In Situ SiC Feeding by Chemical Vapor Deposition for Bulk Growth

In CF-PVT process, SiC feeding by CVD and sublimation are obtained simultaneously in the crucible. The transfer of silicon carbide from the deposition to the sublimation areas occurs through out highly porous graphite foam. EDS mapping, X-ray diffraction and the combination of a simplified thermodynamic model with simulations demonstrated that this transfer results from successive steps of deposition, sublimation and condensation of silicon carbide inside the porous medium at temperatures above 2073K. Introduction The Continuous Feed Physical Vapor Transport (CF-PVT) process was recently developed for bulk growth [1]. The reactor is divided in two main parts (figure 1). The first one is the sublimation chamber, where the SiC single crystal grows by Physical Vapor Transport (PVT). The second area is the feeding chamber where experimental conditions (gas flow, temperature and chemical concentration of precursors) allow the continuous feeding of the polycrystalline source by chemical vapor deposition (CVD) at high temperature. The two areas are separated by a graphite foam. Fig. 1: Schematic representation of the crucible. indicates the localization of the pyrometric measurements (above the crucible and under the source). The aim of this paper is to understand the transport of silicon carbide from the CVD area where the polycrystalline source is deposited to the PVT chamber. The precursor used for CVD is tetramethylsilane (TMS, Si(CH3)4) diluted in argon. It was shown in a previous experimental work [1] that a transfer of matter above 2073K through a porous source medium is observed from the CVD area to the PVT chamber. The aim of this new work is to understand with EDS mapping and a heating element sublimation chamber HTCVD chamber induction coil seed