Preparation and characterization of AlN powders in the AlCl3-NH3-N-2 system

Fine aluminum nitride (AIN) powders were obtained by the chemical vapor dep osition (CVD) process in the AlCl3-NH3-N-2 system at the gas Row rate of 20 0 cm(3)/min for both NH3 and N-2. X-ray diffraction (XRD), scanning electro n microscopy (SEM), transmission electron microscopy (TEM) and electron dif fraction (ED) were utilized to study the preparation and characterization o f the AlN powders. While the reaction temperature of AlCl3 and NH3 is above 600 degrees C, the AlN crystalloids are formed, however, the amorphous AlN powders are obtained below 600 degrees C. When these powders are heat trea ted in NW, atmosphere at temperatures above 1200 degrees C, the amorphous A lN is converted to a crystallized state. The morphology of the particles an d agglomerates of AlN is strongly dependent on the reaction temperature. Th e particle size of the AlN powders decreases from 210 to 12 nm, as the reac tion temperature increases from 600 degrees C to 1150 degrees C, The relati on bt tween the AlN particle size, Dnm, and the reaction temperature, T deg rees C, is experimentally approximated as D = 4830 exp( - 5.225 x 10(-3) T) . (C) 2000 Published by Elsevier Science B.V. All rights reserved.