Chinese scientists have unlocked a revolutionary supercooling innovation in semiconductor technology, paving the way for a 40 per cent leap in the performance of gallium nitride-based radar systems, which are widely used in China’s most advanced stealth aircraft.
The new Chinese-made chips can handle extreme power loads in the X and Ka bands – frequencies critical for advanced radar systems, satellite communications and next-generation wireless computer networks.
“This is the most significant breakthrough in this field in nearly two decades,” northwest China’s Xidian University said on social media on Tuesday.
Zhou Hong, the project leader at the university, noted that the technology significantly improved the detection range of the radar equipment without increasing the size of the chip. He added that when applied to mobile networks, it provided wider signal coverage and cut power costs.
This innovation will help consolidate China’s dominance in third-generation gallium nitride semiconductor technology and future chips, according to the university, a leading institution for electronic warfare technology.
Chinese stealth aircraft such as the J-20 and J-35 use gallium nitride-based radars, allowing them to see farther than their US rivals such as the F-22, which uses older technology. The US military is upgrading the F-35 with gallium nitride radars, but it will not be complete until 2031 – a five-year delay from its original timeline.
China is the world’s largest producer of gallium. Beijing has banned exports of the metal to US defence users.
The scientists spent over two decades working to overcome what they said was the biggest obstacle to more powerful radio frequency chips: overheating.
They transformed the uneven bonding layer in semiconductor devices – an intermediate layer that connects substrates made of different materials – into a smooth film, thereby removing the barriers that had previously trapped heat inside the chip.
This led to a “leap in efficiency” in the chip’s performance and ability to shed heat, according to the team.
Building on this breakthrough, the team developed a gallium nitride microwave device – a specialised chip that can amplify the energy of high-frequency microwave signals, such as 5G and radar.
This new development will strengthen China’s leading position in gallium nitride-based semiconductor technology, which “has reached maturity”, according to a September report by the Chinese Academy of Sciences’ Institute of Physics.
Xidian University said the maturation of this technology would solidify China’s competitive edge in third-generation semiconductors while speeding up the practical use of fourth-generation semiconductors.
The researchers published their findings in the peer-reviewed journal Science Advances on November 19.
According to the team, a key challenge in semiconductor devices lies in how to integrate different material layers efficiently and reliably, as the quality of the interfaces determines overall performance.
This is particularly true of third-generation semiconductors, including gallium nitride, and fourth-generation semiconductors, such as gallium oxide.
Traditional approaches use aluminium nitride as an intermediate “bonding layer”. However, during growth – the process of creating a new, ultra-thin layer on top of a base layer – this layer spontaneously forms countless irregular and uneven “islands” or bumps, according to Zhou.
This ultimately results in significant resistance to heat transfer and accumulated heat within the chip, which can cause performance degradation.
To address this issue, the team developed a new technique that transformed the random and uneven growth process of the bonding layer into precise, uniform growth that can be controlled.
They found that the thermal resistance – the amount of heat flowing per unit of time – of the new structure was reduced by one-third compared with the traditional approach, achieving a “remarkable” improvement in the performance of radio frequency power devices.
Zhou said the true value of their research was that it provided a “replicable paradigm” for addressing the global challenge of integrating diverse chip materials.
Xidian University is a leading public research university in Xian, Shaanxi province, specialising in electronics, information technology and related engineering disciplines. Founded in 1931 as the Radio School of the Central Military Commission of the Communist Party in Ruijin, Jiangxi province, it is the nation’s first engineering institution dedicated to radio technology.
In December, a team from the university developed a smart surface that can convert electromagnetic waves into usable electricity. This technology could be used to develop intelligent stealth systems and next-generation 6G wireless communication. -- SOUTH CHINA MORNING POST
