STUDY OF PRODUCTS FORMED FROM THE REACTIO N BETWEEN ALUMINUM HALIDES AND AMMONIA DURING ALUMINUM NITRIDE SYNTHESIS .2. NITROGEN-COMPOUNDS THERMOLYSIS AND ALUMINUM NITRIDE SYNTHESIS

In recent years, aluminum nitride synthesis has been realized from the reaction between AlX3 and NH3. The resultant compounds (AlX3, 6 NH3) are treated under ammonia atmosphere. These compounds have a different nature according to halide and thus are going to lead to different de composition mechanisms. These will be described thanks to study of var ious pyrolysis (under ammonia, nitrogen, reduced pression). The crysta llized aluminum nitride is obtained from 900-degrees-C under ammonia f low whatever the precursor is. The synthesis rate is low. This one is explained by NH4X presence, bi-product of the synthesis. NH4X interact s with aluminum compounds to form volatil complexes carried by gaseous flow. The best rate is obtained with AlI3 precursor though decomposit ion mechanisms of AlI3, 6 NH3 are more complicated than those of AlBr3 , 6 NH3 or AlCl3, 5 NH3.