Comparative surface studies on wet and dry sacrificial thermal oxidation on silicon carbide

A comparative study on the effect of wet and dry thermal oxidation on 4H-si licon carbide (SIC) and on sacrificial silicon (Si) thermal oxidation on 4H -SiC surface has been conducted using atomic force microscopy (AFM) and X-r ay photoelectron spectroscopy (XPS). The AFM images show the formation of ' nano-islands' of varying density on the SiC surface after the removal of th ermal oxide using hydrofluoric (HF) acid etch. These nano-islands are resis tant to KF acid and have been previously linked to residual carbon [1-3] re sulting from the oxidation process. This paper presents the use of a sacrificial silicon oxidation (SSO) step a s a Form of surface preparation that gives a reproducible clean SIC surface . XPS results show a slight electrical shift in binding energy between the wet and dry thermal oxidation on the standard SLC surface, while the surfac e produced by the: SSO technique shows a minimal shift, (C) 2001 Elsevier S cience B.V. All rights reserved.