Method for manufacturing semiconductor device comprising forming oxide semiconductor by sputtering

• US 9,048,094 B2
• Filed: 07/18/2013
• Issued: 06/02/2015
• Est. Priority Date: 09/24/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Miyanaga, Akiharu, Sakata, Junichiro, Sakakura, Masayuki, Yamazaki, Shunpei
• Primary Examiner(s): GORDON, MATTHEW E
• Application Number:
  US13/945,487
• Publication Number:
  US 20130330914A1
• Time in Patent Office: 684 Days
• Field of Search: 257/43, 257/E21.461, 438/795
• US Class Current: 1/1
• 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 21/477 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/38 - H01L21/449 and H01L21/461 - H01L21/475 take precedence
• 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 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• 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
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

It is an object to provide a thin film transistor having favorable electric characteristics and high reliability and a semiconductor device which includes the thin film transistor as a switching element. An In—Ga—Zn—O-based film having an incubation state that shows an electron diffraction pattern, which is different from a conventionally known amorphous state where a halo shape pattern appears and from a conventionally known crystal state where a spot appears clearly, is formed. The In—Ga—Zn—O-based film having an incubation state is used for a channel formation region of a channel etched thin film transistor.

Claims

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

introducing a substrate into a chamber, wherein the chamber is provided with a magnet system and a target comprising In, Ga and Zn, and wherein a relative density of the target is greater than or equal to 80%;

forming an oxide semiconductor layer by magnetron sputtering using the magnet system and the target over the substrate after reverse sputtering is performed, wherein the substrate is heated during the magnetron sputtering;

patterning the oxide semiconductor layer into an island-shaped region including a channel formation region; and

performing dehydration or dehydrogenation by heat treatment in a heat treatment apparatus after the oxide semiconductor layer is patterned,

wherein the oxide semiconductor layer comprises In, Ga and Zn, and

wherein a purity of an inert gas which is introduced into the heat treatment apparatus during the heat treatment is set greater than or equal to 99.9999%.

2. The method according to claim 1, wherein the substrate is heated at a temperature of 400°

C. to 700°

C. during the magnetron sputtering.

3. The method according to claim 1, further comprising:

performing a preheat treatment, so that an inside of a film deposition chamber is heated, before forming the oxide semiconductor layer.

4. The method according to claim 1, wherein moisture in a sputtering apparatus is removed by using a cryopump.

5. The method according to claim 1, wherein an electron diffraction pattern of the oxide semiconductor layer does not show a halo shape pattern.

6. The method according to claim 1, wherein the oxide semiconductor layer is formed without being exposed to air after the reverse sputtering.

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

forming a gate electrode over a substrate;

forming a gate insulating layer over the gate electrode;

introducing the substrate into a chamber, wherein the chamber is provided with a magnet system and a target comprising In, Ga and Zn, and wherein a relative density of the target is greater than or equal to 80%;

forming an oxide semiconductor layer by magnetron sputtering using the magnet system and the target over the gate insulating layer after reverse sputtering is performed, wherein the substrate is heated during the magnetron sputtering;

patterning the oxide semiconductor layer into an island-shaped region including a channel formation region; and

performing dehydration or dehydrogenation by heat treatment in a heat treatment apparatus after the oxide semiconductor layer is patterned,

wherein the oxide semiconductor layer comprises In, Ga and Zn, and

wherein a purity of an inert gas which is introduced into the heat treatment apparatus during the heat treatment is set greater than or equal to 99.9999%.

8. The method according to claim 7, wherein the substrate is heated at a temperature of 400°

C. to 700°

C. during the magnetron sputtering.

9. The method according to claim 7, further comprising:

performing a preheat treatment, so that an inside of a film deposition chamber is heated, before forming the oxide semiconductor layer.

10. The method according to claim 7, wherein moisture in a sputtering apparatus is removed by using a cryopump.

11. The method according to claim 7, wherein an electron diffraction pattern of the oxide semiconductor layer does not show a halo shape pattern.

12. The method according to claim 7, wherein the oxide semiconductor layer is formed without being exposed to air after the reverse sputtering.

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

introducing a substrate into a chamber, wherein the chamber is provided with a magnet system and a target comprising In, Ga and Zn, and wherein a relative density of the target is greater than or equal to 80%;

forming an oxide semiconductor layer by magnetron sputtering using the magnet system and the target over the substrate while removing moisture with use of a cryopump before, during or after the oxide semiconductor layer is formed, wherein the substrate is heated during the magnetron sputtering;

patterning the oxide semiconductor layer into an island-shaped region including a channel formation region; and

performing dehydration or dehydrogenation by heat treatment in a heat treatment apparatus after the oxide semiconductor layer is patterned,

wherein the oxide semiconductor layer comprises In, Ga and Zn, and

wherein a purity of an inert gas which is introduced into the heat treatment apparatus during the heat treatment is set greater than or equal to 99.9999%.

14. The method according to claim 13, wherein a gas containing oxygen is used when forming the oxide semiconductor layer.

15. The method according to claim 13, wherein the substrate is heated at a temperature of 400°

C. to 700°

C. during the magnetron sputtering.

16. The method according to claim 13, further comprising:

performing a preheat treatment, so that an inside of a film deposition chamber is heated, before forming the oxide semiconductor layer.

17. The method according to claim 13, wherein an electron diffraction pattern of the oxide semiconductor layer does not show a halo shape pattern.

18. The method according to claim 14, wherein the gas containing oxygen is an oxygen gas.