Barrier height modulation in Amorphous IGZO/Metal interface using Trichlorosilane-Based Self-Assembled monolayers

• Published in: Applied surface science 2025-02, Vol.682, p.161693, Article 161693
• Main Authors: Lim, Sungbin, Mah, Dong-Gyun, Yoon, Beomhee, Lee, Hyunho, Cho, Won-Ju, Park, Hamin
• Format: Article
• Language: English
• Subjects: Amorphous InGaZnO; Barrier height; Contact resistance; Fermi level pinning; Self-assembled monolayer
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2024.161693

[Display omitted] •Various self-assembled monolayers were applied to a-IGZO/metal interfaces.•Different carbon chain lengths and metal work functions were investigated.•Temperature-dependent I-V characteristics revealed carrier transport mechanisms.•Barrier height and Fermi level pinning were effectively modulated. Amorphous InGaZnO (a-IGZO) has become a key material for thin-film transistors (TFTs) due to its high mobility, low leakage current, and optical transparency. However, the increasing demands for ultra-high-resolution displays, such as those required for virtual and augmented reality applications, pose challenges related to contact resistance and Fermi level pinning at the a-IGZO/metal interface, as TFTs are scaled down. To address these challenges, we investigated trichlorosilane-based self-assembled monolayers (SAMs) as an interfacial layer between a-IGZO and metal contacts (Al, Ag, and Ni). By employing SAMs with varying carbon chain lengths—methyl trichlorosilane (MTS), octyl trichlorosilane (OTS), and octadecyl trichlorosilane (ODTS)—we aimed to improve interface properties and reduce contact resistance. Our study comprehensively analyzed thermionic emission characteristics, including barrier height, saturation current, ideality factor, and contact resistance, across different metal electrodes. The results show that the SAM layers effectively modulate barrier height and Fermi level pinning, depending on the combination of SAM layers (MTS, OTS, and ODTS) and metal electrodes (Al, Ag, and Ni). Additionally, the study provides insights into the influence of SAM carbon chain length on direct tunneling current and interface passivation, and contributes to a deeper understanding of conduction mechanisms at a-IGZO/metal interfaces.