Researchers say InGaOx FETs could solve silicon scaling issues
A team led by the Institute of Industrial Science at the University of Tokyo, has created a transistor made from gallium-doped indium oxide (InGaOx).
They want to address the problems involved in shrinking silicon-based transistors further as electronics become smaller. By ditching silicon in favour of InGaOx (a material whose orderly, crystal lattice is well suited for electron mobility) they believe they have a way forward.
“We also wanted our crystalline oxide transistor to feature a ‘gate-all-around’ structure, whereby the gate, which turns the current on or off, surrounds the channel where the current flows,” explains Anlan Chen, lead author of the study. “By wrapping the gate entirely around the channel, we can enhance efficiency and scalability compared with traditional gates.”
“Indium oxide contains oxygen-vacancy defects, which facilitate carrier scattering and thus lower device stability,” says Masaharu Kobayashi, senior author. “We doped indium oxide with gallium to suppress oxygen vacancies and in turn improve transistor reliability.”
The team used atomic-layer deposition to coat the channel region of a gate-all-around transistor with a thin film of InGaOx, one atomic layer at a time. After deposition, the film was heated to transform it into the crystalline structure needed for electron mobility. This process ultimately enabled the fabrication of a gate-all-around MOSFET.
“Our gate-all-around MOSFET, containing a gallium-doped indium oxide layer, achieves high mobility of 44.5 cm2/Vs,” explains Chen. “Crucially, the device demonstrates promising reliability by operating stably under applied stress for nearly three hours. In fact, our MOSFET outperformed similar devices that have previously been reported.”
The team believes the research is a step towards the development of reliable, high-density electronic components suited for applications with high computational demand, such as big data and artificial intelligence.
The work is described in a new paper 'A Gate-All-Around Nanosheet Oxide Semiconductor Transistor by Selective Crystallization of InGaOx for Performance and Reliability Enhancement' to be presented at the 2025 Symposium on VLSI Technology and Circuits.
