Method for growing germanium epitaxial films

• US 9,305,779 B2
• Filed: 08/11/2009
• Issued: 04/05/2016
• Est. Priority Date: 08/11/2009
• Status: Expired due to Fees

• Current Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Original Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Inventors: Carothers, Daniel N., Hill, Craig M., Pomerene, Andrew T. S., Vu, Vu A.
• Primary Examiner(s): MCDONOUGH, JAMES E
• Application Number:
  US12/539,003
• Publication Number:
  US 20110036289A1
• Time in Patent Office: 2,429 Days
• Field of Search: 117/94, 117/84, 117/88, 117/89
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0245 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/02645 Seed materials
• CPC Class Codes: H01L 21/02658 Pretreatments cleaning in general H01L21/02041

Abstract

A method for growing germanium epitaxial films is disclosed. Initially, a silicon substrate is preconditioned with hydrogen gas. The temperature of the preconditioned silicon substrate is then decreased, and germane gas is flowed over the preconditioned silicon substrate to form an intrinsic germanium seed layer. Next, a mixture of germane and phosphine gases can be flowed over the intrinsic germanium seed layer to produce an n-doped germanium seed layer. Otherwise, a mixture of diborane and germane gases can be flowed over the intrinsic germanium seed layer to produce a p-doped germanium seed layer. At this point, a bulk germanium layer can be grown on top of the doped germanium seed layer.

Claims

1. A method for growing germanium epitaxial films, said method comprising:

flowing germane gas over a silicon substrate at a first temperature to form an intrinsic germanium seed layer on said silicon substrate;

increasing said first temperature of said silicon substrate to a second temperature;

flowing a mixture of diborane gas and germane gas over said intrinsic germanium seed layer to produce a doped germanium seed layer; and

growing a bulk germanium film layer on top of said doped germanium layer.

2. The method of claim 1, wherein said first temperature is approximately 350°

C.

3. The method of claim 1, wherein said flowing germane gas further includes flowing germane gas at approximately 1.5E⁻

3 mBar.

4. The method of claim 1, wherein said second temperature is approximately 600°

C.

6. The method of claim 1, wherein said mixture of gases is flowed over said intrinsic germanium seed layer at approximately 6E⁻

4 mBar.

7. The method of claim 1, wherein said bulk germanium film layer is intrinsic germanium film.

8. The method of claim 1, wherein said bulk germanium film layer is doped germanium film.

9. The method of claim 1, wherein said flowing a mixture of said gases further includes flowing said mixture of said gases while increasing temperature from said first temperature to said second temperature.

5. A method for growing germanium epitaxial films, said method comprising:

flowing germane gas over a silicon substrate at a first temperature to form an intrinsic germanium seed layer on said silicon substrate;

increasing said first temperature of said silicon substrate to a second temperature;

flowing a mixture of dopant gas and germane gas over said intrinsic germanium seed layer to produce a doped germanium seed layer, wherein said dopant gas contains phosphine; and

growing a bulk germanium film layer on top of said doped germanium layer.

10. A method for growing germanium epitaxial films, said method comprising:

flowing germane gas over a silicon substrate at a first temperature to form an intrinsic germanium seed layer on said silicon substrate;

increasing said first temperature of said silicon substrate to a second temperature;

flowing a mixture of dopant gas and germane gas over said intrinsic germanium seed layer to produce a doped germanium seed layer, wherein said flowing a mixture of said gases further includes flowing a mixture of said gases over said intrinsic germanium seed layer to produce said doped germanium seed layer capable of reducing crystalline defects in said intrinsic germanium seed layer via lattice mismatch reduction; and

growing a bulk germanium film layer on top of said doped germanium layer.