Chinese scientists claim to have developed a “2D” semiconductor material, as thin as a single atom, that promises to revolutionise the industry.
As electronic devices become smaller and smaller, the need for equally diminutive components has increased. The wafer’s creators are hopeful the new material will solve this dilemma.
Reportedly measuring 30.5 centimetres in length, the ultra-thin material is composed of crystalline solids ranging from one to several atoms thick.
Its creators, researchers from the Renmin University of China and the Chinese Academy of Sciences, say the material’s inherent thinness gives it exceptional conductivity without running the risk of overheating inside the device.
A nanometre-thick molybdenum disulphide transistor outperforms its silicon-based counterparts by several factors, according to Renmin University professor and project contributor, Liu Can.
Although silicon has been a staple in the semiconductor industry since the 1940s, ever-decreasing device sizes have found the material wanting in some areas.
As chips become thinner and thinner, their ability to regulate voltage decreases. This presents several issues because current within the system can exist despite the device being off, increasing energy costs and causing potentially destructive overheating.
Much like graphene, an equally thin carbon-based material known for its immense strength-to-weight ratio and electrical resistivity, the team’s wafer prototypes are stackable, meaning their width and shape can be altered to match design specifications.
However, establishing a method of fabricating the ultra-thin material at scale is something the scientists close to the project continue to grapple with.
More than 60 per cent of the chip market relies on large wafers, roughly 30 centimetres in diameter, according to the team’s research paper, published in the July issue of the peer-reviewed academic journal, Science Bulletin.
Wafers that size are incredibly difficult to produce at scale without sacrificing quality. While electronics and communication engineers worldwide have had success manufacturing 5 centimetre atom-thin wafers, scaling up their size using traditional production techniques results in diffusion, a process where molecules become more and more unevenly distributed throughout the wafers as their surface area increases.
To overcome this, the research unit developed a new method that ensured a uniform distribution of molybdenum disulphide molecules. A chalcogenide crystal plate made from zinc sulphide, in conjunction with a solution of sodium molybdate, was introduced into the manufacturing process as an element source, according to a PhD candidate and contributing author, Gue Guodong.
To solve the issue of batch production, the team opted to layer the wafers on top of one another inside columns, filling any gaps between each unit with more material, and ensuring that each wafer is nearly identical in every aspect, which is critical to consistent performance.
Engineers at the Songshan Lake Materials Laboratory have reportedly already designed specialised equipment with an annual production capacity of 20 000 wafers per machine.
While Liu and his team admit they are still some time away from transforming the wafers into functioning chips, they are bullish that further research and development in the new field of 2D semiconductors will overcome their present obstacles.
https://interestingengineering.com/innovation/china-2d-semiconductor-wafer
