Kinetic study of silicon carbide deposited from methyltrichlorosilane precursor

Abstract

The kinetics of silicon carbide (SiC) deposition, in a hot-wall chemical vapor deposition (CVD) reactor, were modeled by analyzing our own deposition rate data as well as reported results. In contrast to the previous attempts which used only the first order lumped reaction scheme, the present model incorporates both homogeneous gas phase and heterogeneous surface reactions. The SiC deposition process was modeled using the following reactions: (i) gas phase decomposition of methyltrichlorosilane (MTS) molecules into two major intermediates, one containing silicon and the other containing carbon, (ii) adsorption of the intermediates onto the surface sites of the growing film, and (iii) reaction of the adsorbed intermediates to form silicon carbide. The equilibrium constant for the gas phase decomposition process was divided into the forward and backward reaction constants as 2.0 × 1025 exp[(448.2 kJ/mol)/RT] and 1.1 × 1032 exp[(-416.2 kJ/mol)/RT], respectively. Equilibrium constants for the surface adsorption reactions of silicon-carrying and carbon-carrying intermediates are 0.5 × 1011 exp[(-21.6 kJ/mol)/RT] and 7.1 × 109 exp[(-33.1 kJ/mol)/RT], while the rate constant for the surface reaction of the intermediates is 4.6 × 105 exp[(-265.1 kJ/mol)/RT].

Microstructure of SiC fiber fabricated by two-stage chemical vapor deposition on tungsten filament

“…Due to the chemical activity of tungsten, it is inevitable that an interfacial reaction takes place between tungsten, silicon and carbon atoms during CVD at high temperature, resulting in a W/SiC interfacial reaction zone formed. According to the W ÀSi and W À C phase diagrams [14], WSi 2 , W 5 Si 3 , WC and W 2 C phases are stable at the depositing temperature of 1323 K. Sone et al [15] and Tsai et al [16] indicated that, during the thermal decomposition of CH 3 SiCl 3 , the adsorption coverage and the concentration of silicon-carrying species on the surface of the filament are much higher than those of carbon-carrying species. Therefore, tungsten silicides may form first due to the reaction of tungsten with silicon in the siliconcarrying species.…”

Structural analysis of chemical vapor deposited β-SiC coatings from CH3SiCl3–H2 gas precursor

“…Moreover, its wide energy band gap and high-saturated drift velocity should make it very useful in high temperature semiconductor applications. SiC coatings (films) have been widely grown by many investigators using CVD method in the past years [4][5][6]; almost all of the studies were concerned with the growth processes or characterization of SiC coatings [7][8][9]. In this paper, b-SiC was deposited on graphite substrate by methyltrichlorosilane (MTS)-H 2 gas system; the goal of this study was to explain the crystal growth mechanism by investigating the structures of the as-deposited coatings.…”

R&D progress of Korean HCSB TBM

“…SiC coating process using chemical vapor deposition methods is widely used to the application of graphite pebbles [15,16]. In order to perform a coating on the graphite pebble at high temperature and pressure, a CVD coating system was specially manufactured as shown in Fig.…”