The present invention relates to a TFT, a TFT array panel, and a method of manufacturing the TFT array panel. A method of manufacturing the TFT array panel includes the steps of forming a first electrode and a second electrode that are separated from each other on a substrate, forming a silicon layer including amorphous silicon and polycrystalline silicon on the substrate, forming a semiconductor by patterning the silicon layer, forming a gate insulating layer on the semiconductor, forming a third electrode that is opposite to the semiconductor on the gate insulating layer, forming a passivation layer on the third electrode, and forming a pixel electrode on the passivation layer. The TFT array panel has high mobility because the TFT include polycrystalline silicon at the channel region of the TFT.