US4094752A
Expired / Lapsed
US
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Method of manufacturing opto-electronic devices
Assignee: US Philips Corp
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Filing: 1975-12-08
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Granted: 1978-06-13
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Expires: 1995-12-08
Abstract
Abstract A method of manufacturing opto-electronic semiconductor devices. The method is characterized in that the material is AsAl x Ga 1-x in which the molar proportion x is lower than 0.3, in that the material is stratified in different layers, and in that a chemical etching treatment is carried out in a bath containing hydrofluoric acid, nitric acid and acetic acid.
Inventors
- 👤 Jacques Vahe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:58
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/819; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/646; H10P50/69; H10P50/691; Y; Y10; Y10S; Y10S438/00; Y10S438/978
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
70 words
A method of manufacturing opto-electronic devices starting from a semiconductor plate mainly constituted by stratified layers of gallium aluminum arsenide of the general formula AsAl x Ga 1-x in which the molar proportion x of aluminum is lower than 0.3, wherein an etching treatment is carried out on said plate in a bath containing hydrofluoric acid, nitric acid and acetic acid for a time sufficient to obtain a desired configuration.
Claim 2
Independent Claim
70 words
A method of manufacturing opto-electronic devices starting from a semiconductor plate mainly constituted by stratified layers of gallium aluminum arsenide of the general formula AsAl x Ga 1-x in which the molar proportion x of aluminum is lower than 0.3, wherein an etching treatment is carried out on said plate in a bath containing hydrofluoric acid, nitric acid and acetic acid for a time sufficient to obtain a desired configuration.
Claim 3
Dependent Claim
48 words
A method as claimed in claim 1, characterized in that the mixture constituting the bath is prepared in the following proportions: hydrofluoric acid, 50% by volume: 2 to 4 volume parts nitric acid, density 1.38: 3 to 7 volume parts glacial acetic acid: 2 to 4 volume parts.
Claim 4
Dependent Claim
46 words
A method as claimed in claim 2, characterized in that the said mixture is prepared in the following proportions: hydrofluoric acid, 50% by volume: 2.5 to 3.5 volume parts nitric acid, density 1.38: 4 to 6 volume parts glacial acetic acid: 2.5 to 3.5 volume parts.
Claim 5
Dependent Claim
94 words
A method as claimed in claim 3, characterized in that the said plate comprises at least one layer of which a first main face is masked while the second main face opposite to the first and at least a part of the lateral faces adjacent the said second main face are free and in that the duration of the etching treatment is controlled in such manner that the profile of the said layer takes the shape of a convex curve at least in the vicinity of the periphery of the said second main face.
Claim 6
Dependent Claim
70 words
A method as claimed in claim 3, characterized in that the said plate comprises at least one first layer of which at least one of its main faces comprises masking elements, while the lateral faces are free, and in that the duration of the etching treatment is controlled in such manner that the area of the said first layer is reduced with respect to the area of the masking elements.
Claim 7
Dependent Claim
33 words
A method as claimed in claim 5, characterized in that the said layer is of the p-type and in that at least one of the masking elements is a layer of the n-type.
Claim 8
Dependent Claim
35 words
A method as claimed in claim 5, characterized in that the said layer has a given doping level, while at least one of the masking elements is of a semiconductor material having a lower doping.
Claim 9
Dependent Claim
95 words
A method as claimed in claim 3, characterized in that the said plate comprises at least one layer of which the variable doping level increases from a first main face of the said layer to a second main face of the said layer opposite to the first and in that the duration of the etching treatment is controlled in such manner that the lateral face of the said layer acquires an acute angle with the plane of the said first main face and an obtuse angle with the plane of the said second main face.
Claim 10
Dependent Claim
151 words
A method as claimed in claim 4, characterized in that the said plate comprises a substrate of the n-type of which the doping level is substantially constant, at least for a certain thickness on the side of the second main face, in that the said second main face is maintained free, while the first main face opposite to the second comprises a p-type layer of which the doping level increases from the face of the said layer in interface with the said substrate up to the opposite face of the said layer and in that the duration of the etching treatment is controlled in such manner that the profile of the said n-type substrate on the side of the free face, a least in the vicinity of the periphery of the said free face, presents the form of a convex curve, while the profile of the said p-type layer becomes trapezoidal.
Claim 11
Dependent Claim
48 words
A method as claimed in claim 9, characterized in that the said n-type substrate comprises, on the side of the said first main face opposite to the second, a layer of which the doping level is higher than the doping level of the first layer of the substrate.
Claim 12
Dependent Claim
160 words
A method as claimed in claim 10, characterized in that the n-type substrate is of gallium arsenide comprising in the thickness of substantially constant impurity level a value of the said impurity level between 10 16 and 2.10 18 impurity atoms per cm 3 and in the layer of increasing doping level, a level of silicon increasing from a value between 10 17 and 5.10 17 impurity atoms per cm 3 in the vicinity of the interface with the said n-type substrate to a value between 10 18 and 5.10 18 impurity atoms per cm 3 , and in that the said p-type layer comprises an increasing level of silicon atoms of which the value is between 5.10 18 and 10 19 atoms per cm 3 at the level of the interface to a value between 10 19 atoms and 10 20 atoms per cm 3 at the level of the face of the said layer opposite to the interface.
Claim 13
Dependent Claim
38 words
A method as claimed in claim 1, characterized in that the etching is accelerated by the application of an outer electric voltage from a source of which the negative terminal is connected to the piece to be etched.
Claim 14
Dependent Claim
26 words
A method as claimed in claim 12, characterized in that the electrolytic etching current is between 10 and 50 mA per mm 2 of etched surface.
Claim 15
Dependent Claim
42 words
A method as claimed in claim 1, characterized in that the said piece to be etched is previously mounted on a base which is at least partially metallic and of which at least the metallic parts are covered with a noble metal.
Claim 16
Dependent Claim
16 words
A method as claimd in claim 14, characterized in that the said noble metal is gold.
Claim 17
Independent Claim
135 words
A method of manufacturing an opto-electronic device from a semiconductor plate mainly constituted by gallium arsenide of the general formula AsAl x Ga 1-x in which the molar proportion x of aluminum is lower than 0.3, said plate comprising an n type substrate having a first free face and a second face covered with a p-type layer, an etch resistant mask covering the outer face of said p-type layer and having unmasked lateral faces, said method comprising etching said plate in a bath containing hydrofluoric acid, nitric acid and acetic acid for a time such that, at least in the vicinity of the periphery of said first free face of said substrate, the profile of said substrate takes the shape of a convex curve while the area of said p type layer is reduced appreciably.
Claim 18
Independent Claim
135 words
A method of manufacturing an opto-electronic device from a semiconductor plate mainly constituted by gallium arsenide of the general formula AsAl x Ga 1-x in which the molar proportion x of aluminum is lower than 0.3, said plate comprising an n type substrate having a first free face and a second face covered with a p-type layer, an etch resistant mask covering the outer face of said p-type layer and having unmasked lateral faces, said method comprising etching said plate in a bath containing hydrofluoric acid, nitric acid and acetic acid for a time such that, at least in the vicinity of the periphery of said first free face of said substrate, the profile of said substrate takes the shape of a convex curve while the area of said p type layer is reduced appreciably.
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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) | 1981-06-12 | 1981-12-12 | 1982-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-12 | 1985-12-12 | 1986-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-12 | 1989-12-12 | 1990-06-13 | $7700.00 | Window Closed / Lapsed |