Method for manufacturing semiconductor device

• US 10,297,679 B2
• Filed: 02/05/2018
• Issued: 05/21/2019
• Est. Priority Date: 07/03/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Oikawa, Yoshiaki, Okazaki, Kenichi, Maruyama, Hotaka
• Primary Examiner(s): Tran, Thanh Y.
• Application Number:
  US15/888,316
• Publication Number:
  US 20180158932A1
• Time in Patent Office: 470 Days
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02664 Aftertreatments planarisation in general H01L21/304
• CPC Class Codes: H01L 21/28008 Making conductor-insulator-semiconductor electrodes
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• 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 29/78696 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

Disclosed is a method to manufacture a thin film transistor having an oxide semiconductor as a channel formation region. The method includes; forming an oxide semiconductor layer over a gate insulating layer; forming a source and drain electrode layers over and in contact with the oxide semiconductor layer so that at least portion of the oxide semiconductor layer is exposed; and forming an oxide insulating film over and in contact with the oxide semiconductor layer. The exposed portion of the oxide semiconductor may be exposed to a gas containing oxygen in the presence of plasma before the formation of the oxide insulating film. The method allows oxygen to be diffused into the oxide semiconductor layer, which contributes to the excellent characteristics of the thin film transistor.

Claims

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

forming a gate electrode layer over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode layer;

forming a partly crystallized oxide semiconductor layer over the gate insulating layer;

forming a conductive film over and in contact with the partly crystallized oxide semiconductor layer;

etching the conductive film to form a source electrode layer and a drain electrode layer over the partly crystallized oxide semiconductor layer;

after forming the source electrode layer and the drain electrode layer, treating the partly crystallized oxide semiconductor layer with plasma of a gas containing an oxygen element in a chamber; and

then

forming an oxide insulating film over the partly crystallized oxide semiconductor layer, the source electrode layer and the drain electrode layer using the gas containing an oxygen element and a deposition gas in the chamber, wherein the oxide insulating film contacts at least a portion of the partly crystallized oxide semiconductor layer between the source electrode layer and the drain electrode layer,

wherein the partly crystallized oxide semiconductor layer is heated at least from the step of treating with the plasma until the formation of the oxide insulating film at a temperature higher than or equal to 100°

C. and lower than or equal to 500°

C.

2. The method according to claim 1, wherein the gas containing an oxygen element contains nitrogen oxide.

3. The method according to claim 1, wherein the deposition gas contains silane.

4. The method according to claim 1, wherein the partly crystallized oxide semiconductor layer comprises indium, gallium and zinc.

5. The method according to claim 1, further comprising a step of heating the partly crystallized oxide semiconductor layer to increase a carrier concentration before the step of treating with the plasma.

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

forming a gate electrode layer over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode layer;

forming an oxide semiconductor layer having a crystal part over the gate insulating layer;

forming a conductive film over and in contact with the oxide semiconductor layer;

etching the conductive film to form a source electrode layer and a drain electrode layer over the oxide semiconductor layer;

after forming the source electrode layer and the drain electrode layer, treating the oxide semiconductor layer with plasma of a gas containing an oxygen element in a chamber; and

then

forming an oxide insulating film over the oxide semiconductor layer, the source electrode layer and the drain electrode layer using the gas containing an oxygen element and a deposition gas in the chamber, wherein the oxide insulating film contacts at least a portion of the oxide semiconductor layer between the source electrode layer and the drain electrode layer,

wherein the oxide semiconductor layer is heated at least from the step of treating with the plasma until the formation of the oxide insulating film at a temperature higher than or equal to 100°

C. and lower than or equal to 500°

C.

7. The method according to claim 6, wherein the gas containing an oxygen element contains nitrogen oxide.

8. The method according to claim 6, wherein the deposition gas contains silane.

9. The method according to claim 6, wherein the oxide semiconductor layer comprises indium, gallium and zinc.

10. The method according to claim 6, further comprising a step of heating the oxide semiconductor layer to increase a carrier concentration before the step of treating with the plasma.

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

forming a gate electrode layer over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode layer;

forming an oxide semiconductor layer having a crystal part over the gate insulating layer;

forming a conductive film over and in contact with the oxide semiconductor layer;

etching the conductive film to form a source electrode layer and a drain electrode layer over the oxide semiconductor layer, wherein an upper portion of the oxide semiconductor layer is exposed between the source electrode layer and the drain electrode layer;

after forming the source electrode layer and the drain electrode layer, treating the exposed upper portion of the oxide semiconductor layer with plasma of a gas containing an oxygen element in a chamber; and

then

forming an oxide insulating film over the oxide semiconductor layer, the source electrode layer and the drain electrode layer using the gas containing an oxygen element and a deposition gas in the chamber, wherein the oxide insulating film contacts at least a portion of the oxide semiconductor layer between the source electrode layer and the drain electrode layer,

wherein the oxide semiconductor layer is heated at least from the step of treating with the plasma until the formation of the oxide insulating film.

12. The method according to claim 11, wherein the oxide semiconductor layer is heated at least from the step of treating with the plasma until the formation of the oxide insulating film at a temperature higher than or equal to 100°

C. and lower than or equal to 500°

C.

13. The method according to claim 11, wherein the gas containing an oxygen element contains nitrogen oxide.

14. The method according to claim 11, wherein the deposition gas contains silane.

15. The method according to claim 11, wherein the oxide semiconductor layer comprises indium, gallium and zinc.

16. The method according to claim 11, further comprising a step of heating the oxide semiconductor layer to increase a carrier concentration before the step of treating with the plasma.