SEMICONDUCTOR DEVICE, POLYCRYSTALLINE SEMICONDUCTOR THIN FILM, PROCESS FOR PRODUCING POLYCRYSTALLINE SEMICONDUCTOR THIN FILM, FIELD EFFECT TRANSISTOR, AND PROCESS FOR PRODUCING FIELD EFFECT TRANSISTOR

• US 20120168748A1
• Filed: 03/09/2012
• Published: 07/05/2012
• Est. Priority Date: 03/23/2007
• Status: Active Grant

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Yano, Koki, Inoue, Kazuyoshi
• Granted Patent: US 8,779,419 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• 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

An object of the present invention is to provide a novel semiconductor device which is excellent in stability, uniformity, reproducibility, heat resistance, durability and the like, and can exert excellent transistor properties. The semiconductor device is a thin-film transistor, and this thin-film transistor uses, as an active layer, a polycrystalline oxide semiconductor thin film containing In and two or more metals other than In and having an electron carrier concentration of less than 1×10¹⁸/cm³.

Claims

1. A semiconductor device which uses a crystalline oxide as a semiconductor,

wherein the crystalline oxide contains In and two or more metals other than In, and the crystalline oxide has an electron carrier concentration of less than 1×

10¹⁸/cm³.

2. The semiconductor device according to claim 1, wherein a relation between the number (═

[In]) of the atoms of In and the sum (═

[X]) of the atoms of the two or more metals other than In contained in the crystalline oxide satisfies a ratio [X]/([X]+[In])=0.0001 to 0.13.

3. The semiconductor device according to claim 1, wherein the crystalline oxide is a crystalline oxide in which when at least the condition of [X]/([X]+[In]) is changed, the electron mobility of the crystalline oxide with respect to the electron carrier concentration thereof increases logarithmically proportionally to the increase of the electron carrier concentration in a predetermined range.

4. The semiconductor device according to claim 1, wherein the two or more metals other than In are a positive bivalent metal and a positive tetravalent metal.

5. The semiconductor device according to claim 4, wherein the positive bivalent metal is at least one element selected from the group consisting of Zn, Mg, Cu, Ni, Co, Ca and Sr,

the positive tetravalent metal is at least one element selected from the group consisting of Sn, Ge, Si, Ti, C, Zr and Hf, and

a relation among the number ( [In]) of the atoms of In, the number (=[M2]) of the atoms of the positive bivalent metal and the number (=[M4]) of the atoms of the positive tetravalent metal contained in the crystalline oxide satisfies the following ratios:

[M2]/([M2]+[M4]+[In])=0.0001 to 0.13; and

[M4]/([M2]+[M4])=0.0001 to 0.3.

6. The semiconductor device according to claim 1, wherein the two or more metals other than In are a positive bivalent metal and a positive trivalent metal.

7. The semiconductor device according to claim 6, wherein the positive bivalent metal is at least one element selected from the group consisting of Zn, Mg, Cu, Ni, Co, Ca and Sr, and

the positive trivalent metal is at least one element selected from the group consisting of Ga, Al, B, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.

8. The semiconductor device according to claim 1, wherein both of the two or more metals other than In are positive bivalent metals.

9. The semiconductor device according to claim 8, wherein the two or more metals other than In are one set selected from the group consisting of Zn and Mg, Zn and Cu, Zn and Co, Zn and Ni, Zn and Ca, and Zn and Sr.

10. The semiconductor device according to claim 1, wherein the concentration of Li, Na and K in the polycrystalline oxide is 1000 ppm or less.

11. The semiconductor device according to claim 1, wherein the crystalline oxide has PAN resistance.

12. The semiconductor device according to claim 1, wherein the crystalline oxide includes, as an impurity, at least one element selected from the group consisting of Ar, Kr, Xe, Ne and N.

13. The semiconductor device according to claim 1, wherein the crystalline oxide is used as an active layer of a thin-film transistor.

14-23. -23. (canceled)