and saturation currents as low as 1.2 and 10(-32) A/cm(2), respectively. The built-in potential in the MOCVD- and ECR-MBE-grown n-p heterojunctions was determined from capacitance-voltage measurements at 2.90+/-0.08 eV and 2.82+/-0.08 eV, respectively. From the built-in potential the energy band offsets for GaN/SiC heterostructures are determined at Delta E-C=0.11+/-0.10 eV and Delta E-V=0.48+/-0.10 eV. (C) 1998 American Institute of Physics.