Abstract
This is the first study which presents integrated geo-spatial prospective life cycle and supply chain sustainability modelling of two compound semiconductors: Indium Gallium Nitride (InGaN) and Indium Gallium Phosphide (InGaP), in 80 international supply chain scenarios, incorporating 11 countries across 4-time horizons-024, 2030, 2040 and 2050. The results show environmental sustainability is geographic- and time- dependent and varied by properties of the supply chain characteristics. The manufacturing of InGaN and InGaP excel in UK based scenarios (~ 70% and 66% impact reduction from 2040 to 2050). Scenarios involving shared fabrication in the UK and US show strong sustainability performance in 2024, those for fabrication in Taiwan (for both materials) and US (InGaN) demonstrate increasing sustainability potential by 2050. Scenarios involving fabrication in China consistently led to a higher environmental impact. However, all 80 configurations demonstrate marked reductions in environmental impacts, primarily due to global electricity grid decarbonisation, and improved emissions controls. Despite this improvement in the clean room energy impact, epitaxial growth and substrate preparation remain the hotspots, calling for process innovation, cleaner precursors (e.g., replacing arsine or phosphine), and advanced material recycling. InGaN generally performs better than InGaP in most categories, attributed to its simpler material inputs and lower toxicity potential. InGaP scenarios exhibit higher marine ecotoxicity, carcinogenic toxicity, and mineral resource scarcity, driven by complex chemistries and Gallium Arsenide (GaAs) substrates. Interestingly, InGaP scenarios significantly outperform InGaN in stratospheric ozone depletion due to limited use of halogenated chemicals. This study provides compelling evidence to support reshoring or nearshoring of compound semiconductor fabrication to regions with cleaner energy profiles and stronger environmental regulations. Scenarios involving the UK, USA and Taiwan (specially in 2050), consistently achieve higher sustainability scores across global warming, toxicity, and resource depletion categories.