Transmission Electron Microscopy Studies of (AIN-Si3N4) Codeposits Obtained by LPCVD

Several (Al,Si,N) compounds have been obtained by LPCVD in a vertical hot-wall reactor using aluminium trichloride, silicon tetrachloride and ammonia as source gases, with nitrogen as the carrier gas. In order to determine both their structure and local chemical composition, several deposits have been examined by analytical transmission electron microscopy combining electron diffraction (ED), high resolution electron microscopy (HREM) and electron energy loss spectroscopy (EELS). It has been confirmed that the chemical composition of the materials as well as the size of the nanocrystals observed in the deposits are strongly dependent on the temperature and the reactive gas flow. It has also been shown that for the range of temperature (1273 K-1373 K) used in this work these nanocrystals have the wurtzite structure of aluminium nitride.