Method of forming an oxide film

• US 6,586,346 B1
• Filed: 10/26/1992
• Issued: 07/01/2003
• Est. Priority Date: 02/06/1990
• Status: Expired due to Fees

• Current Assignee: Hongyong Zhang, Shunpei Yamazaki
• Original Assignee: Hongyong Zhang, Shunpei Yamazaki
• Inventors: Yamazaki, Shunpei, Zhang, Hongyong
• Primary Examiner(s): WILCZEWSKI, MARY A
• Application Number:
  US07/966,607
• Time in Patent Office: 3,900 Days
• Field of Search: 437/235, 437/238, 437/239, 204/192.1, 204/192.12, 204/192.15, 204/192.22, 204/192.23, 438/151, 438/774, 438/770, 438/771, 438/787, 438/788
• US Class Current: 438/774
• CPC Class Codes: C23C 14/10 Glass or silica
• CPC Class Codes: H01L 21/02131 the material being halogen doped silicon oxides, e.g. FSG
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02266 deposition by physical ablation of a target, e.g. sputtering, reactive sputtering, physical vapour deposition or pulsed laser deposition
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/28158 Making the insulator
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/31629 Deposition of halogen doped silicon oxide, e.g. fluorine doped silicon oxide
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate

Abstract

A method of forming an oxide film and a method of manufacturing an electronic device utilizing the oxide film is disclosed. A silicon oxide film is formed on a substrate by sputtering. Therefore, the film formation is carried out at a low temperature. The sputtering atmosphere comprises an oxidizing gas and an inert gas such as argon. In order to prevent fixed electric charges from being generated in the film and to obtain an oxide film of good properties, the proportion of argon is adjusted to 20% or less. Alternatively, a gas including halogen elements such as fluorine is added to the above sputtering atmosphere at a proportion less than 20%. Hereupon, alkali ions and dangling bonds of silicon in the oxide film are neutralized by the halogen elements, whereby a fine oxide film is obtained.

Claims

1. A method of forming a field effect transistor, said method comprising the step of:

depositing an insulating gate oxide film on a semiconductor layer by sputtering a target in an atmosphere comprising an oxidizing gas, an inert gas and a gas comprising fluorine,

wherein the gate oxide film is deposited by a magnetron sputtering method, and

wherein the oxidizing gas and the gas comprising fluorine are present in a range of 80 to 100% of the atmosphere.

2. A method according to claim 1 further comprising the step of annealing the gate oxide film by irradiating with a laser light.

3. A method according to claim 1, wherein the semiconductor layer is formed over a glass substrate.

4. A method according to claim 1 wherein the depositing step is carried out at a temperature not higher than 300°

C.

5. A method according to claim 1, wherein the gas comprising fluorine comprises at least one selected from the group consisting of nitrogen fluoride (NF₃, N₂F₄), hydrogen fluoride (HF), fluorine (F₂), and fluorinated hydrocarbon gas.

6. A method according to claim 1, wherein the gate insulating oxide comprises silicon dioxide.

7. A method of forming a field effect transistor, said method comprising the steps of:

depositing an insulating gate oxide film on a semiconductor layer by sputtering a target in an atmosphere comprising at least an oxidizing gas and a gas comprising fluorine;

annealing the gate oxide film by irradiating with a laser light after the depositing step; and

forming a gate electrode adjacent to the gate oxide film.

8. A method according to claim 7, wherein the oxidizing gas comprises oxygen, ozone, or nitrous oxide.

9. A method according to claim 7, wherein the depositing step is carried out at a temperature not higher than 300°

C.

10. A method according to claim 7, wherein the gas comprising fluorine comprises at least one selected from the group consisting of nitrogen fluoride (NF₃, N₂F₄), hydrogen fluoride (HF), fluorine (F₂), and fluorinated hydrocarbon gas.

11. A method according to claim 7, wherein the gate insulating oxide comprises silicon dioxide.

12. A method of forming a field effect transistor, said method comprising the steps of:

depositing at least an intrinsic semiconductor island over a glass substrate;

forming source and drain regions over the substrate; and

depositing an insulating oxide film on the semiconductor island by sputtering a target in an atmosphere comprising an oxidizing gas, an inert gas and a gas comprising fluorine,

wherein the oxide film is deposited by a magnetron sputtering method, and

wherein the oxidizing gas and the gas comprising fluorine are present in a range of 80 to 100% of the atmosphere.

13. A method according to claim 12, wherein the oxidizing gas comprises oxygen, ozone, or nitrous oxide.

14. A method according to claim 12, wherein the inert gas comprises argon.

15. A method according to claim 12, wherein the oxide film depositing step is carried out at a temperature not higher than 300°

C.

16. A method according to claim 12, wherein the gas comprising fluorine comprises at least one selected from the group consisting of nitrogen fluoride (NF₃, N₂F₄), hydrogen fluoride (HF), fluorine (F₂), and fluorinated hydrocarbon gas.

17. A method according to claim 12, wherein the gate insulating oxide comprises silicon dioxide.

18. A method of forming a field effect transistor, said method comprising the steps of:

depositing at least an intrinsic semiconductor island over a glass substrate;

forming source and drain regions over the glass substrate; and

depositing an insulating gate oxide film on the intrinsic semiconductor island by sputtering a target in an atmosphere comprising an oxidizing gas and a gas comprising fluorine.

19. A method according to claim 18, wherein the oxidizing gas comprises oxygen, ozone, or nitrous oxide.

20. A method according to claim 18, wherein the oxide film depositing step is carried out at a temperature not higher than 300°

C.

21. A method according to claim 18, wherein the gas comprising fluorine comprises at least one selected from the group consisting of nitrogen fluoride (NF₃, N₂F₄), hydrogen fluoride (HF), fluorine (F₂), and fluorinated hydrocarbon gas.

22. A method according to claim 18, wherein the gate insulating oxide comprises silicon dioxide.

23. A method of forming a field effect transistor, said method comprising the step of:

depositing an insulating gate oxide film on a semiconductor layer by sputtering a target in an atmosphere comprising an oxidizing gas, an inert gas and a gas comprising fluorine,

wherein the oxidizing gas and the gas comprising fluorine are present in a range of 80 to 100% of the atmosphere, and

wherein a turbo-molecular pump is utilized while depositing the gate oxide film to prevent back diffusion of oil vapor.

24. A method according to claim 23, wherein the gas comprising fluorine comprises at least one selected from the group consisting of nitrogen fluoride (NF₃, N₂F₄), hydrogen fluoride (HF), fluorine (F₂), and fluorinated hydrocarbon gas.

25. A method according to claim 23, wherein the gate insulating oxide comprises silicon dioxide.