Patent US3640807A successfully refreshed from Google Patents.
US3640807A
Expired / Lapsed
US
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Method of manufacturing a semiconductor device and semiconductor device manufactured by said method
Assignee: US Philips Corp
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Filing: 1970-07-01
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Granted: 1972-02-08
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Expires: 1990-07-01
Abstract
Abstract The invention relates to a method of manufacturing semiconductor devices having thin layers of a semiconductor material. These thin layers are obtained, for example, by forming on a low-ohmic substrate a high-ohmic thin layer and then selectively removing the substrate electrolytically. Difficulties can arise during this removal when a readily conductive layer has been formed on the high-ohmic layer. The difficulties are prevented when the thickness of the high-ohmic layer is at least as large as the thickness of the depletion layer which is formed in the high-ohmic layer during the electrolytic removal of the substrate.
Inventors
- 👤 Hendrikus Josephus Antoni Dijk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:54
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/61; H10P50/613; H10P95/00; Y; Y10; Y10S; Y10S148/00; Y10S148/049; Y10S148/051; Y10S148/085; Y10S148/135; Y10S148/145; Y10S438/00; Y10S438/977
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
88 words
A method as claimed in claim 1, characterized in that for the high-ohmic material silicon is used and that is chosen to be > or = 1.25 X 1015, in which d is the thickness of the high-ohmic material between the substrate and the readily conductive layer in Mu m. ND-NA is the absolute value of the difference between the concentrations of the donors (ND) and the acceptors (NA) in the high-ohmic layer in at/cc. and V is the voltage in volts used during the electrolytic etching treatment.
Claim 2
Dependent Claim
20 words
A method as claimed in claim 2, characterized in that is chosen to be > or = 2 X 1015.
Claim 3
Dependent Claim
23 words
A method as claimed in claim 2, characterized in that the high-ohmic layer is given a thickness of at least 5 Mu m.
Claim 4
Dependent Claim
26 words
A method as claimed in claim 2, characterized in that the high-ohmic layer is given N-type conductivity and a resistivity which is at least 1 ohm.cm.
Claim 5
Dependent Claim
26 words
A method as claimed in claim 2, characterized in that the high-ohmic layer is given P-type conductivity and a resistivity which is at least 0.5 ohm.-cm.
Claim 6
Dependent Claim
22 words
A method as claimed in claim 2, characterized in that the high-ohmic layer is given a resistivity of at most 10 ohm.-cm.
Claim 7
Dependent Claim
28 words
A method as claimed in claim 1, characterized in that after the electrolytic etching treatment, the high-ohmic layer is removed at least partly by a chemical etching process.
References Cited (Backward Citations)
NL6703013A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |