A method for fabricating a thin film transistor (TFT) on a substrate
includes forming a gate electrode; forming a semiconductor layer being
insulated from the gate electrode and partially overlapped with the gate
electrode; sequentially forming first and second gate insulating layers
between the gate electrode and the semiconductor layer, wherein the first
gate insulating layer is formed of a material different from the second
gate insulating layer and at least one of the first and second gate
insulating layers includes a sol-compound; and forming source and drain
electrodes at both sides of the semiconductor layer.