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本文在微晶硅材料性能研究的基础上制备了微晶硅薄膜晶体管(TFT)。发现微晶硅的柱状生长模式会导致其结构和电学性能的不均匀性。由于材料的柱状生长模式使得其晶化百分比、晶粒尺寸和暗电导受到薄膜厚度的调制。平行于衬底和垂直于衬底方向的电导率随着材料沉积条件的变化呈现出不同的变化规律,后者始终保持在10-6s/cm~10-5s/cm量级。确定了用于TFT有源层的微晶硅薄膜沉积条件中的硅烷浓度应高于2%,晶化百分比应为40%~50%左右。制备的微晶硅TFT器件具有良好的稳定性,开态电流的衰退和阈值电压的漂移分别为25%和1V,进而还发现了一种新颖的自恢复现象。
In this paper, microcrystalline silicon thin film transistor (TFT) is prepared based on the research of microcrystalline silicon material properties. It is found that the columnar growth mode of microcrystalline silicon can lead to the non-uniformity of its structure and electrical properties. Due to the columnar growth mode of the material, the percentage of crystallization, the grain size and the dark conductance are modulated to the film thickness. The conductivity parallel to the substrate and perpendicular to the substrate shows different variation with the deposition conditions of the material, the latter is always in the order of 10-6s / cm ~ 10-5s / cm. It is determined that the concentration of silane in the deposition condition of the microcrystalline silicon thin film used for the TFT active layer should be higher than 2% and the crystallization percentage should be about 40% ~ 50%. The prepared microcrystalline silicon TFT device has good stability, the on-state current decay and the threshold voltage drift are 25% and 1V respectively, and then a novel self-recovery phenomenon is also found.