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US4517223A
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Method of making amorphous semiconductor alloys and devices using microwave energy
Assignee: Sovonics Solar Systems
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Filing: 1982-09-24
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Granted: 1985-05-14
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Expires: 2002-09-24
Abstract
Abstract A process for making amorphous semiconductor alloy films and devices at high deposition rates utilizes microwave energy to form a deposition plasma. The alloys exhibit high quality electronic properties suitable for many applications including photovoltaic applications. The process includes the steps of providing a source of microwave energy, coupling the microwave energy into a substantially enclosed reaction vessel containing the substrate onto which the amorphous semiconductor film is to be deposited, and introducing into the vessel reaction gases including at least one semiconductor containing compound. The microwave energy and the reaction gases form a glow discharge plasma within the vessel to deposit an amorphous semiconductor film from the reaction gases onto the substrate. The reactions gases can include silane (SiH 4 ), silicon tetrafluoride (SiF 4 ), silane and silicon tetrafluoride, silane and germane (GeH 4 ), and silicon tetrafluoride and germane. The reaction gases can also include germane or germanium tetrafluoride (GeF 4 ). To all of the foregoing, hydrogen (H 2 ) can also be added. Dopants, either p-type or n-type can also be added to the reaction gases to form p-type or n-type alloy films, respectively. Also, band gap increasing elements such as carbon or nitrogen can be added in the form of, for example, methane or ammonia gas to widen the band gap of the alloys.
Inventors
- 👤 Stanford R. Ovshinsky
- 👤 David D. Allred
- 👤 Lee Walter
- 👤 Stephen J. Hudgens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:49
CPC Classifications
H; H10; H10F; H10F99/00; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32192; H01J37/32211; H01J37/3222; C; C23; C23C; C23C16/00; C23C16/44; C23C16/50; C23C16/511; H01J37/32266; H01J37/32275; H10P; H10P14/00; H10P14/20; H10P14/24; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2905; H10P14/2923; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P14/3438; H10P14/3441; H10P14/3442; H10P14/3444
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
80 words
A process for depositing amorphous semiconductor alloy films onto a substrate comprising: providing a source of microwave energy; coupling said microwave energy into a substantially enclosed reaction vessel containing said substrate; maintaining the pressure within said vessel at about 0.2 Torr or less; and introducing into said vessel reaction gases including at least one semiconductor containing compound to form a glow discharge plasma within said vessel and to deposit an amorphous semiconductor film from said reaction gases onto said substrate.
Claim 2
Dependent Claim
80 words
A process for depositing amorphous semiconductor alloy films onto a substrate comprising: providing a source of microwave energy; coupling said microwave energy into a substantially enclosed reaction vessel containing said substrate; maintaining the pressure within said vessel at about 0.2 Torr or less; and introducing into said vessel reaction gases including at least one semiconductor containing compound to form a glow discharge plasma within said vessel and to deposit an amorphous semiconductor film from said reaction gases onto said substrate.
Claim 3
Dependent Claim
17 words
A process as defined in claim 1 wherein at least one of said reaction gases includes silicon.
Claim 4
Dependent Claim
20 words
A process as defined in claim 2 wherein at least one of said reaction gases is silane (SiH 4 ).
Claim 5
Dependent Claim
21 words
A process as defined in claim 2 wherein at least one of said reaction gases is silicon tetrafluoride (SiF 4 ).
Claim 6
Dependent Claim
22 words
A process as defined in claim 2 wherein said reaction gases are silicon tetrafluoride (SiF 4 ) and hydrogen (H 2 ).
Claim 7
Dependent Claim
22 words
A process as defined in claim 2 wherein said reaction gases are silane (SiH 4 ) and silicon tetrafluoride (SiF 4 ).
Claim 8
Dependent Claim
21 words
A process as defined in claim 2 wherein said reaction gases are silane (SiH 4 ) and germane (GeH 4 ).
Claim 9
Dependent Claim
22 words
A process as defined in claim 2 wherein said reaction gases are silicon tetrafluoride (SiF 4 ) and germane (GeH 4 ).
Claim 10
Dependent Claim
20 words
A process as defined in claims 6, 7 or 8 wherein said reaction gases further include hydrogen (H 2 ).
Claim 11
Dependent Claim
17 words
A process as defined in claim 1 wherein at least one of said reaction gases includes germanium.
Claim 12
Dependent Claim
20 words
A process as defined in claim 10 wherein at least one of said reaction gases is germane (GeH 4 ).
Claim 13
Dependent Claim
21 words
A process as defined in claim 10 wherein at least one of said reaction gases is germanium tetrafluoride (GeF 4 ).
Claim 14
Dependent Claim
19 words
A process as defined in claims 11 or 12 wherein said reaction gases further include hydrogen (H 2 ).
Claim 15
Dependent Claim
16 words
A process as defined in claim 1 wherein said reaction gases include a dopant containing compound.
Claim 16
Dependent Claim
14 words
A process as defined in claim 14 wherein said dopant containing compound includes boron.
Claim 17
Dependent Claim
19 words
A process as defined in claim 15 wherein said dopant containing compound is diborane (B 2 H 6 ).
Claim 18
Dependent Claim
14 words
A process as defined in claim 14 wherein said dopant containing compound includes phosphorus.
Claim 19
Dependent Claim
17 words
A process as defined in claim 17 wherein said dopant containing compound is phosphine (PH 3 ).
Claim 20
Dependent Claim
24 words
A process as defined in claim 1 further comprising the step of introducing a plasma sustaining gas into said vessel with said reaction gases.
Claim 21
Dependent Claim
14 words
A process as defined in claim 19 wherein said plasma sustaining gas is argon.
Claim 22
Dependent Claim
31 words
A process as defined in claim 1 wherein said deposited semiconductor film has a band gap and wherein at least one of said reaction gases includes a band gap adjusting element.
Claim 23
Dependent Claim
19 words
A process as defined in claim 21 wherein said band gap adjusting element is a band gap increasing element.
Claim 24
Dependent Claim
17 words
A process as defined in claim 22 wherein said band gap increasing element is carbon or nitrogen.
Claim 25
Dependent Claim
17 words
A process as defined in claim 23 wherein said reaction gases include ammonia gas (NH 3 ).
Claim 26
Dependent Claim
17 words
A process as defined in claim 23 wherein said reaction gases include methane gas (CH 4 ).
Claim 27
Dependent Claim
19 words
A process as defined in claim 21 wherein said band gap adjusting element is a band gap decreasing element.
Claim 28
Dependent Claim
15 words
A process as defined in claim 26 wherein said band gap decreasing element is germanium.
Claim 29
Dependent Claim
25 words
A process as defined in claim 1 further including the step of maintaining the temperature of said substrate between about 20° Centigrade and 400° Centigrade.
Claim 30
Dependent Claim
23 words
A process as defined in claim 1 wherein said alloy film is deposited at deposition rates of 25 Angstroms per second or greater.
Claim 31
Dependent Claim
34 words
A process as defined in claim 1 further including the step of adjusting the power output of said microwave energy source to provide power densities between about 0.1 to 1 watt per cubic centimeter.
Claim 32
Dependent Claim
17 words
A process as defined in claim 1 wherein the frequency of said microwave energy is 2.45 Gigahertz.
Claim 33
Dependent Claim
91 words
The process as defined in claim 1 wherein said process forms one step in a multi-step process for forming successively deposited alloy layers of opposite (p and n) conductivity type, the n-type layer being formed by introducing into said vessel a reaction gas containing an n-type dopant element which is deposited with the deposited layer to produce an n-type layer and the p-type layer being formed by introducing into said vessel a reaction gas containing a p-type dopant element which is deposited with the deposited layer to produce a p-type layer.
Claim 34
Dependent Claim
33 words
The process as defined in claim 32 wherein there is deposited between said p and n doped layers an intrinsic amorphous semiconductor alloy layer without a p or n dopant element present therein.
Claim 35
Dependent Claim
80 words
A process for depositing a transparent electrically insulating material onto a photovoltaic device comprising: providing a source of microwave energy; coupling said microwave energy into a substantially enclosed reaction vessel containing said device; maintaining the pressure within said vessel at about 0.2 Torr or less; and introducing into said vessel gases including silicon and nitrogen or oxygen to form a glow discharge plasma within said vessel and to deposit a transparent insulating material from said reaction gases onto said device.
Claim 36
Dependent Claim
80 words
A process for depositing a transparent electrically insulating material onto a photovoltaic device comprising: providing a source of microwave energy; coupling said microwave energy into a substantially enclosed reaction vessel containing said device; maintaining the pressure within said vessel at about 0.2 Torr or less; and introducing into said vessel gases including silicon and nitrogen or oxygen to form a glow discharge plasma within said vessel and to deposit a transparent insulating material from said reaction gases onto said device.
Claim 37
Dependent Claim
39 words
A process as defined in claim 34 wherein said transparent material is silicon nitride (Si 3 N 4 ) and wherein said reaction gases are silane gas (SiH 4 ) and nitrogen gas or ammonia gas (NH 3 ).
Claim 38
Dependent Claim
27 words
A process as defined in claim 34 wherein said transparent material is silicon dioxide and wherein said reaction gases are silane gas (SiH 4 ) and oxygen.
Claim 39
Dependent Claim
25 words
A process as defined in claim 34 including the step of continuing said deposition until said transparent material is between one and fifty microns thick.
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) | 1988-05-13 | 1988-11-12 | 1989-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-13 | 1992-11-12 | 1993-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-13 | 1996-11-12 | 1997-05-14 | $7700.00 | Window Closed / Lapsed |