AN INTERFACE STUDY OF VAPOR-DEPOSITED RHENIUM WITH THE 2 (0001) POLARFACES OF SINGLE-CRYSTAL 6H-SIC

The interfaces formed on the two (0001) polar faces of single crystal n-type 6H-SiC by Re evaporation and subsequent annealing were investig ated by X-ray photoelectron spectroscopy (XPS), low energy electron di ffraction (LEED) and work function (WF) measurements. Rhenium was depo sited from submonolayer up to 2 nm thickness and,gradually annealed up to 1100 K. Deposition led to a weakening and eventual disappearance o f the 1 x 1 LEED pattern of the clean surface, an increase of the WF u p to the value of metallic Re and the formation of a Schottky barrier with a height of 0.7 +/- 0.2 eV for both faces. The Re 4f(7/2) peak bi nding energy decreased during deposition from approx. 41.1 eV below mo nolayer coverage, to 40.5 eV for a 2 mm film indicating an island grow th of the film. Annealing of the Re films up to 1100 K on both faces l ed to Re particle coalescence without affecting the low Schottky barri er at the interface, however, there are indications of chemical change s at the interface which could affect the electrical characteristics o f the contact. (C) 1997 Elsevier Science S.A.