Heavy Ion Displacement Damage Effect in Carbon Nanotube Field Effect Transistors

Recent advances in carbon nanotube (CNT)-based integrated circuits have shown their potential in deep space exploration. In this work, the mechanism governing the heavy-ion-induced displacement damage (DD) effect in semiconducting single-walled CNT field effect transistors (FETs), which is one of the factors limiting device robustness in space, was first and thoroughly investigated. CNT FETs irradiated by a Xe ion fluence of 1012 ions/ cm2 can maintain a high on/off current ratio, while transistors' performance failure is observed as the ion fluence increased to 5 x 1012 ions/cm2. Controllable experiments combined with numerical simulations revealed that the degradation mechanism changed as the nonionizing radiation energy built up. The trap generation in the gate dielectric, instead of the CNT channel, was identified as the dominating factor for the high-energy-radiation-induced device failure. Therefore, CNT FETs exhibited a >10x higher DD tolerance than that of Si devices, which was limited by the channel damage under irradiation. More importantly, the distinct failure mechanism determined that CNT FETs can maintain a high DD tolerance of 2.8 x 1013 MeV/g as the technology node scales down to 45 nm node, suggesting the potential of CNT-based VLSI for high-performance and high-robustness space applications.