Chinese researchers have made significant strides in chip manufacturing technology, advancing beyond traditional silicon-based processes. They have successfully developed a complete 32-bit RISC-V processor named Wuji, which is produced on a remarkably thin semiconductor layer measuring just 1 nanometer (nm) in thickness. A noteworthy aspect of this advancement is that the manufacturing process does not necessitate the use of EUV scanners; instead, it can be accomplished using existing lithography equipment available in China.
For over two decades, graphene has garnered interest as a material that could enhance the efficiency and productivity of chip manufacturing. However, the challenge has been that pure graphene is a conductor, complicating the fabrication of transistors.
While atomically thin semiconductors have the potential to address these issues, none have been successfully identified until now. One promising candidate is molybdenum disulfide (MoSโ), which features a hexagonal molecular structure and is only 1 nm thick.
Researchers at the National Laboratory of Integrated Circuits and Systems at Fudan University dedicated approximately five years to developing a method for utilizing MoSโ. Their process involves depositing the material in vapor form onto a substrate, leading to the successful creation of layers of MoSโ on sapphire substrates, enabling the production of working atomically thin circuits.
Remarkably, about 70% of the equipment used in MoSโ chip production is adapted from conventional silicon wafer manufacturing lines, suggesting that this new technology requires relatively low investment for modernization.
The team ultimately constructed a 30 x 30 inverter array that addressed the limitations of MoSโ, which traditionally only supported N-type transistors relying on negatively charged electrons. By incorporating aluminum and gold contacts, they were able to manipulate the gate voltage effectively.
From these inverters, the researchers assembled electronic circuits comprised of 25 basic components, which collectively featured 5,900 active transistors. Although the Wuji chip operates at a frequency of just a few kilohertz, it is capable of executing 32-bit RISC-V instructions in their entirety. The developers highlight this achievement as the creation of the largest processor to date based on atomically thin semiconductors, marking a significant advancement in the field of electronics beyond conventional silicon technologies.
