Surface Structure and Metallization of SiC

A brief enumeration of the relevant UHV characterization techniques follows this introduction. Methods of surface preparation are next considered, after which progress in the determination of the structure and composition of stable surface phases of p and 6H crystals is reviewed. The final section describes work on the SiC interface with 15 different metals, both as-prepared and after thermal annealing. 

1 (Editor s note at the time of going to press, June 1995, the area of knowledge reviewed here had not changed substantially since the cut-off date, May 1993.) 

TABLE I Surface-science techniques applied to (3- and a(6H)-SiC. (The numbers indicate the appropriate 

RHEED Reflection High Energy Electron Diffraction 

The preponderance of research to date has been on (100) surfaces of p-SiC in the form of films deposited on Si substrates. Work on this orientation will be reviewed first, followed by a description of results obtained on p( 111) and 6H(0001) (which appear to be indistinguishable in LEED) and on 6H(0001) surfaces. 

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We shall first review the basic principles of VASP and than describe exemplary applications to alloys and compounds (a) the calculation of the elastic and dynamic properties of a metallic compound (CoSi2), (b) the surface reconstruction of a semiconducting compound (SiC), and (c) the calculation of the structural and electronic properties of K Sbi-j, Zintl-phases in the licpiid state. 

Carbides can be covalent or metal-like, the most important of the covalent carbides being SiC which like carbon crystallizes in both hexagonal and cubic structures. However, contrary to carbon, the basal planes in the hexagonal structure and the (111) faces of the cubic variant are linked by chemical bonds, so the corresponding surface energies should be about 103 rather than 102 mJ/m2. Estimated values for the surface energy of both faces are close to 1500 mJ/m2 (Appendix F). 

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