Gold films epitaxially grown by diffusion at the 3C-SiC/Si interface

A thin layer of gold grown epitaxially in a 3C-SiC/Si interface is observed using conventional (CTEM) and high-resolution electron microscopy (HREM) m ethods. This interlayer was formed after an extended thermal treatment, at 500 degrees C for 500 h, of a 3C-SiC/Si system on which Au was deposited on the surface of SiC for the formation of a Schottky diode. Misfit dislocati ons are observed in both SiC/Au and Au/Si interfaces having Burgers vectors b = 1/2[(1) over bar 10] parallel to the interfaces. Such an epitaxy is ma de in spite of the very high misfit in the Au/Si interface. The net of the misfit dislocations is visible only by cross-section HREM observations. The position of the extra half-planes of the interfacial dislocations is illus trated. An explanation for the mechanism of the Au mass transport through t he unaffected SiC film is given. This is attributed to pipe diffusion throu gh the partial dislocations bounding the stacking faults and inversion doma in boundaries that pre-exist in 3C-SiC. The same diffusion mechanism allows the transport of Si from the 3C-SiC/Si interface to the top surface of SIC on which islands of Si and Au are formed. (C) 1999 Elsevier Science B.V. A ll rights reserved.