Abstract: The present invention relates to a thin film transistor, a method thereof and an organic light emitting device including the thin film transistor. According to an embodiment of the present invention, the thin film transistor includes a substrate, a control electrode, an insulating layer, a first electrode and a second electrode, a first ohmic contact layer and a second ohmic contact layer, and a semiconductor layer. The control electrode is formed on the substrate, and the insulating layer is formed on the control electrode. The first and the second electrodes are formed on the insulating layer. The first ohmic contact layer and the second ohmic contact layer are formed on the first electrode and the second electrode. The semiconductor layer is formed on the first ohmic contact layer and the second ohmic contact layer to fill between the first and the second electrodes.

Abstract: A thin film transistor array substrate is provided. The substrate includes an insulating substrate, a first signal line formed on the insulating substrate, a first insulating layer formed on the first signal line, a second signal line formed on the first insulating layer while crossing over the first signal line, a thin film transistor connected to the first and the second signal lines, a second insulating layer formed on the thin film transistor, the second insulating layer having dielectric constant about 4.0 or less, and the second insulating layer having a first contact hole exposing a predetermined electrode of the thin film transistor, and a first pixel electrode formed on the second insulating layer while being connected to the predetermined electrode of the thin film transistor through the first contact hole.