Manufacturing method of semiconductor device

Patent metadata

Field	Value
Publication number	US-9245959-B2
Application number	US-201414227304-A
Country	US
Kind code	B2
Filing date	Mar 27, 2014
Priority date	Aug 25, 2010
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

One object is to have stable electrical characteristics and high reliability and to manufacture a semiconductor device including a semi-conductive oxide film. Film formation is performed by a sputtering method using a target in which gallium oxide is added to a material that is easy to volatilize compared to gallium when the material is heated at 400° C. to 700° C. like zinc, and a formed film is heated at 400° C. to 700° C., whereby the added material is segregated in the vicinity of a surface of the film and the oxide is crystallized. Further, a semi-conductive oxide film is deposited thereover, whereby a semi-conductive oxide having a crystal which succeeds a crystal structure of the oxide that is crystallized by heat treatment is formed.

First claim

What is claimed is:

1. A manufacturing method of a semiconductor device, comprising the steps of:
forming a first film that contains an oxide including at least a first metal element and a second metal element, over a substrate;
heating the first film to form a first layer that contains a crystal of an oxide including the first metal element as a main metal component and a second layer that is on a side closer to the substrate than the first layer and contains an oxide including the second metal element as a main metal component;
forming a second film that is in contact with the first layer and contains an oxide; and
heating the first layer and the second film,
wherein a concentration of sodium in at least one of the first layer and the second film is lower than 5×10 16 cm −3 .

2. The manufacturing method of a semiconductor device, according to claim 1 , wherein the first layer and the second film comprise semi-conductive oxide.

3. The manufacturing method of a semiconductor device, according to claim 1 , wherein the second film comprises In—Ga—Zn-based oxide semiconductor.

4. The manufacturing method of a semiconductor device, according to claim 1 , wherein a ratio of the second metal element to a metal element in the second film is greater than or equal to 0.2.

5. The manufacturing method of a semiconductor device, according to claim 1 , wherein the first film is formed by a DC sputtering method.

6. A manufacturing method of a semiconductor device, comprising the steps of:
forming a first film that contains an oxide including at least a first metal element and a second metal element, over a substrate;
heating the first film to form a first layer that contains a crystal of an oxide including the first metal element as a main metal component and a second layer that is on a side closer to the substrate than the first layer and contains an oxide including the second metal element as a main metal component;
forming a second film that is in contact with the first layer and contains an oxide; and
heating the first layer and the second film to form a third layer from the first layer and the second film,
wherein a concentration of sodium in at least one of the first layer and the second film is lower than 5×10 16 cm −3 , and
wherein a carrier concentration of the third layer is lower than 1×10 14 cm −3 .

7. The manufacturing method of a semiconductor device, according to claim 6 , wherein the first layer, the second film, and the third layer comprise semi-conductive oxide.

8. The manufacturing method of a semiconductor device, according to claim 6 , wherein the second film comprises In—Ga—Zn-based oxide semiconductor.

9. The manufacturing method of a semiconductor device, according to claim 6 , wherein a ratio of the second metal element to a metal element in the second film is greater than or equal to 0.2.

10. The manufacturing method of a semiconductor device, according to claim 6 , wherein the first film is formed by a DC sputtering method.

11. A semiconductor device comprising:
a gate electrode over a substrate;
a first oxide semiconductor layer with a gate insulating film between the gate electrode and the first oxide semiconductor layer;
a source electrode and a drain electrode over the first oxide semiconductor layer; and
a second oxide semiconductor layer over the source electrode and the drain electrode,
wherein a part of the first oxide semiconductor layer is in contact with a part of the second oxide semiconductor layer.

12. The semiconductor device, according to claim 11 , wherein the first and second oxide semiconductor layers comprise In—Ga—Zn-based oxide semiconductor.

Assignees

• Semiconductor Energy Lab

Inventors

• Yamazaki Shunpei

Classifications

• H10P14/3822

  Controlling the interface between substrate and epitaxial layer, e.g. by ion implantation followed by annealing · CPC title

• H10P14/22

  using physical deposition, e.g. vacuum deposition or sputtering · CPC title

• H10P14/3434 Primary

  being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424) · CPC title

• H10D30/6755

  Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate · CPC title

• H10D30/031

  of thin-film transistors [TFT] · CPC title