Preparation of α‐Si3N4 by direct nitridation using polysilicon waste by diamond wire cutting

Abstract

AbstractWith the rapid development of the semiconductor industry and solar photovoltaic industry, a large number of polysilicon wastes from diamond wire cutting are accumulated, which not only pollute the environment, but also cause safety problems due to the ultrafine particle size and high reactivity. The diamond wire cutting polysilicon waste was used to prepare α‐Si3N4 by direct nitridation method. This method could not only fully recycle the waste and reduce environmental pollution, but also could reduce the production cost of α‐Si3N4. Furthermore, the effects of FeCl3, NaCl, and metal Cu on the nitridation of polysilicon waste are investigated in detail, respectively. It is found that FeCl3 and NaCl are not ideal additives for the preparation of α‐Si3N4. However, α‐Si3N4‐dominated Si3N4 can be obtained via adding 5 wt% Cu after nitridation at 1250°C for 8 hours, and the relative content of α‐Si3N4 reaches 92.37%.