KAUST leads development of prototype 2D microchip

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The first fully integrated and functional microchip based on exotic two-dimensional materials has been developed in a collaboration led by King Abdullah University of Science and Technology (KAUST).

KAUST Professor Mario Lanza and his co-researchers have successfully designed the world's first 2D microchip using synthetic materials
KAUST Professor Mario Lanza and his co-researchers have successfully designed the world's first 2D microchip using synthetic materials - © 2023 KAUST; Mario Lanza

According to the team, their breakthrough demonstrates the potential of 2D materials to expand the functionality and performance of microchip-based technologies.

Functional microdevices based on 2D materials have proved elusive due to the challenges in fabricating and handling such fragile thin films.

Inspired by recent achievements in Mario Lanza’s lab on functional 2D films, the KAUST-led collaboration has now produced and demonstrated a prototype 2D-based microchip. The team’s findings have been published in Nature.

“Our motivation was to increase the technology readiness level of 2D material-based electronic devices and circuits by using conventional silicon-based CMOS microcircuits as a base and standard semiconductor fabrication techniques,” Lanza said in a statement. “The challenge, however, is that synthetic 2D materials can contain local defects such as atomic impurities that can cause small devices to fail. Also, it is very difficult to integrate the 2D material into the microchip without damaging it.”

The research team is said to have optimised the design of the chip to make it easier to fabricate and minimise the effect of defects. According to KAUST, they did this by fabricating standard complementary metal oxide semiconductor (CMOS) transistors on one side of the chip and feeding interconnects through to the underside, where the 2D material could be transferred in small pads less than 0.25μm across.

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“We produced the 2D material - hexagonal boron nitride, or h-BN, on copper foil - and transferred it to the microchip using a low-temperature wet process, and we then formed electrodes over the top by conventional vacuum evaporation and photolithography, which are processes we have in-house,” said Lanza. “In this way we produced a 5×5 array of one-transistor/one-memristor cells connected in a crossbar matrix.”

The exotic properties of 6nm thick 2D h-BN are said to make it an ideal memristor, a component whose resistance can be set by the applied voltage. In this 5×5 arrangement, each of the microscale memristor pads is connected to a single dedicated transistor. This provides the fine voltage control needed to operate the memristor as a functional device with high performance and reliability over thousands of cycles, in this case as a low-power neural network element.

“With this flagship breakthrough, we are now talking with leading semiconducting companies to keep working in this direction,” said Lanza. “We are also considering installing our own wafer-scale industrial processing system for 2D materials at KAUST to advance this capability.”

2D chip