Enhancing sustainability in materials synthesis: a life cycle assessment of metal organic chemical vapor deposition

Achieving environmental sustainability is paramount in laboratory-scale material development. This work evaluates the sustainability of a laboratory-scale thin film deposition process via Metal Organic Chemical Vapor Deposition (MOCVD), employing a cradle-to-gate Life Cycle Assessment approach and the Environmental Footprint 3.1 method. The investigation covered all laboratory phases, including apparatus heating and evacuation, carrier gas and precursor supply and disposal, bubbler and apparatus cleaning procedures, and post-synthesis thermal annealing. Results identified electricity and nitrogen consumption as the primary environmental hotspots. Specifically, process-related stages such as heating, evacuation, and cleaning were revealed to contribute most significantly to the overall environmental impact (78.9%), while the metal organic precursors showed a notably lower impact. Indeed, the respective process step (comprising precursor synthesis, reagent consumption, and the management of by-products and residues) contributed less than 1.2% to the overall impact, highlighting a footprint distribution typical of lab-scale operations where process-related phases dominate the environmental profile. Based on these results, several mitigation strategies were assessed, including adopting renewable energy sources, increasing the number of substrates per growth cycle, reducing process times, and exploring the substitution of the nitrogen-based trap with an absorbent one. The simultaneous implementation of these mitigation strategies resulted in an 83.7% reduction in the total environmental impact. This work provides a transferable roadmap for the sustainable design of chemical vapor deposition processes, guiding future MOCVD research toward a successful low environmental impact transition to higher Technology Readiness Levels.