THIN FILM TRANSISTOR AND METHOD OF PRODUCING THIN FILM TRANSISTOR

• US 20100320459A1
• Filed: 06/15/2010
• Published: 12/23/2010
• Est. Priority Date: 06/22/2009
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: UMEDA, Kenichi, NARA, Yuki, TANAKA, Atsushi, SUZUKI, Masayuki
• Granted Patent: US 8,343,800 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/02667 Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
• CPC Class Codes: H01L 21/02675 using laser beams
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

The invention provides a thin film transistor comprising an active layer, the active layer comprising an IGZO-based oxide material, the IGZO-based oxide material being represented by a composition formula of In_2-xGa_xZnO_4-δ, where 0.75<x<1.10 and 0<δ≦1.29161×exp(−x/0.11802)+0.00153 and being formed from a single phase of IGZO having a crystal structure of YbFe₂O₄, and a method of producing the thin film transistor.

Claims

1. A thin film transistor comprising an active layer, the active layer comprising an IGZO-based oxide material, the IGZO-based oxide material being represented by a composition formula of In_2-xGa_xZnO_4-δ

, where 0.75<

x<

1.10 and 0<

δ

≦

1.29161×

exp(−

x/0.11802)+0.00153 and being formed from a single phase of IGZO having a crystal structure of YbFe₂O₄.

2. The thin film transistor according to claim 1, wherein the active layer has a value of resistivity of from 1×

10²Ω

·

cm to 1×

10⁹ Ω

·

cm.

3. The thin film transistor according to claim 1, wherein x in the composition formula satisfies 0.80<

x<

1.05.

4. A method of producing the thin film transistor according to claim 1, wherein the active layer is produced by a process comprising:

forming a thin film material comprising In, Ga and Zn on a substrate;

heating the thin film material to a crystallization temperature of the thin film material; and

cooling the thin film material from the crystallization temperature to 300°

C. at an average rate of temperature decrease of from 50°

C./hr to 500°

C./hr.

5. The method of producing the thin film transistor according to claim 4, wherein the thin film material is formed on the substrate by gas-phase film formation.

6. The method of producing the thin film transistor according to claim 4, wherein the crystallization temperature is from 700°

C. to 1400°

C.

7. The method of producing the thin film transistor according to claim 4, wherein the average rate of temperature decrease is from 100°

C./hr to 200°

C./hr.

8. A method of producing the thin film transistor according to claim 1, the method comprising:

forming an active layer on a substrate, the active layer comprising an IGZO-based oxide material, the IGZO-based oxide material being represented by a composition formula of In_2-xGa_xZnO_4-δ

, where 0.75<

x<

1.10 and δ

>

0 and being formed from a single phase of IGZO having a crystal structure of YbFe₂O₄; and

controlling the value of δ

to a range of 0<

δ

≦

1.29161×

exp(−

x/0.11802)+0.00153 by subjecting the active layer to post-annealing in an oxidizing atmosphere containing oxygen.

9. The method of producing the thin film transistor according to claim 4, further comprising forming at least a gate insulating layer and a gate electrode on the active layer, and wherein the thin film transistor has a top-gate device structure.

10. The method of producing the thin film transistor according to claim 9, further comprising forming a source electrode and a drain electrode prior to the formation of the gate insulating layer and the gate electrode, and wherein the thin film transistor has a top-contact device structure.