A numerical approach on the selection of the purge flow rate in an atomic layer deposition (ALD) process

Abstract

The variation of the purge flow rate is investigated in a reactor scale simulation of a typical atomic layer deposition (ALD) process. The investigation in its context addresses the possible issues of inadequate deposition rates with regard to the purge flow rate. A three-dimensional reactor is numerically implemented to simulate the physical and chemical processes to fabricate aluminum oxide (Al2O3) thin films. The purge flow rate disparity is focused to examine the effects within the fluid flow, mass transport, along with the chemical kinetics of the ALD process. The fabrication process employs trimethyl-aluminum and ozone (O3) as the metal and oxidant precursors, respectively, and inert argon as the purge gas. The reactor operation is set up to operate at a pressure of 10 torrs, with a substrate temperature of 200 °C. Three purge flow rates of 20, 10, and 5 sccm, respectively, have been examined. It was discovered that the slower flow rate showed, superior mass fraction distribution, reached unity surface coverage, and a time extensive surface deposition rate. A prolonged ozone exposure was crucial in providing an adequately oxidized substrate. The 20, 10, and 5 sccm purge flow rate growth obtained a 0.58, 0.85, and 1.6 Å/cycle, respectively. These findings revealing close similarities to experimental behaviors and recorded growths.