US3922774A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tantalum pentoxide anti-reflective coating
Assignee: Comsat Corp
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Filing: 1974-02-01
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Granted: 1975-12-02
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Expires: 1994-02-01
Abstract
Abstract A solar cell, responsive to light in the short wavelength region, including a non-crystalline tantalum pentoxide, antireflective coating. A method for making a solar cell, responsive to light in the short wavelength region including a noncrystalline tantalum pentoxide, anti-reflective coating. The method includes placing the anti-reflective coating and a metallic current collector on the top surface of the solar cell using the technique of ''''lift-off'''' photolithography and the oxidation of elemental tantalum which is evaporated onto the solar cell.
Inventors
- 👤 Joseph Lindmayer
- 👤 James Frederick Allison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:19
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/69; H10P14/692; H10P14/6938; H10P14/6939; H10P14/69393; C; C25; C25D; C25D11/00; C25D11/02; C25D11/26; H10F; H10F77/00; H10F77/30; H10F77/306; H10F77/311; H10F77/315; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6314; H10P14/6324; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y10; Y10S; Y10S205/00; Y10S205/923
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
104 words
A METHOD OF PLACING AN ELECTRODE AND AN ANTI-REFLECTIVE NON-CRYSTALLINE TANTALUM PENTOXIDE COATING ON A SURFACE OF A SOLAR CELL WHICH IS RESPONSIVE TO LIGHT, INCLUSIVELY, IN THE BLUEVIOLET REGION OF THE SPECTRUM, SAID METHOD COMPRISING THE STEPS OF: A. FORMING A METALLIC COLLECTOR ELECTRODE IN CONTACT WITH A FIRST PATTERNED PART OF SAID TOP SURFACE, B. DEPOSITING ELEMENTAL TANTALUM ON AT LEAST THE PART OF SAID TOP SURFACE OTHER THAN SAID FIRST PATTERNED PART, AND C. OXIDIZING SAID ELEMENTAL TANTALUM UNDER CONDITIONS TO PROVIDE SUBSTANTIALLY NON-CRYSTALLINE TANTALUM PENTOXIDE ON AT LEAST THE PART OF SAID TOP SURFACE OTHER THAN SAID FIRST PATTERNED PART.
Claim 2
Independent Claim
104 words
A METHOD OF PLACING AN ELECTRODE AND AN ANTI-REFLECTIVE NON-CRYSTALLINE TANTALUM PENTOXIDE COATING ON A SURFACE OF A SOLAR CELL WHICH IS RESPONSIVE TO LIGHT, INCLUSIVELY, IN THE BLUEVIOLET REGION OF THE SPECTRUM, SAID METHOD COMPRISING THE STEPS OF: A. FORMING A METALLIC COLLECTOR ELECTRODE IN CONTACT WITH A FIRST PATTERNED PART OF SAID TOP SURFACE, B. DEPOSITING ELEMENTAL TANTALUM ON AT LEAST THE PART OF SAID TOP SURFACE OTHER THAN SAID FIRST PATTERNED PART, AND C. OXIDIZING SAID ELEMENTAL TANTALUM UNDER CONDITIONS TO PROVIDE SUBSTANTIALLY NON-CRYSTALLINE TANTALUM PENTOXIDE ON AT LEAST THE PART OF SAID TOP SURFACE OTHER THAN SAID FIRST PATTERNED PART.
Claim 3
Dependent Claim
109 words
The method as claimed in claim 1 wherein the step of depositing elemental tantalum comprises the ordered steps of: a. placing a first layer of photoresist on the surface of the solar cell through which light enters; b. exposing said first layer of photoresist to light through a first mask having a pattern similar to the desired pattern of said metallic collector electrode; c. developing and rinsing said first layer of photoresist; d. depositing a layer of elemental tantalum over said surface including the layer of photoresist which remained after developing and rinsing; and e. lifting-off said remaining photoresist and the portion of said elemental tantalum overlaying said photoresist.
Claim 4
Dependent Claim
130 words
The method of claim 1 wherein the step of forming a metallic collector electrode comprises the ordered steps of: a. placing a second layer of photoresist covering the oxidized elemental tantalum and the exposed surface of said solar cell. b. exposing said second layer of photoresist to light through a second mask which is a negative of said first mask, c. developing and rinsing said second layer of photoresist, thereby leaving said layer of photoresist only over said oxidized elemental tantalum, d. placing a layer of metal, suitable for use as a current collector, over said surface, including the exposed portions of said solar cell surface and said remaining layer of photoresist, and e. lifting-off said remaining layer of photoresist and the portion of said metal layer overlaying said photoresist.
Claim 5
Dependent Claim
44 words
The method of claim 3 wherein the step of oxidizing comprises thermally oxidizing said elemental tantalum at temperatures between 350* and 525* C to provide substantially non-crystalline tantalum pentoxide on at least the part of said top surface other than said first patterned part.
Claim 6
Dependent Claim
13 words
The method of claim 1 wherein the step of oxidizing comprises anodic oxidation.
Claim 7
Dependent Claim
27 words
The method of claim 5 wherein said anodic oxidation occurs for a period of time sufficient to acquire tantalum pentoxide having an index of refraction of 2.25.
Claim 8
Dependent Claim
57 words
The method of claim 5 wherein the step of anodic oxidation comprises immersing said solar cell with elemental tantalum thereon in an electrolyte and connecting said cell as an anode of an electrolyte circuit, immersing a platinum cathode in said electrolyte, and passing a current through said electrolyte for a sufficient time to anodically oxidize said tantalum.
Claim 9
Independent Claim
110 words
A method of placing an electrode and an anti-reflective non-crystalline tantalum pentoxide coating on a surface of a solar cell which is responsive to light, inclusively, in the blue-violet region of the spectrum, said method comprising the steps of: a. forming a metallic collector electrode in contact with a first patterned part of said top surface, b. depositing elemental tantalum on at least the part of said top surface other than said first patterned part, and c. thermally oxidizing said elemental tantalum at temperatures between 350* and 525* C to provide substantially non-crystalline tantalum pentoxide on at least the part of said top surface other than said first patterned part.
Claim 10
Independent Claim
110 words
A method of placing an electrode and an anti-reflective non-crystalline tantalum pentoxide coating on a surface of a solar cell which is responsive to light, inclusively, in the blue-violet region of the spectrum, said method comprising the steps of: a. forming a metallic collector electrode in contact with a first patterned part of said top surface, b. depositing elemental tantalum on at least the part of said top surface other than said first patterned part, and c. thermally oxidizing said elemental tantalum at temperatures between 350* and 525* C to provide substantially non-crystalline tantalum pentoxide on at least the part of said top surface other than said first patterned part.
Claim 11
Independent Claim
292 words
A method of placing an electrode and an anti-reflective non-crystalline tantalum pentoxide coating on a surface of a solar cell which is responsive to light, inclusively, in the blue-violet region of the spectrum, said method comprising the steps of: a. placing a first layer of photoresist on the surface of the solar cell through which light enters; b. exposing said first layer of photoresist to light through a first mask having a pattern similar to the desired pattern of a metallic collector electrode; c. developing and rinsing said first layer of photoresist; d. depositing a layer of elemental tantalum over said surface including the layer of photoresist which remained after developing and rinsing: e. lifting-off said remaining photoresist in the portion of said elemental tantalum overlying said photoresist to result in a pattern of elemental tantalum on said solar cell surface; f. thermally oxidizing said patterned elemental tantalum to provide substantially non-crystalline tantalum pentoxide by heating said elemental tantalum in an oxidizing atmosphere initially at about 350*C and then raising the temperature to a desired temperature within the range of 450*-525*C; g. placing a second layer of photoresist covering the oxidized elemental tantalum and the exposed surface of said solar cell; h. exposing said second layer of photoresist to light through a second mask which is a negative of said first mask; i. developing and rinsing said second layer of photoresist thereby leaving said layer of photoresist only over said oxidized elemental tantalum; j. placing a layer of metal, suitable for use as a current collector over said surface including the exposed portions of said solar cell surface and said remaining layer of photoresist; and k. lifting-off said remaining layer of photoresist and the portion of said metal layer overlying said photoresist.
Claim 12
Independent Claim
292 words
A method of placing an electrode and an anti-reflective non-crystalline tantalum pentoxide coating on a surface of a solar cell which is responsive to light, inclusively, in the blue-violet region of the spectrum, said method comprising the steps of: a. placing a first layer of photoresist on the surface of the solar cell through which light enters; b. exposing said first layer of photoresist to light through a first mask having a pattern similar to the desired pattern of a metallic collector electrode; c. developing and rinsing said first layer of photoresist; d. depositing a layer of elemental tantalum over said surface including the layer of photoresist which remained after developing and rinsing: e. lifting-off said remaining photoresist in the portion of said elemental tantalum overlying said photoresist to result in a pattern of elemental tantalum on said solar cell surface; f. thermally oxidizing said patterned elemental tantalum to provide substantially non-crystalline tantalum pentoxide by heating said elemental tantalum in an oxidizing atmosphere initially at about 350*C and then raising the temperature to a desired temperature within the range of 450*-525*C; g. placing a second layer of photoresist covering the oxidized elemental tantalum and the exposed surface of said solar cell; h. exposing said second layer of photoresist to light through a second mask which is a negative of said first mask; i. developing and rinsing said second layer of photoresist thereby leaving said layer of photoresist only over said oxidized elemental tantalum; j. placing a layer of metal, suitable for use as a current collector over said surface including the exposed portions of said solar cell surface and said remaining layer of photoresist; and k. lifting-off said remaining layer of photoresist and the portion of said metal layer overlying said photoresist.
Claim 13
Dependent Claim
13 words
The method of claim 9 wherein said metallic grid comprises chrome and gold.
Claim 14
Dependent Claim
17 words
The method of claim 10 further comprising placing a layer of silver over said chrome and gold.
Claim 15
Independent Claim
167 words
A method of placing an electrode and an anti-reflective non-crystalline tantalum pentoxide coating on a surface of a solar cell which is responsive to light, inclusively, in the blue-violet region of the spectrum, said method comprising the steps of: a. forming a metallic collector electrode in contact with a first patterned part of said top surface; b. depositing elemental tantalum on at least the part of said top surface other than said first patterned part; and c. thermally oxidizing said elemental tantalum at temperatures between 350* and 525* C to provide substantially non-crystalline tantalum pentoxide on at least the part of said top surface other than said first patterned part wherein the step of thermally oxidizing comprises placing the solar cell with the elemental tantalum thereon into an oxidation furnace having oxygen flowing therethrough, said oxidation furnace being initially at a temperature of about 350* C, and gradually raising the temperature of said furnace to a final oxidation temperature in the range of 450* to 525* C.
Claim 16
Independent Claim
167 words
A method of placing an electrode and an anti-reflective non-crystalline tantalum pentoxide coating on a surface of a solar cell which is responsive to light, inclusively, in the blue-violet region of the spectrum, said method comprising the steps of: a. forming a metallic collector electrode in contact with a first patterned part of said top surface; b. depositing elemental tantalum on at least the part of said top surface other than said first patterned part; and c. thermally oxidizing said elemental tantalum at temperatures between 350* and 525* C to provide substantially non-crystalline tantalum pentoxide on at least the part of said top surface other than said first patterned part wherein the step of thermally oxidizing comprises placing the solar cell with the elemental tantalum thereon into an oxidation furnace having oxygen flowing therethrough, said oxidation furnace being initially at a temperature of about 350* C, and gradually raising the temperature of said furnace to a final oxidation temperature in the range of 450* to 525* C.
Claim 17
Dependent Claim
25 words
The method of claim 12 wherein said thermal oxidation occurs at a temperature sufficient to acquire tantalum pentoxide having an index of refraction of 2.25.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |