SEMICONDUCTOR THIN FILM AND METHOD FOR MANUFACTURING SAME, AND THIN FILM TRANSISTOR

• US 20090267064A1
• Filed: 10/16/2006
• Published: 10/29/2009
• Est. Priority Date: 11/18/2005
• Status: Active Grant

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Yano, Koki, Tanaka, Nobuo, Inoue, Kazuyoshi, Tanaka, Tokie
• Granted Patent: US 7,906,777 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: C01G 19/00 Compounds of tin
• CPC Class Codes: C01P 2006/40 Electric properties
• 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 present invention provides a semiconductor thin film which can be manufactured at a relatively low temperature even on a flexible resin substrate. As a semiconductor thin film having a low carrier concentration, a high Hall mobility and a large energy band gap, an amorphous film containing zinc oxide and tin oxide is formed to obtain a carrier density of 10⁺¹⁷ cm⁻³ or less, a Hall mobility of 2 cm²/V·sec or higher, and an energy band gap of 2.4 eV or more. Then, the amorphous film is oxidized to form a transparent semiconductor thin film 40.

Claims

1. A semiconductor thin film made by an amorphous film containing zinc oxide, and tin oxide and whose specific resistance is 10 Ω

m to 10⁷ Ω

m.

2. The semiconductor thin film according to claim 1, wherein the film is a non-degenerate semiconductor thin film having a carrier density of 10⁺¹⁷ cm⁻

3 or less, a Hall mobility of 2 cm²/V·

sec or higher, and an energy band gap of 2.4 eV or more.

3. The semiconductor thin film according to claim 1, wherein atom ratio between zinc [Zn] and tin [Sn] in the amorphous film is expressed as Zn/(Zn+Sn)=0.40 to 0.95.

4. The semiconductor thin film according to claim 1, wherein transmittance of wavelength of 550 nm is 75% or higher.

5. A transparent oxide semiconductor thin film according to claim 1, wherein work function is 3.5 to 6.5 eV.

7. A thin film transistor comprising the semiconductor thin film according to claim 1.

6. A method of manufacturing a semiconductor thin film, comprising:

a step of forming an amorphous film containing zinc oxide and tin oxide by physical film forming method; and

a step of performing a post process in which temperature in a film surface in the presence of oxygen becomes a temperature equal to or higher than a substrate temperature at the time of the film formation.