Q&A: Prof Lenny Koh: On semiconductor supply chain visibility and resilience

Following her appearance at Microelectronics UK in September, we talk to Professor Lenny Koh, of the University of Sheffield, around best places and best practices for sustainable and resilient semiconductor production, as well as where the industry should best target its efforts.

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Tell me a bit your career to date, the research you are currently working on, and how you came to be involved in this sector?

I have more than 30 years of experience in transforming manufacturing supply chain, future proofing against uncertainty and disruption, improving resilience and sustainability, and creating low carbon and resource efficient supply chain for the future.  I am Director of AREC at University of Sheffield, Deputy Director of UKRI EPSRC IGNITE Manufacturing Hub, Lead of UKRI EPSRC Compound Semiconductor (CS) Manufacturing Hub - Supply Chain Resilience, Sustainability and LCA, and Lead of route mapping and supply chain, UKRI EPSRC funded CHIMES2 IKC.

The semiconductor sector is undergoing major demand and supply shift and transformation, from innovation to scale-up; and my knowledge and expertise are being put to good use to make a real difference, and create significant and global impact.

You led a study published in April which explored how the environmental impact of semiconductor production could change over time and place. One key conclusion was that reshoring semiconductor manufacturing to the UK and US would be the best way of meeting sustainability goals. Can you outline how the study came to this conclusion?

This is the first study published in Nature Scientific Reports, 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—2024, 2030, 2040 and 2050.

The results show environmental sustainability is geographic- and time- dependent and varied by properties of the supply chain characteristics.

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.

One of the key conclusions is the reshoring implications. The scenario analysis provides compelling evidence to support reshoring or nearshoring of compound semiconductor fabrication to regions with cleaner energy profiles and stronger environmental regulations. Semiconductors produced in the UK and US create some of the lowest overall environmental impacts including global warming, toxicity, and resource depletion categories, due to the regional energy mix.

These findings suggest that strategic reshoring - particularly of energy- and material-intensive phases such as epitaxy and substrate preparation - can substantially reduce lifecycle environmental burdens. Beyond emissions reduction, reshoring can enhance supply chain resilience and align with emerging national policies aimed at sustainable and secure semiconductor production.

The study also found that epitaxy and substrate production are expected to become the biggest sources of sustainability challenges in the future. Where should the industry be focusing its efforts to tackle this challenge in your opinion?

While electricity-intensive cleanroom processes show steep declines in contribution over time (e.g., from ~ 35% to < 10%), impacts from epitaxial growth, substrate preparation, photolithography, and packaging increase in relative importance. For instance, epitaxial growth becomes the dominant contributor to marine ecotoxicity (ME) in InGaP by 2050 (64.7%), underscoring the rising environmental burden of material- and chemical-intensive phases.

Critical hotspots: Regardless of geography, the study identifies epitaxial growth and substrate preparation as the primary environmental and supply chain "hotspots". True resilience and circularity will require process innovations, advanced material recycling, and switching to cleaner precursors (e.g., finding alternatives to hazardous gases like arsine or phosphine).

Your research also explores futureproofing the resilience of supply chains. Can you summarise the key conclusions from your work here and what should industry executives reading this know?

The study models 80 international supply chain scenarios across 11 countries and 4 time horizons (2024, 2030, 2040, and 2050) to evaluate how geographic distribution impacts both environmental sustainability and supply chain resilience.

The resilience-sustainability link: The study highlights how building supply chain resilience through multi-sourcing, distributed fabrication, and reshoring/nearshoring directly intersects with decarbonisation goals. Distributed manufacturing across friendly regions mitigates high geopolitical risks associated with critical minerals.

How has increased volatility across climate change and geopolitical tensions changed the scope of your research in this field? Are the solutions being proposed able to keep up with the potential pace of disruption?

• UK and US scenarios: Manufacturing options heavily integrated within the UK and US showed the strongest immediate sustainability profiles, with UK-based fabrication scenarios achieving a ~66% to 70% reduction in environmental impacts by 2050 as grid electricity decarbonises.
• Taiwan and global shifts: Scenarios leveraging fabrication in Taiwan (for both materials) and the US (for InGaN) demonstrate excellent long-term sustainability and operational readiness by 2050.
• China-centric risks: Scenarios concentrated entirely in China consistently resulted in the highest environmental and toxicity impacts due to reliance on carbon-heavy energy grids.

Our research informs investment and policy decisions to future-proof semiconductor supply chain sustainability and resilience.

More broadly, what do you see as the biggest opportunities for the UK in terms of creating a compound semiconductor supply chain which is sustainable, resilient and competitive?

The rise of AI, data centre, quantum, photonics, power and microelectronics will increase demand and major breakthrough requirement for compound semiconductor.

The study points to UK and USA as best places for sustainable and resilient InGaN and InGaP production. Scale up these manufacturing supply chains would be the biggest opportunities immediately. Going forward, the combination of UK, USA and Taiwan serve as the best places for sustainable and resilient semiconductor production, so preparing for this future now would be a priority.

What was the most interesting thing you found at Microelectronics UK and what did you enjoy most about the event?

Semiconductors are used and deployed everywhere, it is embedded in our electronics, photonics, AI, data centre, LED, powering industry, cities and the world. Semiconductor is used in transport, aerospace, defence in sensor, detector, magnet and system to provide national security and protect our nation. Semiconductor is a critical resource which underpins the functions of our planet and ecosystem, now and even more so in the future.

I enjoyed chairing the panel, with great insights from industry leaders at Microelectronics UK. I had the opportunities to meet with partners, industry leaders, academic pioneers, governmental decision makers. I enjoyed the keynote, the panels and the exhibitions. A very well organised event and a premier conference.

Overall, what would the advice be to industry and supply chain leaders in terms of their future planning and why?

Future-proof by integrating sustainability and resilience into the core of your organisations and supply chain’s decisions.