Chinese scientists have fabricated a new radiation-immune and repairable integrated circuit (IC) for space and nuclear applications.
Unlike previous strategies that have proposed hardening only single components of an electronic part to make them more resistant to radiation, the Chinese team – featuring scientists from Peking University, the Chinese Academy of Sciences (CAS) and Shanghai Tech University – has redesigned all the vulnerable parts of FETs and used new materials that are more resistant to radiation.
“The fabricated ICs based on this type of FET present high radiation tolerance of up to 15 Mrad, which is much higher than that of Si transistors (1 Mrad),” notes Peking University’s Zhiyong Zhang.
He asserts that this combination of high radiation tolerance and thermal recoverability could pay way for new radiation-damage-immune ICs fit for space exploration and nuclear energy applications.
According to the scientists, the radiation-hardened IC has a semiconducting carbon nanotube transistor (CNT) as a channel, an ion gel as its gate and a substrate made of polyimide.
CNTs are intrinsically radiation-resistant semiconductors due to their strong C-C bonds, nanoscale cross sections and their low atomic number.
The primary focus of this study thus lay on making the IC’s gate insulator and substrate more resistant to radiation.
“When designing our radiation-immune IC, we drew inspiration from the liquid metal robot T-1000 in the classic science fiction movie ‘Terminator 2,'” says Zhang.
“We used a quasi-liquid gate insulator – ion gel and a ‘transparent’ substrate. Ion gel gates promote the formation of EDLs at the surface of the CNT channel, which provides a much higher gate efficiency and allows the gate to be recovered after suffering radiation damage.”
“Meanwhile, by replacing the Si/SiO2 substrate of a conventional FET with a thin polyimide substrate, we eliminated effects resulting from high-energy particles being scattered and reflected in a heavy and thick substrate.”
In addition to developing an IC with a high tolerance to radiation, Zhang and his colleagues have also introduced a new method that could be used to recover FETs damaged by radiation.
According to the scientists, radiation-damaged FETs can be repaired by ‘annealing’ them at a moderate temperature of 100 °C for 10 min.
Image and content: Pixabay/Ingrid Fadelli-Tech Xplore