As microelectronics have become an increasingly important part of modern society, the greenhouse gas emissions associated with their use and manufacture have also increased. Semiconductor manufacturing contributes 31% of global greenhouse gas emissions, and an analysis of data from the U.S. Department of Energy's Intergovernmental Panel on Climate Change estimates that greenhouse gas emissions associated with semiconductors could quadruple by 2030.
A team of students from Arizona State University's Ira A. Fulton Schools of Engineering is currently conducting research efforts to reduce the environmental impact of this important field. They are looking for ways to make the production of microelectronics more environmentally friendly. Her research is sponsored by TSMC, one of the world's largest microelectronics manufacturers with an increasing presence as the semiconductor industry rapidly expands in Arizona.
David McComas works with gallium oxide, a type of semiconductor material, at the ASU NanoFab. Photo courtesy of David McComas
The potential for diamond electronics is great
Students in the Fulton Undergraduate Research Initiative, known as FURI, work under the direction of faculty members to apply knowledge gained in the classroom through hands-on research experience. TSMC funded eight FURI projects related to semiconductor manufacturing in the fall 2024 semester, some of which focused on increasing the sustainable use and manufacturing of semiconductors.
The project, sponsored by David McComas, an electrical engineering student at the Fulton School, focuses on reducing the energy consumption of power electronics and radio frequency (RF) electronics. Power electronics convert and regulate electricity to ensure the correct amount and type is used in electrical devices, and RF electronics are used for communications technology.
McComas is researching the use of diamond static induction transistors. Transistors in RF devices amplify electronic signals for transmission in telecommunications and radar systems, while transistors in power electronics control the flow of electrical current.
Diamond is a promising semiconductor material due to its electronic properties, which are an improvement compared to other commonly used materials. These properties include the highest known thermal conductivity of a material, resulting in high heat dissipation and reduced cooling requirements; a high breakdown field, resulting in less material needed to handle high electrical voltages; and a wide bandgap, meaning the material can deliver more power while withstanding the high temperatures created by the heat generated during its use.
The use of diamond as a semiconductor material also reduces power loss in the devices that use it, resulting in less power required to operate diamond devices.
“We can create a new generation of smaller, faster, more efficient and more sustainable devices than the ones we use today,” says McComas.
This lower electricity consumption has the potential to improve environmental impacts, as electricity generation accounted for 25% of U.S. greenhouse gas emissions in 2022, according to the U.S. Environmental Protection Agency.
McComas' Fall 2024 FURI project involves simulating the operation of diamond microelectronics on the ASU Research Computing Sol supercomputer, part of ASU's core research facilities, using computer aided design (TCAD) software. He then analyzes the performance of the simulated devices to plan a process for producing prototypes at the ASU NanoFab, a semiconductor manufacturing facility on the Tempe campus that is also part of the Core Facilities.
By testing various device designs under the supervision of Nidhin Kurian Kalarickal, an assistant professor of electrical engineering at the Fulton School, and Kalarickal's graduate students, McComas aims to maximize the performance benefits that come from using diamond materials.
As a student in Barrett, ASU's The Honors College, McComas made the project part of his required graduate work. His FURI research in fall 2024 builds on his FURI project in spring 2024, and he plans to further explore the feasibility of diamond static induction transistors and their applications in the NanoFab in spring 2025.
After graduating in spring 2025, McComas plans to continue research on diamond electronic devices.
“I have three long-term hopes for this project,” he says. “The first is to use Diamond devices to build a more powerful and resilient wireless infrastructure in the U.S. and globally. Next, the study contributes to the field of diamond manufacturing and catalyzes further innovation. And finally, that systems and circuit engineers use the devices to solve unique and unexpected problems.”
David McComas works with equipment at the ASU NanoFab. Photo courtesy of David McComas
Reducing electronics manufacturing emissions at the source
Jay Schroeder, a chemical engineering student at the Fulton School, decided to focus his sponsored FURI project on a different aspect of sustainability related to semiconductors: reducing greenhouse gas emissions during manufacturing.
Under the supervision of Shuguang Deng, a professor of chemical engineering at the Fulton School, Schroeder is researching the effectiveness of porous, crystalline materials known as zeolites in adsorbing a gas called tetrafluoromethane, which is used during the etching process in semiconductor manufacturing. Etching removes portions of the semiconductor material to allow for the placement of other components later in the manufacturing process.
Tetrafluoromethane is a greenhouse gas that warms the atmosphere about 6,500 times more than carbon dioxide. Current semiconductor manufacturing processes capture the gas through cryogenic distillation, where the gas is compressed and frozen to ensure it does not escape into the air.
The process does not capture all of the tetrafluoromethane emitted and requires a lot of energy to do so. In contrast, zeolite materials can bind the gas molecules to themselves without the need for electricity, while leaving a smaller amount of tetrafluoromethane uncaptured if any escapes at all.
“The gas would simply have to flow over the surface, with or without electricity, and the surface would combine with the tetrafluoromethane, removing it from the air and sticking to the zeolite surface, much like exhaust gases flow through a catalytic converter on a road car.” says Schroeder.
He studies the predicted effectiveness of various zeolite materials using density functional theory, which calculates the expected but unconfirmed properties of materials. Schroeder uses theory to narrow down which zeolite materials are likely to perform well in tetrafluoromethane deposition and then simulates the expected performance using the Grand Canonical Monte Carlo method to more accurately predict zeolite behavior.
After Schroeder completes his portion of the project by conducting simulations, Deng will use the results to determine which zeolite materials to physically test with graduate students in a laboratory setting under various conditions.
Building a future with greener electronics
Deng said TSMC funding has enabled a greater number of research opportunities.
“TSMC’s commitment to supporting sustainability-focused undergraduate research is truly commendable,” he says. “This funding not only advances the sustainability of semiconductors, but also strengthens the broader science, technology, engineering and mathematics ecosystem by investing in young researchers ready to drive future innovation.”
As a mentor for the FURI project, Deng encourages students to participate in semiconductor research through the program.
“Projects like these provide technical experience and help students understand the importance of sustainable practices in technology-driven industries,” he says. “Working on industry-supported research also provides valuable insight into possible career paths and strengthens problem-solving skills that are in high demand in the semiconductor sector.”