Patent US4049488A successfully refreshed from Google Patents.
US4049488A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing a semiconductor device
Assignee: US Philips Corp
•
Filing: 1976-04-08
•
Granted: 1977-09-20
•
Expires: 1996-04-08
Abstract
Abstract The invention relates to a method of manufacturing a semiconductor device in which an etching process is used so as to etch regions consisting of A III B V compounds selectively relative to each other. According to the invention in the etching process an etching bath is used having a water-dissolved oxidizing material and a reducing material constituting together a redox system. In such an etching bath with redox system the selectivity is established by the choice of the concentrations of the materials and of the pH.
Inventors
- 👤 Rudolf Paulus Tijburg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:38
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/646; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0116; H10H; H10H20/00; H10H20/80
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
117 words
A method of manufacturing a semiconductor device having a semiconductor body of A III B V semiconductor material and comprising two adjoining regions of different compositions, one of the regions being etched selectively relative to the other region in a solution of an oxidizing material in water, comprising the steps of providing an etching solution consisting of said oxidizing material and a reducing material which forms a redox system with said oxidizing material, the concentrations of said oxidizing and reducing materials, as well as the pH of the solution, being chosen to be such that the ratio of the relative etching rates of said regions is at least 10:1, and etching said body with said etching solution.
Claim 2
Independent Claim
117 words
A method of manufacturing a semiconductor device having a semiconductor body of A III B V semiconductor material and comprising two adjoining regions of different compositions, one of the regions being etched selectively relative to the other region in a solution of an oxidizing material in water, comprising the steps of providing an etching solution consisting of said oxidizing material and a reducing material which forms a redox system with said oxidizing material, the concentrations of said oxidizing and reducing materials, as well as the pH of the solution, being chosen to be such that the ratio of the relative etching rates of said regions is at least 10:1, and etching said body with said etching solution.
Claim 3
Dependent Claim
16 words
A method as in claim 1, wherein said ratio of etching rates is at least 20:1.
Claim 4
Dependent Claim
16 words
A method as in claim 1, wherein said ratio of etching rates is at least 50:1.
Claim 5
Dependent Claim
26 words
A method as in claim 1, wherein one said region consists essentially of gallium arsenide and the other said region consists essentially of aluminium gallium arsenide.
Claim 6
Dependent Claim
24 words
A method as in claim 1, wherein said regions are of opposite conductivity types and are of the same A III B V compound.
Claim 7
Dependent Claim
16 words
A method as in claim 1, wherein said redox system contains potassium ferricyanide and potassium ferrocyanide.
Claim 8
Dependent Claim
14 words
A method as in claim 1, wherein said redox system contains cero-ions and ceri-ions.
Claim 9
Dependent Claim
14 words
A method as in claim 1, wherein said redox system contains ferri-ions and ferro-ions.
Claim 10
Dependent Claim
14 words
A method as in claim 1, wherein said redox system contains quinone and hydroquinone.
Claim 11
Dependent Claim
16 words
A method as in claim 1, wherein said redox system contains triiodide ions and iodide ions.
Claim 12
Dependent Claim
59 words
A method as in claim 1, wherein one of said regions consists essentially of gallium arsenide and the other of said regions consists essentially of aluminium gallium arsenide and said redox system comprises materials selected from the group consisting of potassium ferricyanide and potassium ferrocyanide, ceri-ions and cero-ions, ferro-ions and ferri-ions, hydroquinone and quinone, and triodide and iodide ions.
Claim 13
Dependent Claim
43 words
A method as in claim 1, wherein said redox system comprises ceri and cero ions and said pH level is about 1.5, said ceri and cero ions being Ce(SO 4 ) 2 . 4H 20 and Ce(NO 3 ) 3 .6H 2 O.
Claim 14
Dependent Claim
34 words
A method as in claim 1, wherein said redox system comprises ferri and ferro ions and said pH level is about 1.7, said ferri and ferro ions being FeC 3 and FeC 2 .
Claim 15
Dependent Claim
25 words
A method as in claim 1, wherein said redox system comprises potassium ferricyanide and potassium ferrocyanide and said pH level is less than about 9.
Claim 16
Dependent Claim
25 words
A method as in claim 1, wherein said redox system comprises triodide and iodide ions and said pH level is about from 3.0 to 9.5.
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) | 1980-09-19 | 1981-03-21 | 1981-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-19 | 1985-03-21 | 1985-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-19 | 1989-03-21 | 1989-09-20 | $7700.00 | Window Closed / Lapsed |