METHOD OF FABRICATING POLYCRYSTALLINE SILICON FILM AND METHOD OF FABRICATING THIN FILM TRANSISTOR USING THE SAME

Abstract

Disclosed herein are methods of fabricating a polycrystalline silicon film and methods of fabricating a thin film transistor (TFT) using the same. The method of fabricating a polycrystalline silicon film includes forming an electrically insulating thermally conductive layer using a material selected from the group consisting of aluminum-containing ceramics, cobalt-containing ceramics, and iron-containing ceramics, on a substrate; forming an amorphous silicon layer on the thermally conductive layer; forming an amorphous silicon island by patterning the amorphous silicon layer; and crystallizing amorphous silicon by annealing the amorphous silicon island. A polycrystalline silicon film having a very large grain size and a TFT using the same can be formed in desired positions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the attached drawings, in which:

FIG. 1 schematically illustrates the heat distribution within a thermally conductive layer when a silicon (Si) island is crystallized, as well as a crystallization process based on the heat distribution, according to an exemplary embodiment of a method of fabricating a polycrystalline silicon film of the present invention;

FIG. 2 schematically illustrates a path of heat flow from a Si island, as well as crystallite nucleus generation and growth based on the path of heat flow according to an exemplary embodiment of the present invention;

FIG. 3 is a scanning electron microscope (SEM) image of a polycrystaine silicon film fabricated according to an exemplary embodiment of the present invention;

FIG. 4 is a SEM image of a polycrystalline silicon film fabricated using a conventional method of the prior art;

FIGS. 5A through 5F schematically illustrate an exemplary embodiment of a method of fabricating a polycrystalline silicon film according to the present invention;

FIGS. 6A and 6B are schematic cross-sectional views of a top gate thin film transistor (TFT) and a bottom gate TFT, respectively, fabricated according to an exemplary embodiment of the present invention; and

FIG. 7 is a flowchart illustrating an exemplary embodiment of a method of fabricating a polycrystalline silicon TFT according to the present invention.

Claims

1. A method of fabricating a polycrystalline silicon film, the method comprising: forming an electrically insulating thermally conductive layer using a material selected from the group consisting of aluminum-containing ceramics, cobalt-containing ceramics, and iron-containing ceramics, on a substrate, forming an amorphous silicon layer on the electrically insulating thermally conductive layer;forming an amorphous silicon island by patterning the amorphous silicon layer; andcrystallizing the amorphous silicon by annealing the amorphous silicon island.

2. The method of claim 1, wherein the aluminum-containing ceramics comprise Al2O3 or AlN.

3. The method of claim 1, wherein the cobalt-containing ceramics comprise CoO or Co3N4.

4. The method of claim 1, wherein the iron-containing ceramics comprise FeO, Fe2O3, Fe3O4, or Fe2N.

5. The method of claim 1, wherein annealing the amorphous silicon island comprises excimer laser annealing the amorphous silicon island.

6. The method of claim 2, wherein annealing the amorphous silicon island comprises excimer laser annealing the amorphous silicon island.

7. The method of claim 3, wherein annealing the amorphous silicon island comprises excimer laser annealing the amorphous silicon island.

8. The method of claim 4, wherein annealing the amorphous silicon island comprises excimer laser annealing the amorphous silicon island.

9. The method of claim 5, wherein an energy density during the annealing of the amorphous silicon island is greater than about 400 milliJoules per centimeter squared.

10. A method of fabricating a thin film transistor, wherein the thin film transistor includes a channel region, a polycrystalline silicon active layer having a source and drain at the ends of the channel region, a gate disposed to correspond to the channel, and a gate insulating layer disposed between the channel region and the gate, the method comprising: forming an electrically insulating thermally conductive layer on a substrate;forming an amorphous silicon layer on the thermally conductive layer;forming an amorphous silicon island having a shape corresponding to the active layer by patterning the amorphous silicon layer; andforming the active layer by annealing the amorphous silicon island.

11. The method of claim 10, wherein the thermally conductive layer is formed of a material selected from the group consisting of aluminum-containing ceramics, cobalt-containing ceramics, and iron-containing ceramics.

12. The method of claim 11, wherein the aluminum-containing ceramics comprise Al2O3 or AlN.

13. The method of claim 11, wherein the cobalt-containing ceramics comprise CoO or Co3N4.

14. The method of claim 11, wherein the iron-containing ceramics comprise FeO, Fe2O3, Fe3O4, or Fe2N.

15. The method of claim 10, wherein annealing the amorphous silicon island comprises excimer laser annealing the amorphous silicon island.

16. The method of claim 11, wherein annealing the amorphous silicon island comprises excimer laser annealing (ELA) the amorphous silicon island.

17. The method of claim 12, wherein annealing the amorphous silicon island comprises excimer laser annealing (ELA) the amorphous silicon island.

18. The method of claim 13, wherein annealing the amorphous silicon island comprises excimer laser annealing (ELA) the amorphous silicon island.

19. The method of claim 14, wherein annealing the amorphous silicon island comprises excimer laser annealing (ELA) the amorphous silicon island.

20. The method of claim 15, wherein an energy density during the annealing of the amorphous silicon island is greater than about 400 milliJoules per centimeter squared.