The evolution of cavities in Si at the 3C-SiC/Si interface during 3C-SiC deposition by LPCVD

The evolution of cavities in the Si-overlayer (SOL) of the silicon on insulator (SOI) wafers, which are formed during the epitaxial growth of 3C-SiC, was studied by combined Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) observations. The effect of the SiC and the SOL thickness, as well as the SiC rate of growth, on the formation of cavities is discussed. The volume of the missing silicon due to the formation of the cavities in the SOL was measured by AFM. It was shown that a small portion of Si ball up at the edges of the cavities inside the buried oxide (BOX) due to instability of the Si/SiO2 system at high temperatures. Another part is consumed in order to form SiC during the carbonization process and finally a significant portion is out-diffused during the deposition of the first 200 nm of the SiC film.