CFD simulation for atomic layer deposition on large scale ceramic membranes

Ceramic membranes are widely used in liquid filtration for their superior chemical resistance, temperature stability and mechanical robustness. Their performance can be further improved by surface modifications, such as liquid phase reactions, which are typically too complicated to control. Atomic layer deposition (ALD), a deposition technique of self-limiting gas/solid phase chemical reactions for growing atomic scale thin films, has been extremely useful for precisely regulating nanoscale pore structures, especially modification and functionalization of porous separation membranes. Most existing ALD equipment are designed for silicon wafer substrate in semiconductor industry, thus design optimization on ALD processes of both precursor flow and surface reactions are needed for application in large-scale ceramic membranes. Computerized fluid dynamics (CFD) modeling was used to investigate ALD process on 1-meter-long single-channeled ceramic membrane by considering both boundary conditions and surface chemical reactions of two precursors pulsed alternatively into the channel. The simulations fitted well with the experimental data at average difference of 1.69% and thus an ALD model for two-way alternatively pulsed rotation was proposed, which would be very helpful in equipment design and process optimization of ALD for large scale ceramic membranes.