Low temperature poly-silicon thin film transistor and fabrication method thereof, array substrate and display device

1. A fabrication method of a poly-silicon thin film transistor, comprising:

S 1 : sequentially forming an active layer, a gate insulation layer, a gate electrode and an interlayer insulation layer on a base substrate, and forming a via hole on source and drain regions of the active layer and in the gate insulation layer and the interlayer insulation layer;

S 2 : forming a first metal layer, the first metal layer and the active layer being in contact with each other at the source and drain regions through the via hole;

S 3 : performing a first heat treatment such that the first metal layer and the active layer react with each other in a contact region of the first metal layer and the active layer to generate a metal silicide, and then performing a hydrogenation treatment on the active layer and the gate insulation layer;

S 4 : forming a second metal layer, the second metal layer being configured for forming a source electrode and a drain electrode, wherein

during performing the hydrogenation treatment on the active layer and the gate insulation layer, the first metal layer is an outermost layer covering the base substrate.

2. The fabrication method of the poly-silicon thin film transistor according to claim 1 , wherein

the forming the active layer in step S 1 includes:

forming an amorphous silicon thin film on the base substrate;

performing a crystallization treatment on the amorphous silicon thin film to form a poly-silicon thin film; and

patterning the poly-silicon thin film to form the active layer.

3. The fabrication method of the poly-silicon thin film transistor according to claim 1 , wherein

after step S 3 and before step S 4 , the method further comprises: removing a portion of the first metal layer provided outside the contact region of the first metal layer and the active layer.

4. The fabrication method of the poly-silicon thin film transistor according to claim 3 , wherein

after removing the portion of the first metal layer provided outside the contact region of the first metal layer and the active layer, the method further comprises: performing a second heat treatment on the metal silicide.

5. The fabrication method of the poly-silicon thin film transistor according to claim 4 , wherein a temperature of the second heat treatment is higher than a temperature of the first heat treatment.

6. The fabrication method of the poly-silicon thin film transistor according to claim 1 , wherein the hydrogenation treatment is performed under a temperature of 250-500° C. for 0.5-3 hours.

7. The fabrication method of the poly-silicon thin film transistor according to claim 1 , wherein the first metal layer is made from one or more of tungsten, titanium, cobalt, and nickel.

8. A poly-silicon thin film transistor fabricated by the method according to claim 1 .

9. The poly-silicon thin film transistor according to claim 8 , wherein the source electrode and the drain electrode of the thin film transistor have a dual-layer structure, in which a first layer is formed by the first metal layer and a second layer is formed by the second metal layer.

10. The poly-silicon thin film transistor according to claim 9 , wherein the first layer is made from tungsten, titanium, cobalt, nickel or a combination thereof, and the second layer is made from TiAl, TiAlTi or a combination thereof.

11. The poly-silicon thin film transistor according to claim 9 , wherein the first layer is not made from TiAl, TiAlTi or a combination thereof.

12. The poly-silicon thin film transistor according to claim 8 , wherein an ohmic contact layer is formed between the source and drain electrodes and the active layer of the thin film transistor, the ohmic contact layer being of a silicide of the first metal layer.

13. An array substrate, comprising the poly-silicon thin film transistor according to claim 8 .

14. A display device, comprising the array substrate according to claim 13 .