Thin film transistor substrate and display using the same

1. A display comprising:

a first thin film transistor on a substrate, the first thin film transistor including a first semiconductor layer, a first gate electrode, a first source electrode and a first drain electrode;

a second thin film transistor on the substrate, the second thin film transistor including a second semiconductor layer, a second gate electrode, a second source electrode and a second drain electrode;

a first storage capacitor electrode at same layer with the first drain electrode on the substrate;

an oxide layer covering the first thin film transistor and the second thin film transistor, and exposing the first storage capacitor electrode;

a nitride layer disposed on the oxide layer and covering the first storage capacitor electrode;

a second storage capacitor electrode including a first metal layer and a second metal layer stacked on the first metal layer with same shape as the first metal layer, and overlapping with the first storage capacitor electrode on the nitride layer;

a planar layer covering the first thin film transistor, the second thin film transistor and the second storage capacitor electrode: and

a pixel electrode disposed on the planar layer,

wherein the first gate electrode overlaps with middle portions of the first semiconductor layer;

the first source electrode contacts a first side of the first semiconductor layer;

the first drain electrode contacts a second side of the first semiconductor layer;

the first drain electrode is exposed by a first pixel contact hole penetrating the nitride layer and the oxide layer; and

the first drain electrode contacts an auxiliary drain electrode disposed at same layer with the second metal layer of the second storage capacitor electrode via the first pixel contact hole; and

wherein the pixel electrode contacts the auxiliary drain electrode via a second pixel contact hole exposing the auxiliary drain electrode penetrating the planar layer.

2. The display according to claim 1 , wherein the auxiliary drain electrode includes:

the second metal layer; and

the first metal layer disposed under the second metal layer around the first pixel contact hole.

3. The display according to the claim 1 , wherein the second thin film transistor is a switching element for selecting a pixel, and

wherein the first thin film transistor is a driving element for supplying video data to the pixel selected by the second thin film transistor.

4. The display according to the claim 1 , wherein the oxide layer has thickness of 3,000 Å at least, and

wherein the nitride layer has thickness of 500 Å to 3,000 Å.

5. The display according to the claim 1 , wherein the first semiconductor layer includes a polycrystalline semiconductor material;

a gate insulating layer covers the first semiconductor layer;

the first gate electrode overlaps with the first semiconductor layer on the gate insulating layer;

the second gate electrode is disposed on the gate insulating layer;

an intermediate insulating layer covers the first gate electrode and the second gate electrode;

the second semiconductor layer includes an oxide semiconductor material and is disposed with the second gate electrode on the intermediate insulating layer;

the first source electrode and the first drain electrode are disposed on the intermediate insulating layer; and

the second source electrode and the second drain electrode are disposed on the second semiconductor layer;

the first thin film transistor includes the first semiconductor layer, the first gate electrode, the first source electrode and the first drain electrode; and

the second thin film transistor includes the second semiconductor layer, the second gate electrode, the second source electrode and the second drain electrode.

6. The display according to the claim 5 , wherein the intermediate insulating layer includes:

a nitride layer; and

an oxide layer on the nitride layer.