Surface preparation for Schottky metal-4H-SiC contacts formed on plasma-etched SiC

Silicon-carbide-based devices frequently require a Schottky gate to be depo sited on a plasma-etched surface. This paper considers the effectiveness of nine different pre-metallization surface preparation procedures in removin g the etch damage. The surfaces were assessed by x-ray phatoelectron spectr oscopy and by current-voltage measurement of nickel Schottky diodes formed on both reactive-ion-etched and non-reactive-ion-etched silicon face 4H-SiC . The treatments included simple UV-ozone and solvent cleans, oxygen plasma , deposited oxide and thermal oxidation. It was confirmed that the only pro cess which removed all traces of surface contamination and etch damage, pro ducing ideal Schottky diodes, was sacrificial oxidation.