Thin-film transistor substrate, method of manufacturing the same, and display device including the same
Provided are a thin-film transistor (TFT) substrate, a method of manufacturing the same, and a display device including the same. The TFT substrate includes a gate electrode formed on a substrate, a gate insulating layer formed on the gate electrode, an oxide semiconductor pattern formed on the gate insulating layer, a source electrode formed on the oxide semiconductor pattern, a drain electrode formed on the oxide semiconductor pattern to face the source electrode, and a pixel electrode formed on the gate insulating layer.
1. A method of manufacturing a TFT substrate, the method comprising:
forming a gate electrode on a substrate;
forming a gate insulating layer on the gate electrode;
forming an oxide semiconductor layer pattern on the gate insulating layer;
forming an oxide semiconductor pattern and a pixel electrode pattern from the oxide semiconductor layer pattern;
forming semiconductor protective film patterns over the oxide semiconductor pattern;
forming a source electrode and a drain electrode on the semiconductor protective film patterns such that the semiconductor protective film patterns separate the oxide semiconductor pattern from the source and drain electrodes, wherein the drain electrode faces the source electrode; and
performing a plasma-treatment process on the pixel electrode pattern causing the material of the pixel electrode pattern to change from semiconductive to conductive to form a pixel electrode,
wherein the oxide semiconductor pattern is formed using a photosensitive film pattern as an etch mask and the source electrode and the drain electrode are formed using the same photosensitive film pattern used to form the oxide semiconductor pattern as an etch mask.
2. The method of claim 1 , wherein the pixel electrode is formed extending from the oxide semiconductor pattern.
3. The method of claim 1 , wherein the forming of the oxide semiconductor pattern and the forming of the source and drain electrodes comprise:
forming an oxide semiconductor layer on the gate insulating layer;
forming a conductive layer on the oxide semiconductor layer;
forming a first photosensitive film pattern on the conductive layer; and
forming the oxide semiconductor pattern and the pixel electrode pattern by etching the oxide semiconductor layer using the first photosensitive film pattern and forming a conductive layer pattern by etching the conductive layer,
wherein the first photosensitive film pattern comprises a first region and a second region which is thinner than the first region.
4. The method of claim 3 , wherein the first photosensitive film pattern is formed using a halftone mask or a slit mask.
5. The method of claim 3 , wherein a side of the oxide semiconductor pattern shares an etched surface with the source electrode.
6. The method of claim 3 , wherein the pixel electrode pattern extends from the oxide semiconductor pattern.
7. The method of claim 6 , further comprising, before the forming of the pixel electrode, forming a passivation film covering the source electrode and the drain electrode and exposing the pixel electrode pattern.
8. The method of claim 1 , wherein the plasma-treatment process is performed using a hydrogen-containing gas.
9. The method of claim 1 , wherein the plasma-treatment process is performed using a high-frequency RF power of approximately 100 to 400 mW/cm 2 -time.
10. The method of claim 1 , further comprising forming one or more oxide semiconductor protection film patterns between the oxide semiconductor pattern and the source and drain electrodes.
11. The method of claim 10 , further comprising forming a contact region by performing a plasma-treatment process on the one or more oxide semiconductor protection film patterns using a hydrogen-containing gas.
12. The method of claim 11 , wherein the contact region of the one or more oxide semiconductor protection film patterns electrically connects the pixel electrode and the drain electrode.