高频等离子体化学气相沉积法制氮化硅超细粉的工艺研究

TECHNICAL STUDIES ON PREPARATION OF Si_3N_4 POWDER BY RADIO FREQUENCY PLASMA CHEMICAL VAPOR DEPOSITION

以Ar气为载气，SiCl4和NH3为原料，在高频等离子体化学气相沉积反应器中，制备了超细无定形的Si3N4粉未．该粉具有粒度小、粒径窄和分散均匀的特点，氮含量在36％以上．实验中发现，当SiCl4进料口在前，NH3进料口在后，且两个进料口均在高频等离子体尾焰处，经脱NH4Cl的产物中氮含量较高．而反应物NH3也不宜太过量，以NH3：SiCl4=8：1为好．Si3N4的晶型转变在1400“C下处理8h。

Amorphous and ultrafine Si3N4 powder was prepared from SiCl4 and NH3 by using the aseo nequency Plasma Chemical Vapor Deposition (RFPCVD) method. Before the crystalline structure transformation, the average diameter of the particles is 20~30 nm and the size distribtion is narrow. It is found in the experiment that the inlet position of SiCl4 should be higher than that of NH3, and they should be located at the hind part of the plasma torch.The best molar proportion of NH3 to SiCl4 should be 8:1. Thus, the highest mount of nitride content could be obtained. The crystalline structure transformation should be performed under 1 400 C for 8 hours.