本論文利用磁控式共濺鍍系統，以三個靶材共濺鍍成長銦鎵鋅氧化物做為透明薄膜電晶體之通道層薄膜，並探討膜內原子組成比例最適宜做為薄膜電晶體之通道層。在本研究中利用磁控式三靶共濺鍍系統，以不同的氧化銦、氧化鎵以及鋅靶材的成長瓦數以及調整濺鍍環境的氣體流量比例，控制膜內的銦、鎵、鋅以及氧原子的比例。一般來說，在銦鋅氧化物(IZO)的薄膜內載子的傳輸是由銦的5s 軌域互相重疊所形成的，而且銦鋅氧化物很容易產生載子。但因為太好的導電性，使銦鋅氧化物不適合作為薄膜電晶體的通道層。混入鎵離子在銦鋅氧化物內，形成銦鎵鋅氧化物可以降低由氧缺位所形成的載子。在本研究中尋找銦鎵鋅氧化物的最佳的原子組成與成長環境，並藉著能量散佈分析儀分析薄膜內的組成比例與HP 4156C 量測薄膜電晶體的電性。本研究利用不同的成長條件找出最適合的銦鎵鋅氧化物薄膜電晶體，發現在成長時通入10 mtorr 的氬氣與氧氣，流量的比例為Ar/O2=55/45，氧化銦與氧化鎵的射頻瓦數分別為50 W 與25 W，鋅的直流瓦數為10 W。由以上的條件所製作元件的場效移動率、臨界電壓、開關比以及次臨界擺幅分別為63.8 cm2 /V-s、1.9V、1.9×107 以及 0.25 V/decade。

In this work, we reported the high performances of transparent thin-film transistors (TFTs) with indium gallium zinc oxide (IGZO) channel layer which was deposited using trinal In2O3, Ga2O3, and Zn targets in a magnetron co-sputtering system. Different respective target power and various sputtering gas flow ratios were controlled to deposit different composition of IGZO films. In general, the carrier transport path in IZO film was formed by In 5s orbital overlapping each other, and the carriers were produced easily from IZO film. Therefore, the IZO film was not suitable for the channel layer of TFTs due to its too high conductance. Incorporating Ga ions would be an important issue in IGZO films for suppressing carrier generation via oxygen vacancy formation. Therefore in this work, the optimal content and optimal deposition conditions of IGZO films was investigated by measuring the content using Energy-dispersive X-ray spectroscopy (EDS) and the performances of the resulting TFTs using HP 4156 C Semiconductor Parameter Analyzer. In our experimental results, we found the optimal deposition conditions for the IGZO channel layer. The co-sputtering was carried out at a gas flow ratio of Ar/O2=55/45, a chamber pressure of 10 mTorr, the input RF power of the In2O3 target and Ga2O3 target was, respectively, 50 W and 25W, and the input DC power of the Zn target was 10 W. The field-effect mobility(μFE), threshold voltage, on-off-ratio and subthreshold gate swing (S.S) of the IGZO TFTs were 63.8 cm2 /V-s, 1.9V, 1.9×107 and 0.25 V/decade, respectively. The mechanisms of the optimal IGZO transparent thin film transistors were investigated in this work.

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