Method for forming silicon film and method for manufacturing power storage device

Patent metadata

Field	Value
Publication number	US-10072331-B2
Application number	US-201213537294-A
Country	US
Kind code	B2
Filing date	Jun 29, 2012
Priority date	Jul 8, 2011
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

A formation method of a silicon film which contributes to improvements in cycle characteristics and an increase in charge/discharge capacity and can be used as an active material layer is provided. In addition, a manufacturing method of a power storage device including the silicon film is provided. The formation method is as follows. A crystalline silicon film is formed over a conductive layer by an LPCVD method. The supply of a source gas is stopped and heat treatment is performed on the silicon film while the source gas is exhausted. The silicon film is grown to have whisker-like portions by an LPCVD method while the source gas is supplied into the reaction space. A power storage device is manufactured using, as an active material layer included in a negative electrode, the silicon film grown to have whisker-like portions.

First claim

What is claimed is:

1. A method for forming a silicon film, comprising:
forming a first silicon film over a conductive layer by a low-pressure chemical vapor deposition method by supplying a source gas which contains a deposition gas containing silicon into a reaction space at a temperature range which is suitable for forming the first silicon film by the low-pressure chemical vapor deposition method;
stopping the supply of the source gas and exhausting the source gas from the reaction space, wherein the reaction space is kept at the temperature range; and
forming a second silicon film over the first silicon film so that the second silicon film has whisker-like portions by a low-pressure chemical vapor deposition method by supplying the source gas whose flow rate is higher than that of the source gas used in forming the first silicon film into the reaction space at the temperature range, wherein the conductive layer is not placed out of the reaction space in any period of the above processes.

2. The method for forming a silicon film, according to claim 1 , wherein a mixed layer containing silicon and a metal element of the conductive layer is formed between the first silicon film and the conductive layer.

3. The method for forming a silicon film, according to claim 1 , wherein the first silicon film is crystalline and the second silicon film is amorphous.

4. The method for forming a silicon film, according to claim 1 , wherein the temperature range is higher than 530° C. and lower than 650° C.

5. The method for forming a silicon film, according to claim 1 , wherein silicon hydride, silicon fluoride, or silicon chloride is used for the deposition gas containing silicon.

6. The method for forming a silicon film, according to claim 1 , wherein the conductive layer contains a metal element which forms silicide by reacting with silicon.

7. The method for forming a silicon film, according to claim 6 , wherein the metal element is zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, or nickel.

8. A method for manufacturing a power storage device including at least a positive electrode, a negative electrode, and an electrolyte, comprising:
forming an active material layer included in the negative electrode, comprising;
a first step of supplying a source gas at a first flow rate into a reaction space at a temperature range to form a silicon film including a seed crystal over a conductive layer by a low-pressure chemical vapor deposition method, wherein the source gas contains a deposition gas containing silicon;
a second step comprising stopping the supply of the source gas and exhausting the source gas from the reaction space, wherein the reaction space is kept at the temperature range; and
a third step of resuming the supply of the source gas at a second flow rate into the reaction space at the temperature range to grow the silicon film by the low-pressure chemical vapor deposition method so that the second silicon film has whisker-like portions,
wherein the first flow rate is lower than the second flow rate,
wherein the temperature range is suitable for forming the silicon film by the low-pressure chemical vapor deposition method, and
wherein the conductive layer is not placed out of the reaction space in any period from the first step to the third step.

9. The method for manufacturing a power storage device, according to claim 8 , wherein a mixed layer containing silicon and a metal element of the conductive layer is formed between the conductive layer and the silicon film.

10. The method for manufacturing a power storage device, according to claim 8 , wherein the silicon film comprises an amorphous portion.

11. The method for manufacturing a power storage device, according to claim 8 , wherein the temperature range is higher than 530° C. and lower than 650° C.

12. The method for manufacturing a power storage device, according to claim 8 , wherein silicon hydride, silicon fluoride, or silicon chloride is used for the deposition gas containing silicon.

13. The method for manufacturing a power storage device, according to claim 8 , wherein the conductive layer contains a metal element which forms silicide by reacting with silicon.

14. The method for manufacturing a power storage device, according to claim 13 , wherein the metal element is zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, or nickel.

15. A method for forming a silicon film, comprising:
a first step of forming a silicon film over a conductive layer by a low-pressure chemical vapor deposition method by supplying a source gas which contains a deposition gas containing silicon into a reaction space at a temperature range which is suitable for forming the silicon film by the low-pressure chemical vapor deposition method;
a second step of stopping the supply of the source gas and exhausting the source gas from the reaction space, wherein the reaction space is kept at the temperature range; and
a third step of resuming the supply of the source gas whose flow rate is higher than that of the source gas used in the first step into the reaction space at the temperature range to grow the silicon film having whisker-like portions by the low-pressure chemical vapor deposition method, wherein the conductive layer is not placed out of the reaction space in any period from the first step to the third step.

16. The method for forming a silicon film, according to claim 15 , wherein a mixed layer containing silicon and a metal element of the conductive layer is formed between the conductive layer and the silicon film.

17. The method for forming a silicon film, according to claim 15 , wherein the silicon film comprises an amorphous portion.

18. The method for forming a silicon film, according to claim 15 , wherein the temperature range is higher than 530° C. and lower than 650° C.

19. The method for forming a silicon film, according to claim 15 , wherein silicon hydride, silicon fluoride, or silicon chloride is used for the deposition gas containing silicon.

20. The method for forming a silicon film, according to claim 15 , wherein the conductive layer contains a metal element which forms silicide by reacting with silicon.

Assignees

• Takeuchi Toshihiko
• Kuriki Kazutaka
• Ishikawa Makoto
• Semiconductor Energy Lab

Inventors

• Takeuchi Toshihiko
• Kuriki Kazutaka
• Ishikawa Makoto

Classifications

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01G11/50

  specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation · CPC title

• C23C16/56

  After-treatment · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01G11/30

  characterised by their material · CPC title