本論文研究重點是在探討n型二硫化鎢（WS₂）電晶體的介電層。二硫化鎢是一種過渡金屬硫屬化物（TMDCs），因該材料具有優異的光學和電學性能，尤其是材料表面缺乏懸鍵對載子遷移率的影響，使其成為極具潛力的半導體材料。然而，二硫化鎢在大氣環境易受氧氣和水氣的影響，導致材料氧化或p型摻雜效應，使其電子傳輸特性下降，影響電晶體的性能。因此，本研究的目的是尋找一個穩定的介電層材料來保護通道材料，以提高二硫化鎢電晶體在大氣中的穩定性。

本研究詳細分析了不同介電材料的特性及成長方式，也探討了不同介電層對元件電性的影響，並成功以電漿輔助原子層沉積之氧化鉿作為介電層，加上熱蒸鍍鋁金屬後高壓氧化之氧化鋁，作為介電層前鈍化層，使n型二硫化鎢電晶體於大氣環境有效開關，且電晶體之電性表現與介電層製程前無明顯差異。該電晶體之開電流約為10⁻⁶A，關電流約為10⁻¹¹A，次臨界擺幅由約為1270mV/dec，臨界電壓約為4V，載子遷移率約為0.9cm²/V·s。

The focus of this thesis is on investigating the dielectric layer of n-type tungsten disulfide (WS₂) transistors. Tungsten disulfide, a type of transition metal dichalcogenide (TMDC), has excellent optical and electrical properties. One of its key advantages is the absence of dangling bonds on the material’s surface, which improves the carrier mobility of the material, making it a promising semiconductor material. However, WS₂ is susceptible to oxidation or p-type doping effects due to exposure to oxygen and moisture in the atmosphere, which degrades its electronic transport properties and affects transistor performance. Therefore, the goal of this study is to identify a stable dielectric material to protect the channel material and improve the stability of WS₂ transistors in ambient conditions.
This study analyzes the properties of different dielectric materials and their deposition methods, and it also explores the impact of different dielectric layers on device performance. The study successfully utilized plasma-enhanced atomic layer deposition (PEALD) of hafnium oxide as the dielectric layer, combined with thermally evaporated aluminum followed by high-pressure oxidation to form aluminum oxide, serving as a passivation layer for the dielectric layer. This approach allowed the n-type tungsten disulfide transistors to effectively switch in atmospheric conditions, with its electrical performance showing no significant difference compared to before dielectric layer processing. The device exhibited an on-current of approximately 10⁻⁶A, an off-current of approximately 10⁻¹¹A, a subthreshold swing of about 1270 mV/dec, a threshold voltage of around 4 V, and a carrier mobility of approximately 0.9 cm²/V·s.

[1] J. A. Fleming, The Thermionic Valve and Its Developments in Radio-telegraphy and Telephony, Wireless Press, Limited, London, 1919, p. 279.
[2] J. Bardeen and W. H. Brattain, “The transistor, a semi-conductor triode,” Physical Review, vol. 74, no. 2, p. 230, 1948.
[3] J. Kilby, “Invention of the Integrated Circuit,” IEEE Transactions on Electron Devices, vol. ed-23, no. 7, p. 648-654, 1976.
[4] A. K. Geim and K. S. Novoselov, “The rise of graphene,” Nature materials, vol. 6, no. 3, pp. 183–191, 2007.
[5] M. Chhowalla, H. S. Shin, G. Eda, L.-J. Li, K. P. Loh, and H. Zhang, “The chem- istry of two-dimensional layered transition metal dichalcogenide nanosheets,” Na- ture chemistry, vol. 5, no. 4, pp. 263–275, 2013.
[6] Q. H. Wang, K. Kalantar-Zadeh, A. Kis, J. N. Coleman, and M. S. Strano, “Elec- tronics and optoelectronics of two-dimensional transition metal dichalcogenides,” Nature nanotechnology, vol. 7, no. 11, pp. 699–712, 2012.
[7] I. Song, C. Park, and H. C. Choi, “Synthesis and properties of molybdenum disulphide: from bulk to atomic layers,” RSC Advances, vol. 5, no 10, pp. 7495–7514, 2014.
[8] S. Chen, Y. Pan, D. Wang, and H. Deng, “Structural Stability and Electronic and Optical Properties of Bulk WS2 from First-Principles Investigations,” Journal of Electronic Materials, vol. 49, no. 12, pp. 7363–7369, 2020.
[9] H. Yuan, H. Wang, and Y. Cui, “Two-dimensional layered chalcogenides: from ra- tional synthesis to property control via orbital occupation and electron filling,” Ac- counts of chemical research, vol. 48, no. 1, pp. 81–90, 2015.
[10] A. Kuc, N. Zibouche, and T. Heine, “Influence of quantum confinement on the electronic structure of the transition metal sulfide t s 2,” Physical Review B, vol. 83, no. 24, p. 245213, 2011.
[11] Y. Zhang, Y. Zhang, Q. Ji, J. Ju, H. Yuan, J. Shi, T. Gao, D. Ma, M. Liu, Y. Chen, et al., “Controlled growth of high-quality monolayer ws2 layers on sapphire and imaging its grain boundary,” ACS nano, vol. 7, no. 10, pp. 8963–8971, 2013.
[12] H. Li, Y. Li, A. Aljarb, Y. Shi, and L. J. Li, “Epitaxial Growth of Two-Dimensional Layered Transition-Metal Dichalcogenides: Growth Mechanism, Controllability, and Scalability,” Chemical Reviews, vol. 118, no. 13, pp. 6134-6150, 2018.
[13] K. Liu, Q. Zhao, B. Li, and X. Zhao, “Raman Spectroscopy: A Novel Technology for Gastric Cancer Diagnosis,” Frontiers in Bioengineering and Biotechnology, vol. 10, article 856591, pp. 1-11, 2022.
[14] A. Berkdemir, H. R. Gutiérrez, A. R. Botello-Méndez, et al., “Identification of individual and few layers of WS2 using Raman Spectroscopy,” Scientific Reports, vol. 3, article 1755, pp. 1-8, 2013.
[15] Ying Chen et al., “Growth of a Large, Single-Crystalline WS2 Monolayer for High-Performance Photodetectors by Chemical Vapor Deposition,” Micromachines, vol. 12, no. 2, article 137, pp. 1-8, Jan. 2021.
[16] Y. W. Huan, S. M. Sun, C. J. Gu, W. J. Liu, S. J. Ding, H. Y. Yu, C. T. Xia, and D. W. Zhang, “Recent Advances in β-Ga2O3–Metal Contacts,” Nanoscale Research Letters, vol. 13, article 246, pp. 1-10, 2018.
[17] A. Grillo and A. Di Bartolomeo, “A current-voltage model for double schottky barrier devices,” Advanced Electronic Materials, vol. 7, no. 2, pp. 2000979, 2021.
[18] Z. Wang, W. Zang, Y. Shi, X. Zhu, G. Rao, Y. Wang, J. Chu, C. Gong, X. Gao, H. Sun, S. Huanglong, D. Yang, and P. Wangyang, “Extraction and Analysis of the Characteristic Parameters in Back-to-Back Connected Asymmetric Schottky Diode,” Physica Status Solidi A, vol. 217, no. 8, article 1901018, pp. 1-9, 2020.
[19] D. Ovchinnikov, A. Allain, Y. S. Huang, D. Dumcenco, and A. Kis, “Electrical transport properties of single-layer ws2,” ACS nano, vol. 8, no. 8, pp. 8174–8181, 2014.
[20] Z. Yin, H. Li, H. Li, L. Jiang, Y. Shi, Y. Sun, G. Lu, Q. Zhang, X. Chen, and H. Zhang, “Single-Layer MoS2 Phototransistors,” ACS Nano, vol. 6, no. 1, pp. 74-80, 2011.
[21] Z. Hu, Z. Wu, C. Han, J. He, Z. Ni, and W. Chen, “Two-dimensional transition metal dichalcogenides: interface and defect engineering,” Chemical Society Reviews, vol. 47, no. 9, pp. 3100-3128, 2018.
[22] Z. Yu, Z.-Y. Ong, Y. Pan, Y. Cui, R. Xin, Y. Shi, B. Wang, Y. Wu, T. Chen, Y.-W. Zhang, G. Zhang, and X. Wang, “Realization of Room-Temperature Phonon-Limited Carrier Transport in Monolayer MoS2 by Dielectric and Carrier Screening,” Advanced Materials, vol. 28, no. 3, pp. 547–552, 2016.
[23] H. C. M. Knoops, S. E. Potts, A. A. Bol, and W. M. M. Kessels, “Atomic Layer Deposition,” in Handbook of Crystal Growth, 2nd ed., Elsevier, 2015, ch. 27, pp. 1101-1134.
[24] F. Zhuo, J. Wu, B. Li, M. Li, C. L. Tan, Z. Luo, H. Sun, Y. Xu, and Z. Yu, “Modifying the power and performance of 2-dimensional mos2 field effect transistors,” Research, vol. 6, article 0057, pp. 1-10, 2023.
[25] A. Vincze, J. Jakabovic, R. Srnánek, A. Šatka, J. Kovác jr., and J. Kovác, “Surface and Interface Properties of Thin Pentacene and Parylene Layers,” Central European Journal of Physics, vol. 7, no. 2, pp. 270-278, 2009.
[26] B. Ma, A. Sun, X. Gao, X. Bao, and J. Li, “Preparation of parylene-coated bonded NdFeB magnets,” Journal of Magnetism and Magnetic Materials, vol. 467, pp. 114-119, 2018.
[27] M. Janeta, Ł. John, J. Ejfler, and S. Szafert, “High-Yield Synthesis of Amido-Functionalized Polyoctahedral Oligomeric Silsesquioxanes by Using Acyl Chlorides,” Chemistry – A European Journal, vol. 20, no. 48, pp. 15966-15974, 2014.
[28] M. Lee, N. Zine, A. Baraket, M. Zabala, F. Campabadal, R. Caruso, M. G. Trivella, N. Jaffrezic-Renault, and A. Errachid, “A novel biosensor based on hafnium oxide: Application for early stage detection of human interleukin-10,” Sensors and Actuators B: Chemical, vol. 175, pp. 201-207, 2012.
[29] X. C. Lo, J. Y. Li, M. T. Lee, and D. J. Yao, “Frequency Shift of a SH-SAW Biosensor with Glutaraldehyde and 3-Aminopropyltriethoxysilane Functionalized Films for Detection of Epidermal Growth Factor,” Biosensors, vol. 10, no. 92, pp. 1-11, 2020.
[30] F. Ghasemi and A. Salimi, “Advances in 2D-based field effect transistors as biosensing platforms: From principle to biomedical applications,” Microchemical Journal, vol. 187, article 108432, 2023.