Thin film transistor and method for preparing the same

1. A method of manufacturing a thin film transistor, the method comprising the steps of:

A) forming a gate electrode on a substrate;

B) forming an insulating layer on the substrate and the gate electrode;

C) forming a semiconductor layer on the insulating layer by using a zinc oxide material that comprises Si as a channel material;

C1) performing a nitrogen doping treatment on the semiconductor layer by using a plasma nitrification process;

C2) performing an oxygen heat treatment to the semiconductor layer that is subjected to the nitrogen doping treatment; and

D) forming a source electrode and a drain electrode so as to be connected to the semiconductor layer.

2. The method of manufacturing a thin film transistor according to claim 1 , wherein in the forming of the semiconductor layer of step C), the zinc oxide material comprising Si is a material comprising ZnO, ZnO:Al, ZnO:Ga, ZnO:In, or a complex oxide thereof and Si in an amount of more than 0 to 30 mol % or less.

3. The method of manufacturing a thin film transistor according to claim 2 , wherein in the forming of the semiconductor layer of step C), the zinc oxide material comprising Si is a material comprising ZnO, ZnO:Al, ZnO:Ga, ZnO:In, or a complex oxide thereof and Si in an amount of more than 0 to 30 mol % or less.

4. The method of manufacturing a thin film transistor according to claim 2 , wherein in the forming of the semiconductor layer of step C), the zinc oxide material comprising Si is ZnO—In 2 O 3 —SiO 2 .

5. The method of manufacturing a thin film transistor according to claim 4 , wherein content of Si is more than 0 to 30 mole % or less, content of Zn is more than 0 to 66 mole % or less, and content of In is more than 0 to 33 mole % or less in ZnO—In 2 O 3 —SiO 2 .

6. The method of manufacturing a thin film transistor according to claim 4 , wherein a mole % ratio of Zn:In:Si of ZnO—In 2 O 3 —SiO 2 is 1:1:1.

7. The method of manufacturing a thin film transistor according to claim 2 , wherein in the forming of the semiconductor layer of step C), the channel material is a zinc oxide material comprising Si used alone or a material containing the zinc oxide material comprising Si and a Group 1 or 5 material of the periodic table.

8. The method of manufacturing a thin film transistor according to claim 1 , wherein in the forming of the semiconductor layer of step C), the zinc oxide material comprising Si is ZnO—In 2 O 3 —SiO 2 .

9. The method of manufacturing a thin film transistor according to claim 8 , wherein content of Si is more than 0 to 30 mole % or less, content of Zn is more than 0 to 66 mole % or less, and content of In is more than 0 to 33 mole % or less in ZnO—In 2 O 3 —SiO 2 .

10. The method of manufacturing a thin film transistor according to claim 8 , wherein a mole % ratio of Zn:In:Si of ZnO—In 2 O 3 —SiO 2 is 1:1:1.

11. The method of manufacturing a thin film transistor according to claim 1 , wherein in the forming of the semiconductor layer of step C), the channel material is a zinc oxide material comprising Si used alone or a material containing the zinc oxide material comprising Si and a Group 1 or 5 material of the periodic table.

12. The method of manufacturing a thin film transistor according to claim 1 , wherein the plasma nitrification process of step C1) uses one or more selected from NH 3 , N 2 O, N 2 , NO, and NF 3 .

13. The method of manufacturing a thin film transistor according to claim 1 , wherein the plasma nitrification process of step C1 is performed at a temperature of 200 to 500° C. for 60 min or less.

14. The method of manufacturing a thin film transistor according to claim 1 , wherein the plasma nitrification process of step C1 is an ICP (Inductively Coupled Plasma) type of plasma nitrification process.

15. The method of manufacturing a thin film transistor according to claim 1 , wherein in step C2, a rapid thermal annealing method is performed under an oxygen atmosphere at a temperature of 200 to 500° C. for 1 hour or less as the oxygen heat treatment.