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US5418019A
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Method for low temperature plasma enhanced chemical vapor deposition (PECVD) of an oxide and nitride antireflection coating on silicon
Assignee: Georgia Tech Research Corp
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Filing: 1994-05-25
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Granted: 1995-05-23
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Expires: 2014-05-25
Abstract
Abstract A sequential plasma-enhanced chemical vapor deposition (PECVD) of SiN and SiOx produces a very effective double-layer antireflection coating. This antireflection coating is compared with the frequently used and highly efficient double-layer MgF2/ZnS coating. It is shown that the double-layer SiOx/SiN coating improves the short-circuited current (Jsc) by 47%, open-circuit voltage (Voc) by 3.7%, and efficiency (Eff) by 55% for silicon cells with oxide surface passivation. The counterpart MgF2/ZnS coating gives smaller improvement in Voc and Eff. However, if silicon cells do not have the oxide passivation, the PECVD SiOx/SiN gives much greater improvement in the cell parameters, 57% in Jsc, 8% in Voc, and 66% in efficiency, compared to the MgF2/ZnS coating which improves Jsc by 50%, Voc by 2%, and cell efficiency by 54%. This significant additional improvement results from the PECVD deposition-induced surface/defect passivation. The internal quantum efficiency (IQE) measurements showed that the PECVD SiOx/SiN coating absorbs fair amount of photons in the short-wavelength range (<500 nm), however, the improved surface/defect passivation more than compensates for the loss in Jsc and gives higher improvement in the cell efficiency compared to the MgF2/ZnS coating.
Inventors
- 👤 Zhizhang Chen
- 👤 Ajeet Rohatgi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:56
CPC Classifications
H; H10; H10F; H10F77/00; H10F77/30; H10F77/306; H10F77/311; H10F77/315; C; C23; C23C; C23C16/00; C23C16/22; C23C16/30; C23C16/34; C23C16/345; C23C16/40; C23C16/401; C23C16/402; C23C16/56; G; G02; G02B; G02B1/00; G02B1/10; G02B1/11; G02B1/113; G02B1/115; Y; Y02; Y02E; Y02E10/00; Y02E10/50
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
54 words
A method for forming an antireflection coating for a surface of silicon, comprising the steps of: forming a silicon nitride coating with a refractive index of about 2.3 on the silicon using plasma enhanced chemical vapor deposition and; forming a silicon oxide coating on said silicon nitride coating using plasma enhanced chemical vapor deposition.
Claim 2
Independent Claim
54 words
A method for forming an antireflection coating for a surface of silicon, comprising the steps of: forming a silicon nitride coating with a refractive index of about 2.3 on the silicon using plasma enhanced chemical vapor deposition and; forming a silicon oxide coating on said silicon nitride coating using plasma enhanced chemical vapor deposition.
Claim 3
Dependent Claim
27 words
The method of claim 1, further comprising the step of heating said silicon nitride coating in combination with said silicon oxide coating with a light radiating source.
Claim 4
Dependent Claim
11 words
The method of claim 1, wherein said silicon is n-type silicon.
Claim 5
Dependent Claim
11 words
The method of claim 1, wherein said silicon is p-type silicon.
Claim 6
Dependent Claim
17 words
The method of claim 1, wherein said silicon oxide coating has a refractive index of about 1.45.
Claim 7
Dependent Claim
23 words
The method of claim 1, wherein said silicon nitride coating and said silicon oxide coating are both formed below about 275 degrees Celsius.
Claim 8
Dependent Claim
35 words
The method of claim 1, wherein an electromagnetic plasma excitation signal having a frequency of about 13.6 megahertz is employed during formation of said silicon nitride coating and during formation of said silicon oxide coating.
Claim 9
Dependent Claim
27 words
The method of claim 1, wherein a plasma comprising silane (SiH 4 ) and ammonia (NH 3 ) is employed during formation of said silicon nitride coating.
Claim 10
Dependent Claim
28 words
The method of claim 1, wherein a plasma comprising silane (SiH 4 ) and nitrous oxide (N 2 O) is employed during formation of said silicon oxide coating.
Claim 11
Dependent Claim
20 words
The method of claim 2, wherein said heating step is performed at about 350 degrees Celsius for about 20 minutes.
Claim 12
Dependent Claim
31 words
The method of claim 2, wherein said heating step includes the step of utilizing a forming gas having hydrogen so that said hydrogen migrates to and passivates defects within said silicon.
Claim 13
Dependent Claim
24 words
The method of claim 11, wherein said forming gas comprises about 90 percent by volume nitrogen gas and 10 percent by volume hydrogen gas.
Claim 14
Independent Claim
83 words
A method for forming an antireflection coating for a surface of silicon, comprising the steps of: forming a silicon nitride coating on the silicon using plasma enhanced chemical vapor deposition; forming a silicon oxide coating on said silicon nitride coating using plasma enhanced chemical vapor deposition; and manipulating a refractive index associated with said silicon nitride coating during formation of said silicon nitride coating by adjusting an amount of silicon in said silicon nitride coating so that said refractive index is about 2.3.
Claim 15
Independent Claim
83 words
A method for forming an antireflection coating for a surface of silicon, comprising the steps of: forming a silicon nitride coating on the silicon using plasma enhanced chemical vapor deposition; forming a silicon oxide coating on said silicon nitride coating using plasma enhanced chemical vapor deposition; and manipulating a refractive index associated with said silicon nitride coating during formation of said silicon nitride coating by adjusting an amount of silicon in said silicon nitride coating so that said refractive index is about 2.3.
Claim 16
Independent Claim
98 words
A method for forming an antireflection coating for a surface of silicon, comprising the steps of: forming silicon nitride coating on the silicon using plasma enhanced chemical vapor deposition; forming silicon oxide coating on said silicon nitride coating using plasma enhanced chemical vapor deposition; manipulating a refractive index associated with said silicon nitride coating during formation of said silicon nitride coating by adjusting an amount of silicon in said silicon nitride coating so that said refractive index is about 2.3; and heating said silicon nitride coating in combination with said silicon oxide coating with a light radiating source.
Claim 17
Independent Claim
98 words
A method for forming an antireflection coating for a surface of silicon, comprising the steps of: forming silicon nitride coating on the silicon using plasma enhanced chemical vapor deposition; forming silicon oxide coating on said silicon nitride coating using plasma enhanced chemical vapor deposition; manipulating a refractive index associated with said silicon nitride coating during formation of said silicon nitride coating by adjusting an amount of silicon in said silicon nitride coating so that said refractive index is about 2.3; and heating said silicon nitride coating in combination with said silicon oxide coating with a light radiating source.
Claim 18
Dependent Claim
26 words
The method of claim 13, further comprising the step of heating said silicon nitride film in combination with silicon oxide coating with a light radiating source.
Claim 19
Dependent Claim
11 words
The method of claim 13, wherein said silicon is n-type silicon.
Claim 20
Dependent Claim
11 words
The method of claim 13, wherein said silicon is p-type silicon.
Claim 21
Dependent Claim
17 words
The method of claim 13, wherein said silicon oxide coating has a refractive index of about 1.45.
Claim 22
Dependent Claim
28 words
The method of claim 13, wherein said silicon nitride coating and said silicon oxide coating are both formed at a temperature of about 250 to 300 degrees Celsius.
Claim 23
Dependent Claim
27 words
The method of claim 13, wherein an electromagnetic plasma excitation signal having a frequency of about 13.6 megahertz is employed during formation of said silicon nitride coating.
Claim 24
Dependent Claim
51 words
The method of claim 13, wherein a plasma containing silane (SiH 4 ) and ammonia (NH 3 ) is employed during formation of said silicon nitride coating and wherein said refractive index is manipulated and said amount of silicon is adjusted by controlling the ratio of said silane and said ammonia.
Claim 25
Dependent Claim
28 words
The method of claim 13, wherein a plasma containing silane (SiH 4 ) and nitrous oxide (N 2 O) is employed during formation of said silicon oxide coating.
Claim 26
Dependent Claim
15 words
The method of claim 15, wherein said heating step is performed at about 350° C.
Claim 27
Dependent Claim
19 words
The method of claim 14, wherein said silicon oxide coating is formed with a refractive index of about 1.45.
Claim 28
Dependent Claim
15 words
The method of claim 14, wherein said heating step is performed at about 350° C.,
Claim 29
Dependent Claim
31 words
The method of claim 14, wherein said heating step includes the step of utilizing a forming gas having hydrogen so that said hydrogen migrates to and passivates defects within said silicon.
Claim 30
Dependent Claim
23 words
The method of claim 26, wherein said forming gas comprises about 90% by volume nitrogen gas and about 10% by volume hydrogen gas.
References Cited (Backward Citations)
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