Crystallization of an amorphous silicon nitride powder produced in a radiofrequency thermal plasma

Crystallization behavior of an amorphous silicon nitride powder produced in an RF thermal plasma by the vapor-phase reaction of silicon tetrachloride and ammonia has been investigated. Effects of annealing conditions such as temperature and duration of heat treatment on the properties of powders wer e studied. Changes in the chemical and phase compositions, as well as in th e morphology of powders were measured and interpreted. Annealing of the amo rphous silicon nitride powder at 1450 degrees C for 120 min resulted in a p owder of about 80% crystalline phase content with an alpha/beta ratio of ab out 6.5. (C) 1999 Elsevier Science Ltd and Techna S.r.l. All rights reserve d.