Unsteady heat and mass transfer on the codeposition of SiO2/GeO2 during the modified chemical vapor deposition process

A numerical analysis of unsteady heat and mass transfer on the codeposition of SiO2 and GeO2 in the modified chemical vapor deposition has been carried out. An earlier study showed that the optimized torch speed variation could be used to enhance the deposition uniformity of single component SiO2 particle. However, this optimized torch speed resulted in the deterioration of GeO2 deposition uniformity for multi-component SiO2/GeO2 deposition in the present study. To ensure the uniformity of both SiO2 and GeO2, a control strategy may need variations of two parameters at least. Parametric studies, varying three different operating conditions over time (maximum wall temperature, torch speed and in-take amount of GeCl4), reveals that the uniformity of SiO2 deposition can be maintained by torch speed variation and that of GeO2 can be obtained by increasing the in-take flow rate of GeCl4 over time.