Leveraging computational thermodynamics to guide SiC-ZrC chemical vapor deposition process development

Chemical Vapor Deposition of Zirconium Compounds: A Review

“…As the coverage of atomic hydrogen on the surface increases, more surface sites are blocked per unit surface area, reducing the area available for benzene to adsorb in the lowest energy orientation [110]. Additional experimental support can be found when comparing the results of ZrC deposition to thermodynamic predictions, where a greater suppression of carbon deposition is observed with increasing hydrogen concentration than is predicted from thermodynamic equilibrium alone [88,91,104,106,121]. Once zirconium and carbon species are bound to the surface, several possible reaction paths can be envisioned.…”

“…Reports on the vapor deposition of zirconium silicides are very limited. The only instances found are in a historic review of CVD precursor systems [1] and a recent report on the Zr-Si-C codeposition system [104]. ZrSi and ZrSi 2 were found to codeposit with ZrC and SiC from ZrCl 4 -CH 3 SiCl 3 -CH 4 -H 2 at 1200 • C and 50 torr, depending primarily on precursor gas ratio [104].…”

“…Studies have primarily focused on ZrX4-CxHy-H2 systems. The most popular system by far has been ZrCl4-CH4-H2 [68,89,90,94,[97][98][99][100][101][102][103][104]; however, investigations have included zirconium bromide or iodide [91,[105][106][107][108], as well as other hydrocarbons such as propane Atomic hydrogen radicals have been shown to significantly reduce the activation energy of dissociation reactions, for example, in thermal CVD of CH 4 or plasma-enhanced CVD of BCl 3 [81][82][83][84][85]. Accordingly, the addition of H 2 to ZrCl 4 might improve the dissociation rate of chlorides via the abstraction of chlorine by atomic hydrogen (Equation ( 5)).…”

“…Studies have primarily focused on ZrX 4 -C x H y -H 2 systems. The most popular system by far has been ZrCl 4 -CH 4 -H 2 [68,89,90,94,[97][98][99][100][101][102][103][104]; however, investigations have included zirconium bromide or iodide [91,[105][106][107][108], as well as other hydrocarbons such as propane and hexane [68,89,90,103]. Typical deposition conditions are temperatures of 1000-1400 • C; total reaction pressures are reported up to 760 torr; however, published partial pressures of zirconium halides are consistently below 50 torr and are typically around 25 torr.…”

“…The only instances found are in a historic review of CVD precursor systems [1] and a recent report on the Zr-Si-C codeposition system [104]. ZrSi and ZrSi 2 were found to codeposit with ZrC and SiC from ZrCl 4 -CH 3 SiCl 3 -CH 4 -H 2 at 1200 • C and 50 torr, depending primarily on precursor gas ratio [104]. Computational analysis of the Zr-Si-C system by minimization of Gibbs free energy predicted ZrSi x deposition from 1150 to 1350 • C (maximum temperature limit studied) and from 0 to 160 torr within the precursor composition window reported [104].…”