Ni/Heavily-Doped 4H-SiC Schottky Contacts

Abstract

In this work, we focus on the electrical characterization of Ni Schottky contact on n-type heavily doped (ND>1019 cm−3) 4H-SiC layer, achieved by P-ion implantation. In particular, the forward current–voltage characterization of Schottky diodes showed a reduced turn-on voltage for the Ni/heavily-doped 4H-SiC if compared to a reference Ni/4H-SiC Schottky contact fabricated under similar conditions but without implant. Moreover, it was observed the predominance of a thermionic-field-emission (TFE) mechanism for the current transport through the interface. From a current-voltage-temperature (I-V-T) study, the temperature-dependence of the Schottky barrier and doping concentration were evaluated, obtaining a reduction of the barrier (from 1.77 to 1.66 eV), while the doping concentration maintains constant around 1.96×1019 cm-3. This study provides useful insights for a deeper comprehension of the electrical behavior of Ni contacts and can have possible applications in 4H-SiC Schottky diode technology.