Formation of B, Al, Ga, and Si nitrides from their oxides: a reactive laser ablation study

Abstract

Nitrides such as Si₃N₄ and GaN are made by the reaction of the respective oxide with N₂ or NH₃. In order to understand the mechanism of formation of nitrides, reactive laser ablation of B₂O₃, Al₂O₃, Ga₂O₃, and SiO₂ in pure form, as well as in mixture with carbon, has been carried out in an atmosphere of nitrogen or ammonia in a pulsed supersonic jet. The reaction of N₂ with SiO₂ gives nitridic species such as Si₂N_y (y≤5) in the vapor phase. On reaction with N₂ in the presence of carbon, B₂O₃ and Ga₂O₃ yield species of the type B_xN_y and GaN_y, respectively. Nitridic species are preponderant in the reaction with ammonia only in the case of SiO₂. Al₂O₃ predominantly gives oxynitridic species under the reaction conditions examined.