How to avoid concentration unsteadiness with a CVD precursor delivery system employing bubbler?

INERA Conference: Vapor Phase Technologies for Metal Oxide and Carbon Nanostructures

物理学;材料科学

Peev, G.^1 ; Peshev, D.^1

University of Chemical Technology and Metallurgy, Department of Chemical Engineering, 8 Kl. Ohridsky Blvd., Sofia

1756, Bulgaria^1

关键词: Bubble velocities;    Carrier gas;    Delivery systems;    Electronic materials;    Gas bubble;    Liquid layer;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/764/1/012012/pdf
DOI  :  10.1088/1742-6596/764/1/012012

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

An approach of great certainty is suggested as to avoid concentration unsteadiness with a CVD delivery system employing bubbler. Assuming that the carrier gas has to be saturated of precursor vapour during the entire CVD experiment a set of equations has been selected from the literature for calculating the height of liquid layer in the bubbler which is necessary to this aim. The selection is made on the prerequisites that gas bubbles are spherical, diffusion of precursor vapour in them is molecular and it takes place during their rising only, which has a velocity equal to the terminal bubble velocity of rising. The errors at levels lower than the one for saturation are discussed. Heights of Al(CH3)3calculated using the approach are compared to those at which the bubbler controlling LED indicator of Dow Electronic Materials lights green, amber or red.