Patent US5348618A successfully refreshed from Google Patents.
US5348618A
Expired / Lapsed
US
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Method of making silicon quantum wires
Assignee: PAMERA MANAGEMENT Co LLC
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Filing: 1990-12-06
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Granted: 1994-09-20
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Expires: 2010-12-06
Abstract
Abstract A method of making semiconductor quantum wires employs a semiconductor wafer as starting material. The wafer is weakly doped p type with a shallow heavily doped p layer therein for current flow uniformity purposes. The wafer is anodised in 20% aqueous hydrofluoric acid to produce a layer microns thick with 70% porosity and good crystallinity. The layer is subsequently etched in concentrated hydrofluoric acid, which provides a slow etch rate. The etch increases porosity to a level in the region of 80% or above. At such a level, pores overlap and isolated quantum wires are expected to form with diameters less than or equal to 3 nm. The etched layer exhibits photoluminescence emission at photon energies well above the silicon bandgap (1.1 eV) and extending into the red region (1.6-2.0 eV) of the visible spectrum.
Inventors
- 👤 Leigh-Trevor Canham
- 👤 John M. Keen
- 👤 Weng Y. Leong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:05
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/822; H10H20/826; H10H20/8264; B; B82; B82Y; B82Y10/00; H10P; H10P50/00; Y; Y10; Y10S; Y10S438/00; Y10S438/96; Y10S438/962
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
43 words
A method of producing silicon quantum wires comprising the steps of: (1) anodizing crystalline silicon material (14) to produce a porous layer therein, and (2) etching the porous layer to widen the pores sufficiently to produce pore overlap thereby defining discrete quantum wires.
Claim 2
Independent Claim
43 words
A method of producing silicon quantum wires comprising the steps of: (1) anodizing crystalline silicon material (14) to produce a porous layer therein, and (2) etching the porous layer to widen the pores sufficiently to produce pore overlap thereby defining discrete quantum wires.
Claim 3
Dependent Claim
25 words
A method according to claim 1 wherein said etching step includes etching to form discrete quantum wires with a width not greater than 3 nm.
Claim 4
Dependent Claim
52 words
A method according to claim 1 wherein said anodizing step produces porosity in the range 20% to 80%, and said etching step includes etching at a rate in the range 0.0001 nm to 10 nm per minute to provide an increase in porosity to a value in the range 60% to 90%.
Claim 5
Dependent Claim
25 words
A method according to claim 3 wherein said etching step includes etching at a rate in the range 0.01 nm to 10 nm per minute.
Claim 6
Dependent Claim
30 words
A method according to claim 1 said anodizing step includes anodizing in one of aqueous and ethanoic hydrofluoric acid having a concentration in the range 10% to 50% by weight.
Claim 7
Dependent Claim
38 words
A method according to claim 5 wherein said anodizing step includes anodizing at a current density in the range 0.5 mAmp/cm 2 to 500 mAmp/cm 2 applied for a time in the range 10 seconds to 6000 seconds.
Claim 8
Dependent Claim
31 words
A method according to claim 1 wherein said etching step includes etching using one of aqueous and ethanoic hydrofluoric acid having a concentration in the range 5% to 50% by weight.
Claim 9
Dependent Claim
31 words
A method according to claim 1 wherein said etching step includes etching using one of aqueous and ethanoic hydrofluoric acid having a concentration in the range 6.7% to 50% by weight.
Claim 10
Dependent Claim
18 words
A method according to claim 1 wherein said anodizing step includes anodizing using an electrolyte containing a surfactant.
Claim 11
Dependent Claim
18 words
A method according to claim 1 wherein said etching step includes etching using an etchant containing a surfactant.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-19 | 1998-03-21 | 1998-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-19 | 2002-03-21 | 2002-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-19 | 2006-03-21 | 2006-09-20 | $7700.00 | Window Closed / Lapsed |