Method for manufacturing transistor

Patent metadata

Field	Value
Publication number	US-9601601-B2
Application number	US-201414454126-A
Country	US
Kind code	B2
Filing date	Aug 7, 2014
Priority date	Dec 19, 2008
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

A hydrogen barrier layer is selectively provided over an oxide semiconductor layer including hydrogen and hydrogen is selectively desorbed from a given region in the oxide semiconductor layer by conducting oxidation treatment, so that regions with different conductivities are formed in the oxide semiconductor layer. After that, a channel formation region, a source region, and a drain region can be formed with the use of the regions with different conductivities formed in the oxide semiconductor layer.

First claim

The invention claimed is:

1. A method for manufacturing a semiconductor device comprising the steps of:
forming a source electrode and a drain electrode over a substrate;
forming an oxide semiconductor layer over the substrate;
forming a layer over the oxide semiconductor layer;
etching the layer selectively so as to leave a part of the layer overlapping with a source region and a drain region of the oxide semiconductor layer, and so as to expose a channel formation region of the oxide semiconductor layer; and
performing an oxidizing treatment to the oxide semiconductor layer having the channel formation region exposed and the source region and the drain region overlapped with the part of the layer so as to desorb hydrogen from the channel formation region of the oxide semiconductor layer,
wherein the channel formation region after performing the oxidizing treatment includes hydrogen at a lower concentration than the source region and the drain region, and
wherein the layer comprises any one of silicon nitride, silicon nitride oxide, silicon oxynitride, aluminum oxide, aluminum nitride, aluminum oxynitride, titanium oxide, tantalum oxide, and tantalum nitride.

2. The method for manufacturing a semiconductor device according to claim 1 , further comprising the steps of:
forming a gate insulating layer over the oxide semiconductor layer; and
forming a gate electrode over the gate insulating layer,
wherein the gate electrode overlaps with the channel formation region.

3. The method for manufacturing a semiconductor device according to claim 1 , wherein the oxide semiconductor layer comprises indium.

4. The method for manufacturing a semiconductor device according to claim 1 , wherein concentration gradient of hydrogen is formed between the channel formation region and the source region and the drain region.

5. The method for manufacturing a semiconductor device according to claim 1 , wherein the layer is a hydrogen barrier layer.

6. A method for manufacturing a semiconductor device, comprising the steps of:
forming a source electrode and a drain electrode over a substrate;
forming an oxide semiconductor layer over the substrate;
forming a first layer over the oxide semiconductor layer;
etching the first layer selectively so as to leave a part of the first layer overlapping with a source region and a drain region of the oxide semiconductor layer, and so as to expose a channel formation region of the oxide semiconductor layer;
forming a second layer so as to be in contact with the channel formation region of the oxide semiconductor layer; and
performing an oxidizing treatment to the oxide semiconductor layer having the channel formation region in contact with the second layer and the source region and the drain region overlapped with the part of the first layer so as to desorb hydrogen from the channel formation region of the oxide semiconductor layer,
wherein the channel formation region after performing the oxidizing treatment includes hydrogen at a lower concentration than the source region and the drain region, and
wherein the first layer comprises any one of silicon nitride, silicon nitride oxide, silicon oxynitride, aluminum oxide, aluminum nitride, aluminum oxynitride, titanium oxide, tantalum oxide, and tantalum nitride.

7. The method for manufacturing a semiconductor device according to claim 6 , further comprising the steps of:
forming a gate insulating layer over the oxide semiconductor layer; and
forming a gate electrode over the gate insulating layer,
wherein the gate electrode overlaps with the channel formation region.

8. The method for manufacturing a semiconductor device according to claim 6 , wherein the oxide semiconductor layer comprises indium.

9. The method for manufacturing a semiconductor device according to claim 6 , wherein concentration gradient of hydrogen is formed between the channel formation region and the source region and the drain region.

10. The method for manufacturing a semiconductor device according to claim 6 , wherein the first layer is a hydrogen barrier layer.

11. The method for manufacturing a semiconductor device according to claim 6 , wherein the second layer comprises a material selected from the group consisting of an amorphous silicon, a polycrystalline silicon and a tungsten oxide.

12. The method for manufacturing a semiconductor device according to claim 6 , wherein the second layer is a hydrogen adsorption layer which adsorbs hydrogen included in the oxide semiconductor layer in the oxidizing treatment.

13. The method for manufacturing a semiconductor device according to claim 1 , wherein a concentration of hydrogen included in the channel formation region of the oxide semiconductor layer and a concentration of hydrogen included in the source region and the drain region of the oxide semiconductor layer are measured by secondary ion mass spectrometry.

14. The method for manufacturing a semiconductor device according to claim 6 , wherein a concentration of hydrogen included in the channel formation region of the oxide semiconductor layer and a concentration of hydrogen included in the source region and the drain region of the oxide semiconductor layer are measured by secondary ion mass spectrometry.

15. The method for manufacturing a semiconductor device according to claim 1 , wherein a concentration of hydrogen included in the channel formation region of the oxide semiconductor layer is greater than or equal to 1×10 16 atoms/cm 3 and less than or equal to 1×10 21 atoms/cm 3 .

16. The method for manufacturing a semiconductor device according to claim 6 , wherein a concentration of hydrogen included in the channel formation region of the oxide semiconductor layer is greater than or equal to 1×10 16 atoms/cm 3 and less than or equal to 1×10 21 atoms/cm 3 .

17. The method for manufacturing a semiconductor device comprising the steps of:
forming a source electrode and a drain electrode over a substrate;
forming an oxide semiconductor layer over the substrate;
forming a layer over the oxide semiconductor layer;
etching the layer selectively so as to leave a part of the layer overlapping with a source region and a drain region of the oxide semiconductor layer; and
performing an oxidizing treatment to the oxide semiconductor layer having the channel formation region exposed and the source region and the drain region overlapped with the part of the layer so as to desorb hydrogen from the channel formation region of the oxide semiconductor layer,
wherein the channel formation region after performing the oxidizing treatment includes hydrogen at a lower concentration than the source region and the drain region, and
wherein the oxidizing treatment is at least one of heat treatment in an oxygen atmosphere, heat treatment in a nitrogen atmosphere, and oxygen plasma treatment.

Assignees

• Semiconductor Energy Lab

Inventors

• Sakata Junichiro

Classifications

• H10P14/3426

  Oxides · CPC title

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10P14/3434

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

• H10P14/38

  characterised by treatments done after the formation of the materials · CPC title

• H10P14/22

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