DIFFUSION OF GOLD IN 3C-SIC EPITAXIALLY GROWN ON SI - STRUCTURAL CHARACTERIZATION

The structural characteristics of gold/3C-SiC contacts, subjected to a long annealing at 500 degrees C for 500 h for aging investigation, we re studied by transmission electron microscopy. After the aging test a bout 50% of the gold which was deposited on the SiC surface was diffus ed through the 2.5 mu m thick 3C-SiC to the SiC/Si interface forming a n almost continuous gold film resulting in a SiC/Au/Si structure. The intermediate gold film is in perfect epitaxial relation to the 3C-SiC overgrown and the Si substrate, in spite of the 25% misfit between the Au and Si. Moire fringes produced by the interference of the Au and S i lattices reveal that the two lattices are perfectly relaxed. No line ar or planar defects were observed in the gold film. No Au precipitate s were observed inside the 3C-SiC overgrown or in the Si-substrate. A mechanism responsible for the formation of the intermediate gold film in the SiC/Si interface is proposed. (C) 1997 Elsevier Science S.A.