Characterization of polycrystalline SiC films grown by HW-CVD using silicon tetrafluoride

Abstract

SiC films were synthesized by hot-wire chemical vapor deposition using a tungsten filament and a gas mixture of SiF 4 and CH 4 . The etching of the substrate instead of the film growth occurred on the samples prepared using only source gases without H 2 dilution. The atomic or molecular hydrogen was believed to control the density of radicals containing F in a gas phase or on a growth surface. Polycrystalline 3C-SiC(111) films were successfully obtained at substrate temperatures lower than 500 o C by using H 2 dilution. The growth mode limited by source-gas supply was found to be important to obtain polycrystalline SiC films. The SiC film grown at higher deposition pressure was amorphous and contained no Si-H x bonds but 6% fluorine. In SiF 4 /CH 4 /H 2 system, the radicals containing F are considered to play very important roles in the reactions both on a growth surface and in a gas-phase.

High‐Speed Preparation of <111>‐ and <110>‐Oriented β‐SiC Films by Laser Chemical Vapor Deposition

“…The lattice image in Fig. (c) shows that the dark striations corresponded to twins parallel to the (111) plane, as commonly observed in β‐SiC . The lattice distance along the growth direction was approx 0.25 nm which is in agreement with the d ‐value of the β‐SiC (111) plane.…”

“…Si(CH 3 ) 4 has been employed in low pressure CVD (LPCVD) as a nonexplosive and noncorrosive precursor; however, resulting deposition rates of β‐SiC films were less than 3 μm/h . Although TCVD and PECVD can prepare <111>‐ and <110>‐oriented β‐SiC films, highly oriented β‐SiC films are difficult to prepare with high deposition rates and in the form of a thick film.…”

Growth Mechanism and Defects of <111>‐Oriented β‐SiC Films Deposited by Laser Chemical Vapor Deposition

“…However, most of these efforts are taken to avoid the planar defects in (111) plane by growing <100>‐oriented β‐SiC. In theory, the β‐SiC with {111} planar defects, such as twin or anti‐phase, has a lower energy than the nondeficient β‐SiC; hence, these planar defects are commonly existed in β‐SiC . Recently, three efficient methods: Switch‐Back‐Epitaxy (SBE), Inverted Silicon Pyramids (ISP), and Pendeo‐Epitaxial‐Growth (PEG) for growing <100>‐oriented β‐SiC with less defects have been developed.…”

Summary Report on the Volatile Radionuclide and Immobilization Research for FY2011 at PNNL

“…Since industrial scale fabrication of SiC monoliths with physical vapor deposition methods is a wellestablished technology (Abe et al 2008;Jiangang et al 2006;Saddow et al 2001;Moon et al 2001;Sugiyama et al 1998), there is little, if any, technology development needed to produce dense, pure SiC. While there are many polymorphs of SiC, the cubic 3C structure is preferred for nuclear and structural applications, such as ceramic composite fibers and matrices and fine-grained coatings for TRISO nuclear fuel particles.…”