Thin film transistor and display unit

• US 8,497,504 B2
• Filed: 11/02/2011
• Issued: 07/30/2013
• Est. Priority Date: 02/09/2009
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Arai, Toshiaki, Morosawa, Narihiro, Tokunaga, Kazuhiko, Sagawa, Hiroshi, Miura, Kiwamu
• Primary Examiner(s): YEUNG LOPEZ, FEIFEI
• Application Number:
  US13/287,689
• Publication Number:
  US 20120043548A1
• Time in Patent Office: 636 Days
• Field of Search: None
• US Class Current: 257/43
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate
• CPC Class Codes: H01L 29/458 for thin film silicon, e.g. source or drain electrode
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs

Abstract

A thin film transistor with which oxygen is easily supplied to an oxide semiconductor layer and favorable transistor characteristics are able to be restored and a display unit including the same. The thin film transistor includes, sequentially over a substrate, a gate electrode, a gate insulting film, an oxide semiconductor layer including a channel region, and a channel protective layer covering the channel region A source electrode and a drain electrode are formed on the oxide semiconductor layer located on both sides of the channel protective layer, and at least one of the source electrode and the drain electrode has an aperture to expose the oxide semiconductor layer.

Claims

1. A thin film transistor comprising layers stacked over a substrate, in the order listed:

a gate electrode;

a gate insulting film;

an oxide semiconductor layer including a channel region; and

a channel protective layer covering the channel region and formed within the boundaries of the gate electrode,

wherein,

a source electrode and a drain electrode are formed on the oxide semiconductor layer located on both sides of the channel protective layer, and

a protrusion region in which the top surface of the oxide semiconductor layer is exposed from an end of the source electrode or the drain electrode is provided along a side opposed to a side overlapped with the channel protective layer of at least one of the source electrode and the drain electrode.

2. The thin film transistor according to claim 1, wherein the oxide semiconductor layer has the protrusion region in which the oxide semiconductor layer is exposed from the end of the source electrode or the drain electrode along a side other than the side overlapped with the channel protective layer.

3. The thin film transistor according to claim 1, wherein the channel region is formed in a region within 20 μ

m from the protrusion region.

4. The thin film transistor according to claim 1, wherein:

the source electrode and the drain electrode include a metal layer containing aluminum, copper, silver, or molybdenum as a main component, and

the source electrode and the drain electrode are made of a single layer film of the metal layer, or a laminated film composed of the metal layer and another metal layer or metal compound layer containing titanium, vanadium, niobium, tantalum, chromium, tungsten, nickel, zinc, or indium as a main component.

5. The thin film transistor according to claim 4, wherein a layer contacted with the oxide semiconductor layer of the source electrode and the drain electrode is composed of a metal that does not make oxygen detached from the oxide semiconductor layer or a metal compound that does not make oxygen detached from the oxide semiconductor layer.

6. The thin film transistor according to claim 4, wherein the layer contacted with the oxide semiconductor layer of the source electrode and the drain electrode is composed of at least one of molybdenum, molybdenum oxide, molybdenum nitride, molybdenum nitroxide, titanium oxide, titanium nitride, titanium nitroxide, aluminum nitride, and copper oxide.

7. The thin film transistor according to claim 4, wherein an uppermost layer of the source electrode and the drain electrode is composed of one of titanium, titanium oxide, titanium nitride, and titanium nitroxide.

8. The thin film transistor according to claim 1, wherein the layer contacted with the oxide semiconductor layer of the source electrode and the drain electrode is composed of a conductive metal oxide, a conductive metal nitride, or a conductive metal nitroxide.

9. A display unit comprising:

a thin film transistor; and

a display device,

wherein,

the thin film transistor includes layers stacked over a substrate, in the order listed, (a) a gate electrode, (b) a gate insulting film, (c) an oxide semiconductor layer including a channel region, and (d) a channel protective layer covering the channel region and formed within the boundaries of the gate electrode,

a source electrode and a drain electrode are formed on the oxide semiconductor layer located on both sides of the channel protective layer, and

a protrusion region in which the top surface of the oxide semiconductor layer is exposed from an end of the source electrode or the drain electrode is provided along a side opposed to a side overlapped with the channel protective layer of at least one of the source electrode and the drain electrode.

10. The display unit according to claim 9, wherein the display device is an organic light emitting device having an organic layer including a light emitting layer between an anode and a cathode.