Electrical characterization of GaN/SiC n-p heterojunction diodes

TLDR

GaN/SiC heterojunction diodes were fabricated by growing epitaxial n‑type GaN films via MOCVD and ECR‑MBE on p‑type 6H‑SiC wafers and characterized. The diodes exhibit ideality factors of 1.2, saturation currents of 10^−32 A cm^−2, built‑in potentials of 2.90 ± 0.08 eV (MOCVD) and 2.82 ± 0.08 eV (ECR‑MBE), and band‑edge offsets of ΔEC = 0.11 ± 0.10 eV and ΔEV = 0.48 ± 0.10 eV.

Abstract

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/cm2, 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 ΔEC=0.11±0.10 eV and ΔEV=0.48±0.10 eV.