Synthesis of SiC by high temperature C+ implantation into SiO2 - The role of Si/SiO2 interface

The evolution of SiC in the Si/SiO2 interface during high temperature implantation of C+ in the range of 1000 to 1100 degrees C, has been studied by transmission electron microscopy (TEM) and secondary ion mass spectroscopy. Microcrystalline zones of Si and SiC inside the oxide have been observed. During implantation carbon atoms diffuse toward the SiO2/Si interface. forming an epitaxial SiC layer. It is proposed that this profess is facilitated by the dangling and strained Si-O bonds at the SiO2/Si interface. The quality of the SiC epitaxial layer has been systematically studied by cross-sectional and plane view TEM observations. The SiC film consists of individual grains which are found to be in epitaxial relation with the Si substrate as the related Moire patterns reveal. The residual strain and the misorientation of the grains with the Si matrix have been estimated from the periodicity and the rotation of the Moire patterns. The quality of this SiC layer is better than the SiC layers formed by the standard carbonization process. This improvement is attributed to the very slow growth rate of the 3C-SiC layer which is controlled by the low C+ current density.