Thin film transistor array substrate and organic light-emitting diode display employing the same

1. A thin film transistor (TFT) array substrate comprising at least one TFT, wherein the TFT comprises:

a substrate;

a semiconductor pattern comprising a source region, a channel region, and a drain region;

a gate insulating layer covering the semiconductor pattern;

a side gate electrode electrically insulated from the semiconductor pattern and formed over at least one side of the channel, region; and

a top gate electrode formed over the gate insulating layer so as to partially overlap the semiconductor pattern, wherein the side gate electrode and the top gate electrode are electrically connected to each other, and

wherein at least a portion of the side gate electrode is formed inside a via hole penetrating through the gate insulating layer.

2. The TFT array substrate of claim 1 , further comprising a first interlayer dielectric layer covering the top gate electrode, wherein at least a portion of the side gate electrode is formed inside a via hole penetrating through, the gate insulating layer and the first interlayer dielectric layer, and wherein the side gate electrode is connected to the top gate electrode through the via hole.

3. The TFT array substrate of claim 1 , further comprising a storage capacitor comprising.

a first electrode connected to the top gate electrode; and

a second electrode formed over an upper portion of the first electrode and electrically insulated from the first electrode.

4. The TFT array substrate of claim 3 , wherein the top gate electrode is integrally formed on the same layer as the first electrode.

5. The TFT array substrate of claim 1 , wherein the channel region is non-linear.

6. The TFT array substrate of claim 1 , further comprising:

a source electrode connected to the source region; and

a drain electrode connected to the drain region,

wherein the side gate electrode is formed of the same material as the source and drain electrodes.

7. A thin film transistor (TFT) array substrate comprising:

a substrate;

a semiconductor pattern comprising a source region, a channel region, and a drain region;

a gate insulating layer covering the semiconductor pattern;

a side gate electrode electrically insulated from the semiconductor pattern and, formed over at least one side of the semiconductor pattern;

a top gate electrode formed over the gate insulating layer so as to partially overlap the semiconductor pattern;

a first interlayer dielectric layer covering the top gate electrode;

a storage capacitor configured to use the top gate electrode as a first electrode, wherein the storage capacitor comprises a second electrode formed over the first interlayer dielectric layer and overlapping the first electrode; and

a second interlayer dielectric layer formed over the second electrode,

wherein at least a portion of the side gate electrode is formed inside a via hole penetrating through the gate insulating layer, the first interlayer dielectric layer, and the second interlayer dielectric layer.

8. The TFT array substrate of claim 7 , further comprising:

a source electrode formed over the second interlayer dielectric layer and connected to the source region through a first contact hole; and

a drain electrode formed over the second interlayer dielectric layer and connected to the drain region through a second contact hole,

wherein the first and second contact holes penetrate through the gate insulating layer and the first and second interlayer dielectric layers.

9. The TFT array substrate of claim 8 , wherein the source and drain electrodes are formed of the same material as the side gate electrode.

10. The TFT array substrate of claim 8 , further comprising:

a planarization layer at least partially covering the source and drain electrodes and comprising an opening which exposes a portion of the drain electrode; and

a pixel electrode formed over the planarization layer and connected to the drain electrode.

11. The TFT array substrate of claim 10 , wherein at least a portion of the side gate electrode is formed, inside a via hole penetrating through the gate insulating layer, the first and second interlayer dielectric layers, and the planarization layer.

12. The TFT array substrate of claim 10 , wherein the side gate electrode is formed of the same material as the pixel electrode.

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

the TFT array substrate of claim 1 ;

source and drain electrodes respectively connected to the source and drain regions; and

an OLED electrically connected to the source electrode or the drain electrode.

14. The display of claim 13 , wherein the OLED comprises a pixel electrode, an intermediate layer comprising an organic light-emitting layer, and an opposite electrode.

15. The display of claim 14 , wherein the side gate electrode is formed of the same material as the pixel electrode.

16. The display of claim 13 , wherein, the side gate electrode is formed of the same material as the source electrode or the drain electrode.

17. The display of claim 13 , further comprising a storage capacitor comprising a first electrode, a second electrode and an interlayer dielectric layer formed between the first electrode and the second electrode, wherein the top gate electrode is configured to be used as the first electrode, and wherein the second electrode overlaps the top gate electrode.

18. The display of claim 13 , wherein the side gate electrode is higher than the top gate electrode.

19. The display of claim 13 , wherein a bottom surface of the side gate electrode is closer to the surface than a bottom surface of the top gate electrode.

20. The TFT array substrate of claim 1 , wherein the semiconductor pattern and the side gate electrode are formed on the same layer.