Semiconductor device and method for manufacturing the same

• US 8,796,681 B2
• Filed: 09/04/2012
• Issued: 08/05/2014
• Est. Priority Date: 09/07/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamade, Naoto, Koezuka, Junichi
• Primary Examiner(s): Tran, Long K
• Assistant Examiner(s): Tran, Dzung
• Application Number:
  US13/602,489
• Publication Number:
  US 20130056727A1
• Time in Patent Office: 700 Days
• Field of Search: 257/43, 257/88, 257/64, 257/347, 438/99
• US Class Current: 257/43
• 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 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/10 with semiconductor regions connected to an electrode not carrying current to be rectified, amplified or switched and such electrode being part of a semiconductor device which comprises three or more electrodes
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

A semiconductor device which is miniaturized and has sufficient electrical characteristics to function as a transistor is provided. In a semiconductor device including a transistor in which a semiconductor layer, a gate insulating layer, and a gate electrode layer are stacked in that order, an oxide semiconductor film which contains at least four kinds of elements of indium, gallium, zinc, and oxygen, and in which the percentage of the indium is twice or more as large as each of the percentage of the gallium and the percentage of the zinc when the composition of the four elements is expressed in atomic percentage is used as the semiconductor layer. In the semiconductor device, the oxide semiconductor film is a film to which oxygen is introduced in the manufacturing process and contains a large amount of oxygen, and an insulating layer including an aluminum oxide film is provided to cover the transistor.

Claims

1. A method for manufacturing a semiconductor device, comprising the steps of:

performing polishing treatment on a surface of an oxide insulating layer;

forming an oxide semiconductor film over the oxide insulating layer after the polishing treatment;

introducing oxygen into the oxide semiconductor film after forming the oxide semiconductor film;

forming a gate insulating film over the oxide semiconductor film;

forming a gate electrode layer over the gate insulating film, wherein the gate electrode layer overlaps with the oxide semiconductor film;

selectively introducing a dopant to the oxide semiconductor film using the gate electrode layer as a mask; and

forming an insulating layer over the oxide semiconductor film and the gate electrode layer, wherein the insulating layer comprises an aluminum oxide film.

2. The method for manufacturing a semiconductor device according to claim 1, wherein an average surface roughness of the oxide insulating layer is less than or equal to 0.15 nm.

3. The method for manufacturing a semiconductor device according to claim 1, wherein the oxide semiconductor film comprises indium, gallium, zinc, and oxygen, and an atomic percentage of the indium is twice or more as large as each of an atomic percentage of the gallium and an atomic percentage of the zinc.

4. The method for manufacturing a semiconductor device according to claim 1, wherein the insulating layer has a stacked layer structure.

5. The method for manufacturing a semiconductor device according to claim 1, wherein the insulating layer has a stacked layer structure comprising the aluminum oxide film and a silicon oxide film over the aluminum oxide film.

6. The method for manufacturing a semiconductor device according to claim 1, wherein a concentration of oxygen in the oxide semiconductor film is greater than or equal to 1×

10¹⁸/cm³ and less than or equal to 3×

10²¹/cm³.

13. The method for manufacturing a semiconductor device according to claim 1, wherein the oxide semiconductor film is formed by a sputtering method using an oxide target having a composition of indium:

gallium;

zinc=3;

1;

2.

7. A method for manufacturing a semiconductor device, comprising the steps of:

performing polishing treatment on a surface of an oxide insulating layer;

forming an oxide semiconductor film over the oxide insulating layer after the polishing treatment;

introducing oxygen into the oxide semiconductor film after forming the oxide semiconductor film;

processing the oxide semiconductor film to be an island-shaped oxide semiconductor film;

forming a gate insulating film over the island-shaped oxide semiconductor film;

forming a gate electrode layer over the gate insulating film, wherein the gate electrode layer overlaps with the island-shaped oxide semiconductor film;

selectively introducing a dopant to the island-shaped oxide semiconductor film using the gate electrode layer as a mask; and

forming an insulating layer over the island-shaped oxide semiconductor film and the gate electrode layer, wherein the insulating layer comprises an aluminum oxide film.

8. The method for manufacturing a semiconductor device according to claim 7, wherein an average surface roughness of the oxide insulating layer is less than or equal to 0.15 nm.

9. The method for manufacturing a semiconductor device according to claim 7, wherein the oxide semiconductor film comprises indium, gallium, zinc, and oxygen, and an atomic percentage of the indium is twice or more as large as each of an atomic percentage of the gallium and an atomic percentage of the zinc.

10. The method for manufacturing a semiconductor device according to claim 7, wherein the insulating layer has a stacked layer structure.

11. The method for manufacturing a semiconductor device according to claim 7, wherein the insulating layer has a stacked layer structure comprising the aluminum oxide film and a silicon oxide film over the aluminum oxide film.

12. The method for manufacturing a semiconductor device according to claim 7, wherein a concentration of oxygen in the oxide semiconductor film is greater than or equal to 1×

10¹⁸/cm³ and less than or equal to 3×

10²¹/cm³.

14. The method for manufacturing a semiconductor device according to claim 7, wherein the oxide semiconductor film is formed by a sputtering method using an oxide target having a composition of indium:

gallium;

zinc=3;

1;

2.