Ion-beam synthesis of amorphous SiC films: Structural analysis and recrystallization

The analysis of SiC films obtained by carbon ion implantation into amorphous Si (preamorphized by Ge ion implantation) has been performed by infrared and Raman scattering spectroscopies, transmission electron microscopy, Rutherford backscattering, and x-ray photoelectron spectroscopy (XPS). The data obtained show the formation of an amorphous Si1-xCx layer on top of the amorphous Si one by successive Ge and C implantations. 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 implanted region, with a composition in the range 0.35 < x < 0.6. This points out the existence of a partial chemical order in the layer, in between the cases of perfect mixing and complete chemical order. Recrystallization of the layers has been achieved by ion-beam induced epitaxial crystallization (IBIEC), which gives rise to a nanocrystalline SiC layer. However, recrystallization is not complete, observing still the presence of Si-Si and C-C bonds in an amorphous phase. Moreover, the distribution of the different bonds in the IBIEC processed samples is similar to that from the as-implanted ones. This suggests that during IBIEC homopolar bonds are not broken, and only regions with dominant Si-C heteropolar bonds recrystallize. (C) 1996 American Institute of Physics.