OXIDE SEMICONDUCTOR FIELD EFFECT TRANSISTOR AND METHOD FOR MANUFACTURING THE SAME

• US 20100276688A1
• Filed: 12/19/2008
• Published: 11/04/2010
• Est. Priority Date: 12/25/2007
• Status: Active Grant

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Kasami, Masashi, Inoue, Kazuyoshi, Kawashima, Hirokazu, Yano, Koki, Tomai, Shigekazu
• Granted Patent: US 8,461,583 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: H01L 29/263 Amorphous materials
• 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 field effect transistor including a semiconductor layer including a composite oxide which contains In, Zn, and one or more elements X selected from the group consisting of Zr, Hf, Ge, Si, Ti, Mn, W, Mo, V, Cu, Ni, Co, Fe, Cr, Nb, Al, B, Sc, Y and lanthanoids in the following atomic ratios (1) to (3):

In/(In+Zn)=0.2 to 0.8  (1)

In/(In+X)=0.29 to 0.99  (2)

Zn/(X+Zn)=0.29 to 0.99  (3).

Claims

1. A field effect transistor comprising a semiconductor layer comprising a composite oxide which comprises In, Zn, and one or more elements X selected from the group consisting of Zr, Hf, Ge, Si, Ti, Mn, W, Mo, V, Cu, Ni, Co, Fe, Cr, Nb, Al, B, Sc, Y and lanthanoids (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) in the following atomic ratios (1) to (3):

In/(In+Zn)=0.2 to 0.8 

 

(1)

In/(In+X)=0.29 to 0.99 

 

(2)

Zn/(X+Zn)=0.29 to 0.99 

 

(3).

2. The field effect transistor according to claim 1, wherein the element X is one or more elements selected from the group consisting of Al, B, Sc, Y and lanthanoids (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) and the semiconductor layer comprises the element X in the following atomic ratio (2)'"'"':

In/(In+X)=0.59 to 0.99 

 

(2)′

.

3. The field effect transistor according to claim 1, wherein the element X is Al or B.

4. The field effect transistor according to claim 1 wherein the element X is Sc or Y.

5. The field effect transistor according to claim 1, wherein the element X is a lanthanoid (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu).

6. The field effect transistor according to claim 1, wherein the element X is Zr.

7. The field effect transistor according to claim 1, wherein the semiconductor layer is an amorphous film which has an electron carrier concentration of 10¹³ to 10¹⁸/cm³ and a band gap of 2.0 to 6.0 eV.

8. The field effect transistor according to claim 1, wherein the semiconductor layer is a nondegenerate semiconductor.

9. A target for a semiconductor layer comprising a composite oxide which comprises In, Zn, and one or more elements X selected from the group consisting of Zr, Hf, Ge, Si, Ti, Mn, W, Mo, V, Cu, Ni, Co, Fe, Cr, Nb, Al, B, Sc, Y and lanthanoids (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) in the following atomic ratios (1) to (3):

In/(In+Zn)=0.2 to 0.8 

 

(1)

In/(In+X)=0.29 to 0.99 

 

(2)

Zn/(X+Zn)=0.29 to 0.99 

 

(3).

10. The target for a semiconductor layer according to claim 9, wherein the element X is one or more elements selected from the group consisting of Al, B, Sc, Y and lanthanoids (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu), and the target further comprises one or more elements selected from the group consisting of Sn, Ge, Si, Ti, Zr and Hf in an amount of 100 to 10000 atomic ppm.

11. A method for producing a field effect transistor comprising the steps of forming a semiconductor layer by DC or AC sputtering by using the target according to claim 9, and subjecting the semiconductor layer to a heat treatment at 70 to 350°

C.