The Flow Evolution of the Atomic Layer Deposition Process: A Numerical Study of the Implimentation of a Porous Plate

Nano-fabrication techniques are an ever-growing field that has led to the leading cutting edge nano-technologies of today. Atomic layer deposition (ALD) has manifested itself as a key player to produce highly uniform and conformal nano thin film products. However, to obtain components with enhanced properties, research is tasked to focus on the in-depth understanding of the transport phenomena of the ALD process. To accomplish this, computational techniques are adopted to efficiently analyse the ALD process. This study models the flow evolution and mass transport within an ALD reactor with and without a perforated plate to fabricate $A1_{2}O_{3}$. Within the study a perforated plate inside the shower head temporal ALD reactor is modelled as a porous medium. The numerical model of the perforated plate inside an ALD reactor is simplified by defining a region in space as a porous zone instead of directly modelling the complex perforated plate geometry inside the ALD reactor. The numerical model is then solved using ANSYS Fluent. The integration of the porous medium into the numerical modelling of the ALD process ultimately decreases the number of elements required to accurately model the ALD process, and therefore, decreases the computational resources required to analyse the process. It is found that the porous medium promotes uniform flow of gas, thus preventing circulating flow within the reactor. The perforated plate increases the uniformity of precursor distribution with O3 having a greater increase in uniformity than TMA. This is due to the difference in density.