US5397429A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing photoluminescing porous silicon using spark erosion
Assignee: University of Florida
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Filing: 1993-09-14
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Granted: 1995-03-14
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Expires: 2013-09-14
Abstract
Abstract A high frequency, high voltage spark generator is used to create a large number of sparks to erode the surface of a silicon wafer to a depth of up to 100 microns. After a sufficient amount of erosion has occurred, but prior to any macro-scale removal of material, the surface layer of the silicon wafer becomes porous and photoluminescing. The method can be performed in ambient atmosphere and temperature, or in specific gas atmospheres and at different temperatures. The method produces photoluminescing porous silicon layers on p-type, n-type, low-doped, high-doped or undoped silicon wafers.
Inventors
- 👤 Rolf E. Hummel
- 👤 Sung-Sik Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:38
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/822; H10H20/826; H10H20/8264
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
85 words
A method for the manufacture of a photoluminescing porous silicon layer on a silicon wafer substrate comprising the steps of: (A) providing a high voltage, high frequency spark generator capable of delivering a high number of sparks to the surface of a silicon wafer substrate; (B) eroding a portion of the surface of a silicon wafer substrate to a depth of less than 100 microns by the application of a high number of sparks to said silicon wafer surface to create a porous surface layer.
Claim 2
Independent Claim
85 words
A method for the manufacture of a photoluminescing porous silicon layer on a silicon wafer substrate comprising the steps of: (A) providing a high voltage, high frequency spark generator capable of delivering a high number of sparks to the surface of a silicon wafer substrate; (B) eroding a portion of the surface of a silicon wafer substrate to a depth of less than 100 microns by the application of a high number of sparks to said silicon wafer surface to create a porous surface layer.
Claim 3
Dependent Claim
15 words
The method of claim 1, where said spark generator produces at least approximately 1000 volts.
Claim 4
Dependent Claim
14 words
The method of claim 1, where said spark generator produces at least 10,000 volts.
Claim 5
Dependent Claim
17 words
The method of claim 1, where said spark generator operates at frequencies of at least one kilohertz.
Claim 6
Dependent Claim
13 words
The method of claim 1, where said eroding is performed at room temperature.
Claim 7
Dependent Claim
13 words
The method of claim 1, where said eroding is performed in ambient atmosphere.
Claim 8
Dependent Claim
15 words
The method of claim 1, where said eroding is performed in a specific gas atmosphere.
Claim 9
Dependent Claim
28 words
The method of claim 1, where said porous surface layer comprises particles ranging from 3 to 125 nanometers in diameter and pores ranging from 10 to 2000 nanometers.
Claim 10
Dependent Claim
13 words
The method of claim 1, where said spark generator comprises a metal electrode.
Claim 11
Dependent Claim
13 words
The method of claim 1, where said spark generator comprises a silicon electrode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-03-13 | 1998-09-12 | 1999-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-03-13 | 2002-09-12 | 2003-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-03-13 | 2006-09-12 | 2007-03-14 | $7700.00 | Window Closed / Lapsed |