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EP-4739028-A1 - THIN FILM TRANSISTOR, METHOD FOR MANUFACTURING THE SAME, AND DISPLAY APPARATUS COMPRISING THE SAME

EP4739028A1EP 4739028 A1EP4739028 A1EP 4739028A1EP-4739028-A1

Abstract

The present disclosure provides a thin film transistor comprising a gate electrode, an active layer, a source electrode, and a drain electrode, wherein the active layer includes a first channel part overlapping the source electrode, a second channel part overlapping the drain electrode, and a connection part connecting the first channel part and the second channel part, and the connection part is a conductorized region. Additionally, a manufacturing method of the thin film transistor and a display apparatus including the thin film transistor mentioned above are disclosed.

Inventors

  • CHOI, Sungju
  • KO, YOUNGHYUN
  • JANG, JAEMAN
  • RYU, JIHEE

Assignees

  • LG Display Co., Ltd.

Dates

Publication Date
20260506
Application Date
20250807

Claims (15)

  1. A thin film transistor comprising: a gate electrode (150); an active layer (130) at least partially overlapping the gate electrode (150); a source electrode (161) on the active layer (130); and a drain electrode (162), wherein the active layer (130) includes: a first channel part (CN1, CN) between the source electrode (161) and the gate electrode (150); and a connection part (130c, 130d) connected to the first channel part (CN1, CN) and/or exposed by the source electrode (161), wherein the connection part (130c, 130d) is a conductorized region.
  2. The thin film transistor of claim 1, wherein the drain electrode (162) is provided on the active layer (130), the active layer (130) includes a second channel part (CN2) between the drain electrode and the gate electrode and the connection part (130c) is connecting the first channel part (CN1) and the second channel part (CN2).
  3. The thin film transistor of claim 1 or 2, wherein the connection part (130c, 130d) is doped with a dopant and a dopant concentration of the connection part (130c, 130d) is higher than a dopant concentration of the first channel part (CN1, CN) and/or a dopant concentration of the second channel part (CN2).
  4. The thin film transistor according to any one of the preceding claims, wherein the active layer (130c) further includes: a first contact part (130a) contacting the source electrode (161), the first channel part (CN1, CN) being between the connection part (130c) and the first contact part (130a), and/or a second contact part (130b) contacting the drain electrode (162), the second channel part (CN2) being between the connection part (130c) and the second contact part (130b).
  5. The thin film transistor according to any one of the preceding claims, wherein the connection part (130c, 130d) overlaps the gate electrode (150); and/or wherein at least a portion of the connection part (130c, 130d) is exposed by the gate electrode (150).
  6. The thin film transistor according to any one of the preceding claims in combination with claim 2, wherein the gate electrode (150) comprises: a first gate electrode (151) overlapping the first channel part (CN1) and the source electrode (161); and a second gate electrode (152) overlapping the second channel part (CN2) and the drain electrode (162), wherein at least a portion of the connection part (130c) is exposed by the gate electrode (150).
  7. The thin film transistor according to any one of the preceding claims, further comprising: an interlayer insulating layer (170) on the active layer (130), wherein the source electrode (161) and/or the drain electrode (162) are disposed on the interlayer insulating layer (170) and connected to the active layer (130) through a contact hole (CH1, CH2) in the interlayer insulating layer (170).
  8. The thin film transistor of claim 7, wherein the interlayer insulating layer (170) is on the connection part (130c), or wherein at least a portion of the connection part (130c) is exposed by the interlayer insulating layer (170).
  9. The thin film transistor according to any one of the preceding claims, further comprising: a capping layer (145) in contact with the connection part (130c), the capping layer (145) having reducing property.
  10. The thin film transistor of claim 9, wherein the capping layer (145) includes at least one of titanium, molybdenum, aluminum, indium, and zinc.
  11. The thin film transistor according to claim 1, further comprising: a gate insulating layer (140) covering the gate electrode (150), the gate insulating layer (140) being disposed between the gate electrode (150) and the active layer (130), wherein a first end of the connection part (130d) that is connected to the first channel part (CN) has a first height that is higher than a second end of the connection part (130d) opposite thereto.
  12. The display apparatus according to any one of the preceding claims, wherein the active layer (130) comprises an oxide semiconductor layer.
  13. A display apparatus comprising: a substrate (110); a thin film transistor according to any one of the preceding claims; and a light-emitting element (710) configured to emit light, the light-emitting element (170) being connected to one of the source electrode (161) or the drain electrode (162) of the thin film transistor, wherein the connection part (130c, 130d) of the active layer (130) is exposed by at least one of the source electrode (161) and the drain electrode (162).
  14. A manufacturing method of a thin film transistor comprising: forming a gate electrode (150) on a substrate (110); forming an active layer (130) on the gate electrode (150), the active layer (130) at least partially overlapping the gate electrode (150); forming a source electrode (161) on the active layer (130), and selectively conductorizing a region of the active layer (130) using the source electrode (161)as mask.
  15. The manufacturing method of claim 13, wherein a region of the active layer (130) that is overlapping the source electrode (161) is not conductorized during the selective conductorizing and is a first channel part (CN, CN1) connected to the conductorized region; and/or wherein selectively conductorizing a region of the active layer (130) comprises a dopant doping of the active layer (130).

Description

This application claims the benefit of priority of the Republic of Korea Patent Application No. 10-2024-0153511 filed on November 1, 2024. BACKGROUND Field of Technology The present disclosure relates to a thin film transistor, a method for manufacturing the same, and a display apparatus including the thin film transistor. Discussion of the Related Art Since thin film transistors may be manufactured on glass or plastic substrates, they are widely used as switching elements or driving elements in display apparatuses such as liquid crystal display apparatuses or organic light emitting devices. Thin film transistors may be classified into amorphous silicon thin film transistors in which amorphous silicon is used as the active layer, polycrystalline silicon thin film transistors in which polycrystalline silicon is used as the active layer, and oxide semiconductor thin film transistors in which oxide semiconductor is used as the active layer, depending on the material constituting the active layer. Among these, the oxide semiconductor thin film transistors that have high mobility and a large resistance variation depending on the oxygen content have the advantage of being able to easily obtain desired property. Since the oxide constituting the active layer may be formed at a relatively low temperature during the manufacturing process of oxide semiconductor thin film transistors, the manufacturing cost is low. Additionally, since oxide semiconductors are transparent due to the nature of oxides, they are also advantageous in implementing transparent display. High resolution displays include a large number of thin film transistors. In order to arrange a large number of thin film transistors in a given area, the size of the thin film transistors must be reduced. However, when the size of the thin film transistor is reduced, the channel length also becomes shorter, which may deteriorate the operating stability of the thin film transistor or cause a characteristic deviation between multiple thin film transistors, which may deteriorate the display quality of the display apparatus. In order for a thin film transistor to operate stably, the channel must have an effective channel length greater than a certain value. In the case of a thin film transistor with a coplanar structure, control over the conductorized region is important to secure the channel length. In a thin film transistor, a phenomenon in which a conductorized region penetrates into a channel may occur. If the length of the conductorized region penetrated into the channel is not constant, the effective channel length of the thin film transistor becomes not constant, and characteristic deviation may occur between the thin film transistors. In particular, if the effective channel length is not constant in a short channel thin film transistor with a short channel length, the characteristic deviation between the thin film transistors becomes significant, making it difficult to manufacture a large area panel. Therefore, in order to manufacture a high resolution display apparatus with excellent display quality, it is necessary to increase the integration density of thin film transistors by shortening the channel length of the thin film transistors and at the same time secure characteristic uniformity between the thin film transistors. SUMMARY It is an object of the present invention to provide a thin film transistor, a display apparatus having the same and a manufacturing method of a thin film transistor, wherein the thin film transistor has a short channel. It is an object of the present invention to provide a thin film transistor having a short channel with a short length while having excellent uniformity, and a display apparatus having the same and a manufacturing method of manufacturing the same. It is a further object of the present invention to overcome one or more of the problems in the prior art, as discussed above. At least one of these objects is solved by the features of the independent claims. The present disclosure provides a technology that may easily form a short channel by using a source electrode and a drain electrode as masks in the conductorization process. The present disclosure provides a technology of using a source electrode and a drain electrode as masks in the conductorization process so that a channel part may be defined by the source electrode and the drain electrode. In addition, The present disclosure provides a technology that allows a channel part to be defined by self-alignment as the channel part is defined by the source electrode and the drain electrode.. The present disclosure provides a manufacturing method of a thin film transistor in which a source electrode and a drain electrode are used as masks for a conductorization process. In one aspect of the present disclosure, a thin film transistor comprises: a gate electrode; an active layer that is spaced apart from the gate electrode and at least partially overlapping the gate elect