Method for treating surface of silicon

• US 5,122,482 A
• Filed: 03/23/1990
• Issued: 06/16/1992
• Est. Priority Date: 03/31/1989
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Square Enix
• Original Assignee: Agency of Industrial Science & Technology, Ministry of International Trade & Industry (Government of Malaysia)
• Inventors: Kondo, Yasushi, Hayashi, Yutaka
• Primary Examiner(s): Hearn, Brian E.
• Assistant Examiner(s): Everhart, B.
• Application Number:
  US07/498,221
• Time in Patent Office: 816 Days
• Field of Search: 437/225, 437/228, 427/36, 427/38, 427/39, 427/54.1, 156/643, 156/646, 148/DIG. 17
• US Class Current: 438/694
• CPC Class Codes: H01L 21/02046 Dry cleaning only H01L21/02085 takes precedence
• CPC Class Codes: H01L 21/02049 with gaseous HF
• CPC Class Codes: Y10S 148/017 Clean surfaces

Abstract

In a method for treating the surface of either crystalline or amorphous silicon a silicon material is maintained in a non-oxidizing atmosphere with a reduced pressure, a gas selected from among hydrides of phosphorus, fluorides of phosphorus, hydrides of arsenic, fluorides of arsenic, hydrides of boron, fluorides of boron and fluorides of silicon is excited and the excited gas is supplied onto the surface of the silicon material for a prescribed period of time. During this period the temperature of the silicon material is maintained within a range higher than the temperature at which the molecules of the selected gas would, were the gas not excited, liquefy at the reduced pressure and deposit on the material and lower than the temperature at which the gas decomposes. The method enables the silicon material surface to be cleaned and/or protected by treatment at a relatively low temperature. The treatment has the effect of improving various electrical, chemical and physical characteristics of the surface of silicon material and as such improves the performance and characteristics of a device or integrated circuit including the silicon material.

Claims

1. A method for treating the surface of silicon comprising the steps of maintaining a silicon material in a non-oxidating atmosphere with a reduced pressure, exciting a gas selected from among hydrides of phosphorus, fluorides of phosphorus, hydrides of arsenic, fluorides of arsenic, hydrides of boron, fluorides of boron and fluorides of silicon and supplying the excited gas onto the surface of the silicon material for a prescribed period of time, and during this time maintaining the temperature of the silicon material within a range higher than the temperature at which the molecules of the selected gas would, were the gas not excited, liquefy at the reduced pressure and deposit on the material and lower than the temperature at which the gas decomposes.

2. A method in accordance with claim 1, wherein the selected gas is excited by plasma excitation.

3. A method in accordance with claim 1, wherein the selected gas is excited by ultraviolet ray excitation.

4. A method in accordance with claim 1, wherein the selected gas is excited by X-ray excitation.

5. A method in accordance with claim 1, wherein the selected gas is excited by electron beam excitation.

6. A method in accordance with claim 1, wherein the pressure of the non-oxidating atmosphere is of the order of 0.1-5 Torr, the excited gas is plasma-excited phosphine gas, and the temperature at which the silicon material is maintained is about 150°

-300°

C.

7. A method in accordance with claim 1, wherein the pressure of the non-oxidizing atmosphere is of the order of 0.1-5 Torr, the excited gas is plasma-excited diborane gas, and the temperature at which the silicon material is maintained is about 200°

-350°

C.

8. A method for treating the surface of silicon comprising the steps of, in a process conducted immediately before epitaxially growing a crystalline semiconductor layer on the surface of a crystalline semiconductor material, maintaining the silicon material in a non-oxidizing atmosphere with a reduced pressure, exciting a gas selected from among hydrides of phosphorus, fluorides of phosphorus, hydrides of arsenic, fluorides of arsenic, hydrides of boron, fluorides of boron and fluorides of silicon and supplying the excited gas onto the surface of the silicon material for a prescribed period of time, and during this time maintaining the temperature of the silicon material within a range higher than the temperature at which the molecules of the selected gas would, were the gas not excited, liquefy at the reduced pressure and deposit on the material and lower than the temperature at which the gas decomposes.

9. A method in accordance with claim 8, wherein the selected gas is excited by plasma excitation.

10. A method in accordance with claim 8, wherein the selected gas is excited by ultraviolet ray excitation.

11. A method in accordance with claim 8, wherein the selected gas is excited by X-ray excitation.

12. A method in accordance with claim 8, wherein the selected gas is excited by electron beam excitation.

13. A method in accordance with claim 8, wherein the pressure of the non-oxidizing atmosphere is of the order of 0.1-5 Torr, the excited gas is plasma-excited phosphine gas, and the temperature at which the silicon material is maintained is about 150°

-300°

C.

14. A method according to claim 13, further comprising the step of sublimating phosphorus from the surface of the treated silicon material by heating the silicon to 400°

-500°

C. after treating the surface of the silicon material and before epitaxially growing a crystalline semiconductor layer on the surface thereof.

15. A method in accordance with claim 8, wherein the pressure of the non-oxidizing atmosphere is of the order of 0.1-5 Torr, the excited gas is plasma-excited diborane gas, and the temperature at which the silicon material is maintained is about 200°

-350°

C.

16. A method for treating the surface of silicon comprising the steps of, in a process conducted immediately before depositing a material forming a junction exhibiting rectifier characteristics or ohmic characteristics on the surface of a crystalline semiconductor material, maintaining the silicon material in a non-oxidizing atmosphere with a reduced pressure, exciting a gas selected from among hydrides of phosphorus, fluorides of phosphorus, hydrides of arsenic, fluorides of arsenic, hydrides of boron, fluorides of boron and fluorides of silicon and supplying the excited gas onto the surface of the silicon material for a prescribed period of time, and during this time maintaining the temperature of the silicon material within a range higher than the temperature at which the molecules of the selected gas would, were the gas not excited, liquefy at the reduce pressure and deposit on the material and lower than the temperature at which the gas decomposes.

17. A method in accordance with claim 16, wherein the selected gas is excited by plasma excitation.

18. A method in accordance with claim 16, wherein the selected gas is excited by ultraviolet ray excitation.

19. A method in accordance with claim 16, wherein the selected gas is excited by X-ray excitation.

20. A method in accordance with claim 16, wherein the selected gas is excited by electron beam excitation.

21. A method in accordance with claim 16, wherein the pressure of the non-oxidizing atmosphere is of the order of 0.1-5 Torr, the excited gas is plasma-excited phosphine gas, and the temperature at which the silicon material is maintained is about 150°

-300°

C.

22. A method in accordance with claim 16, wherein the pressure of the non-oxidizing atmosphere is of the order of 0.1-5 Torr, the excited gas is plasma-excited diborane gas, and the temperature at which the silicon material is maintained is about 200°

-350°

C.

23. A method for treating the surface of silicon comprising the steps of, in a process conducted immediately before depositing an amorphous semiconductor on the surface of a crystalline semiconductor material, maintaining the silicon material in a non-oxidizing atmosphere with a reduced pressure, exciting a gas selected from among hydrides of phosphorus, fluorides of phosphorus, hydrides of arsenic, fluorides of arsenic, hydrides of boron, fluorides of boron and fluorides of silicon and supplying the excited gas onto the surface of the silicon material for a prescribed period of time, and during this time maintaining the temperature of the silicon material within a range higher than the temperature at which the molecules of the selected gas would, were the gas not excited, liquefy at the reduced atmosphere and deposit on the material and lower than the temperature at which the gas decomposes.

24. A method in accordance with claim 23, wherein the selected gas is excited by plasma excitation.

25. A method in accordance with claim 23, wherein the selected gas is excited by ultraviolet ray excitation.

26. A method in accordance with claim 23, wherein the selected gas is excited by X-ray excitation.

27. A method in accordance with claim 23, wherein the selected gas is excited by electron beam excitation.

28. A method in accordance with claim 23, wherein the pressure of the non-oxidizing atmosphere is of the order of 0.1-5 Torr, the excited gas is plasma-excited phosphine gas, and the temperature at which the silicon material is maintained is about 150°

-300°

C.

29. A method in accordance with claim 23, wherein the pressure of the non-oxidizing atmosphere is of the order of 0.1-5 Torr, the excited gas is plasma-excited diborane gas, and the temperature at which the silicon material is maintained is about 200°

-350°

C.

30. A method for treating the surface of silicon comprising a first surface treatment and a second surface treatment,

the first surface treatment comprising the steps of exciting a gas selected from among hydrides of phosphorus, fluorides of phosphorus, hydrides of arsenic, fluorides of arsenic, hydrides of boron, fluorides of boron and fluorides of silicon and supplying the excited gas onto the surface of the silicon material for a prescribed period of time, and during this time maintaining the temperature of the silicon material within a range higher than the temperature at which the molecules of the selected gas would, were the gas not excited, liquefy at the reduced pressure and deposit on the material and lower than the temperature at which the gas decomposes, and

the second treatment step comprising the step of again subjecting the silicon material treated in the first treatment step to heat treatment in a reduced-pressure atmosphere after it has been exposed to an unclean atmosphere.

31. A method in accordance with claim 30, wherein the selected gas is excited by plasma excitation.

32. A method in accordance with claim 30, wherein the selected gas is excited by ultraviolet ray excitation.

33. A method in accordance with claim 30, wherein the selected gas is excited by X-ray excitation.

34. A method in accordance with claim 30, wherein the selected gas is excited by electron beam excitation.

35. A method in accordance with claim 30, wherein the pressure of the non-oxidizing atmosphere is of the order of 0.1-5 Torr, the excited gas is plasma-excited phosphine gas, and the temperature at which the silicon material is maintained is about 150°

-300°

C.

36. A method in accordance with claim 30, wherein the pressure of the non-oxidizing atmosphere is of the order of 0.1-5 Torr, the excited gas is plasma-excited diborane gas, and the temperature at which the silicon material is maintained is about 200°

-350°

C.

37. A method in accordance with claim 30, wherein the temperature of the silicon material in the second treatment step is about 400°

-500°

C.