THIN FILM FIELD-EFFECT TRANSISTOR AND DISPLAY DEVICE

• US 20100059747A1
• Filed: 09/08/2009
• Published: 03/11/2010
• Est. Priority Date: 09/11/2008
• Status: Abandoned Application

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: NAKAYAMA, Masaya, KOITO, Naoki
• Application Number:
  US12/554,989
• Publication Number:
  US 20100059747A1
• Time in Patent Office: Days
• 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 29/78681 having a semiconductor body comprising AIIIBV or AIIBVI or AIVBVI semiconductor materials, or Se or Te
• 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: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621
• CPC Class Codes: H10K 10/466 Lateral bottom-gate IGFETs comprising only a single gate
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/342 comprising iridium

Abstract

The invention provides a thin film field-effect transistor including, on a substrate, a gate electrode, a gate insulating film, an active layer including an oxide semiconductor, a source electrode, a drain electrode, a resistive layer including an oxide semiconductor and positioned between the active layer and at least one of the source electrode or the drain electrode, the resistive layer having an electric conductivity that is lower than the electric conductivity of the active layer, the electric conductivity of the active layer being from 10⁻⁴ Scm⁻¹ to less than 10² Scm⁻¹, the ratio of the electric conductivity of the active layer to the electric conductivity of the resistive layer (electric conductivity of active layer/electric conductivity of resistive layer) being from 10¹ to 10¹⁰, and at least one of the source electrode or the drain electrode including a layer including Ti or a Ti alloy positioned at the side facing the resistive layer.

Claims

1. A thin film field-effect transistor comprising, on a substrate, a gate electrode, a gate insulating film, an active layer comprising an oxide semiconductor, a source electrode, a drain electrode, a resistive layer comprising an oxide semiconductor and positioned between the active layer and at least one of the source electrode or the drain electrode, the resistive layer having an electric conductivity that is lower than the electric conductivity of the active layer, the electric conductivity of the active layer being from 10⁻

4 Scm<sup>−

1</sup> to less than 10² Scm<sup>−

1</sup>, the ratio of the electric conductivity of the active layer to the electric conductivity of the resistive layer (electric conductivity of active layer/electric conductivity of resistive layer) being from 10¹ to 10¹⁰, and at least one of the source electrode or the drain electrode comprising a layer comprising Ti or a Ti alloy positioned at the side facing the resistive layer.

2. The thin film field-effect transistor according to claim 1, wherein the active layer is in contact with the gate insulating film.

3. The thin film field-effect transistor according to claim 1, wherein the ratio of the electric conductivity of the active layer to the electric conductivity of the resistive layer (electric conductivity of active layer/electric conductivity of resistive layer) is from 10² to 10¹⁰.

4. The thin film field-effect transistor according to claim 3, wherein the ratio of the electric conductivity of the active layer to the electric conductivity of the resistive layer (electric conductivity of active layer/electric conductivity of resistive layer) is from 10² to 10⁸.

5. The thin film field-effect transistor according to claim 1, wherein the source electrode and the drain electrode include the layer comprising Ti or a Ti alloy positioned at the side facing the resistive layer.

6. The thin film field-effect transistor according to claim 1, wherein the electric conductivity of the active layer is from 10⁻

1 Sccm<sup>−

1</sup> to less than 10² Scm<sup>−

1</sup>.

7. The thin film field-effect transistor according to claim 1, wherein at least one of the oxide semiconductor of the active layer or the oxide semiconductor of the resistive layer comprises an amorphous oxide.

8. The thin film field-effect transistor according to claim 1, wherein at least one of the oxide semiconductor of the active layer or the oxide semiconductor of the resistive layer comprises an oxide or a composite oxide of at least one selected from the group consisting of In, Ga and Zn.

9. The thin film field-effect transistor according to claim 1, wherein the substrate comprises a flexible resin substrate.

10. A display device comprising the thin film field-effect transistor according to claim 1.