A team of researchers at Peking University claims to have overcome technological limitations in boosting chip performance with relatively simple means. The scientists have literally changed the direction of transistor manufacturing, abandoning both modern scanners and silicon.
Image source: Peking University
It is generally accepted that the release of 2-nm semiconductors and solutions with lower technological standards is associated with the transition to EUV lithography and new transistor architectures. All this requires colossal costs for development and production resources. However, even with the availability of such resources, the export of high-tech equipment is strictly limited by the United States and its partners. In particular, China is prohibited from selling EUV scanners and even modern versions of 193-nm DUV scanners.
A team of scientists from Peking University initially worked on a new chip manufacturing technology in an attempt to circumvent sanctions, but ended up achieving a fundamentally new result: they created a manufacturing process for 2D transistors using materials that do not contain silicon. The researchers claim that typical equipment used in the semiconductor industry is suitable for making these “fundamentally new” transistors. At least, the chip was made on an experimental university line, which is unlikely to be equipped with cutting-edge technology.
Bismuth oxides were used as materials for the transistor channel and gate: Bi₂O₂Se for the channel and Bi₂SeO₅ for the gate. Due to their properties, these materials can be applied to the substrate in atomically thin and uniform layers, which ensures the repeatability of the process and the stability of the transistor characteristics. It is for this property that a transistor based on Bi₂O₂Se and Bi₂SeO₅ is considered a 2D transistor. Architecturally, it is a gate-array field-effect transistor (GAAFET). The developers describe its structure as a “braided bridge” instead of the traditional FinFET “skyscrapers”.
According to the researchers, the high permittivity of the materials used allows for the creation of ultra-thin gate structures that do not allow leakage currents, which reduces the switching voltage of the transistors. This, in turn, increases the switching speed of the transistors while reducing energy consumption.
The scientists claim that their 2D transistors are 40% faster than state-of-the-art 3nm transistors from TSMC and Intel, while reducing power consumption by 10%. They also developed a simple logic circuit based on the new transistors and experimentally confirmed their impressive performance.