Lee Hanbin, Park So-Jeong, Im Jeong Yeon, Kim Dae Hwan, Kim Dong Myong, Kang Min-Ho, Choi Sung-Jin
School of Electrical Engineering, Kookmin University, Seoul 02707, Republic of Korea.
Department of Advanced Technology, DGIST, Daegu 42988, Republic of Korea.
Nanotechnology. 2025 Aug 13;36(33). doi: 10.1088/1361-6528/adf752.
Owing to their excellent electrical and mechanical properties, carbon nanotube thin-film transistors (CNT-TFTs) have emerged as promising candidates for high-performance TFTs. In particular, the long mean free path and quasi-ballistic transport characteristics of charge carriers in CNT make the contact properties a critical factor in device performance. As a result, significant research has been conducted on extracting the contact resistance in CNT-TFTs. However, previous studies have not sufficiently accounted for the asymmetric characteristics of CNT-TFTs. Since CNT-TFTs fabricated using solution-based processes inherently exhibit asymmetric properties, considering the effective gate bias, which reflects the voltage drop across individual contact resistances, is important when analyzing the device characteristics. In this work, we propose a method for accurately extracting individual contact resistances that accounts for these effects in CNT-TFTs. This approach is independent of the contact resistance method (CRM), applicable to large-area devices, and enables accurate threshold voltage extraction under asymmetric contact conditions. We also compare the resistances extracted using the proposed method with those obtained via a method that does not consider the voltage drop across individual contact resistances to analyze the impact of the voltage drop. Finally, using the extracted individual contact resistances, we eliminate the mobility degradation effects caused by the contact resistances and extract the intrinsic mobility. We expect that the proposed technique will serve as a robust approach for accurate characterization, modeling, and simulation of CNT-TFTs and their associated circuits, as it reliably extracts individual contact resistances across various semiconducting CNT purities.
由于具有优异的电学和力学性能，碳纳米管薄膜晶体管（CNT-TFTs）已成为高性能薄膜晶体管的有前途的候选者。特别是，碳纳米管中电荷载流子的长平均自由程和准弹道传输特性使接触特性成为器件性能的关键因素。因此，在提取碳纳米管薄膜晶体管的接触电阻方面已经进行了大量研究。然而，以前的研究没有充分考虑碳纳米管薄膜晶体管的不对称特性。由于采用基于溶液的工艺制造的碳纳米管薄膜晶体管固有地表现出不对称特性，在分析器件特性时，考虑反映各个接触电阻上电压降的有效栅极偏置非常重要。在这项工作中，我们提出了一种在碳纳米管薄膜晶体管中准确提取各个接触电阻的方法，该方法考虑了这些影响。这种方法独立于接触电阻法（CRM），适用于大面积器件，并且能够在不对称接触条件下准确提取阈值电压。我们还将使用所提出的方法提取的电阻与通过不考虑各个接触电阻上电压降的方法获得的电阻进行比较，以分析电压降的影响。最后，利用提取的各个接触电阻，我们消除了由接触电阻引起的迁移率退化效应，并提取了本征迁移率。我们期望所提出的技术将成为一种强大的方法，用于准确表征、建模和模拟碳纳米管薄膜晶体管及其相关电路，因为它能够可靠地提取各种半导体碳纳米管纯度下的各个接触电阻。
