MEASUREMENT OF COMPLETE AUGER-ELECTRON EMISSION ANGULAR-DISTRIBUTIONS FROM BETA-SIC FILMS ON SI(100)

The structure of epitaxial beta-SiC thin films grown on Si(100) has been investigated by measuring Auger electron emission angular distributions over an essentially complete hemisphere of angles of emission above the film surface. The beta-SiC films were grown by rapid thermal chemical vapor deposition, in which the heated Si(100) surface was carbonized with propane. Auger emission angular distributions were measured for carbon at 268 eV, and for silicon at 86 and 1605 eV, allowing the film structure to be probed from the viewpoint of each element. The Auger measurements probe the film structure to a depth of several atomic layers. Each of the distributions displayed distinct, fourfold symmetric features, demonstrating the crystalline character of the beta-SiC films. Comparison of the measured angular distributions with geometric projections and simulations for the known beta-SiC structure indicates that the films consist of interspersed [100] crystalline domains (each domain having twofold symmetry), with 90-degrees in-plane rotational orientations between domains. These findings are consistent with scanning tunneling microscopy observations of the outermost atomic layer.