Study on Photo Leakage Current of Low Temperature poly Silicon Thin Film Transistors
|關鍵字:||低溫;多晶矽;薄膜電晶體;光;漏電流;Low Temperature;poly silicon;Thin Film Trsnsistor;Photo;Leakage Current|
The market for liquid crystal displays has been rapidly expanding in recent years. The demand for a high luminance and a high contrast ratio in liquid crystal displays (LCDs), such as small-medium LCDs for projection device, mobile displays and displays for cars, is continuing to grow and seems insatiable. However, high luminance would increase photo leakage current (PLC) in the TFTs, which diminishes the voltages that are held across the pixel electrodes, which in turn, would cause a low contrast ratio Consequently, it is necessary to suppress the PLC in LCDs with high luminosity. There are three schemes to suppress the PLC. First scheme is to vary the center of generated / recombined between the buffer layer and poly-Si active layer so that the electron-hole pairs which were excited by back light. Second one is using the light-absorption structure sot that less light can reach the active layers of TFTs. The last one is using light-shielding structure, here we employ the opaque material to shield the light, it is the most effective to cut-off the light from the light source. Unfortunately, this method still has some side effect that we will have detail discuss later. In this thesis, we focus upon those methods and have examined how the PLC changes depending upon structural parameters of TFTs and pursuit a desirable device structures of the TFTs. This work has been done for the TFTs with low-temperature poly-Si (LTPS). In this article, we present the experimental results of how to the PLC changes depending on the different structure parameters of the TFTs, such as shielding and absorbing materials under the active poly-Si layer. Then, we have some discussion of the results and conclusion.
|Appears in Collections:||Thesis|