SEMICONDUCTOR THIN FILM, METHOD FOR PRODUCING THE SAME, AND THIN FILM TRANSISTOR

• US 20090090914A1
• Filed: 11/16/2006
• Published: 04/09/2009
• Est. Priority Date: 11/18/2005
• Status: Abandoned Application

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Yoshinaka, Masahiro, Shibuya, Tadao, Shimane, Yukio, Inoue, Kazuyoshi, Yano, Koki
• Application Number:
  US12/094,069
• Publication Number:
  US 20090090914A1
• Time in Patent Office: Days
• US Class Current: 257/66
• CPC Class Codes: C01G 19/00 Compounds of tin
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

A transparent semiconductor thin film 40 having low carrier concentration and a large energy band gap is produced by forming a thin film which contains indium oxide and an oxide of a positive divalent element, and then oxidizing or crystallizing the thin film.

Claims

1. A semiconductor thin film containing indium, a positive divalent element, and oxygen and whose specific resistance obtained by a four-terminal method is 10⁻

1 Ω

m to 10⁸ Ω

m.

2. The semiconductor thin film according to claim 1, wherein carrier density is less than 2×

10⁺¹⁷ cm<sup>−

3</sup>.

3. The semiconductor thin film according to claim 1, wherein the positive divalent element is one or more elements selected from zinc, magnesium, copper, cobalt, nickel, and calcium.

4. The semiconductor thin film according to claim 1, wherein an energy band gap between a conduction band and a valence band is 2.8 eV or more.

5. The semiconductor thin film according to claim 1, wherein the thin film is a film containing crystalline material.

6. The semiconductor thin film according to claim 1, wherein atom ratio between indium [In] and a positive divalent element [X] in the thin film is expressed as X/(X+In)=0.0001 to 0.1.

7. The semiconductor thin film according to claim 1, wherein the semiconductor thin film contains bixbite crystal of indium oxide.

15. A thin film transistor using the semiconductor thin film according to claim 1.

17. The thin film transistor according to claim 15, wherein a device configuration is a bottom gate configuration.

8. A method for producing a semiconductor thin film, comprising:

a film forming step of forming a thin film containing indium oxide and an oxide of a positive divalent element; and

a step of oxidizing or crystallizing the thin film.

9. The method for manufacturing a semiconductor thin film according to claim 8, wherein, in the oxidizing step or crystallizing step, the thin film is subject to heat treatment in the presence or absence of oxygen under conditions of 80 to 650°

C. and 0.5 to 12,000 minutes.

10. The method for manufacturing a semiconductor thin film according to claim 8, wherein, in the oxidizing step or crystallizing step, the thin film is subject to heat treatment in the presence or absence of oxygen by a lamp annealer (LA), a rapid thermal annealer (RTA), or a laser annealer.

11. The method for manufacturing a semiconductor thin film according to claim 8, wherein the oxidizing step or crystallizing step is an ozone process.

12. The method for manufacturing a semiconductor thin film according to claim 8, wherein, in the oxidizing step or crystallizing step, at least a part of the thin film is crystallized from an amorphous film to a crystalline film.

13. The method for manufacturing a semiconductor thin film according to claim 8, wherein the thin film is formed physically at a substrate temperature of 200°

C. or less in the film forming step.

14. The method for manufacturing a semiconductor thin film according to claim 8, wherein atom ratio between indium [In] and a positive divalent element [X] in the thin film is expressed as X/(X+In)=0.0001 to 0.1.

16. A thin film transistor using a semiconductor thin film manufactured by the method for manufacturing a semiconductor thin film according to claim 8.

18. A sputtering target containing indium, a positive divalent element, and oxygen, wherein atom ratio between the indium [In] and the positive divalent element [X] is expressed as X/(X+In)=0.0001 to 0.1.

19. The sputtering target according to claim 18, wherein the positive divalent element is one or more elements selected from zinc, magnesium, copper, cobalt, nickel, and calcium.

20. The sputtering target according to claim 18, wherein the sputtering target is for manufacturing a semiconductor thin film.

21. The sputtering target according to claim 18, wherein sintered density is 99% or higher, and bulk resistance is 0.01 to 100 mΩ

cm.