Abstract
In the recently TFT-LCD fabrication demands, some problems exist while developing large-area AM-LCD with high resolution. As TFT-LCD becomes larger in size and higher in resolution, we can not neglect the influence brought by resistance and capacitor of gate. So that incomplete image comes up but it can be solved by making thicker and wider lines at a loss of aperture ratio. Therefore, applying copper with low resistivity property material be gate metal is a way to resolve RC delay (Resistance Capacitor Delay). And then copper has better resistance to electro-migration because its activation energy of electro-migration reaches about 0.97eV.But taking copper as gate material also encounters some problems: poor adhesion to glass substrates, etching method etc...The feasibility of using Cu/CuMg as a gate electrode and a source/drain metal for a-Si:H TFT has been investigated in this work. The issue of adhesion between the Cu film and glass substrates has been overcome by introducing the Cu/CuMg alloy. Furthermore, a wet etching process of Cu-based gate metal has been proposed by using the copper etchant in the conventional printed circuit boards (PCBs). The experimental result showed superior performance of a-Si:H TFT with desired electrode taper angle and minimal loss of critical dimension.In addition, for effectively reducing the off-state signal loss resulted from the a-Si:H TFTs photo leakage current, the a-Si:H TFTs with the use of ITO as source-drain metal have been fabricated for this study. A remarkable transformation in photo leakage current has been observed under the 3300cd/m2 CCFL backlight illumination. The source-drain barrier height engineering has been proposed for this study.