OXYGEN AND HYDROGEN EFFECTS ON THE CHEMICAL-VAPOR DEPOSITION OF ALUMINUM NITRIDE FILMS

Aluminium nitride has been obtained by chemical vapor deposition using AlCl3 and NH3 as precursors. Progressive introduction of N2O in the g as mixture has shown the possibility of inserting oxygen in the AlN la ttice. This involves strong changes of surface morphology of the depos it and the formation of less-crystallized materials. When hydrogen is added to the gas mixture, these effects are reduced. Electron energy l oss spectroscopy has shown that, in this case, oxygen is mainly concen trated on the external parts of AlN crystals, the structure of which h as been found consistent with the wurtzite structure.