Jun 6, 2022

Healing Achilles heel of two-dimensional transistors


Source: Screenshot: nature electronics, June, 2022
Jun 6, 2022

Stability – in the sense of stable operation thorough lifetime – is one of the key characteristics that an electronic device need to present to be suitable for applications. And it is the Achilles heel of transistors based on two-dimensional materials, which typically show much worse stability than devices based on silicon. A team of researchers from TU Wien, AMO GmbH, RWTH Aachen University and Wuppertal University has now demonstrated a novel engineering approach to enhance the electrical stability of two-dimensional transistors by carefully tuning the Fermi energy. The results have been reported in Nature Electronics

Devices based on graphene

Today, there is little doubt that devices based on graphene and other two-dimensional (2D) materials can exceed the state of the art for certain applications, thanks to their intrinsic properties. Two-dimensional materials are also seen as some of the most promising candidates for realizing ultimately scaled transistors at the end of the roadmap of silicon technology.  However, devices based on 2D materials often show poor electrical stability, meaning that their behavior changes depending on their operation history. 

“Component reliability is one aspect that is often neglected in research. This is precisely where we have been working for several years, because it is of central importance for applications." explains Professor Max Lemme, scientific director of AMO GmbH and Head of the Chair of Electronic Devices at RWTH. The instability is not only caused by 2D materials themselves, but mostly by charges trapped into the oxide-insulator used to fabricate the transistors. "Ideally, one would like to use a different insulator with fewer charge traps," says Lemme, "but there are no scalable solutions for this yet. In our work, we have shown instead that it is possible to use a standard insulator such as aluminum oxide and to significantly suppress the adverse effects of the charge traps in the oxide, by adjusting the charge carrier density in the 2D material."

Stable and reliable 2D materials transistors for semiconductor technology

The work combines a thorough theoretical analysis of the novel approach – dubbed by the authors ‘stability-based design’ – and a proof of principle demonstration of the concept, performed by measuring different types of graphene-based FETs. The key idea of the approach is to try to engineer the combination 2D-material/insulator in such a way that the energy of the charge traps in the insulator is as different as possible from the one of the charge carriers in the 2D material. Lemme explains: “Graphene based FETs were the ideal test bed for our approach, as it is relatively easy to tune the energy of charge carriers in graphene. The approach, however, is applicable to all FETs based on 2D semiconductors”.  These results represent a major step forward towards stable and reliable 2D materials transistors to be integrated in semiconductor technology. 

Contact: Prof. Max C. Lemme, AMO GmbH 
lemme@amo.de

Member profile

Recommended articles

Jan 14, 2025

The first Chemnitzer Seminar of the year 2025 is entitled “Test and Reliability Solutions – new opportunities for electronic components …

Dec 16, 2024

The NEPOMUQ research project, a collaboration between AMO GmbH and the University of Wuppertal, focuses on the development of integrated …

Jun 19, 2025

On May 21 and 22, 2025, Dortmund became the European hub for micro- and high-tech innovations. Under the motto “Tech …

Recommended events

Feb 4 - 6, 2026
Discover the Future of Photonics with IVAM
Sep 9 - 11, 2026
Manufacturing Processes for Medical Technology
Mar 24 - 26, 2026
Leading European trade fair for autonomous technologies & robotics. Present yourself at the new IVAM joint stand!