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近年来,微晶硅(μc-Si:H)被认为是一种制作TFT的有前景的材料。采用PECVD法,在低于200℃时制作了微晶硅TFTs ,其制作条件类似于非晶态TFTs。微晶硅TFTs器件的迁移率超过了30cm2/Vs ,而阈值电压是2.5V。在长沟道器件(50~200μm)中观测到了这种高迁移率。但对于短沟道器件(2μm) ,迁移率就降低到了7cm2/Vs。此外,该TFTs的阈值电压随着沟道长度的减少而增大。文章采用了一种简单模型解释了迁移率、阈值电压随着沟道长度的缩短而分别减少、增加的原因在于源漏接触电阻的影响。
In recent years, microcrystalline silicon (μc-Si: H) is considered as a promising material for TFT fabrication. PECVD method was used to fabricate microcrystalline silicon TFTs below 200 ° C. The fabrication conditions are similar to those of amorphous TFTs. The mobility of microcrystalline silicon TFTs exceeds 30cm2 / Vs and the threshold voltage is 2.5V. This high mobility was observed in long channel devices (50-200 μm). However, for short channel devices (2μm), the mobility is reduced to 7cm2 / Vs. In addition, the threshold voltage of the TFTs increases as the channel length decreases. In this paper, a simple model is used to explain the mobility. The threshold voltage decreases with the decrease of the channel length, respectively. The reason for the increase is due to the influence of the source-drain contact resistance.