SURFACE-STRUCTURE OF 3C-SIC(111) GROWN ON SI(111) SURFACE BY C-60 PRECURSOR

The surface structure of cubic 3C-SiC(111) films prepared by thermal r eaction of a Si(111) substrate with C-60 molecules has been studied by combined in situ measurements of scanning tunneling microscopy and hi gh resolution electron energy loss spectroscopy (HREELS-STM). The (2Xn ) surface reconstructions such as (2X2), (2X3) were observed under low reaction temperatures (<900 degrees C), and the Si-terminated SiC(111 )-(3X3) was obtained by annealing the sample at higher temperatures (s imilar to 1100 degrees C). Optical surface phonon energies of 113+/-2 meV for SiC prepared at low temperatures and 116+/-2 meV for the films with (3X3) surface reconstruction were measured. The diffusivity of S i atoms from the substrate through the SiC film at various temperature s is suggested as the reason for the formation of different surface re constructions of the SiC. (C) 1996 American Institute of Physics.