Forward thermionic field emission transport and significant image force lowering caused by high electric field at metal/heavily-doped SiC Schottky interfaces

We investigated the doping concentration dependence of the barrier height and forward carrier transport mechanism in Ni/SiC Schottky barrier diodes (SBDs) in the wide range of 6.8 × 1015- 1.8 × 10 19 cm − 3 . Forward current-voltage characteristics in heavily-doped SiC SBDs ( > 2.6 × 10 17 cm − 3 ) can be well reproduced by a thermionic field emission model. The barrier height decreased with increasing doping concentration and the barrier height drop in the most heavily-doped SBD ( 1.8 × 10 19 cm − 3 ) was about 0.2 eV, which quantitatively agreed with the image force lowering of 0.18 eV caused by the high electric field.