Thin film transistor, manufacturing method thereof, array substrate and electronic device

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

forming an active layer pattern on a base substrate;

forming a gate insulating layer on the active layer pattern, the gate insulating layer comprising a first portion, a second portion, and a third portion, the third portion being on both sides of the first portion, the second portion being between the first portion and the third portion on at least one side, and a thickness of the second portion being greater than a thickness of the third portion;

forming a gate electrode located at a side of the gate insulating layer far from the base substrate; and

performing an ion doping process on the active layer pattern using the gate electrode as a mask under a same ion doping condition,

wherein orthographic projections of the first portion, the second portion, and the third portion on the base substrate coincide with an orthographic projection of the active layer pattern on the base substrate; an orthographic projection of the first portion coincides with an orthographic projection of the gate electrode on the base substrate;

wherein a slope angle of the second portion immediately adjacent to a side edge of the gate electrode is substantially equal to a slope angle of the side edge of the gate electrode.

2. The method according to claim 1 , wherein in the ion doping process, a part of the active layer pattern, an orthographic projection of which on the base substrate coincides with the third portion, is converted into a source region and a drain region, and a part of the active layer pattern, an orthographic projection of which on the base substrate coincides with the second portion, is converted into a lightly doped drain region.

3. The method according to claim 2 , wherein the source region, the drain region and the lightly doped drain region are formed simultaneously in the ion doping process.

4. The method according to claim 2 , wherein in the ion doping process, a part of the active layer pattern, an orthographic projection of which on the base substrate coincides with the first portion, forms a channel region.

5. The method according to claim 2 , wherein the forming the gate insulating layer and the gate electrode on the active layer pattern comprises:

forming a gate insulating layer film on the active layer pattern;

forming the gate electrode on the gate insulating film; and

using the gate electrode as a mask, etching the gate insulating film to form the gate insulating layer comprising the first portion, the second portion, and the third portion.

6. The method according to claim 5 , wherein the gate insulating film is etched using the gate electrode as the mask under a condition that a photoresist pattern for forming the gate electrode is retained on the gate electrode.

7. The method according to claim 2 , further comprising:

forming a source electrode which is electrically connected with the source region; and

forming a drain electrode opposite to the source electrode and electrically connected to the drain region.

8. The method according to claim 1 , wherein the forming the gate insulating layer on the active layer pattern comprises:

forming a gate insulating layer film on the active layer pattern; and

patterning the gate insulating layer film by a photolithography process to form the gate insulating layer comprising the first portion, the second portion, and the third portion.

9. The method according to claim 1 , wherein the second portion comprises a slope portion inclined from the first portion to the third portion.

10. The method according to claim 1 , wherein the second portion comprises a stepped portion extending from the first portion to the third portion.

11. The method according to claim 1 , wherein a thickness of the second portion is less than or equal to a thickness of the first portion.

12. A thin film transistor comprising:

a base substrate;

an active layer structure located on the base substrate;

a gate insulating layer on the active layer structure, the gate insulating layer comprising a first portion, a second portion, and a third portion, the third portion being on both sides of the first portion, the second portion being between the first portion and the third portion on at least one side, and a thickness of the second portion being greater than a thickness of the third portion; and

a gate electrode, wherein the gate electrode is located on a side of the gate insulating layer far from the base substrate, and an orthographic projection of the gate electrode coincides with an orthographic projection of the first portion on the base substrate,

wherein a slope angle of the second portion immediately adjacent to a side edge of the gate electrode is substantially equal to a slope angle of the side edge of the gate electrode.

13. The thin film transistor according to claim 12 , wherein orthographic projections of the first portion, the second portion, and the third portion on the base substrate coincide with an orthographic projection of the active layer structure on the base substrate.

14. The thin film transistor according to claim 12 , wherein the active layer structure comprises a source region, a drain region and a lightly doped drain region, an orthographic projection of the source region and the drain region on the base substrate coincides with an orthographic projection of the third portion on the base substrate, and an orthographic projection of the lightly doped drain region on the base substrate coincides with an orthographic projection of the second portion on the base substrate.

15. The thin film transistor according to claim 12 , wherein the active layer structure further comprises a channel region, and the channel region coincides with an orthographic projection of the gate electrode on the base substrate.

16. The thin film transistor according to claim 12 , wherein the second portion comprises a slope portion inclined from the first portion to the third portion, or the second portion comprises a stepped portion extending from the first portion to the third portion.

17. The thin film transistor according to claim 12 , wherein a thickness of the second portion is less than or equal to a thickness of the first portion.

18. An array substrate comprising the thin film transistor according to claim 12 .

19. An electronic device comprising the thin film transistor according to claim 12 .

20. A method of manufacturing a thin film transistor, comprising:

forming an active layer pattern on a base substrate;

forming a gate insulating layer on the active layer pattern, the gate insulating layer comprising a first portion, a second portion, and a third portion, the third portion being on both sides of the first portion, the second portion being between the first portion and the third portion on at least one side, and a thickness of the second portion being greater than a thickness of the third portion;

forming a gate electrode located at a side of the gate insulating layer far from the base substrate; and

performing an ion doping process on the active layer pattern using the gate electrode as a mask under a same ion doping condition,

wherein orthographic projections of the first portion, the second portion, and the third portion on the base substrate coincide with an orthographic projection of the active layer pattern on the base substrate; an orthographic projection of the first portion coincides with an orthographic projection of the gate electrode on the base substrate;

wherein the ion doping process is performed by controlling an ion implantation dose and an ion implantation depth so that a peak position of the ion implantation dose does not exceed a region of the active layer pattern overlapping the third portion,

wherein a slope angle of the second portion immediately adjacent to a side edge of the gate electrode is substantially equal to a slope angle of the side edge of the gate electrode.