Neutron displacement damage effects in carbon nanotube devices: influence of device structure

Single-walled carbon nanotubes (SWCNTs) exhibit exceptional electronic properties and radiation tolerance, making them promising candidates for next-generation high-frequency, low-power, and extreme-environment electronics. In radiation environments such as space, energetic neutrons can induce displacement damage, compromising device reliability. In this work, neutrons (>1 MeV) were employed to investigate displacement damage effects in carbon nanotube field-effect transistors (CNTFETs). Devices with three architectures: top-gate (TG), local bottom-gate (LBG), and global bottom-gate (GBG), and multiple channel widths are irradiated at fluences of 1 × 10 9 to 4 × 10 13 n/cm 2 . TG devices with large channel areas exhibit exceptional radiation tolerance, with a slight increase in off-state current ( I off ) at high fluence, indicating minimal neutron-induced defects in the CNT channel. Long term room-temperature storage has a slight impact on I on / I off and threshold voltage but reduces transconductance and subthreshold swing. At the maximum fluence of 4 × 10 13 n/cm 2 , radiation tolerance is governed by device architecture, channel dimensions, and gate oxide thickness. LBG devices with micrometer-scale channels show minimal degradation, but performance drops sharply when the channel width is reduced to 300 nm LBG devices are also air-sensitive, requiring controlled post-irradiation storage. Notably, GBG devices exhibit substantially superior radiation tolerance to LBG devices at reduced channel dimensions. Raman, TEM and XPS analyses indicate that device degradation originates from traps in the HfO 2 dielectric and at its interface with the CNT, rather than from CNT channel damage. These findings provide critical experimental insights for the structural design and optimization of CNTFETs in extreme radiation environments.