Manufacturing methods of thin film transistor having an ohmic contact region and array substrate including the same

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

S 01 , forming an active layer on a base substrate;

S 02 , forming a gate insulation layer on the active layer;

S 03 , forming a gate metal layer on the gate insulation layer;

S 04 , forming a photoresist which is patterned and is completely located within a region where the active layer is located;

S 05 , over-etching the gate metal layer to form a gate, so that the photoresist is suspended at two ends thereof;

S 06 , performing ion implantation on the active layer, so that a region of the active layer not shielded by the photoresist and the gate becomes an ohmic contact region;

S 07 , removing a part of the gate and/or a part of the photoresist on the gate, so as to expose a portion of the active layer adjacent to the ohmic contact region;

S 08 , performing an ion implantation on the active layer so that the exposed portion of the active layer adjacent to the ohmic contact region becomes a lightly doped region, and a portion of the active layer shielded by the photoresist and/or the gate becomes a channel region;

S 09 , stripping off the photoresist;

S 10 , forming an interlayer insulation layer above the gate, and forming through holes in the interlayer insulation layer and the gate insulation layer by a patterning process above the ohmic contact region; and

S 11 , forming a source-drain metal layer above the interlayer insulation layer and in the through holes, and forming a source and a drain through a patterning process, wherein the source and the drain are electrically connected to the ohmic contact region through the through holes respectively,

wherein the step S 04 further comprises a step of:

forming the photoresist to include a completely preserved area and partially preserved areas located at two ends of the completely preserved area, and

the step S 05 further comprises steps of:

over-etching the gate metal layer to form a pre-gate-structure, so that the partially preserved area at one end of the completely preserved area is suspended, and the partially preserved area at the other end of the completely preserved area is partially suspended; and

removing the partially preserved area of the photoresist at the one end of the completely preserved area by an ashing process, so that a part of the pre-gate-structure covered by the partially preserved area of the photoresist which is at the one end of the completely preserved area partially suspended is exposed, and thinning the completely preserved area, and

wherein the ohmic contact region includes a source ohmic contact region and a drain ohmic contact region, and the step S 06 further comprises a step of:

performing ion implantation on the active layer, so that regions of the active layer not shielded by the photoresist and/or the pre-gate-structure become the source ohmic contact region and the drain ohmic contact region,

the step 07 further comprises a step of:

removing an exposed portion of the pre-gate-structure by etching to form the gate covered by the photoresist, so that a portion of the active layer adjacent to the drain ohmic contact region is exposed, and

the step S 08 further comprises a step of:

performing ion implantation on the active layer so that the exposed portion of the active layer adjacent to the drain ohmic contact region becomes the lightly doped region, and a portion of the active layer shielded by both the photoresist and the gate becomes the channel region.

2. The manufacturing method of a thin film transistor of claim 1 , wherein the step S 04 further comprises steps of:

forming a layer of the photoresist on the gate metal layer, shielding the photoresist using a gray scale mask plate and patterning the photoresist through an exposure and a development, so that the photoresist is completely located within the region where the active layer is located, a part of the photoresist corresponding to a complete transmission area of the gray scale mask plate is removed, a part of the photoresist corresponding to a semi-light-transmitting area of the gray scale mask plate is partially remained to form a partially preserved area at the one end of the completely preserved area, a part of the photoresist corresponding to a shielding area of the gray scale mask plate is completely remained to form the completely preserved area.

3. A manufacturing method of an array substrate, comprising providing a base substrate and forming pixels arranged in a matrix on the base substrate, each pixel is provided with a thin film transistor therein, wherein the manufacturing method of the array substrate further comprises forming the thin film transistor through the manufacturing method of a thin film transistor of claim 1 by using the base substrate as a base substrate for forming the thin film transistor.