本文利用射頻磁控濺鍍法沉積非晶氧化銦鎢薄膜，討論薄膜在不同製程條件下的特性，並將這些薄膜作為紫外光感測器與薄膜電晶體之主動層，對其特性與現象進行討論與分析。
首先以磁控濺鍍的方式，在不同氧分壓的製程條件下，沉積氧化銦鎢薄膜，並分別探討其薄膜光學特性、薄膜結構特性及薄膜表面/縱深分析。實驗結果中，在光學特性上，薄膜於可見光區穿透率有80%，轉換為吸收光譜計算能隙的結果，能隙約位在3.13–3.39 eV。結構特性上，從X射線繞射分析（XRD）結果可以得知，隨著氧流量比例增高，氧化銦鎢薄膜有愈趨明顯的峰值，而經過退火處理的薄膜峰值又比未退火的更明顯。由原子力顯微鏡（AFM）的分析結果中，可以發現經過退火後，薄膜表面的RMS值明顯降低，表示退火有助於表面粗糙度的改善。薄膜表面/縱深分析上，從X射線光電子能譜（XPS）圖得知，氧流量從2%提升至10%的過程中，氧流量為6%的氧化銦鎢薄膜裡氧空缺最少。

實驗的第二部分是將氧化銦鎢薄膜應用於光感測器，透過改變氧流量及退火溫度，來比較其對元件的影響。隨著氧流量增加，暗電流被有效抑制。在氧流量比例為10%的狀況下，暗電流為5.88*10^(-12) 安培，光暗電流比為4.56*104，響應為1.9*10^(-2)安培/瓦，響應拒斥比為2.68*10^4。透過退火處理，薄膜中載子急劇增加，造成元件產生過大電流，降低元件表現。
實驗第三部分，使用二氧化矽做為氧化銦鎢薄膜電晶體之閘極介電層，透過調整氧分壓及退火溫度，製備最佳化參數。室溫下得到的場效電子遷移率為0.23 cm^2/V∙s、臨界電壓為0.4 V，次臨界擺幅為0.45 V/decade，開關電流比為2.8 × 10^4。經過退火處理，薄膜中載子上升四個數量級，造成元件電流過大，降低整體元件電性表現。由實驗結果可知，透過退火處理無法改善元件特性。最後，薄膜電晶體延伸應用至光電晶體，在偏壓施加-2 V時得到其響應拒斥比為6.06*10^3。

In this thesis, indium tungsten oxide (IWO) is deposited by RF magnetron sputtering. The IWO film properties are discussed in detail under different processing ambiences. Afterwards, the deposited IWO thin films were used as channel layer for UV photodetectors and thin film transistors (TFTs). Analyses were then carried out and discussion on the device characteristics was contained.

First, the RF sputtering system was manipulated to grow films under various gas partial pressures. Film properties were investigated thoroughly in terms of three aspects which were optical, structural, and surface/depth element analyses. The optical analysis results showed that the transmittance in the visible light region were 80%, and the energy bandgap was about 3.13-3.39 eV in correspondence. In structural analysis, the X-ray diffraction analysis (XRD) revealed that while the oxygen flow ratio of the film increased, the crystalline phase and the peak intensities became apparent. After annealing processes, the peak intensities were much more obvious than the as-deposited IWO thin films. The diagram generated by atomic force spectroscopy (AFM) showed the RMS values of IWO thin films are reduced after annealing processes, and it indicated that annealing could improve the surface roughness. In material element analysis, the X-ray photoelectron spectroscopy (XPS) results suggested that the oxygen flow ratio rising from 2% to 10%, the 6% IWO thin films had the least oxygen vacancies.

Second, the IWO thin films were applied to UV photodetectors. By adjusting oxygen flow ratio and annealing temperature, the investigation was made to compare the effects toward IWO devices. As the oxygen flow ratio increased, the dark current was effectively suppressed. At the oxygen flow ratio of 10%, the dark current was 5.88*10-12 A, the on-off current ratio was 4.56*10^4, the photoresponsivity was 1.9*10^(-2) A/W, and the rejection ratio was 2.68*10^4. With post-annealing treatment, the electron carriers in the IWO thin film were significantly rising, causing the devices to excessive current and degrading the device performances.

Third, IWO TFTs with silica (SiO2) as the gate dielectric layer were realized. With the adjustments on oxygen partial pressures as well as annealing temperature, the best parameters were utilized. The transfer characteristics of optimized IWO TFTs at the room temperature make the results in a field effect mobility of 0.23 cm^2/V∙s, threshold voltage of 0.4 V, subthreshold swing of 0.45 V/decade, and on-off current ratio of 2.8 × 10^4. With post-annealing procedures, the electron carriers in the IWO thin film were significantly increasing for 4 orders, leading the devices to excessive current and degrading the overall device performances. Therefore, the IWO devices did not make improvement after annealing treatment. At the last, thin film transistors were operated under light illumination for examining performance. The rejection ratio of IWO phototransistor was about 6.06*10^3 at the bias voltage of -2 V.

[1] M. Qu, C.-H. Chang, T. Meng, Q. Zhang, P.-T. Liu, and H.-P. D. Shieh, “Stability study of indium tungsten oxide thin-film transistors annealed under various ambient conditions,” Phys. status solidi, vol. 214, no. 2, p. 1600465–n/a, 2017.
[2] J. Pan, W. Wang, D. Wu, Q. Fu, and D. Ma, “Tungsten Doped Indium Oxide Thin Films Deposited at Room Temperature by Radio Frequency Magnetron Sputtering,” J. Mater. Sci. Technol., vol. 30, no. 7, pp. 644–648, 2014.
[3] W. Miao et al., “Transparent conductive In2O3:Mo thin films prepared by reactive direct current magnetron sputtering at room temperature,” Thin Solid Films, vol. 500, no. 1, pp. 70–73, 2006.
[4] X. Xiu, Z. Pang, M. Lv, Y. Dai, L. Ye, and S. Han, “Transparent conducting molybdenum-doped zinc oxide films deposited by RF magnetron sputtering,” Appl. Surf. Sci., vol. 253, no. 6, pp. 3345–3348, 2007.
[5] Q. Zhang, X. Li, and G. Li, “Dependence of electrical and optical properties on thickness of tungsten-doped indium oxide thin films,” Thin Solid Films, vol. 517, no. 2, pp. 613–616, 2008.
[6] E. Chong, Y. S. Chun, and S. Y. Lee, “Amorphous silicon–indium–zinc oxide semiconductor thin film transistors processed below 150 °C,” Appl. Phys. Lett., vol. 97, no. 10, p. 102102, Sep. 2010.
[7] T. Kamiya, K. Nomura, and H. Hosono, “Present status of amorphous In-Ga-Zn-O thin-film transistors,” Sci. Technol. Adv. Mater., vol. 11, no. 4, 2010.
[8] J. S. Park, W.-J. Maeng, H.-S. Kim, and J.-S. Park, “Review of recent developments in amorphous oxide semiconductor thin-film transistor devices,” Thin Solid Films, vol. 520, no. 6, pp. 1679–1693, 2012.
[9] P.-T. Liu, Y.-T. Chou, and L.-F. Teng, “Environment-dependent metastability of passivation-free indium zinc oxide thin film transistor after gate bias stress,” Appl. Phys. Lett., vol. 95, no. 23, p. 233504, Dec. 2009.
[10] S. Aikawa, P. Darmawan, K. Yanagisawa, T. Nabatame, Y. Abe, and K. Tsukagoshi, “Thin-film transistors fabricated by low-temperature process based on Ga- and Zn-free amorphous oxide semiconductor,” Appl. Phys. Lett., vol. 102, no. 10, p. 102101, Mar. 2013.
[11] J.-S. Park, K. Kim, Y.-G. Park, Y.-G. Mo, H. D. Kim, and J. K. Jeong, “Novel ZrInZnO Thin-film Transistor with Excellent Stability,” Adv. Mater., vol. 21, no. 3, pp. 329–333, 2009.
[12] S. Aikawa, T. Nabatame, and K. Tsukagoshi, “Effects of dopants in InOx-based amorphous oxide semiconductors for thin-film transistor applications,” Appl. Phys. Lett., vol. 103, no. 17, p. 172105, Oct. 2013.
[13] H. Li, M. Qu, and Q. Zhang, “Influence of Tungsten Doping on the Performance of Indium–Zinc–Oxide Thin-Film Transistors,” IEEE Electron Device Lett., vol. 34, no. 10, pp. 1268–1270, 2013.
[14] T. Kizu et al., “Low-temperature processable amorphous In-W-O thin-film transistors with high mobility and stability,” Appl. Phys. Lett., vol. 104, no. 15, p. 152103, Apr. 2014.
[15] Z. Yang, T. Meng, Q. Zhang, and H. P. D. Shieh, “Stability of Amorphous Indium–Tungsten Oxide Thin-Film Transistors Under Various Wavelength Light Illumination,” IEEE Electron Device Lett., vol. 37, no. 4, pp. 437–440, 2016.
[16] R. K. Gupta, K. Ghosh, R. Patel, and P. K. Kahol, “Effect of thickness on optoelectrical properties of Mo-doped indium oxide films,” Appl. Surf. Sci., vol. 255, no. 5, Part 2, pp. 3046–3048, 2008.
[17] R. K. Gupta, K. Ghosh, and P. K. Kahol, “Thickness dependence of optoelectrical properties of tungsten-doped indium oxide films,” Appl. Surf. Sci., vol. 255, no. 21, pp. 8926–8930, 2009.
[18] X. Li, Q. Zhang, W. Miao, L. Huang, and Z. Zhang, “Transparent conductive oxide thin films of tungsten-doped indium oxide,” Thin Solid Films, vol. 515, no. 4, pp. 2471–2474, 2006.
[19] Y. Li, W. Wang, J. Zhang, and R. Wang, “Preparation and properties of tungsten-doped indium oxide thin films,” Rare Met., vol. 31, no. 2, pp. 158–163, 2012.
[20] C.-H. Lin and C. W. Liu, “Metal-Insulator-Semiconductor Photodetectors,” Sensors , vol. 10, no. 10. 2010.
[21] E. M. and F. O. and F. Calle, “Wide-bandgap semiconductor ultraviolet photodetectors,” Semicond. Sci. Technol., vol. 18, no. 4, p. R33, 2003.
[22] M. L. and L. S. and T. T. and M. I. and J. A. and Y. Koide, “Comprehensive Investigation of Single Crystal Diamond Deep-Ultraviolet Detectors,” Jpn. J. Appl. Phys., vol. 51, no. 9R, p. 90115, 2012.
[23] S. V. Averin, P. Kuznetzov, V. A. Zhitov, and N. Alkeev, Solar-blind MSM-photodetectors based on Al x Ga1- x N heterostructures, vol. 39. 2007.
[24] S. K. Pandey, V. Awasthi, S. Verma, and S. Mukherjee, “Blue electroluminescence from Sb-ZnO/Cd-ZnO/Ga-ZnO heterojunction diode fabricated by dual ion beam sputtering,” Opt. Express, vol. 22, no. 25, pp. 30983–30991, 2014.
[25] E. M. and E. M. and J. L. P. and F. C. and F. O. and P. Gibart, “III nitrides and UV detection,” J. Phys. Condens. Matter, vol. 13, no. 32, p. 7115, 2001.
[26] K. Nomura, H. Ohta, A. Takagi, T. Kamiya, M. Hirano, and H. Hosono, “Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors,” Nature, vol. 432, p. 488, Nov. 2004.
[27] M. Kimura, T. Kamiya, T. Nakanishi, K. Nomura, and H. Hosono, “Intrinsic carrier mobility in amorphous In–Ga–Zn–O thin-film transistors determined by combined field-effect technique,” Appl. Phys. Lett., vol. 96, no. 26, p. 262105, Jun. 2010.
[28] T. Kamiya and H. Hosono, “Material characteristics and applications of transparent amorphous oxide semiconductors,” Npg Asia Mater., vol. 2, p. 15, Jan. 2010.
[29] K. Nomura, T. Kamiya, H. Ohta, M. Hirano, and H. Hosono, “Defect passivation and homogenization of amorphous oxide thin-film transistor by wet O2 annealing,” Appl. Phys. Lett., vol. 93, no. 19, p. 192107, Nov. 2008.
[30] A. K. and T. K. W. and J. Kanicki, “Advanced Multilayer Amorphous Silicon Thin-Film Transistor Structure: Film Thickness Effect on Its Electrical Performance and Contact Resistance,” Jpn. J. Appl. Phys., vol. 47, no. 5R, p. 3362, 2008.
[31] M. Ito et al., “76.3: 32-inch LCD Panel Using Amorphous Indium-Gallium-Zinc-Oxide TFTs,” J. Phys. Condens. Matter, vol. 18, no., pp. 1136–1138, Nov. 2010.
[32] Y. G. Mo et al., “Amorphous-oxide TFT backplane for large-sized AMOLED TVs,” J. Soc. Inf. Disp., vol. 19, no. 1, pp. 16–20, 2011.
[33] M. Ito et al., “Application of amorphous oxide TFT to electrophoretic display,” J. Non. Cryst. Solids, vol. 354, no. 19, pp. 2777–2782, 2008.
[1] T. Zhai et al., “A Comprehensive Review of One-Dimensional Metal-Oxide Nanostructure Photodetectors,” Sensors , vol. 9, no. 8. 2009.
[2] S. Hwang, J. H. Lee, C. H. Woo, J. Y. Lee, and H. K. Cho, “Effect of annealing temperature on the electrical performances of solution-processed InGaZnO thin film transistors,” Thin Solid Films, vol. 519, no. 15, pp. 5146–5149, 2011.
[3] A. Van Der Ziel and E. R. Chenette, “Noise in Solid State Devices,” Adv. Electron. Electron Phys., vol. 46, no. C, pp. 313–383, 1978.
[4] D. Reynolds, D. Look, B. Jogai, and C. Litton, “Neutral-donor-bound-exciton complexes in ZnO crystals,” Phys. Rev. B - Condens. Matter Mater. Phys., vol. 57, no. 19, pp. 12151–12155, 1998.
[5] E. Monroy, F. Calle, E. Munoz, F. Omnes, P. Gibart, and J. a Munoz, “AlxGa1-xN : Si Schottky barrier photodiodes with fast response and high detectivity,” Appl. Phys. Lett., vol. 73, pp. 2146–2148, 1998.
[6] D. A. Neamen, Semiconductor physics and devices: Basic Principles. 2003.
[7] W. Kern and J. L. Vossen, Thin Film Processes II. 2012.
[8] C. Y. Chang, ULSI technology. McGraw-Hill, 1996.
[9] W.-T. Chen et al., “Oxygen-Dependent Instability and Annealing/Passivation Effects in Amorphous In–Ga–Zn–O Thin-Film Transistors,” IEEE Electron Device Lett., vol. 32, no. 11, pp. 1552–1554, 2011.
[10] D. A. Glocker and S. I. Shah, Handbook of thin film process technology [: 1997 edition. IOP, 1997.
[1] K.Remashan et al., “Effect of N2O Plasma Treatment on the Performance of ZnO TFTs,” Electrochem. Solid-State Lett. , vol. 11, no. 3, pp. H55–H59, Mar.2008.
[1] P.Bergonzo andR. B.Jackman, “Chapter 6 Diamond-based radiation and photon detectors,” in Thin-Film Diamond II, vol. 77, C. E.Nebel andJ. B. T.-S. and S.Ristein, Eds.Elsevier, 2004, pp. 197–309.
[2] E. M. and F. O. and F.Calle, “Wide-bandgap semiconductor ultraviolet photodetectors,” Semicond. Sci. Technol., vol. 18, no. 4, p. R33, 2003.
[3] N.Biyikli, O.Aytur, I.Kimukin, T.Tut, andE.Ozbay, “Solar-blind AlGaN-based Schottky photodiodes with low noise and high detectivity,” Appl. Phys. Lett., vol. 81, no. 17, pp. 3272–3274, Oct.2002.
[4] J. D.Brown, J.Li, P.Srinivasan, J.Matthews, andJ. F.Schetzina, “Solar-Blind AlGaN Heterostructure Photodiodes,” MRS Internet J. Nitride Semicond. Res., vol. 5, no. 1, p. e9, 2000.
[5] Z.Lu, F.Meng, Y.Cui, J.Shi, Z.Feng, andZ.Liu, “High quality of IWO films prepared at room temperature by reactive plasma deposition for photovoltaic devices,” J. Phys. D. Appl. Phys., vol. 46, no. 8, 2013.
[6] S.-P.Chang, L.-Y.Chang, andJ.-Y.Li, “The Influence of Different Partial Pressure on the Fabrication of InGaO Ultraviolet Photodetectors,” Sensors , vol. 16, no. 12. 2016.
[1] K. Nomura, H. Ohta, A. Takagi, T. Kamiya, M. Hirano, and H. Hosono, “Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors,” Nature, vol. 432, no. 7016, pp. 488–492, 2004.
[2] J. H. Noh et al., “Indium Oxide Thin-Film Transistors Fabricated by RF Sputtering at Room Temperature,” IEEE Electron Device Lett., vol. 31, no. 6, pp. 567–569, 2010.
[3] D.-K. K. and H.-S. J. and H. B. K. and Y.-R. K. and S.-W. K. and J.-H. Bae, “Enhanced electrical properties in solution-processed InGaZnO thin-film transistors by viable hydroxyl group transfer process,” Jpn. J. Appl. Phys., vol. 57, no. 5S, p. 05GC02, 2018.
[4] S. Aikawa, T. Nabatame, and K. Tsukagoshi, “Effects of dopants in InOx-based amorphous oxide semiconductors for thin-film transistor applications,” Appl. Phys. Lett., vol. 103, no. 17, p. 172105, Oct. 2013.
[5] P.-T. Liu, Y.-T. Chou, and L.-F. Teng, “Environment-dependent metastability of passivation-free indium zinc oxide thin film transistor after gate bias stress,” Appl. Phys. Lett., vol. 95, no. 23, p. 233504, Dec. 2009.
[6] S. Aikawa, P. Darmawan, K. Yanagisawa, T. Nabatame, Y. Abe, and K. Tsukagoshi, “Thin-film transistors fabricated by low-temperature process based on Ga- and Zn-free amorphous oxide semiconductor,” Appl. Phys. Lett., vol. 102, no. 10, 2013.
[7] H. Li, M. Qu, and Q. Zhang, “Influence of Tungsten Doping on the Performance of Indium–Zinc–Oxide Thin-Film Transistors,” IEEE Electron Device Lett., vol. 34, no. 10, pp. 1268–1270, 2013.
[8] T. Kizu et al., “Low-temperature processable amorphous In-W-O thin-film transistors with high mobility and stability,” Appl. Phys. Lett., vol. 104, no. 15, p. 152103, Apr. 2014.