US4024029A
Expired / Lapsed
US
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Electrodeposition
Assignee: National Research Development Corp UK
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Filing: 1975-10-16
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Granted: 1977-05-17
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Expires: 1995-10-16
Abstract
Abstract The invention concerns a method of electrodeposition onto a semiconductor. The surface lattice structure of the semiconductor is first disturbed, by an ion beam or otherwise, and then the semiconductor is immersed in an electroplating solution. When the semiconductor is irradiated with light of sufficiently short wavelength to generate free charge carriers therein, ions from the solution are deposited on the semiconductor surface. Metal ions are deposited by this technique only on the disturbed regions of the semiconductor surface, providing an excellent selective deposition process. Multiple layers may be deposited, and even different metals on different regions of the semiconductor surface. The method is particularly suited to the production of solid slate devices such as, for example, gallium arsenide field effect transistors.
Inventors
- 👤 Norman Rain
- 👤 Arthur Basil Joseph Sullivan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:24
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/61; H10P50/617; C; C25; C25D; C25D7/00; C25D7/12; H10P14/00; H10P14/40; H10P14/46; H10P14/47; H10P32/00; H10P32/10; H10P32/16; H10P34/00; H10P34/40; H10P34/42; H10P34/422; H10P52/00; H10P95/00; Y; Y10; Y10S; Y10S430/00; Y10S430/143
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
95 words
A method of depositing a material onto a semiconductor having a surface lattice structure including successive the steps of: 1. bombarding the semiconductor with a beam of ions to produce damage in the surface lattice structure, 2. immersing the semiconductor in an electroplating solution suitable for depositing the said material onto the semiconductor, and 3. supplying radiative energy to the semiconductor, the said radiative energy consisting at least partially of a wavelength sufficiently short to generate free carriers in the semiconductor, in order to deposit the said material from the electroplating solution onto the semiconductor.
Claim 2
Independent Claim
95 words
A method of depositing a material onto a semiconductor having a surface lattice structure including successive the steps of: 1. bombarding the semiconductor with a beam of ions to produce damage in the surface lattice structure, 2. immersing the semiconductor in an electroplating solution suitable for depositing the said material onto the semiconductor, and 3. supplying radiative energy to the semiconductor, the said radiative energy consisting at least partially of a wavelength sufficiently short to generate free carriers in the semiconductor, in order to deposit the said material from the electroplating solution onto the semiconductor.
Claim 3
Dependent Claim
57 words
A method of depositing a material onto a semiconductor according to claim 1 in which the surface lattice structure is damaged by bombardment of the semiconductor surface by a beam of ions of at least one chemical species selected from the group comprising those which do not significantly affect the electrical properties of the semiconductor material bombarded.
Claim 4
Dependent Claim
46 words
A method of depositing a material onto a semiconductor according to claim 2 in which the material to be deposited is an element which forms negative ions when in solution, deposition of the said element taking place on non-bombarded regions of the semiconductor surface lattice structure.
Claim 5
Dependent Claim
44 words
A method of depositing material onto a semiconductor according to claim 3 in which material is deposited in a predetermined pattern by the step of bombarding only such areas of the semiconductor surface lattice structure on which material is not required to be deposited.
Claim 6
Independent Claim
140 words
A method of depositing a metal electropositive with respect to hydrogen in the electrochemical series onto a semiconductor, the semiconductor having a surface lattice structure, which method includes the successive steps of: 1. bombarding the semiconductor with a beam of ions to product damage into at least a part of the surface lattice structure of the semiconductor while preserving the chemical composition and crystallinity of the surface lattice structure, 2. immersing the semiconductor in an electroplating solution containing ions of the said metal, the said solution being adapted for electroplating the said metal ions onto the semiconductor, 3. supplying radiative energy to the semiconductor, the said radiative energy consisting at least partially of a wavelength sufficiently short to generate free carriers in the semiconductor, in order to deposit the said metal onto the disturbed surface lattice structure of the semiconductor.
Claim 7
Independent Claim
140 words
A method of depositing a metal electropositive with respect to hydrogen in the electrochemical series onto a semiconductor, the semiconductor having a surface lattice structure, which method includes the successive steps of: 1. bombarding the semiconductor with a beam of ions to product damage into at least a part of the surface lattice structure of the semiconductor while preserving the chemical composition and crystallinity of the surface lattice structure, 2. immersing the semiconductor in an electroplating solution containing ions of the said metal, the said solution being adapted for electroplating the said metal ions onto the semiconductor, 3. supplying radiative energy to the semiconductor, the said radiative energy consisting at least partially of a wavelength sufficiently short to generate free carriers in the semiconductor, in order to deposit the said metal onto the disturbed surface lattice structure of the semiconductor.
Claim 8
Dependent Claim
60 words
A method of depositing a metal onto a semiconductor according to claim 5 in which the surface lattice structure of the semiconductor is damaged by bombardment of the semiconductor surface by a beam of ions of at least one chemical species selected from the group comprising those which do not significantly affect the electrical properties of the semiconductor material bombarded.
Claim 9
Dependent Claim
33 words
A method of depositing a metal onto a semiconductor according to claim 6 in which the semiconductor is gallium arsenide and the metal is selected from the group comprising silver, gold and platinum.
Claim 10
Dependent Claim
44 words
A method of depositing a metal onto a semiconductor according to claim 6 in which deposition to a predetermined pattern is effected by the step of bombarding selectively only such areas of the semiconductor on which the said metal is required to be deposited.
Claim 11
Dependent Claim
44 words
A method of depositing a metal onto a semiconductor according to claim 8 in which the method includes the step of etching the semiconductor subsequent to bombardment and prior to deposition of the metal so that non-bombarded regions of the semiconductor are preferentially eroded.
Claim 12
Dependent Claim
106 words
A method of depositing multiple layers of metal onto a gallium arsenside crystal, each metal being selected from the group comprising silver, gold and platinum, the said method including the steps of: 1. Depositing a first metal by the method of claim 9. 2. Placing the gallium arsenide crystal in a solution suitable for electroplating a second metal onto gallium arsenide, and 3. Supplying radiative energy to the gallium arsenide crystal, the said radiative energy consisting at least partially of a wavelength sufficiently short to generate free carriers in gallium arsenide, in order to deposit the said second metal on top of the said first metal.
Claim 13
Independent Claim
81 words
A method of depositing a plurality of different metals onto respective surface regions of a semiconductor comprising the steps of: 1. Bombarding each surface region with a respective dose of ions, each dose being sufficiently large to make a respective metal deposit on the respective surface region when immersed in an appropriate respective solution containing ions of the respective metal and irradiated with light consisting at least partially of a wavelength sufficiently short to generate free carriers in the semiconductor, and
Claim 14
Independent Claim
81 words
A method of depositing a plurality of different metals onto respective surface regions of a semiconductor comprising the steps of: 1. Bombarding each surface region with a respective dose of ions, each dose being sufficiently large to make a respective metal deposit on the respective surface region when immersed in an appropriate respective solution containing ions of the respective metal and irradiated with light consisting at least partially of a wavelength sufficiently short to generate free carriers in the semiconductor, and
Claim 15
Dependent Claim
78 words
Immersing the semiconductor in successive solutions each containing ions of a respective metal to be deposited, the order of immersion in successive solutions being in descending order of the respective ion dosage required to make the respective metal deposit from the respective solution onto the semiconductor when irradiated with light consisting at least partially of a wavelength sufficiently short to generate free charge carriers in the semiconductor, the semiconductor being irradiated with the said light during each immersion.
Claim 16
Dependent Claim
78 words
Immersing the semiconductor in successive solutions each containing ions of a respective metal to be deposited, the order of immersion in successive solutions being in descending order of the respective ion dosage required to make the respective metal deposit from the respective solution onto the semiconductor when irradiated with light consisting at least partially of a wavelength sufficiently short to generate free charge carriers in the semiconductor, the semiconductor being irradiated with the said light during each immersion.
Claim 17
Independent Claim
202 words
A method of depositing a layer of silver onto a first surface region of a gallium arsenide crystal semiconductor and a second metal selected from the group comprising gold and platinum onto a second such surface region, which method comprises the steps of: 1. Bombarding the first surface region with protons to achieve a dose of more than 5 × 10 16 ions/sq cm 2. Bombarding the second surface region with protons to achieve a dose of less then 5 × 10 16 ions/sq cm 3. Immersing the gallium arsenide crystal in a silver electroplating solution. 4. Supplying radiative energy to the gallium arsenide, the said radiative energy consisting at least partially of a wavelength sufficiently short to generate free charge carriers in the gallium arsenide crystal, so that the first surface region becomes plated with silver. 5. Immersing the gallium arsenide in a solution suitable for plating the said second metal onto gallium arsenide, and 6. Supplying radiative energy to the gallium arsenide, the said radiative energy consisting at least partially of a wavelength sufficiently short to generate free charge carriers in the gallium arsenide crystal, so that at least the second surface region becomes plated by the said second metal.
Claim 18
Independent Claim
202 words
A method of depositing a layer of silver onto a first surface region of a gallium arsenide crystal semiconductor and a second metal selected from the group comprising gold and platinum onto a second such surface region, which method comprises the steps of: 1. Bombarding the first surface region with protons to achieve a dose of more than 5 × 10 16 ions/sq cm 2. Bombarding the second surface region with protons to achieve a dose of less then 5 × 10 16 ions/sq cm 3. Immersing the gallium arsenide crystal in a silver electroplating solution. 4. Supplying radiative energy to the gallium arsenide, the said radiative energy consisting at least partially of a wavelength sufficiently short to generate free charge carriers in the gallium arsenide crystal, so that the first surface region becomes plated with silver. 5. Immersing the gallium arsenide in a solution suitable for plating the said second metal onto gallium arsenide, and 6. Supplying radiative energy to the gallium arsenide, the said radiative energy consisting at least partially of a wavelength sufficiently short to generate free charge carriers in the gallium arsenide crystal, so that at least the second surface region becomes plated by the said second metal.
Claim 19
Dependent Claim
78 words
A method of depositing a metal onto a semiconductor according to claim 5 including the further step of electrically connecting to the said semiconductor a sacrificial anodic electrode, such that, during electrolysis, electrolytic deposition takes place at a predetermined cathodic surface region of the said semiconductor whereas corresponding electrolytic erosion takes place at least partially at the surface of the sacrificial anodic electrode whereby erosion of anodic surface regions of the said semiconductor is at least partly avoided.
Claim 20
Dependent Claim
78 words
A method of depositing a metal onto a semiconductor according to claim 6 including the further step of electrically connecting to the said semiconductor a sacrificial anodic electrode, such that, during electrolysis, electrolytic deposition takes place at a predetermined cathodic surface region of the said semiconductor whereas corresponding electrolytic erosion takes place at least partially at the surface of the sacrificial anodic electrode whereby erosion of anodic surface regions of the said semiconductor is at least partly avoided.
Claim 21
Dependent Claim
78 words
A method of depositing a metal onto a semiconductor according to claim 7 including the further step of electrically connecting to the said semiconductor a sacrificial anodic electrode, such that, during electrolysis, electrolytic deposition takes place at a predetermined cathodic surface region of the said semiconductor whereas corresponding electrolytic erosion takes place at least partially at the surface of the sacrificial anodic electrode whereby erosion of anodic surface regions of the said semiconductor is at least partly avoided.
Claim 22
Dependent Claim
78 words
A method of depositing a metal onto a semiconductor according to claim 8 including the further step of electrically connecting to the said semiconductor a sacrificial anodic electrode, such that, during electrolysis, electrolytic deposition takes place at a predetermined cathodic surface region of the said semiconductor whereas corresponding electrolytic erosion takes place at least partially at the surface of the sacrificial anodic electrode whereby erosion of anodic surface regions of the said semiconductor is at least partly avoided.
Claim 23
Dependent Claim
78 words
A method of depositing a metal onto a semiconductor according to claim 9 including the further step of electrically connecting to the said semiconductor a sacrificial anodic electrode, such that, during electrolysis, electrolytic deposition takes place at a predetermined cathodic surface region of the said semiconductor whereas corresponding electrolytic erosion takes place at least partially at the surface of the sacrificial anodic electrode whereby erosion of anodic surface regions of the said semiconductor is at least partly avoided.
Claim 24
Dependent Claim
78 words
A method of depositing a metal onto a semiconductor according to claim 10 including the further step of electrically connecting to the said semiconductor a sacrificial anodic electrode, such that, during electrolysis electrolytic deposition takes place at a predetermined cathodic surface region of the said semiconductor whereas corresponding electrolytic erosion takes place at least partially at the surface of the sacrificial anodic electrode whereby erosion of anodic surface regions of the said semiconductor is at least partly avoided.
Claim 25
Dependent Claim
78 words
A method of depositing a metal onto a semiconductor according to claim 11 including the further step of electrically connecting to the said semiconductor a sacrificial anodic electrode, such that, during electrolysis, electrolytic deposition takes place at a predetermined cathodic surface region of the said semiconductor whereas corresponding electrolytic erosion takes place at least partially at the surface of the sacrificial anodic electrode whereby erosion of anodic surface regions of the said semiconductor is at least partly avoided.
Claim 26
Dependent Claim
78 words
A method of depositing a metal onto a semiconductor according to claim 12 including the further step of electrically connecting to the said semiconductor a sacrificial anodic electrode, such that, during electrolysis, electrolytic deposition takes place at a predetermined cathodic surface region of the said semiconductor whereas corresponding electrolytic erosion takes place at least partially at the surface of the sacrificial anodic electrode whereby erosion of anodic surface regions of the said semiconductor is at least partly avoided.
Claim 27
Dependent Claim
13 words
A gallium arsenide field effect transistor made by the method of claim 7.
References Cited (Backward Citations)
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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) | 1980-05-16 | 1980-11-15 | 1981-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-16 | 1984-11-15 | 1985-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-16 | 1988-11-15 | 1989-05-17 | $7700.00 | Window Closed / Lapsed |