本論文主在探討增強型下閘極氧化鋅透明薄膜電晶體元件特性，利用射頻共濺鍍系統濺鍍成長氧化鋅緩衝層與含微量鋁金屬氧化鋅通道層薄膜，並比較有無氧化鋅緩衝層之氧化鋅透明薄膜電晶體特性。在本研究中，以X-ray繞射儀分析發現所沉積之氧化鋅緩衝層薄膜/含微量鋁金屬之氧化鋅通道層薄膜具單相之六角纖鋅礦結構，並且比較有無沉積氧化鋅緩衝層薄膜對含微量鋁金屬之氧化鋅通道層薄膜的影響，發現通道層薄膜之晶粒大小分別從沒有沉積氧化鋅緩衝層時的19.4nm增加至有氧化鋅緩衝層時的21.7nm，由此薄膜量測結果表示在沉積含微量鋁金屬氧化鋅通道層前，先沉積氧化鋅緩衝層有助於改善通道層的結晶性及晶粒之大小。而在薄膜電晶體元件電特性研究發現，氧化鋅透明薄膜電晶體之場效載子移動率與電流開關比會因為增加氧化鋅緩衝層而得到改善，起因於增加氧化鋅緩衝層使得含微量鋁金屬之氧化鋅通道層結晶性改善進而提升元件特性。最大汲源極電流從沒有沉積氧化鋅緩衝層時的69.6μA增加至有緩衝層厚度為80nm時的284.8 μA，電流開關比(Ion/Ioff)達107以上，元件載子遷移率則從32.5增加至122.0 cm2/V-s。而次臨界斜率由0.39 V/decade下降至0.24 V/decade，態位密度由5.72×1011 eV-1cm-2下降至2.69×1011 eV-1cm-2。

Al-doped ZnO (ZnO:Al) transparent thin-film transistors (TTFTs) with and without ZnO buffer layer were fabricated by a magnetron RF co-sputtering system. The deposited ZnO buffer layer/ZnO:Al channel layer exhibited single-phase hexagonal wurtzite structure measured by X-ray diffraction. The grain size of ZnO:Al channel layer with and without ZnO buffer layer are 21.7 nm and 19.4 nm, respectively. It indicated that the ZnO buffer layer caused a better crystalline structure of the ZnO:Al channel layer. The electric properties, such as the field-effect carrier mobility, on-to-off current ratio of the fabricated ZnO based TTFTs with buffer layer, proved that the TTFTs with buffer layers have better performances, which can be attributed to the improvement of the crystalline structure of the ZnO:Al channel layer due to the insertion of the ZnO buffer layer. The maximum IDS of ZnO:Al channel layer without and with ZnO buffer layer 80 nm are 69.5 μA and 284.8 μA. The ZnO buffer layers caused the increase of effective field-effect carrier mobility of the TTFTs from 32.5 to 122.0 cm2/V-s. Furthermore, the subthreshold swing and the maximum density of states values of TTFTs decreased from 0.39 to 0.24 V/decade and 5.72×1011 to 2.69×1011 eV-1cm-2, respectively. The on-to-off current ratio of the TTFTs with the ZnO buffer layer is up to 107. It is concluded that the addition of buffer layers improves the performances of TTFTs.

Chapter 1
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Chapter 2
[2.1] 戴亞翔: TFT-LCD 面板的驅動與設計 (五南出版社, 新竹, 2008)。
[2.2] S. M. Sze: Physics of semiconductor device (New York: John Wiley & Sons, second, 1981).
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Chapter 3
[3.1] S. M. Sze: Physics of semiconductor device (New York: John Wiley & Sons, second, 1981).
[3.2] 戴亞翔: TFT-LCD 面板的驅動與設計 (五南出版社, 新竹, 2008)。
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Chapter 4
[4.1] C. T. Lee, W. M. Shien, H. Y. Lee and C. H. Chou: IEEE LEOS Annual Meeting Conference Proceeding, CA, USA, MG3, (2008) p. 65.
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