Method of preventing surface roughening during hydrogen prebake of SiGe substrates

• US 6,958,286 B2
• Filed: 01/02/2004
• Issued: 10/25/2005
• Est. Priority Date: 01/02/2004
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Chen, Huajie, Sadana, Devendra K., Murphy, Richard J., Mocuta, Dan M., Bedell, Stephan W.
• Primary Examiner(s): Zarabian, Amir
• Assistant Examiner(s): Tran, Thanh Y.
• Application Number:
  US10/751,208
• Publication Number:
  US 20050148161A1
• Time in Patent Office: 662 Days
• Field of Search: 438/584, 438/602, 438/604, 438/607, 438/933, 438/752, 438/753
• US Class Current: 438/602
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/06 Silicon
• CPC Class Codes: C30B 29/52 Alloys
• CPC Class Codes: H01L 21/02046 Dry cleaning only H01L21/02085 takes precedence
• CPC Class Codes: H01L 21/02052 Wet cleaning only H01L21/02085 takes precedence
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0243 Surface structure
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02658 Pretreatments cleaning in general H01L21/02041
• CPC Class Codes: H01L 21/02661 In-situ cleaning
• CPC Class Codes: Y10S 438/933 Germanium or silicon or Ge-Si on III-V

Abstract

The invention forms an epitaxial silicon-containing layer on a silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface and avoids creating a rough surface upon which the epitaxial silicon-containing layer is grown. In order to avoid creating the rough surface, the invention first performs a hydrofluoric acid etching process on the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. This etching process removes most of oxide from the surface, and leaves a first amount of oxygen (typically 1×10¹³−1×10¹⁵/cm² of oxygen) on the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. The invention then performs a hydrogen pre-bake process which heats the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface sufficiently to remove additional oxygen from the surface and leave a second amount of oxygen, less than the first amount, on the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. The heating process leaves an amount of at least 5×10¹²/cm² of oxygen (typically, between approximately 1×10¹³/cm² and approximately 5×10¹³/cm² of oxygen) on the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. By leaving a small amount of oxygen on the silicon germanium, patterned strained silicon, or patterned silicon-on-insulator surface, the heating processes avoid changing the roughness of the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. Then the process of epitaxially growing the epitaxial silicon-containing layer on the silicon germanium, patterned strained silicon, or patterned silicon-on-insulator surface is performed.

Claims

1. A method of forming an epitaxial silicon-containing layer on a silicon germanium surface, said method comprising:

performing an ex-situ chemical oxide removal process on said silicon germanium surface so as to partially remove oxygen from said silicon germanium surface and leave a first amount of oxygen on said silicon germanium surface;

heating said silicon germanium surface sufficiently to remove additional oxygen from said silicon germanium surface and leave a second amount of oxygen, less than said first amount, on said silicon germanium surface; and

epitaxially growing said epitaxial silicon-containing layer on said silicon germanium surface.

2. The method in claim 1, wherein said ex-situ chemical oxide removal and heating processes increase the roughness of said silicon germanium surface by less than 1 Å

RMS.

3. The method in claim 1, wherein said silicon-containing layer comprises one of Si, Si_xGe_1-x, Si_xC_1-x, and Si_xGe_yC_1-x-y.

4. The method in claim 1, wherein said ex-situ chemical oxide removal comprises a hydrofluoric acid etch.

5. The method in claim 4, where said hydrofluoric acid comprises a H₂O:

HF solution with ratio of 10;

1 to 500;

1.

6. The method in claim 1, wherein said first amount of oxygen is less than 1×

10¹⁵/cm².

7. The method in claim 1, wherein said second amount of oxygen is at least 5×

10¹²/cm².

8. The method in claim 1, wherein said second amount of oxygen is between approximately 1×

10¹³/cm² and approximately 5×

10¹³/cm².

9. The method in claim 1, wherein said heating process is performed in a hydrogen-containing ambient.

10. A method of forming an epitaxial silicon-containing layer on a silicon surface, said method comprising:

performing an ex-situ chemical oxide removal process on said silicon surface so as to partially remove oxygen from said silicon surface and leave a first amount of oxygen on said silicon surface;

heating said silicon surface sufficiently to remove additional oxygen from said silicon surface and leave a second amount of oxygen, less than said first amount, on said silicon surface; and

epitaxially growing said epitaxial silicon-containing layer on said silicon surface.

11. The method in claim 10, wherein said silicon surface comprises one of a patterned strained silicon surface and a patterned thin silicon-on-insulator (SOI) surface.

12. The method in claim 10, wherein said ex-situ chemical oxide removal and heating processes increase the roughness of said silicon surface by less than 1 Å

RMS.

13. The method in claim 10, wherein said silicon-containing layer comprises one of Si, Si_xGe_1-x, Si_xC_1-x, and Si_xGe_yC_1-x-y.

14. The method in claim 10, wherein said ex-situ chemical oxide removal comprises a hydrofluoric acid etch.

15. The method in claim 14, where said hydrofluoric acid comprises a H₂O:

HF solution with ratio of 10;

1 to 500;

1.

16. The method in claim 10, wherein said first amount of oxygen is less than 1×

10¹⁵/cm².

17. The method in claim 10, wherein said second amount of oxygen is at least 5×

10¹²/cm².

18. The method in claim 10, wherein said second amount of oxygen is between approximately 1×

10¹³/cm² and approximately 5×

10¹³/cm².

19. The method in claim 10, wherein said heating process is performed in a hydrogen-containing ambient.

20. A method of forming an epitaxial silicon-containing layer on a silicon surface, wherein said silicon surface comprises one of a patterned strained silicon surface and a patterned thin silicon-on-insulator (SOI) surface, said method comprising:

performing an ex-situ chemical oxide removal process on said silicon surface so as to partially remove oxygen from said silicon surface and leave a first amount of oxygen on said silicon surface;

heating said silicon surface sufficiently to remove additional oxygen from said silicon surface and leave a second amount of oxygen, less than said first amount, on said silicon surface; and

epitaxially growing said epitaxial silicon-containing layer on said silicon surface.