US5357899A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Epitaxial silicon membranes
Assignee: International Business Machines Corp
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Filing: 1993-09-13
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Granted: 1994-10-25
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Expires: 2013-09-13
Abstract
Abstract The subject invention provides a silicon membrane material made from silicon that is epitaxially deposited at low temperatures greater than or equal to 500° C. and doped with controlled amounts of boron and germanium. A silicon membrane structure is provided and made by one or more layers of ultra thin epitaxially deposited silicon layers that are precisely controlled in both thickness and composition. At least one of the layers is doped with boron in a concentration range greater than 2×10 20 atoms of boron per cubic centimeter of silicon, or with germanium in a concentration range greater than 5×10 20 atoms of germanium per cubic centimeter of silicon, or with a combination of boron and germanium in these concentration ranges. A silicon membrane fabrication process is also provided which requires no additional masking film to protect the membrane surface during KOH etching of the bulk silicon substrate.
Inventors
- 👤 Ernest Bassous
- 👤 Bernard S. Meyerson
- 👤 Kevin J. Uram
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:02
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/22; G01; G01L; G01L9/00; G01L9/0041; G01L9/0042; H; H10; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/644
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
131 words
A method of producing an epitaxial silicon membrane, said method comprising the steps of: growing one or more films of silicon epitaxially using chemical vapor deposition at a temperature in a range of about 500° to about 850° C. on a substrate surface; and doping at least one of said silicon films during said growing with a dopant selected from the group consisting of: boron in a concentration range greater than 2×10 20 atoms of boron/cm 3 of silicon; germanium in a concentration range greater than 5×10 20 atoms of germanium/cm 3 of silicon; and boron and germanium, said boron in a concentration range greater than 2×10 20 atoms of boron/cm 3 of silicon and said germanium in a concentration range greater than 5×10 20 atoms of germanium/cm 3 of silicon.
Claim 2
Independent Claim
131 words
A method of producing an epitaxial silicon membrane, said method comprising the steps of: growing one or more films of silicon epitaxially using chemical vapor deposition at a temperature in a range of about 500° to about 850° C. on a substrate surface; and doping at least one of said silicon films during said growing with a dopant selected from the group consisting of: boron in a concentration range greater than 2×10 20 atoms of boron/cm 3 of silicon; germanium in a concentration range greater than 5×10 20 atoms of germanium/cm 3 of silicon; and boron and germanium, said boron in a concentration range greater than 2×10 20 atoms of boron/cm 3 of silicon and said germanium in a concentration range greater than 5×10 20 atoms of germanium/cm 3 of silicon.
Claim 3
Dependent Claim
27 words
The method of claim 1 wherein said substrate has two surfaces and said growing step comprises growing said films of silicon on both of said surfaces simultaneously.
Claim 4
Dependent Claim
10 words
The method of claim 1 wherein said substrate comprises silicon.
Claim 5
Independent Claim
133 words
A method of selectively etching an epitaxial silicon membrane, said method comprising the steps of: doping portions of said silicon membrane with a dopant selected from the group consisting of: boron in a concentration range greater than 2×10 20 atoms of boron/cm 3 of silicon; germanium in a concentration range greater than 5×10 20 atoms of germanium/cm 3 of silicon; and boron and germanium, said boron in a concentration range greater than 2×10 20 atoms of boron/cm 3 of silicon and said germanium in a concentration range greater than 5×10 20 atoms of germanium/cm 3 of silicon, other portions of said silicon membrane not being so doped; and etching the resulting silicon membrane with a strongly alkaline anisotropic chemical etching solution so as to selectively remove said other portions of said silicon membrane.
Claim 6
Independent Claim
133 words
A method of selectively etching an epitaxial silicon membrane, said method comprising the steps of: doping portions of said silicon membrane with a dopant selected from the group consisting of: boron in a concentration range greater than 2×10 20 atoms of boron/cm 3 of silicon; germanium in a concentration range greater than 5×10 20 atoms of germanium/cm 3 of silicon; and boron and germanium, said boron in a concentration range greater than 2×10 20 atoms of boron/cm 3 of silicon and said germanium in a concentration range greater than 5×10 20 atoms of germanium/cm 3 of silicon, other portions of said silicon membrane not being so doped; and etching the resulting silicon membrane with a strongly alkaline anisotropic chemical etching solution so as to selectively remove said other portions of said silicon membrane.
Claim 7
Dependent Claim
16 words
The method of claim 4 wherein said strongly alkaline anisotropic chemical etching solution comprises potassium hydroxide.
References Cited (Backward Citations)
US5259918A
Cited
US5286334A
Cited
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