2D Chip with Almost 6,000 Transistors Researchers Develop Atomically Thin 32-Bit RISC Processor

Researchers from China have developed a functional 2D RISC-V processor made of molybdenum disulphide that combines 5,931 transistors on just three atomic layers.

With the RV32-WUJI, a Chinese research team has created the most complex processor based on a two-dimensional semiconductor to date. The chip consists of 5,931 transistors made from molybdenum disulphide (MoS₂). The resulting chip is just three atomic layers thick.

MoS₂ is a semiconductor material with an atomically thin structure: a molybdenum layer is embedded between two layers of sulphur. According to the accompanying study, which the researchers published in the journal Nature, this geometry makes it possible to create functional transistors in a layer just a few angstroms thick - a property that conventional silicon technologies can no longer physically achieve.

Slow but functional

In contrast to previous laboratory demonstrations, the team manufactured the chip with existing CMOS compatibilities on sapphire substrates. A complete standard cell library with 25 logic gates was also developed - from AND to OR. This made it possible to realize a complete 32-bit RISC-V architecture.

The processor currently operates at kilohertz frequencies and requires just 0.43 milliwatts for simple arithmetic operations. Although it is significantly slower and simpler than modern silicon chips, it is a proof-of-concept at university laboratory level - with an impressive production yield of 99.8 percent, as the researchers claim

Challenges such as the lack of doping options were solved using alternative methods: different metals such as aluminum and gold were used for wiring in order to specifically influence threshold values. Machine learning was also used to optimize individual process steps.

A decisive step towards smaller, more economical chips?

However, the production process still reveals some serious weaknesses. With 8-bit registers, a yield of just 71 percent was achieved. A 64-bit register could only be successfully produced in 7 percent of cases. However, the overall progress shows that 2D materials are moving beyond individual demonstrations towards system integration: According to the researchers, the previous record for a functional logic chip of the same fabrication size would have been just 156 molybdenum sulphide transistors.

The long-term goal is to use it in energy-efficient applications with low complexity - for example in edge chips for IoT end devices or intelligent sensor technology. The extremely flat material with low power consumption offers an interesting option for this.

The RV32-WUJI is therefore not a replacement for silicon, but a blueprint for scalable, monomolecular electronics with industrial potential. If the technological path continues, 2D semiconductors could open up new niches in chip design in the medium term.(sg)