為了延續摩爾定律（Moore′s Law），元件尺寸的微縮並帶來了許多嚴峻挑戰，例如短通道效應（Short-channel effects）、穿隧效應以及高接觸電阻，這些因素嚴重惡化了電晶體的效能。二維（2D）材料如二硫化鉬（MoS₂），憑藉其原子級薄、無懸鍵（Dangling bonds）的表面以及尺寸微縮下維持之高載子遷移率（Carrier mobility），已成為下一代電子元件極具潛力的候選材料。 然而，當金屬與 MoS₂ 接觸時，由於費米能階釘扎（Fermi level pinning effect， FLP）和蕭特基能障（Schottky barrier）的形成，往往會限制載子的注入，這成為了元件優化中的主要瓶頸。因此，目前已開發出多種策略來應對這些挑戰並提升接觸效能，包括相位工程（Phase engineering）、邊緣接觸（Edge contact）、嵌入緩衝層（Inserting buffer layers）、凡得瓦接觸（Van der Waals contacts）、能隙態飽和（gap state saturation， GSS）以及分子或化學摻雜。然而這些方法目前仍遭遇較不穩定及製程較不相容等問題。 在本研究中，採用了本實驗室過去所發展的低損傷電漿處理用於部分移除 MoS₂ 表面的硫（S）原子，從而部分顯露出底層的鉬（Mo）原子。這種界面改質使得在金屬沉積過程中，能夠形成直接的金屬－鉬（Metal–Mo）鍵結，可提升導通電流等電性提升。我們進一步研究了一系列具有不同功函數（Work functions）的接觸金屬釔（Yttrium， Y）和钪（Scandium， Sc），以探索它們與經電漿處理的MoS₂之間的界面交互作用，並評估它們對電晶體元件特徵電學效能的影響。 結果表明，經過電漿處理後的元件，相較於未經電漿處理的參考元件，其導通電流增加了 4.5 倍，開關比（on/off ratio）提升了約 1.4 個數量級，載子遷移率提高了約 4.2 倍。推測是由於介面的N-type 摻雜及金屬不同功函數之調節所導致，並證明該製程在提升元件電學效能方面的有效性。;To sustain the continuation of Moore′s Law， continuous device scaling has introduced several critical challenges， including short-channel effects， quantum tunneling， and high contact resistance， all of which severely degrade transistor performance. Two-dimensional (2D) materials， such as molybdenum disulfide (MoS₂)， have emerged as promising candidates for next-generation electronic devices owing to their atomically thin structure， dangling-bond-free surface， and high carrier mobility that can be maintained under aggressive scaling. However， Fermi-level pinning (FLP) and Schottky barrier formation at the metal/MoS₂ interface impede efficient carrier injection and remain major bottlenecks in device optimization. Various contact-engineering strategies， including phase engineering， edge contacts， buffer-layer insertion， van der Waals contacts， gap-state saturation (GSS)， and molecular or chemical doping， have been proposed to address these challenges. Nevertheless， these approaches still suffer from limitations such as poor stability and limited process compatibility. In this study， a low-damage plasma treatment developed in our previous work was employed to partially remove sulfur atoms from the MoS₂ surface， thereby exposing the underlying molybdenum atoms. This interfacial modification promotes the formation of direct metal–Mo bonds during metal deposition， resulting in improved carrier injection and enhanced electrical performance. Furthermore， two contact metals with different work functions， Yttrium (Y) and Scandium (Sc)， were investigated to examine their interfacial interactions with plasma-treated MoS₂ and evaluate their influence on transistor characteristics. Compared with untreated reference devices， the plasma-treated devices exhibited a 4.5-fold increase in on-state current， a 1.4-order-of-magnitude improvement in the on/off current ratio， and a 4.2-fold enhancement in carrier mobility. These improvements are attributed to interfacial n-type doping induced by the plasma treatment together with modulation of the contact properties by different metal work functions， demonstrating the effectiveness of the proposed approach for enhancing the electrical performance of MoS₂ transistors.
