Epitaxial silicon membranes
First Claim
1. 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×
1020 atoms of boron/cm3 of silicon;
germanium in a concentration range greater than 5×
1020 atoms of germanium/cm3 of silicon; and
boron and germanium, said boron in a concentration range greater than 2×
1020 atoms of boron/cm3 of silicon and said germanium in a concentration range greater than 5×
1020 atoms of germanium/cm3 of silicon.
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Accused Products
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 2×1020 atoms of boron per cubic centimeter of silicon, or with germanium in a concentration range greater than 5×1020 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.
14 Citations
5 Claims
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1. 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; anddoping 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×
1020 atoms of boron/cm3 of silicon;
germanium in a concentration range greater than 5×
1020 atoms of germanium/cm3 of silicon; and
boron and germanium, said boron in a concentration range greater than 2×
1020 atoms of boron/cm3 of silicon and said germanium in a concentration range greater than 5×
1020 atoms of germanium/cm3 of silicon. - View Dependent Claims (2, 3)
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4. A method of selectively etching an epitaxial silicon membrane, said method comprising the steps of:
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doping portions of said silicon membrane with a dopant selected from the group consisting of;
boron in a concentration range greater than 2×
1020 atoms of boron/cm3 of silicon;
germanium in a concentration range greater than 5×
1020 atoms of germanium/cm3 of silicon; and
boron and germanium, said boron in a concentration range greater than 2×
1020 atoms of boron/cm3 of silicon and said germanium in a concentration range greater than 5×
1020 atoms of germanium/cm3 of silicon, other portions of said silicon membrane not being so doped; andetching the resulting silicon membrane with a strongly alkaline anisotropic chemical etching solution so as to selectively remove said other portions of said silicon membrane. - View Dependent Claims (5)
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Specification