This interview features a postdoctoral researcher from UCLouvain’s RF-SOI Group, who shares insights into the university’s role in the Move2THz project, with a particular focus on sustainability and the environmental impact of emerging InP-based RF technologies across the ICT value chain.

𝑸: 𝑪𝒐𝒖𝒍𝒅 𝒚𝒐𝒖 𝒃𝒓𝒊𝒆𝒇𝒍𝒚 𝒊𝒏𝒕𝒓𝒐𝒅𝒖𝒄𝒆 𝒚𝒐𝒖𝒓𝒔𝒆𝒍𝒇, 𝒚𝒐𝒖𝒓 𝒂𝒄𝒂𝒅𝒆𝒎𝒊𝒄 𝒃𝒂𝒄𝒌𝒈𝒓𝒐𝒖𝒏𝒅, 𝒂𝒏𝒅 𝒕𝒉𝒆 𝒖𝒏𝒊𝒗𝒆𝒓𝒔𝒊𝒕𝒚 𝒚𝒐𝒖 𝒓𝒆𝒑𝒓𝒆𝒔𝒆𝒏𝒕?
A: I am a postdoctoral researcher at UCLouvain since 2025, within the “RF-SOI Group” led by Pr. Jean-Pierre Raskin and Pr. Dimitri Lederer. I obtained my PhD in 2024 on the topic of substrate-related parasitic effects in the GaN-on-Si technology for RF applications. I am now working on emerging RF technologies and their environmental impact.
UCLouvain is the largest French-speaking university of Belgium and is located in Louvain-la-Neuve, about 30 km south of Brussels. We also host the technological platform WELCOME, an electrical characterization hub with growing expertise in characterization from DC to 325 GHz.

𝑸: 𝑾𝒉𝒂𝒕 𝒊𝒔 𝒚𝒐𝒖𝒓 𝒖𝒏𝒊𝒗𝒆𝒓𝒔𝒊𝒕𝒚’𝒔 𝒓𝒐𝒍𝒆 𝒊𝒏 𝒕𝒉𝒆 𝑴𝒐𝒗𝒆2𝑻𝑯𝒛 𝒑𝒓𝒐𝒋𝒆𝒄𝒕?
A: Our group’s signature has always been the research of a physical understanding of semiconductor material properties, and their impact on active devices and circuits. Originally active in the SOI world, we are now extending our reach to other technologies such as GaN-on-Si or, through Move2THz, InP/InPOSi.
The variety of the tasks we are involved in within Move2THz represents quite well our wide interests. In WP2, UCLouvain together with INCIZE are responsible for the specific characterization of InP and InPOSi substrates fabricated by SOITEC. The goal is to ensure that their RF properties are not negatively impacting overlying circuitry. In WP4, we will assist the effort of characterizing and modelling the new transistors developed by the partners of the project. Finally, we will design a demonstrator oscillator circuit in WP5 using ETHZ’s InP platform.

𝑸: 𝑾𝒉𝒂𝒕 𝒅𝒐𝒆𝒔 𝒕𝒉𝒆 𝒏𝒂𝒎𝒆 𝑴𝒐𝒗𝒆2𝑻𝑯𝒛 𝒔𝒕𝒂𝒏𝒅 𝒇𝒐𝒓, 𝒂𝒏𝒅 𝒘𝒉𝒂𝒕 𝒅𝒐 𝒚𝒐𝒖 𝒔𝒆𝒆 𝒂𝒔 𝒕𝒉𝒆 𝒎𝒐𝒔𝒕 𝒊𝒏𝒏𝒐𝒗𝒂𝒕𝒊𝒗𝒆 𝒐𝒓 𝒅𝒊𝒔𝒕𝒊𝒏𝒄𝒕𝒊𝒗𝒆 𝒂𝒔𝒑𝒆𝒄𝒕𝒔 𝒐𝒇 𝒕𝒉𝒊𝒔 𝒑𝒓𝒐𝒋𝒆𝒄𝒕?
A: From a scientific point of view, the integration of an InP layer on a Si substrate raises very interesting research questions and forces us to look beyond our “SOI-blinders”. The development of a new technology, potentially opening new market opportunities also requires a broader thinking about its impact.

𝑸: 𝑺𝒖𝒔𝒕𝒂𝒊𝒏𝒂𝒃𝒊𝒍𝒊𝒕𝒚 𝒊𝒔 𝒂 𝒌𝒆𝒚 𝒕𝒐𝒑𝒊𝒄 𝒊𝒏 𝒚𝒐𝒖𝒓 𝒖𝒏𝒊𝒗𝒆𝒓𝒔𝒊𝒕𝒚’𝒔 𝒃𝒓𝒐𝒂𝒅𝒆𝒓 𝒓𝒆𝒔𝒆𝒂𝒓𝒄𝒉 𝒘𝒐𝒓𝒌. 𝑭𝒓𝒐𝒎 𝒚𝒐𝒖𝒓 𝒑𝒆𝒓𝒔𝒑𝒆𝒄𝒕𝒊𝒗𝒆, 𝒉𝒐𝒘 𝒅𝒐𝒆𝒔 𝒕𝒉𝒆 𝑴𝒐𝒗𝒆2𝑻𝑯𝒛 𝒑𝒓𝒐𝒋𝒆𝒄𝒕 𝒂𝒑𝒑𝒓𝒐𝒂𝒄𝒉 𝒔𝒖𝒔𝒕𝒂𝒊𝒏𝒂𝒃𝒊𝒍𝒊𝒕𝒚, 𝒂𝒏𝒅 𝒉𝒐𝒘 𝒂𝒓𝒆 𝒔𝒖𝒔𝒕𝒂𝒊𝒏𝒂𝒃𝒊𝒍𝒊𝒕𝒚 𝒄𝒐𝒏𝒔𝒊𝒅𝒆𝒓𝒂𝒕𝒊𝒐𝒏𝒔 𝒓𝒆𝒇𝒍𝒆𝒄𝒕𝒆𝒅 𝒊𝒏 𝒕𝒉𝒆 𝒕𝒆𝒄𝒉𝒏𝒐𝒍𝒐𝒈𝒊𝒆𝒔 𝒂𝒏𝒅 𝒑𝒓𝒐𝒄𝒆𝒔𝒔𝒆𝒔 𝒃𝒆𝒊𝒏𝒈 𝒅𝒆𝒗𝒆𝒍𝒐𝒑𝒆𝒅?
A: Indeed, UCLouvain has been questioning the impacts of ICT and exploring alternative electronics through the works of Pr. David Bol and Pr. Jean-Pierre Raskin.
Within Move2THz, the sustainability aspect is mostly considered through the usage of the critical material In and the energy efficiency at high frequency enabled by using InP-based electronics. A task dedicated to the life cycle inventory (LCI) of InP and InPOSi is set up to quantify the environmental impacts of the technologies developed in Move2THz.
More precisely, the SmartCut process promises to reuse the donor InP wafer several times by transferring only a very thin InP layer on a less impactful and cheaper Si wafer. The InP content per wafer is thus significantly reduced compared to InP bulk. Furthermore, InP amplifiers realize the best efficiency at sub-THz frequencies. However, it is important to place such efficiency gains in the context of the future deployment of InP (or InPOSi) technologies to assess the overall environmental impact of their development.

𝑸: 𝑾𝒉𝒚 𝒊𝒔 𝒊𝒕 𝒑𝒂𝒓𝒕𝒊𝒄𝒖𝒍𝒂𝒓𝒍𝒚 𝒄𝒉𝒂𝒍𝒍𝒆𝒏𝒈𝒊𝒏𝒈 𝒕𝒐 𝒂𝒔𝒔𝒆𝒔𝒔 𝒕𝒉𝒆 𝒆𝒏𝒗𝒊𝒓𝒐𝒏𝒎𝒆𝒏𝒕𝒂𝒍 𝒊𝒎𝒑𝒂𝒄𝒕 𝒐𝒇 𝑰𝑪𝑻 𝒔𝒚𝒔𝒕𝒆𝒎𝒔 𝒂𝒄𝒓𝒐𝒔𝒔 𝒕𝒉𝒆𝒊𝒓 𝒆𝒏𝒕𝒊𝒓𝒆 𝒍𝒊𝒇𝒆 𝒄𝒚𝒄𝒍𝒆?
A: The ICT value chain is incredibly complex. For the fabrication of a single chip, several hundreds of process steps are needed, most of which happen inside foundries and involve highly specialized equipment, materials and energy consumption. Combined with the opacity of the manufacturing processes to external players, the task of life cycle assessment (LCA) practitioners is far from straightforward. Recently, the establishment of a fab model by imec or the use of more aggregated data can be highlighted as steps toward a more transparent assessment of the impact of semiconductor manufacturing.

𝑸: 𝑼𝒔𝒊𝒏𝒈 𝒅𝒊𝒈𝒊𝒕𝒂𝒍 𝒅𝒆𝒗𝒊𝒄𝒆𝒔 𝒔𝒖𝒄𝒉 𝒂𝒔 𝒔𝒎𝒂𝒓𝒕𝒑𝒉𝒐𝒏𝒆𝒔 𝒂𝒔 𝒂𝒏 𝒆𝒙𝒂𝒎𝒑𝒍𝒆, 𝒘𝒉𝒆𝒓𝒆 𝒅𝒐 𝒕𝒉𝒆 𝒎𝒂𝒊𝒏 𝒆𝒏𝒗𝒊𝒓𝒐𝒏𝒎𝒆𝒏𝒕𝒂𝒍 𝒉𝒐𝒕-𝒔𝒑𝒐𝒕𝒔 𝒐𝒄𝒄𝒖𝒓, 𝒂𝒏𝒅 𝒘𝒉𝒂𝒕 𝒓𝒐𝒍𝒆 𝒅𝒐 𝒊𝒏𝒕𝒆𝒈𝒓𝒂𝒕𝒆𝒅 𝒄𝒊𝒓𝒄𝒖𝒊𝒕𝒔 𝒑𝒍𝒂𝒚 𝒊𝒏 𝒕𝒉𝒆𝒔𝒆 𝒊𝒎𝒑𝒂𝒄𝒕𝒔?
A: For user equipment (e.g. smartphones) that have a relatively short use phase (2-3 years), about 70 % of their global warming potential occurs during the manufacturing phase. ICs account for more than a third of this manufacturing impact. Furthermore, it has been estimated that the ICT sector represents ~3-6 % of the greenhouse gases emissions worldwide, which is comparable with the aviation sector. Putting the numbers together, it appears that as institutions active in semiconductor manufacturing, we have a key role to play. Indeed, all economic sectors must decrease their emissions to maintain the planetary systems within a safe operating space.

𝑸: 𝑬𝒇𝒇𝒊𝒄𝒊𝒆𝒏𝒄𝒚 𝒊𝒎𝒑𝒓𝒐𝒗𝒆𝒎𝒆𝒏𝒕𝒔 𝒂𝒓𝒆 𝒐𝒇𝒕𝒆𝒏 𝒔𝒆𝒆𝒏 𝒂𝒔 𝒂 𝒔𝒐𝒍𝒖𝒕𝒊𝒐𝒏, 𝒃𝒖𝒕 𝒕𝒉𝒆𝒚 𝒄𝒂𝒏 𝒂𝒍𝒔𝒐 𝒍𝒆𝒂𝒅 𝒕𝒐 𝒓𝒆𝒃𝒐𝒖𝒏𝒅 𝒆𝒇𝒇𝒆𝒄𝒕𝒔. 𝑯𝒐𝒘 𝒄𝒂𝒏 𝒄𝒐𝒎𝒃𝒊𝒏𝒊𝒏𝒈 𝒆𝒇𝒇𝒊𝒄𝒊𝒆𝒏𝒄𝒚 𝒘𝒊𝒕𝒉 𝒔𝒖𝒇𝒇𝒊𝒄𝒊𝒆𝒏𝒄𝒚-𝒐𝒓𝒊𝒆𝒏𝒕𝒆𝒅 𝒄𝒉𝒐𝒊𝒄𝒆𝒔 𝒉𝒆𝒍𝒑 𝒓𝒆𝒅𝒖𝒄𝒆 𝒕𝒉𝒆 𝒐𝒗𝒆𝒓𝒂𝒍𝒍 𝒆𝒏𝒗𝒊𝒓𝒐𝒏𝒎𝒆𝒏𝒕𝒂𝒍 𝒊𝒎𝒑𝒂𝒄𝒕 𝒐𝒇 𝒆𝒎𝒆𝒓𝒈𝒊𝒏𝒈 𝑰𝑪𝑻 𝒕𝒆𝒄𝒉𝒏𝒐𝒍𝒐𝒈𝒊𝒆𝒔?
A: The rebound effect can be defined as a mechanism through which an improvement in a technology’s efficiency (of resources, of energy, of emissions) does not necessarily lead to an absolute decrease of the consumption or emission of said resource. This happens because the technology becomes more accessible and thus its usage increases. The rebound effect is well documented for the ICT sector, where more functionality “per silicon area” does not bring a decrease in the number of wafers being sold, but rather the opposite, leading to an overall rise in emissions from the sector over time.
Countering the rebound effect is difficult and requires to reflect, ahead of the development, about how the technology will be used. The increase in technology usage should stay limited (an approach that could be labelled as sufficiency) in order for the efficiency gains to have net positive impact (defined as an absolute decrease in consumption or emission). As engineers working on emerging technologies, this exercise and resulting appropriate choices are crucial for reducing our footprint.

We sincerely thank our speaker for taking the time to share these insights and perspectives, and we wish them continued success and inspiration in their future research endeavors.

You can find more information on project Green Innovation here: https://www.move2thz.eu/news/advancing-sustainability-through-move2thz-innovation