OXIDE THIN FILM TRANSISTOR AND METHOD OF FABRICATING THE SAME

• US 20140339537A1
• Filed: 09/13/2013
• Published: 11/20/2014
• Est. Priority Date: 05/14/2013
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: BAE, JongUk
• Granted Patent: US 9,941,410 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• CPC Class Codes: H01L 29/78636 with supplementary region or layer for improving the flatness of the device
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

The present disclosure relates to an oxide thin film transistor and a fabricating method thereof. In the oxide thin film transistor, which uses amorphous zinc oxide (ZnO) semiconductor as an active layer, damage to the oxide semiconductor due to dry etching may be minimized by forming source and drain electrodes in a multilayered structure having at least two layers, and improving stability and reliability of a device by employing a dual passivation layer structure, which includes a lower layer for overcoming a deficiency and an upper layer for minimizing external affection, on the multilayered source and drain electrodes.

Claims

1. A thin film transistor, comprising:

a gate electrode made of a first conductive film;

a gate insulating layer formed on the gate electrode;

an active layer formed on the gate insulating layer, the active layer made of an oxide semiconductor having zinc based oxide;

source and drain electrodes formed on the active layer;

a lower passivation layer formed on the source and drain electrodes and on the active layer disposed between the source and drain electrodes, the lower passivation layer made of an insulating layer including oxide; and

an upper passivation layer formed on the lower passivation layer, the upper passivation layer made of an insulating layer having higher density than the lower passivation layer.

2. The thin film transistor of claim 1, wherein the source and drain electrodes comprise first source and drain electrodes which are made of a second conductive film and are formed on the active layer, and second source and drain electrodes which are made of a third conductive film and are formed on the first source and drain electrodes.

3. The thin film transistor of claim 1, further comprising an in-situ protection layer formed by oxidizing the second conductive film, the protection layer is formed on the region other than the source and drain electrodes.

4. The thin film transistor of claim 1, wherein the first source and drain electrodes comprise at least one of Ti, Ti alloy, Mo and Mo alloy, the second source and drain electrodes comprise at least one of Cu, Ag and Mo.

5. The thin film transistor of any of claim 1, wherein the lower passivation layer comprise at least one of TiOx, TaOx, AlOx and SiOx.

6. A thin film transistor, comprising:

an active layer made of an oxide semiconductor having zinc based oxide;

source and drain electrodes formed on the active layer;

a gate insulating layer formed on the active layer disposed between the source and drain electrodes;

a gate electrode which is made of a first conductive film and is formed on the gate insulating layer;

a lower passivation layer formed on the source and drain electrodes and on the active layer disposed between the source and drain electrodes, the lower passivation layer made of an insulating layer including oxide; and

an upper passivation layer formed on the lower passivation layer, the upper passivation layer made of an insulating layer having higher density than the lower passivation layer.

7. The thin film transistor of claim 6, wherein the source and drain electrodes comprise first source and drain electrodes which are made of a second conductive film and are formed on the active layer, and second source and drain electrodes which are made of a third conductive film and are formed on the first source and drain electrodes.

8. The thin film transistor of claim 6, further comprising an in-situ protection layer formed by oxidizing the second conductive film, the protection layer is formed on the region other than the source and drain electrodes.

9. The thin film transistor of claim 6, wherein the first source and drain electrodes comprise at least one of Ti, Ti alloy, Mo and Mo alloy, the second source and drain electrodes comprise at least one of Cu, Ag and Mo.

10. The thin film transistor of any of claim 6, wherein the lower passivation layer comprise at least one of TiOx, TaOx, AlOx and SiOx.

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

forming a gate electrode made of a first conductive film;

forming a gate insulating layer on the gate electrode;

forming an active layer on the gate insulating layer, the active layer made of an oxide semiconductor having zinc based oxide;

forming source and drain electrodes on the active layer;

forming a lower passivation layer on the source and drain electrodes and on the active layer disposed between the source and drain electrodes, the lower passivation layer made of an insulating layer including oxide; and

forming an upper passivation layer on the lower passivation layer, the upper passivation layer made of an insulating layer having higher density than the lower passivation layer.

12. The method of claim 11, wherein the source and drain electrodes comprise first source and drain electrodes which are made of second conductive film and are formed on the active layer, and second source and drain electrodes which are made of third conductive film and are formed on the first source and drain electrodes.

13. The method of claim 11, further comprising step of forming an in-situ protection layer formed by oxidizing the second conductive film, the protection layer is formed on the region other than the source and drain electrodes.

14. The method of claim 11, wherein the first source and drain electrodes comprise at least one of Ti, Ti alloy, Mo and Mo alloy, the second source and drain electrodes comprise at least one of Cu, Ag and Mo.

15. The method of any of claim 11, wherein the lower passivation layer comprise at least one of TiOx, TaOx, AlOx and SiOx.

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

forming an active layer made of an oxide semiconductor having zinc based oxide;

forming a gate insulating layer on the active layer disposed between the source and drain electrodes;

forming a gate electrode made of a first conductive film on the gate insulating layer;

forming source and drain electrodes on the active layer;

forming a lower passivation layer on the source and drain electrodes and on the active layer disposed between the source and drain electrodes, the lower passivation layer made of an insulating layer including oxide; and

forming an upper passivation layer on the lower passivation layer, the upper passivation layer made of an insulating layer having higher density than the lower passivation layer.

17. The method of claim 16, wherein the source and drain electrodes comprise first source and drain electrodes which are made of second conductive film and are formed on the active layer, and second source and drain electrodes which are made of third conductive film and are formed on the first source and drain electrodes.

18. The method of claim 16, further comprising step of forming an in-situ protection layer formed by oxidizing the second conductive film, the protection layer is formed on the region other than the source and drain electrodes.

19. The method of claim 16, wherein the first source and drain electrodes comprise at least one of Ti, Ti alloy, Mo and Mo alloy, the second source and drain electrodes comprise at least one of Cu, Ag and Mo.

20. The method of any of claim 16, wherein the lower passivation layer comprise at least one of TiOx, TaOx, AlOx and SiOx.