Latest 2D Chip: 6,000 Transistors, 3 Atoms Thick

16/05/2025
A microchip with nearly 6,000 transistors, each only three atoms thick, is the most complex microprocessor made from a two-dimensional material to date, scientists in China say.

The new device was made using the semiconductor molybdenum disulfide, which consists of a sheet of molybdenum atoms sandwiched between two layers of sulfur atoms. Scientists hope 2D materials such as molybdenum disulfide will allow Moore’s Law to continue once it becomes impossible to make further progress using silicon.

“Although 2D materials have been widely advocated for more than a decade, the real limitation to their current development is not the performance of any single device, as many 2D electronic devices work very well at the laboratory level,” says Wenzhong Bao, a professor at Fudan University’s school of microelectronics, in Shanghai. “The reason why people continue to question the practicality of 2D materials is the lack of an integrated technology system that is scalable, repeatable, and compatible with industrial processes.”

2D Chip Breakthrough

The new microchip, named RV32-WUJI, possesses 5,931 molybdenum disulfide transistors fabricated using existing CMOS technologies. In comparison, the previous largest 2D logic circuit was made up of 156 molybdenum disulfide transistors, the researchers say. These new findings mark “the transition of 2D semiconductor materials from device-level laboratory research to system-level engineering applications, providing a viable alternative to semiconductor technology in the post-silicon era,” Bao says.

RV32-WUJI is equipped with a RISC-V architecture capable of executing standard 32-bit instructions. (“RISC” stands for “reduced instruction set computer.”) First introduced in 2010, RISC-Voffers an open-source, modular core set of instructions to help foster broad adoption and innovation.The new processor is built on an insulating sapphire substrate that electronically isolates the transistors from each other. The researchers also developed a complete standard cell library for the new chip, which contains 25 types of logic units to perform basic functions, such as AND and OR.

The intricate nature of 2D semiconductors and of wafer-scale fabrication procedures can lead to many possible points of failure. To address these challenges, Bao’s team used machine learning to help them optimize each process step. All in all, despite only having lab-level fabrication capabilities, the researchers achieved a manufacturing yield of 99.77 percent.

“Based on our existing research results, we plan to explore a wide range of application scenarios for 2D integrated circuits, such as edge computing chips for Internet of Things terminals and smart sensing chips,” Bao says. “These application scenarios will not only more quickly demonstrate the competitiveness of 2D semiconductors, but also provide positive feedback for the development of higher-density chips in the future.”

Currently the transistor channel regions, a key feature size for devices, are 3 micrometers long. The scientists plan to use better lithography tools “to further shrink the channel to improve integration density, “ Bao says.

RV32-WUJI consumes only 0.43 milliwatts of power when operated at a frequency of 1 kilohertz to perform arithmetic. Bao acknowledges that silicon chips may possess millions of times more transistors and operating frequencies millions of times faster than the new device. However, he adds, their new work is based on university-laboratory-level equipment and clean room environments. By contrast, “with the silicon-based semiconductors from the last century to the present, the world has invested a huge amount of R&D resources,” Bao says. If the industry embraces 2D semiconductors, “we believe the pace of catching up with silicon-based performance will be faster than we can imagine.”

The scientists detailed their findings 2 April in the journal Nature.

Source: https://tinyurl.com/475zvf3y via IEEE Spectrum