Crystalline tantalum carbide and ditungsten carbide formation via hot wire chemical vapor deposition using the precursor of 1-methylsilacyclobutane

Abstract

An efficient method for the preparation of crystalline tantalum carbide (TaC) was reported using a new methyl-substituted precursor, 1-methylsilacyclobutane (MSCB), in the hot-wire chemical vapor deposition process with a tantalum filament. The ability of MSCB to produce methyl radicals on heated Ta filament allows for the formation of crystalline TaC (cubic Fm-3m) in a wide temperature range of 1600–2200°C. This corroborates the key role of the radical species formed via the precursor's decomposition on the hot metal wire in the type of metal alloys formed on the wire surface. The growth rate of TaC achieved at 0.12μm/min and 0.35μm/min, respectively, for 1600°C and 2200°C is much higher than the value obtained from using CH4/H2 mixtures as the C-containing precursor. Crystalline ditungsten carbide (W2C) was formed by treating the tungsten filament with MSCB at the relatively high temperatures of 2200–2400°C, with a deposition rate of 2.1μm/min at 2400°C. The method reported in this work is a useful method to produce crystalline TaC or W2C without the use of the corrosive metal halide precursors.