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

Abstract

Silicon-carbide-based devices frequently require aSchottky gate to be deposited on a plasma-etched surface. Thispaper considers the effectiveness of nine differentpre-metallization surface preparation procedures in removingthe etch damage. The surfaces were assessed by x-rayphotoelectron spectroscopy and by current-voltage measurementof nickel Schottky diodes formed on both reactive-ion-etchedand non-reactive-ion-etched silicon face 4H-SiC. Thetreatments included simple UV-ozone and solvent cleans, oxygenplasma, deposited oxide and thermal oxidation. It was confirmedthat the only process which removed all traces of surfacecontamination and etch damage, producing ideal Schottky diodes,was sacrificial oxidation.