Formation of Cr ohmic contact on graphitized 6H-SiC(0001) surface

Ohmic electrical contacts were formed at room temperature on n-type, Si-oriented 6H-SiC substrates, with Cr layers vapor-deposited under ultra-high vacuum conditions on the samples being graphitized prior to the deposition. The contacts reveal a very good linearity of the local I–V characteristics. This method of ohmic contact formation does not require the use of samples with high doping concentration and the application of high-temperature annealing during the processing of contacts. Results of characterization of the contacts and of the in situ graphitization process of the SiC substrates, obtained by X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and atomic force microscopy (AFM) with conducting tip, are given in this paper.