Thermionic-Field Emission Barrier Between Nanocrystalline Diamond and Epitaxial 4H-SiC

A novel Schottky-like rectifying heterojunction between two low-doped widebandgap semiconductors is presented. The conduction mechanism of p-type nanocrystalline diamond and n-type 4H-SiC with a near-unity ideality factor was determined via two-terminal current-voltage measurements as a function of temperature and SiC doping concentration. I-V characteristics at 300 and 510 K were fit at low forward bias with good agreement using thermionic emission theory. A wide temperature range ideality factor analysis revealed a thermionic-field rectifying barrier to low-doped and moderately doped SiC epilayers, which could lead to improved contacts for SiC-based piezoresistors, resonators, and microelectromechanical systems.