Growth of SiC whiskers by VLS process

Abstract

β-SiC whiskers were synthesized by the vapor-liquid-solid (VLS) process using Fe catalyst. Whiskers show smooth surfaces and no ramifications. They have uniform diameter (0.5-1 μm) and lengths between 50 and 300 μm. A catalyst droplet was observed on the tip of almost all the whiskers. The transport of iron from the substrate surface to the SiO generators, where growth took place, occurs fundamentally via vapor phase. Fe was deposited over surfaces containing C, and whisker growth was produced where there were Fe droplets of appropriate size and SiO available in great quantity. The need for reaching a threshold size (2–3 μm) of the catalyst droplet before whisker growth is proposed as a possible explanation for the formation of whiskers with uniform size in zones with a high partial pressure of SiO.