About the oxidation of SiCl₄ and GeCl₄ in homogeneous gaseous phase

A computational fluid dynamics model for co-deposition of silica and germania in the MCVD process

“…Calculations carried out by McAfee et al [13,14], Yan et al [18] and Wood et al [5] showed that GeO becomes a significant product in GeCl 4 oxidation at temperatures above 1700, 1800 and 1900 K, respectively. Unfortunately, even though limited data are available for the GeO M GeO 2 equilibrium reaction [5,19], no forward or backward reaction rate data could be found in the literature, as also noted recently by Tandon and Murtagh [20]. The absence of any relevant kinetics meant that GeO, and thus reaction (3), was not included in our extended MCVD model.…”

“…However, this is not the case for GeCl 4 oxidation. This reaction 'starts' at around 1400 K at which temperature the GeO 2 formed is a liquid [19]. As the MCVD model does not explicitly include any solid-liquid transitions, the specific heat capacity of the GeO 2 formed was modified to include the latent heat of fusion associated with this phase change.…”

Impact of chlorine dissociation for modified chemical vapor deposition

“…In previous modeling studies [1,2], the sole reaction considered was the irreversible oxidation of silicon tetrachloride (SiCl 4 ) [3]. SiCl 4 ðgÞ þ O 2 ðgÞ !…”

Manufacture of optical waveguide preforms by modified chemical vapor deposition

“…This process is described by the energy and precursor vapor balances and the general dynamic equation for the silica aerosol. Assuming negligible axial heat diffusion (Pe, >> I), negligible free convection (Kays and Perkins, 1985; Figure 29), and firstorder SiCI, oxidation kinetics (Powers, 1978;French et al, 1978;Kleinert et al, 1980), the energy balance inside the preform tube is:…”