LAMINATE STRUCTURE INCLUDING OXIDE SEMICONDUCTOR THIN FILM LAYER, AND THIN FILM TRANSISTOR

• US 20130221351A1
• Filed: 12/27/2011
• Published: 08/29/2013
• Est. Priority Date: 12/28/2010
• Status: Active Grant

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Ebata, Kazuaki, Tomai, Shigekazu, Matsuzaki, Shigeo, Tsuruma, Yuki, Yano, Koki
• Granted Patent: US 8,785,927 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 21/02488 Insulating materials
• 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 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 21/02667 Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
• 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 stacked layer structure including an oxide layer and an insulating layer, the oxide layer having a carrier concentration of 10¹⁸/cm³ or less and an average crystal diameter of 1 μm or more; and the crystals of the oxide layer being arranged in a columnar shape on the surface of the insulating layer.

Claims

1. A stacked layer structure comprising an oxide layer and an insulating layer,

the oxide layer having a carrier concentration of 10¹⁸/cm³ or less and an average crystal diameter of 1 μ

m or more; and

the crystals of the oxide layer being arranged in a columnar shape on the surface of the insulating layer.

2. The stacked layer structure according to claim 1, wherein a material which the oxide layer comprises is selected from indium oxide, Ga-doped indium oxide, Al-doped indium oxide, Zn-doped indium oxide and Sn-doped indium oxide.

3. The stacked layer structure according to claim 2, wherein the Ga-doped indium oxide has an atomic ratio Ga/(Ga+In) of 0.01 to 0.09.

4. The stacked layer structure according to claim 2, wherein the Al-doped indium oxide has an atomic ratio Al/(Al+In) of 0.01 to 0.05.

16. A thin film transistor comprising:

the oxide layer and the insulating layer in the stacked layer structure according to claim 1 as a channel layer and a gate insulating film respectively; and

a protecting film which comprises SiNx being provided on the oxide layer.

17. A display apparatus comprising the thin film transistor according to claim 16.

5. A method for producing a stacked layer structure comprising an oxide layer and an insulating layer comprising the steps of:

(1) preparing an insulating layer;

(2) forming on the insulating layer an oxide thin film such that Rrms (root-mean-square-roughness) in a 20×

20 μ

m² area becomes 1.0 to 5.3 Å

; and

(3) subjecting the oxide thin film to heat treatment at 150 to 500°

C.

6. The method for producing a stacked layer structure according to claim 5, wherein the oxide layer is formed in an atmosphere of a mixed gas containing rare gas atoms and one or more molecules selected from water molecules, oxygen molecules and nitrous oxide molecules.

7. The method for producing a stacked layer structure according to claim 6, wherein the oxide layer is formed in an atmosphere of a mixed gas containing rare gas and at least water.

8. The method for producing a stacked layer structure according to claim 7, wherein the water is contained in the atmosphere at a partial pressure ratio of 0.1% to 25%.

9. The method for producing a stacked layer structure according to claim 5, wherein the oxide layer comprises a material selected from indium oxide, Ga-doped indium oxide, Al-doped indium oxide, Zn-doped indium oxide and Sn-doped indium oxide.

10. The method for producing a stacked layer structure according to claim 9, wherein the Ga-doped indium oxide has an atomic ratio Ga/(Ga+In) of 0.01 to 0.09.

11. The method for producing a stacked layer structure according to claim 9, wherein the Al-doped indium oxide has an atomic ratio Al/(Al+In) of 0.01 to 0.05.

12. The method for producing a stacked layer structure according to claim 5, wherein the oxide layer formation in the step (2) is conducted by a sputtering method in which substrates are sequentially carried at positions opposing to three or more targets arranged in parallel in a vacuum chamber with a predetermined distance being provided therebetween, and when a negative potential and a positive potential are alternately applied to each of the targets from alternating power sources, at least one of outputs from the alternating power sources is applied to two or more targets that are connected in a branched manner while switching the targets, whereby plasma is caused to be generated on the targets.

13. The method for producing a stacked layer structure according to claim 12, wherein the alternating current density of the alternating power source is 3 W/cm² or more and 20 W/cm² or less.

14. The method for producing a stacked layer structure according to claim 12, wherein the frequency of the alternating power source is 10 kHz to 1 MHz.

15. A stacked layer structure produced by the method according to claim 5.

18. A thin film transistor comprising:

the oxide layer and the insulating layer in the stacked layer structure according to claim 15 as a channel layer and a gate insulating film respectively; and

a protecting film which comprises SiNx being provided on the oxide layer.

19. A display apparatus comprising the thin film transistor according to claim 18.