Fabrication method of a liquid crystal display device using small molecule organic semiconductor material
View Patent ↗A liquid crystal display structure is provided. The liquid crystal display structure includes a pixel region and a thin film transistor on the substrate. The thin film transistor is adjacent to the pixel region and includes a gate electrode; a gate insulating layer having a top surface; a source electrode and a drain electrode at the top surface of the gate insulating layer; a semiconductor layer disposed at the top surface of the gate insulating layer, the semiconductor layer between the source electrode and the drain electrode defining a channel region, the semiconductor layer including a small molecule organic semiconductor material; and a first passivation layer covering the channel region, a top surface of the first passivation layer coinciding with or being below a top surface of each of the source electrode and the drain electrode.
1. A method of fabricating a liquid crystal display structure, comprising the steps of:
forming a gate electrode on a substrate;
forming a gate insulating layer;
forming a metal layer on the gate insulating layer and a photoresist pattern on the metal layer;
forming a source electrode, a drain electrode, and a channel region between the source electrode and the drain electrode above the gate insulating layer by etching the metal layer corresponding to an open portion of the photoresist pattern;
forming a semiconductor layer by evaporating a small molecule organic semiconductor material on the gate insulating layer including a pixel region and the photoresist pattern;
forming a first passivation layer covering the semiconductor layer; and
removing the semiconductor layer and the first passivation layer overlapping the photoresist pattern with the photoresist pattern.
2. The method of claim 1 , wherein the step of forming the gate insulating layer includes forming the gate insulating layer having a level top surface.
3. The method of claim 2 , wherein the steps of forming the semiconductor layer and the first passivation layer include forming the semiconductor layer and the first passivation layer so that a sum of a thickness of the semiconductor layer and a thickness of the first passivation layer is equal to or smaller than a thickness of the source electrode and the drain electrode.
4. The method of claim 1 , further comprising:
forming a second passivation layer above the first passivation layer; and
directly contacting the second passivation layer to the top surface of each of the source electrode and the drain electrode.
5. The method of claim 1 , wherein the step of forming the gate insulating layer includes forming the gate insulating layer in a pixel region.
6. The method of claim 5 , wherein the step of forming the semiconductor layer includes:
evaporating the small molecule organic semiconductor material in the pixel region; and
directly contacting the small molecule organic semiconductor material in the pixel region to a top surface of the gate insulating layer in the pixel region.
7. A method of fabricating a liquid crystal display structure, comprising the steps of:
forming a gate electrode on a substrate;
forming a gate insulating layer;
forming a metal layer on the gate insulating layer and a photoresist pattern on the metal layer;
forming a source electrode, a drain electrode, and a channel region between the source electrode and the drain electrode above the gate insulating layer by etching the metal layer corresponding to an open portion of the photoresist pattern;
forming a semiconductor layer by evaporating a small molecule organic semiconductor material in the channel region after applying a shadow mask having an opening corresponding to the channel region, the source electrode and the drain electrode;
forming a first passivation layer covering the semiconductor layer; and
removing the semiconductor layer and the first passivation layer overlapping the photoresist pattern with the photoresist pattern.
8. The method of claim 7 , wherein the step of forming the gate insulating layer includes forming the gate insulating layer in a pixel region.
9. The method of claim 8 , further comprising:
forming the first passivation layer in the pixel region; and
directly contacting the first passivation layer in the pixel region to a top surface of the gate insulating layer in the pixel region.
10. The method of claim 1 , wherein the step of forming the gate electrode includes forming the gate electrode on a plastic substrate.
11. The method of claim 10 , wherein each of said forming steps is performed under a temperature of less than about 200 degrees Celsius.
12. The method of claim 1 , wherein a top surface of the first passivation layer coincide with or is below a top surface of each of the source electrode and the drain electrode.