On reactions between silicon and nitrogen

An attempt is made to rationalize various reaction mechanisms for the formation of Si3N4 from gaseous nitrogen and solid silicon. It is suggested that a fundamental difference betweenα- andβ-Si3N4 is that the former results from silicon complexing with molecular nitrogen and the latter results from complexing with essentially atomic nitrogen. Well established mechanisms (as well as controversial ones) are analysed in the light of this difference and are shown to be operative under various reaction conditions. The influence of some common reaction variables are interpreted with respect to their influence on either silicon or nitrogen or both.