Organic thin film transistor including organic insulating layer and substrate including the same

1. An organic thin film transistor, comprising:

a gate electrode having a first thickness on a substrate, the first thickness being about equal to or more than 5000 Å;

an organic insulating layer on the gate electrode and the substrate, a portion of the organic insulating layer on the substrate having a second thickness about equal to or more than 9000 Å, and a portion of the organic insulating layer on the gate electrode having a third thickness of about 2000 Å to 5000 Å, a ratio of the first to third thicknesses being greater than about 1;

a semiconductor layer on the organic insulating layer; and

source and drain electrodes on the organic insulating layer and contacting both side portions of the semiconductor layer,

wherein a distance between inner sides of the source and drain electrodes is the same as a width of the gate electrode,

wherein the organic insulating layer comprises photo acrylic having a dielectric constant of 2.6 to 4.

2. The transistor according to claim 1 , wherein the source and drain electrodes are disposed on the semiconductor layer.

3. The transistor according to claim 1 , wherein the semiconductor layer is disposed on the source and drain electrodes.

4. The transistor according to claim 1 , wherein the organic insulating layer has a planar upper surface.

5. The transistor according to claim 1 , wherein the semiconductor layer comprises at least one of an organic low molecule semiconductive material or an organic high molecule semiconductive material.

6. The transistor according to claim 1 , wherein the gate electrode comprises at least one of gold (Au), silver (Ag), copper (Cu) or molybdenum (Mo).

7. The transistor according to claim 1 , wherein the substrate is a flexible substrate, and the flexible substrate is placed on a rigid substrate to prevent warping of the flexible substrate.

8. A substrate for a liquid crystal display device including an organic thin film transistor, comprising:

a gate electrode having a first thickness on a substrate, the first thickness being about equal to or more than 5000 Å;

an organic insulating layer on the gate electrode and the substrate, a portion of the organic insulating layer on the substrate having a second thickness about equal to or more than 9000 Å, and a portion of the organic insulating layer on the gate electrode having a third thickness of about 2000 Å to 5000 Å, a ratio of the first to third thicknesses being greater than about 1;

a semiconductor layer on the organic insulating layer;

source and drain electrodes on the organic insulating layer and contacting both side portions of the semiconductor layer;

a passivation layer on the source and drain electrodes, the passivation layer having a contact hole exposing the drain electrode; and

a pixel electrode on the passivation layer and contacting the drain electrode through the contact hole,

wherein a distance between inner sides of the source and drain electrodes is the same as a width of the gate electrode,

wherein the organic insulating layer comprises photo acrylic having a dielectric constant of 2.6 to 4.

9. The substrate according to claim 8 , wherein the semiconductor layer comprises at least one of an organic low molecule semiconductive material or an organic high molecule semiconductive material.

10. The substrate according to claim 8 , wherein the gate electrode comprises at least one of gold (Au), silver (Ag), copper (Cu) or molybdenum (Mo).

11. The substrate according to claim 8 , wherein the substrate is a flexible substrate, and the flexible substrate is placed on a rigid substrate to prevent warping of the flexible substrate.

12. An organic thin film transistor, comprising:

a gate electrode having a first thickness on a substrate, the first thickness being about equal to or more than 5000 Å;

an organic insulating layer on the gate electrode and the substrate, a portion of the organic insulating layer on the substrate having a second thickness about equal to or more than 9000 Å, and a portion of the organic insulating layer on the gate electrode having a third thickness of about 2000 Å to 5000 Å, a ratio of the first to third thicknesses being greater than about 1, the organic insulating layer comprising at least one of benzo-cyclo-butene (BCB) or photo acrylic;

a semiconductor layer on the organic insulating layer; and

source and drain electrodes on the organic insulating layer and contacting both side portions of the semiconductor layer,

wherein a distance between inner sides of the source and drain electrodes is the same as a width of the gate electrode,

wherein the organic insulating layer comprises photo acrylic having a dielectric constant of 2.6 to 4.

13. The transistor according to claim 12 , wherein a ratio of the second to third thicknesses is greater than about 1.8.

14. The transistor according to claim 12 , wherein the source and drain electrodes are disposed on the semiconductor layer.

15. The transistor according to claim 12 , wherein the semiconductor layer is disposed on the source and drain electrodes.

16. The transistor according to claim 12 , wherein the substrate is a flexible substrate, and the flexible substrate is placed on a rigid substrate to prevent warping of the flexible substrate.