Thin film transistor, organic light-emitting diode display including the same, and manufacturing method thereof

A thin film transistor (TFT), comprising:

• a substrate;
• a first gate electrode formed over the substrate;
• a first insulating layer formed over the substrate and the first gate electrode;
• a semiconductor layer formed over the first insulating layer, wherein the semiconductor layer at least partially overlaps the first gate electrode;
• a second insulating layer formed over the semiconductor layer wherein the first and second insulating layers have a pair of connection holes formed therethrough, the pair of connection holes including a first connection hole and a second connection hole that are formed on opposing sides of the semiconductor layer;
• a second gate electrode electrically connected to the first gate electrode via the connection holes, wherein the connection holes respectively expose portions of the first gate electrode;
• and
• a third insulating layer formed over the second gate electrode and the second insulating layer.

An organic light-emitting diode (OLED) display, comprising:

• a substrate;
• a thin film transistor (TFT) formed over the substrate;
• and
• an OLED connected to the TFT,
• wherein the TFT includes:
• a first gate electrode formed over the substrate;
• a first insulating layer formed over the substrate and the first gate electrode;
• a semiconductor layer formed over the first insulating layer, wherein the semiconductor layer at least partially overlaps the first gate electrode;
• a second insulating layer formed over the first insulating layer and the semiconductor layer, wherein the first and second insulating layers have a pair of connection holes formed therethrough, the pair of connection holes including a first connection hole and a second connection hole that are formed on opposing sides of the semiconductor layer;
• a second gate electrode electrically connected to the first gate electrode via the connection holes, wherein the connection holes respectively expose portions of the first gate electrode;
• a third insulating layer formed over the second gate electrode and the second insulating layer.

A manufacturing method of a thin film transistor (TFT), comprising:

• forming a first gate electrode over a substrate, wherein the first gate electrode has two ends;
• forming a first insulating layer over the first gate electrode;
• forming a semiconductor layer, having two ends, over the first insulating layer so as to at least partially overlap the first gate electrode, wherein the two ends of the first gate electrode include a first end and a second end that are on opposing sides of the semiconductor layer;
• forming a second insulating layer over the first insulating layer and the semiconductor layer, wherein the first and second insulating layers have a pair of connection holes formed therethrough, and wherein the connection holes respectively expose the first and second ends of the first gate electrode;
• forming a second gate electrode over the second insulating layer, wherein the second gate electrode is electrically connected to the first gate electrode via the connection holes;
• forming a third insulating layer over the second gate electrode and the second insulating layer.