Method of fabricating a thin film transistor with multiple gates using metal induced lateral crystallization
View Patent ↗A thin film transistor with multiple gates using an MILC process which is capable of materializing multiple gates without increasing dimensions and a method thereof. The thin film transistor has a semiconductor layer which is formed on a insulating substrate in a zigzag shape; and a gate electrode which is equipped with one or more slots intersecting with the semiconductor layer, the semiconductor layer includes two or more body parts intersecting with the gate electrode; and one or more connection parts connecting each neighboring body part, wherein a part overlapping the semiconductor layer in the gate electrode acts as a multiple gate, and MILC surfaces are formed at a part which does not intersect with the gate electrode in the semiconductor layer.
1. A method of fabricating a thin film transistor with multiple gates using an MILC process, the method comprising:
forming an amorphous silicon film on an insulating substrate, the amorphous silicon film having at least one area formed in a rectangular shape having one side open;
forming a gate electrode to intersect with at least two different areas of the amorphous silicon film;
forming an interlayer insulating film over the insulating substrate, the interlayer insulating film having contact holes exposing portions of the amorphous silicon film;
forming a metal layer contacting the exposed portions of the amorphous silicon film through the contact holes;
forming a semiconductor layer comprising a polycrystalline silicon film by crystallizing the amorphous silicon film using the MILC process; and
forming source/drain electrodes contacting the semiconductor layer through the contact holes.
2. The method according to claim 1 , wherein the source/drain electrodes are formed by patterning deposited source/drain electrode materials after removing the metal layer and depositing the source/drain electrode materials.
3. The method according to claim 1 , wherein the source/drain electrodes are formed in a second layered structure by sequentially patterning source/drain electrode materials and metal layer after depositing the source/drain electrode materials on the metal layer.
4. The method according to claim 1 , wherein the metal layer forms a metal silicide on the front surface of the silicon film at a thickness of several hundreds of angstroms.
5. The method according to claim 1 , wherein the rectangular shape has at least one cutout portion extending into the rectangular shape from the one side of the rectangular shape that is open.
6. The method according to claim 5 , wherein each of the least one cutout portion is a rectangular cutout portion.
7. The method according to claim 5 , wherein the at least one cutout portion separates the at least two different areas of the amorphous silicon film from one another.
8. The method according to claim 5 , wherein the gate electrode intersects with the at least one cutout portion.
9. The method according to claim 1 , wherein the forming of a semiconductor layer comprising a polycrystalline silicon film is performed after the forming of a gate electrode.
10. The method according to claim 1 , wherein the forming of a semiconductor layer comprising a polycrystalline film comprises using the metal layer contacting the exposed portions of the amorphous silicon film through the contact holes in the MILC process to crystallize the amorphous silicon film and form the polycrystalline silicon film.
11. A method of fabricating a thin film transistor with multiple gates using an MILC process, the method comprising:
forming an amorphous silicon film on an insulating substrate;
patterning the amorphous silicon film to form a rectangular amorphous silicon area having at least one cutout portion extending into the rectangular amorphous silicon area from one side of the rectangular amorphous silicon area;
forming a gate insulating film on the rectangular amorphous silicon area;
forming a gate electrode on the gate insulating film so that the gate electrode opposes at least two portions of the rectangular amorphous silicon area separated from one another by the at least one cutout portion;
forming an interlayer insulating film on the gate insulating film and the gate electrode;
forming contact holes through the interlayer insulating film and the gate insulating film to expose portions of the rectangular amorphous silicon area;
forming a metal layer contacting the exposed portions of the rectangular amorphous silicon area through the contact holes;
crystallizing at least a portion of the rectangular amorphous silicon area using the metal layer contacting the exposed portions of the rectangular amorphous silicon area through the contact holes in the MILC process to form a polycrystalline silicon area extending away from the contact holes; and
forming source and drain electrodes contacting the polycrystalline silicon area through the contact holes.
12. The method according to claim 11 , wherein the crystallizing of at least a portion of the rectangular amorphous silicon area is performed after the forming of a gate electrode.