Spark plasma sintering of W-30Si refractory targets: Microstructure, densification and mechanical properties

W-30Si refractory targets were widely used as gate materials in the field of semiconductor integrated circuits. This work aimed to study the microstructure, densification mechanism, and mechanical properties of W-30Si targets prepared by spark plasma sintering (SPS). The results manifested that the punch displacement and relative density rose as temperatures increased, and the sintering route processed at 1200 degrees C included four parts. A fully dense target can be obtained at 1200 degrees C, while part of Si would volatilize at 1220 degrees C. No significant variation was observed in grain sizes from 1000 to 1200 degrees C, thus it was believed that the consolidation predominated over this temperature range. The effective stress exponent (n) was generally regarded as a parameter closely related to the densification mechanism. At the initial stage of 1000 to 1200 degrees C and the late stage of 1000 degrees C (n < 1), the particle rearrangement had a major influence on the densification. At the late stage of 1050 to 1200 degrees C (1 < n < 2), the grain boundary diffusion was a significant factor for consolidation, and the activation energy (n = 1.5) was estimated to be 931.40 kJ/mol. Besides, the microhardness rose with increasing temperatures. The present study laid the groundwork for future research on the fabrication of W-30Si targets by SPS.

Automated summary

This study investigated the microstructure, densification mechanism, and mechanical properties of W-30Si targets prepared by spark plasma sintering (SPS). The results revealed that the effective stress exponent and temperature played crucial roles in the densification mechanism. Additionally, the microhardness increased with increasing temperature.