ERC Advanced Grant for research on ferroelectric transistors
Lars-Erik Wernersson, professor of nanoelectronics, has received an ERC Advanced Grant for the integration of new materials into the high-performance, energy-efficient transistors and circuit solutions of the future.
Jonas Andersson – Publicerad den 22 april 2021
Silicon is the current material of choice for most transistors and other components. The problem is that in certain cases these parts consume a lot of energy and get hot, which can lead to overheating in high-speed electronics and reduce the operating time of mobile electronics and battery-driven sensor networks. Future needs point to a demand for even better energy-efficient materials. These can be complemented with, or integrated into, silicon components in order to achieve the best possible effect from the strengths of each technology.
Traditional transistors are limited by how low the operating voltage can be without compromising performance. Avoiding this problem requires new transistors that use completely different physical processes.
“We have developed a III-V technology platform that includes ferroelectric materials, and our material integration is unique. No one else in Europe besides our research team has access to equivalent technology and performance. Theoretically, you may be able to reduce operating voltage for certain important applications thereby increasing energy efficiency by up to 100 times”, says Lars-Erik Wernersson.
The millimetre-wave frequency spectrum
The researchers working on the project will study the dynamic properties of transistors and circuits, particularly in the millimetre-wave frequency spectrum. As the technology develops and demand for rapidly sending large volumes of information continues to increase, there will be a need to utilise a considerably higher frequency spectrum than is used today.
Lars-Erik Wernersson’s research team is looking at frequencies in the 30-300 GHz range. As a comparison, today’s 5G technology operates at around 30 GHz and there is radar that uses 60 GHz. The coming 6G and 7G technologies will need to use increasingly higher frequencies.
“With higher frequencies, the technology also becomes more energy-intensive. Innovations to increase performance and reduce energy consumption can change how we build systems and this has considerable value for the environment, the economy and society”, says Lars-Erik Wernersson.
A new generation of energy-efficient circuit technology
The new materials can be used in many areas such as communications technology, AI and machine learning as well as the Internet of Things (information technology for the growing number of units with sensors or computers that are connected via the internet). In addition to being more energy-efficient, the higher performance also enables the introduction of new functionality.
Ferro-transistors are based on ferroelectric materials, which are materials that can have an in-built electric field. Such a material can provide an extra voltage boost so that a transistor “senses” a higher operating voltage than is actually being used. In principle, this approach enables the operating voltage to be reduced without affecting the component’s performance.
“The material also remembers how it has been placed and can remember this for up to ten years. This can be of considerable benefit in machine learning where the technology constantly needs to be adapted in line with its development. Overall, this project will create a breeding ground for a new generation of energy-efficient circuit technology in Sweden and the world”, says Lars-Erik Wernersson.
He explains that their work involves applied basic research, and therefore MAX IV, where the new materials can be studied in detail, is very useful. However, what is essentially material science is to be capitalised in applied research and the development of new transistors and circuit solutions.
“The opportunity to understand how materials behave at an atomic level gives us considerable advantages when we look at how they can be integrated into applications”, says Lars-Erik Wernersson.
The ERC Advanced Grant will provide Lars-Erik Wernersson with EUR 2.5 million over a five-year period.
“It is a real honour. The good thing about the ERC is that they give us the chance to conduct applied basic research, in other words the opportunity to explore things without knowing exactly where it might lead. It is a considerable risk, but also has great potential if we succeed”, concludes Lars-Erik Wernersson.
Transistors are the building blocks for all modern electronics. The transistor acts as a voltage-controlled switch that can be turned on or off. Transistors are becoming smaller and the smallest are produced using nanotechnology.
The millimetre-wave frequency spectrum
30–300 GHz has wavelengths from 10 to 1 mm and creates opportunities for new communication channels with high bit rates. Higher frequencies were previously considered to be unsuitable for mobile systems due to disadvantages such as difficulties in obtaining a sufficiently strong signal, the signal absorption of raindrops (rain fade) and the need for a clear sightline between sender and receiver (the signal is blocked by obstacles such as buildings). One advantage, however, is that it enables the use of very small antennas.
The III-V technology platform
The III-V technology platform focuses on materials in groups three and five of the periodic table. These are characterised by very good transport and optical properties.