Thermodynamics of the Production of Condensed Phases in the CVD of Methyltrichlorosilane Pyrolysis

Abstract

Production conditions of the condensed phases (b-SiC, silicon, and graphite) in the CVD of methyltrichlorosilane (MTS) pyrolysis are investigated in detail with thermodynamic analyses based on a relatively complete and refined database. Production of the condensed phases is examined as a function of temperature, pressure, and the initial gas ratio of H 2 / MTS. The results show that the composition of the condensed phase is quite sensitive to both temperature and the molar ratio of H 2 /MTS, whereas it is less sensitive to pressure. The ideal conditions for the deposition of b-SiC are temperatures between 1300 and 1500 K, H 2 /MTS ratios between 10 and 10 5 , and with pressures as low as convenient. The co-deposition of C or Si with b-SiC is mainly controlled by the ratio of H 2 /MTS. The co-deposition of C with b-SiC should be in low H 2 /MTS ratios (<10) and the codeposition of Si with b-SiC needs high H 2 /MTS ratios (>10 4 ). The results are in very good agreement with experimental findings and previous theoretical investigations. The present work is also instructive as to the experimental conditions relating to continuous regions of temperatures, pressures, and the H 2 /MTS ratios.

Thermodynamic Analysis on the Codeposition of SiC–Si3N4 Composite Ceramics by Chemical Vapor Deposition using SiCl4–NH3–CH4–H2–Ar Mixture Gases

“…When δ is 10, the phases are simple and the region of SiC–Si 3 N 4 phase reaches the maximum. Therefore, the ideal conditions of codeposition of SiC–Si 3 N 4 phase are β in the range of 0.5–5, α in the range of 0–1 (α in the range 0–1 does not include zero and one), and δ = 10, the dilution ratio in this study is consistent with others …”

“…Therefore, the ideal conditions of codeposition of SiC-Si 3 N 4 phase are b in the range of 0.5-5, a in the range of 0-1 (a in the range 0-1 does not include zero and one), and d = 10, the dilution ratio in this study is consistent with others. 30…”

Calculation and synthesis of ZrC by CVD from ZrCl4–C3H6–H2–Ar system with high H2 percentage

“…According to previous experimental and theoretical results on the deposition of ZrC [15,16] and SiC [21,22], the ratio of reactant gases is critical in the synthesis process. To facilitate the calculation, the relationship between ˛, ˇ and the production of condensedphases (ZrC and C) was firstly illustrated.…”

Computational thermodynamic study of SiC chemical vapor deposition from MTS‐H2*

“…12 It should be noted that the co-deposition of SiC and free Si have been predicted to occur at very high H 2 /MTS ratios (>~10 4 ) in previous thermodynamic analyses. 46,48 Figure 2 shows the fraction of selected gas species at equilibrium as a function of deposition temperature under 13.3 kPa (i.e., 100 Torr, the median pressure considered in this work) at H 2 /MTS ratios of 10, 30, 60, and 100. MTS decomposed to such a large extent that only less than 0.03% remains for all cases.…”