Comparative Study of the Environmental Impact of Depositing Al2O3 by Atomic Layer Deposition and Spatial Atomic Layer Deposition

With increasing concerns about the environmental impacts of human activities, novel nanotechnologies and nanomaterials are being explored as key solutions to tackle pollution and pave the way for a more sustainable future. One such technology that has gained attention is atomic layer deposition (ALD), which can be used to prepare thin films with precise control over thickness and composition. Spatial ALD (SALD), in particular, presents high deposition rates and can be performed at high pressure and has emerged as a promising alternative to conventional ALD. However, to the best of our knowledge, there is no literature reporting on its environmental performance compared to that of ALD. Herein, we present a comparative life cycle assessment (LCA) study between conventional ALD and SALD to quantify and compare their environmental impacts. The study focuses on the deposition of a 20 nm alumina thin film from trimethylaluminum (TMA) and water at 200 °C as the functional unit, considering the use of typical lab-scale reactors, with the SALD being based on the close-proximity approach. Different region-based scenarios were evaluated, considering the film production in Europe, in France, and in Taiwan. Our results reveal that electricity consumption is the primary contributor to most impact categories for both ALD and SALD processes, followed by the TMA precursor. The results indicate that for the alumina process and the assumptions considered, SALD has a notably better environmental performance than ALD for the majority of the assessed impact categories, in all three regions considered.