由於液晶顯示器(Liquid Critical Display)的低消耗功率，薄化量輕，低電壓驅動等特性，已被廣泛使用於各種顯示用,例如行動電話、PDA、筆記型電腦等。非晶矽薄膜電晶體極(Amorphous Silicon Thin-Film Transistors) ，係應用於主動矩陣式液晶顯示器(Active Matrix LCD)之畫素開關。Amorphous silicon TFT的主動層材料時，有兩個重要目標：增加其載子遷移率(mobility)及降低其在背光源照射下的漏電流；增加載子遷移率(mobility)是為了用於大面積高解析度的面板，當解析度增加且TFT channel width or length 不變之情形下， Pixel Changing Time 變短，載子遷移率就必須增加，另外一方面因為非晶矽氫(Hydrogenated Amorphous Silicon)的光導電係數較高因此在光照射下會有較大的漏電流，當面板應用於須以強背光照射的產品時如多媒體顯示器、液晶電視時，因此降低光漏電流便成為一項重要的課題。在TFT導通時，電荷會經由TFT儲存於液晶電容及儲存電容中，在TFT關閉後利用上述兩個電容使液晶轉動，以60Hz為例，當每秒顯示60張畫面，因電容的電壓必須維持定值至少1/60秒，光漏電流過大會造成TFT在關閉時，電容中的電荷會由因有所流失，所提供的電壓就會減少，造成液晶旋轉的角度不足，所顯示的顏色不準確。鑑於此，本論文將探討非晶矽薄膜電晶體以不同製程參數實驗設計法完成系統性的參數設計研究方法，並量測在背光源照射下，所產生的光漏電流變化，以有效的取得最佳參數設計。由實驗結果得知，不同非晶矽製程參數對於本研究之問題有相當的影響，而後以實驗結果的最佳參數組合進行確認實驗，得到訊號雜音比(S/N ratio) 的預測值與實際值誤差為1.031% ，結果顯示所找出的最佳參數組合可以有效降低光漏電流問題及改善液晶顯示器的顯示效果。

Because of the liquid crystal display low consumption power, thin and slim take, such characteristics as the low-voltage is driven, have already been used extensively used as switching device for various active matrix liquid crystal displays (AM-LCDs), such as cell phones, personal digital assistants (PDAs) and laptop personal computers and so on. The a-Si TFT is particularly advantageous to the production of large screen displays and facilitates mass production. When applying an a-Si:H layer, the main objectives are to enhance the field effect mobility and to reduce the off-state photo leakage current under backlight illumination. The increase of field effect mobility results in wide application of a-Si:H TFTs in high resolution LCD. On the other hand, a-Si:H has high photoconductivity that results in high photo leakage current of a-Si:H TFT under light illumination. The off-state leakage current under backlight illumination is a serious problem, in particular the projection or multi-media displays that require high intensity backlight illumination. So, reduction of the photo leakage current for amorphous silicon is an important design consideration in achieving high image-quality LCD. When TFT is led openly, the electric charge will be stored in the electric capacity of the liquid crystal and stored in the electric capacity via pixel device, in TFT utilize above-mentioned two electric capacities make liquid crystal rotate after shutting off, takes 60Hz as an example, act as per second to show 60 pictures, because voltage of electric capacity must keep at least one second such as definite value. The excess photo leakage current by photo illumination of a-Si will cause the whirling angle of liquid crystal insufficient, the color shown or other display non-uniformity in the LCD will be inaccurate. In view of this, this paper probe making processing parameters design and research with experimental design law, and photo leakage current is examined under the circumstances that the backlight source with effective making the best parameter. From this experiment learning to make by experimental result, every processing parameter there is suitable influence. And then make up and confirm the experiment with the best parameter of the experimental result, get error for the predicted signal/noise value and the actual signal/noise value was 1.031%, this research result prove that photo leakage current issue could be reduced when the processing parameters were under optimal designed and improve the display performance of the liquid crystal display effectively.

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