Array substrate for in-plane switching mode liquid crystal display device and method of fabricating the same

1. An array substrate for an in-plane switching mode liquid crystal display device, comprising:

a substrate;

a gate line on the substrate;

a common electrode in a pixel region on the substrate;

a gate insulating layer on the gate line and the common electrode;

a data line on the gate insulating layer crossing the gate line to define the pixel region;

a thin film transistor formed at a crossing of the gate line and data line;

a passivation layer on the thin film transistor and the data line;

a concave portion through the gate insulating layer and the passivation layer; and

a pixel electrode in the concave portion,

wherein a bottom surface of the pixel electrode in the concave portion is substantially parallel to a top surface of the substrate and contacts the gate insulating layer.

2. The array substrate according to claim 1 , wherein the pixel electrode includes one of indium-tin-oxide and indium-zinc-oxide.

3. The array substrate according to claim 1 , wherein at least one of the gate insulating layer and the passivation layer includes at least one of silicon nitride and silicon oxide.

4. The array substrate according to claim 1 , wherein the pixel electrode and the concave portion have first and second widths, respectively, along the gate line, and wherein the first width is substantially same as the second width.

5. The array substrate according to claim 1 , wherein the pixel electrode has substantially the same height as the common electrode.

6. The array substrate according to claim 1 , wherein the thin film transistor includes a gate electrode connected to the gate line, an active layer and an ohmic contact layer on the gate electrode, a source electrode connected to the data line, and a drain electrode connected to the pixel electrode.

7. The array substrate according to claim 6 , wherein the passivation layer includes a drain contact hole exposing a portion of the drain electrode.

8. A liquid crystal display device, comprising:

a color filter substrate;

an array substrate facing the color filter substrate, the array substrate including:

a substrate,

a gate line on the substrate,

a common electrode in a pixel region on the array substrate,

a gate insulating layer on the gate line and the common electrode,

a data line on the gate insulating layer crossing the gate line to define the pixel region,

a thin film transistor formed at a crossing of the gate line and data line,

a passivation layer on the thin film transistor and the data line,

a concave portion through the gate insulating layer and the passivation layer, and

a pixel electrode in the concave portion; and

a liquid crystal layer interposed between the color filter substrate and the array substrate,

wherein a bottom surface of the pixel electrode in the concave portion is substantially parallel to a top surface of the substrate and contacts the gate insulating layer.

9. The liquid crystal device according to claim 8 , wherein the pixel electrode includes one of indium-tin-oxide and indium-zinc-oxide.

10. The liquid crystal device according to claim 8 , wherein at least one of the gate insulating layer and the passivation layer includes at least one of silicon nitride and silicon oxide.

11. The liquid crystal device according to claim 8 , wherein the pixel electrode and the concave portion have first and second widths, respectively, along the gate line, and wherein the first width is substantially same as the second width.

12. The liquid crystal device according to claim 8 , wherein the pixel electrode has substantially the same height as the common electrode.

13. The liquid crystal device according to claim 8 , wherein the thin film transistor includes a gate electrode connected to the gate line, an active layer and an ohmic contact layer on the gate electrode, a source electrode connected to the data line, and a drain electrode connected to the pixel electrode.

14. The array substrate according to claim 13 , wherein the passivation layer includes a drain contact hole exposing a portion of the drain electrode.

15. A method of fabrication an array substrate for an in-plane switching mode liquid crystal display device, comprising:

forming a gate line on a substrate;

forming a common electrode in a pixel region on the substrate;

forming a gate insulating layer on the gate line and the common electrode;

forming a data line on the gate insulating layer crossing the gate line to define the pixel electrode;

forming a thin film transistor at a crossing of at a crossing of the gate line and the data line;

forming a passivation layer on the thin film transistor and the data line;

forming a concave portion through the passivation layer and the gate insulating layer; and

forming a pixel electrode in the concave portion,

wherein a bottom surface of the pixel electrode in the concave portion is substantially parallel to a top surface of the substrate and contacts the gate insulating layer.

16. The method according to claim 15 , wherein the pixel electrode includes one of indium-tin-oxide and indium-zinc-oxide.

17. The method according to claim 15 , wherein at least one of the gate insulating layer and the passivation layer includes at least one of silicon nitride and silicon oxide.

18. The method according to claim 15 , wherein the pixel electrode and the concave portion have first and second widths, respectively, along the gate line, and wherein the first width is substantially same as the second width.

19. The method according to claim 15 , wherein the pixel electrode has substantially the same height as the common electrode.

20. The method according to claim 15 , wherein the forming the thin film transistor includes a forming a gate electrode connected to the gate line, a forming an active layer and an ohmic contact layer on the gate electrode, a forming a source electrode connected to the data line, and a forming a drain electrode connected to the pixel electrode.

21. The method according to claim 20 , wherein the forming the concave portion exposes a portion of the drain electrode.