ION-BEAM SYNTHESIS OF AMORPHOUS SIC FILMS - STRUCTURAL-ANALYSIS AND RECRYSTALLIZATION

The analysis of SiC films obtained by carbon ion implantation into amo rphous Si (preamorphized by Ge ion implantation) has been performed by infrared and Raman scattering spectroscopies, transmission electron m icroscopy, Rutherford backscattering, and x-ray photoelectron spectros copy (XPS). The data obtained show the formation of an amorphous Si1-x Cx layer on top of the amorphous Si one by successive Ge and C implant ations. The fitting of the XPS spectra indicates the presence of about 70% of Si-C bonds in addition to the Si-Si and C-C ones in the implan ted region, with a composition in the range 0.35 < x < 0.6. This point s out the existence of a partial chemical order in the layer, in betwe en the cases of perfect mixing and complete chemical order. Recrystall ization of the layers has been achieved by ion-beam induced epitaxial crystallization (IBIEC), which gives rise to a nanocrystalline SiC lay er. However, recrystallization is not complete, observing still the pr esence of Si-Si and C-C bonds in an amorphous phase. Moreover, the dis tribution of the different bonds in the IBIEC processed samples is sim ilar to that from the as-implanted ones. This suggests that during IBI EC homopolar bonds are not broken, and only regions with dominant Si-C heteropolar bonds recrystallize. (C) 1996 American Institute of Physi cs.