Reducing the Gate-Induced Drain-Leakage Current of Carbon-Nanotube Transistors by Subliming Dispersants with Back-End-of-Line Compatible Temperature

Abstract

Carbon nanotube field-effect transistors (CNTFETs) are promising for monolithic 3D integration with silicon CMOS circuits in back-end-of-line (BEOL) processes. Further reduction in off-state leakage is essential for practical applications. In this study, we develop a low-temperature cleaning process for CNT-deposited wafers using a sublimable CNT dispersant. The process is carried out below 250 °C, making it BEOL-compatible, and does not deteriorate CNT morphology or lattice structure, as confirmed by atomic force microscopy and Raman spectroscopy. As a result, gate-induced drain leakage current originating from residual dispersants is reduced by approximately one order of magnitude. In addition, improvements in on-current, subthreshold slope, and threshold voltage variability are observed after the cleaning process. This study demonstrates a material-enabled approach to improve the transfer characteristics of CNTFETs and provides a practical route toward low-power CNT electronics.