U.S. patent application number 10/802102 was filed with the patent office on 2004-09-09 for barrier layer for an article and method of making said barrier layer by expanding thermal plasma.
Invention is credited to Schaepkens, Marc.
Application Number | 20040175512 10/802102 |
Document ID | / |
Family ID | 29399092 |
Filed Date | 2004-09-09 |
United States Patent
Application |
20040175512 |
Kind Code |
A1 |
Schaepkens, Marc |
September 9, 2004 |
Barrier layer for an article and method of making said barrier
layer by expanding thermal plasma
Abstract
An article comprising a substrate having a barrier layer. The
barrier layer is disposed on the surface of the substrate and
resistant to transmission of moisture and oxygen. Methods of
depositing such a barrier layer on the substrate are also
disclosed. The article may include additional layers, such as, but
not limited to, an adhesion layer, abrasion resistant layers,
radiation-absorbing layers, radiation-reflective layers, and
conductive layers. Such articles include, but are not limited to,
light emitting diodes (LEDs), liquid crystal displays (LCDs),
photovoltaic articles, electrochromic articles, and organic
electroluminescent devices (OELDs).
Inventors: |
Schaepkens, Marc; (Ballston
Spa, NY) |
Correspondence
Address: |
GENERAL ELECTRIC COMPANY
GLOBAL RESEARCH
PATENT DOCKET RM. BLDG. K1-4A59
SCHENECTADY
NY
12309
US
|
Family ID: |
29399092 |
Appl. No.: |
10/802102 |
Filed: |
March 16, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10802102 |
Mar 16, 2004 |
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10063917 |
May 23, 2002 |
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6743524 |
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Current U.S.
Class: |
428/1.1 ;
257/E23.002 |
Current CPC
Class: |
H01L 51/5253 20130101;
H01L 2924/12044 20130101; Y10T 428/31507 20150401; Y10T 428/31855
20150401; Y10T 428/266 20150115; Y10T 428/265 20150115; Y02T 50/60
20130101; H01L 2924/0002 20130101; C23C 16/345 20130101; Y10S
428/913 20130101; Y10T 428/31681 20150401; C23C 16/513 20130101;
C09K 2323/00 20200801; Y10T 428/31721 20150401; H01L 23/564
20130101; H01L 2924/0002 20130101; H01L 2924/00 20130101 |
Class at
Publication: |
428/001.1 |
International
Class: |
C09K 019/00 |
Claims
1. An article, said article comprising: a) a substrate; and b) at
least one barrier layer disposed on at least one surface of said
substrate, wherein said barrier layer comprises an inorganic
material, and wherein said barrier layer is resistant to
transmission of moisture and oxygen therethrough and has a water
vapor transmission rate (WVTR) at 25.degree. C. and 100% relative
humidity of less than about 2 g/m.sup.2-day and an oxygen
transmission rate (OTR) at 25.degree. C. and 100% oxygen
concentration of less than about 2 cc/m.sup.2-day.
2. The article according to claim 1, further including at least one
layer, wherein said at least one layer is disposed adjacent to said
barrier layer.
3. The article according to claim 2, wherein said at least one
barrier layer is interposed between said at least one layer and
said substrate.
4. The article according to claim 2, wherein said at least one
layer is interposed between said at least one barrier layer and
said substrate.
5. The article according to claim 4, wherein said at least one
layer comprises an adhesion layer for promoting adhesion of said at
least one barrier layer to said substrate.
6. The article according to claim 5, wherein said adhesion layer
comprises at least one of: a metal in elemental form, a carbide of
said metal, an oxycarbide of said metal, an oxide of said metal,
and a nitride of said metal, wherein said metal is one of silicon,
aluminum, titanium, zirconium, hafnium, tantalum, gallium,
germanium, zinc, tin, cadmium, tungsten, molybdenum, chromium,
vanadium, and platinum; amorphous carbon; a ceramic material,
wherein said ceramic material comprises at least one of glass,
silica, alumina, zirconia, boron nitride, boron carbide, and boron
carbonitride; a silicone; a siloxane; a polymer; an epoxide; an
acrylate; an acrylonitrile; a xylene; a styrene; and combinations
thereof.
7. The article according to claim 2, wherein said at least one
layer comprises at least one of an abrasion resistant layer, an
ultraviolet radiation-absorbing layer, an infrared
radiation-reflecting layer, and an electrically conducting
layer.
8. The article according to claim 7, wherein said abrasion
resistant layer comprises at least one of: a carbide of a metal, an
oxycarbide of said metal, an oxide of said metal, and a nitride of
said metal, wherein said metal is one of silicon, aluminum,
titanium, zirconium, hafnium, tantalum, gallium, germanium, zinc,
tin, cadmium, tungsten, molybdenum, chromium, vanadium, and
platinum; amorphous carbon; a ceramic material, wherein said
ceramic material comprises at least one of glass, silica, alumina,
zirconia, boron nitride, boron carbide, and boron carbonitride; a
silicone; a siloxane; polymerized monomers; polymerized oligomers;
an organic polymer; an inorganic-organic polymer; an epoxide; an
acrylate; an acrylonitrile; a xylene; a styrene; and combinations
thereof.
9. The article according to claim 7, wherein said ultraviolet
radiation-absorbing layer comprises at least one of titanium oxide,
zinc oxide, cerium oxide, a polymer, and combinations thereof.
10. The article according to claim 7, wherein said infrared
radiation-reflecting layer comprises at least one of silver,
aluminum, indium, tin, indium tin oxide, cadmium stannate, zinc,
and combinations thereof.
11. The article according to claim 7, wherein said electrically
conducting layer comprises at least one of silver, aluminum,
indium, tin, indium tin oxide, cadmium stannate, zinc, and
combinations thereof.
12. The article according to claim 1, wherein said inorganic
material comprises at least one of an oxide, a nitride, and a
carbide of a metal, and combinations thereof.
13. The article according to claim 12, wherein said metal is one of
silicon, aluminum, zinc, indium, tin, a transition metal, and
combinations thereof.
14. The article according to claim 13, wherein said transition
metal is titanium.
15. The article according to claim 13, wherein said inorganic
material comprises titanium oxide.
16. The article according to claim 13, wherein said inorganic
material comprises silicon nitride.
17. The article according to claim 1, wherein said barrier layer
has a thickness in a range from about 10 nm to about 10,000 nm.
18. The article according to claim 17, wherein said barrier layer
has a thickness in a range from about 20 nm to about 500 nm.
19. The article according to claim 1, wherein said barrier layer
has a water vapor transmission rate of up to about 0.2
g/m.sup.2-day.
20. The article according to claim 1, wherein said barrier layer
has an oxygen transmission rate at 25.degree. C. and 100% oxygen
concentration of up to about 0.2 cc/m.sup.2-day.
21. The article according to claim 1, wherein the article is one of
a light emitting diode (LED), a liquid crystal display (LCD), a
photovoltaic article, a flat panel display device, an
electrochromic article, an organic integrated circuit, and an
organic electroluminescent device (OELD).
22. The article according to claim 1, wherein said barrier layer is
deposited on said substrate by: injecting at least one reagent into
an expanding thermal plasma; reacting said at least one reagent in
said expanding thermal plasma to form at least one deposition
precursor; and depositing said at least one deposition precursor on
said substrate at a rate of at least about 200 nm/min to form said
barrier layer on said substrate.
23. The article according to claim 1, wherein said substrate
comprises one of glass, a polymeric material, silicon, a metallic
web, and fiberglass.
24. The article according to claim 23, wherein said polymeric
material comprises one of a polycarbonate, a polyethylene
terephtalene, a polyethylene naphthalene, a polyimide, a
polyethersulfone, a polyacrylate, a polynorbornene, and
combinations thereof.
25. The article according to claim 23, wherein said metallic web
comprises one of aluminum and steel.
26. A barrier layer deposited on a substrate, said barrier layer
comprising at least one of a metal oxide, a metal nitride, a metal
carbide, and combinations thereof, and wherein each of said metal
nitride, said metal carbide, and said metal oxide contains at least
one of silicon, aluminum, zinc, indium, tin, a transition metal,
and combinations thereof, and wherein said barrier layer is
resistant to transmission of moisture and oxygen therethrough and
has a water vapor transmission rate (WVTR) at 25.degree. C. and
100% relative humidity of less than about 2 g/m.sup.2-day and an
oxygen transmission rate (OTR) at 25.degree. C. and 100% oxygen
concentration of less than about 2 cc/m.sup.2-day.
27. The barrier layer according to claim 26, wherein said
transition metal is titanium.
28. The barrier layer according to claim 26, wherein said barrier
layer comprises titanium oxide.
29. The barrier layer according to claim 26, wherein said barrier
layer comprises silicon nitride.
30. The barrier layer according to claim 26, wherein said barrier
layer has a thickness in a range from about 10 nm to about 10,000
nm.
31. The barrier layer according to claim 30, wherein said barrier
layer has a thickness in a range from about 20 nm to about 500
nm.
32. The barrier layer according to claim 26, wherein said barrier
layer has a water vapor transmission rate of up to about 0.2
g/m.sup.2-day.
33. The barrier layer according to claim 26, wherein said barrier
layer has an oxygen transmission rate at 25.degree. C. and 100%
oxygen concentration of up to about 0.2 cc/m.sup.2-day.
34. The barrier layer according to claim 26, wherein said barrier
layer is deposited on said substrate by: injecting a first reagent
into an expanding thermal plasma, said first reagent comprising at
least one of silicon, aluminum, zinc, indium, tin, a transition
metal, and combinations thereof; injecting a second reagent into
said expanding thermal plasma, the second reagent comprising at
least one of oxygen, nitrogen, hydrogen, water, and ammonia;
reacting said first reagent and said second reagent in said
expanding thermal plasma to form at least one deposition precursor;
and depositing said at least one deposition precursor on said
substrate at a rate of at least about 200 nm/min to form said
barrier layer on said substrate.
35. The barrier layer according to claim 34, wherein the at least
one deposition precursor is deposited at a rate of at least about
600 nm/min to form the barrier layer on said substrate.
36. The barrier layer according to claim 34, wherein the at least
one deposition precursor is deposited on said substrate at a rate
of at least about 3,000 nm/min to form the barrier layer on said
substrate.
37. An article, said article comprising: a) a substrate; and b) at
least one barrier layer, said at least one barrier layer comprising
at least one of a metal oxide, a metal nitride, a metal carbide,
and combinations thereof, wherein each of said metal nitride, said
metal carbide, and said metal oxide contains at least one of
silicon, aluminum, zinc, indium, tin, a transition metal, and
combinations thereof, and wherein said barrier layer is resistant
to transmission of moisture and oxygen therethrough and has a water
vapor transmission rate (WVTR) at 25.degree. C. and 100% relative
humidity of less than about 2 g/m.sup.2-day and an oxygen
transmission rate (OTR) at 25.degree. C. and 100% oxygen
concentration of less than about 2 cc/m.sup.2-day.
38. The article according to claim 37, further including at least
one layer, wherein said at least one layer is disposed adjacent to
said barrier layer.
39. The article according to claim 38, wherein said at least one
barrier layer is interposed between said at least one layer and
said substrate.
40. The article according to claim 38, wherein said at least one
layer is interposed between said at least one barrier layer and
said substrate.
41. The article according to claim 40, wherein said at least one
layer comprises an adhesion layer for promoting adhesion of said at
least one barrier layer to said substrate.
42. The article according to claim 41, wherein said adhesion layer
comprises at least one of: a metal in elemental form, a carbide of
said metal, an oxycarbide of said metal, an oxide of said metal,
and a nitride of said metal, wherein said metal is one of silicon,
aluminum, titanium, zirconium, hafnium, tantalum, gallium,
germanium, zinc, tin, cadmium, tungsten, molybdenum, chromium,
vanadium, and platinum; amorphous carbon; a ceramic material,
wherein said ceramic material comprises at least one of glass,
silica, alumina, zirconia, boron nitride, boron carbide, and boron
carbonitride; a silicone; a siloxane; a polymer; an epoxide; an
acrylate; an acrylonitrile; a xylene; a styrene; and combinations
thereof.
43. The article according to claim 38, wherein said at least one
layer comprises at least one of an abrasion resistant layer, an
ultraviolet radiation-absorbing layer, infrared
radiation-reflecting layer, and an electrically conducting
layer.
44. The article according to claim 43, wherein said abrasion
resistant layer comprises at least one of: a carbide of a metal, an
oxycarbide of said metal, an oxide of said metal, and a nitride of
said metal, wherein said metal is one of silicon, aluminum,
titanium, zirconium, hafnium, tantalum, gallium, germanium, zinc,
tin, cadmium, tungsten, molybdenum, chromium, vanadium, and
platinum; amorphous carbon; a ceramic material, wherein said
ceramic material comprises at least one of glass, silica, alumina,
zirconia, boron nitride, boron carbide, and boron carbonitride; a
silicone; a siloxane; polymerized monomers; polymerized oligomers;
an organic polymer; an inorganic-organic polymer; an epoxide; an
acrylate; an acrylonitrile; a xylene; a styrene; and combinations
thereof.
45. The article according to claim 43, wherein said ultraviolet
radiation-absorbing layer comprises at least one of titanium oxide,
zinc oxide, cerium oxide, a polymer, and combinations thereof.
46. The article according to claim 43, wherein said infrared
radiation-reflecting layer comprises silver, aluminum, indium, tin,
indium tin oxide, cadmium stannate, zinc, and combinations
thereof.
47. The article according to claim 43, wherein said electrically
conducting layer comprises silver, aluminum, indium, tin, indium
tin oxide, cadmium stannate, zinc, and combinations thereof.
48. The article according to claim 37, wherein said transition
metal is titanium.
49. The article according to claim 48, wherein said barrier layer
comprises titanium oxide.
50. The article according to claim 37, wherein said barrier layer
comprises silicon nitride.
51. The article according to claim 37, wherein said barrier layer
has a thickness in a range from about 10 nm to about 10,000 nm.
52. The article according to claim 51, wherein said barrier layer
has a thickness in a range from about 20 nm to about 500 nm.
53. The article according to claim 37, wherein said barrier layer
has a water vapor transmission rate of up to about 0.2
g/m.sup.2-day.
54. The article according to claim 37, wherein said barrier layer
has an oxygen transmission rate at 25.degree. C. and 100% oxygen
concentration of up to about 0.2 cc/m.sup.2-day.
55. The article according to claim 37, wherein the article is one
of a light emitting diode (LED), a liquid crystal display (LCD), a
photovoltaic article, a flat panel display device, an
electrochromic article, an organic integrated circuit, and an
organic electroluminescent device (OELD).
56. The article according to claim 37, wherein said barrier layer
is deposited on said substrate by: injecting a first reagent into
an expanding thermal plasma, said first reagent comprising at least
one of silicon, aluminum, zinc, indium, tin, a transition metal,
and combinations thereof; injecting a second reagent into said
expanding thermal plasma, the second reagent comprising at least
one of oxygen, nitrogen, and ammonia; reacting said first reagent
and said second reagent in said expanding thermal plasma to form at
least one deposition precursor; and depositing said at least one
deposition precursor on said substrate at a rate of at least about
200 nm/min to form said barrier layer on said substrate.
57. The article according to claim 37, wherein said substrate
comprises one of glass, a polymeric material, silicon, a metallic
web, and fiberglass.
58. The article according to claim 57, wherein said polymeric
material comprises one of a polycarbonate, a polyethylene
terephtalene, a polyethylene naphthalene, a polyimide, a
polyethersulfone, a polyacrylate, a polynorbomene, and combinations
thereof.
59. The article of claim 57, wherein said metallic web comprises
one of aluminum and steel.
60. A method of forming a coated article, the coated article
comprising a substrate and a barrier layer disposed thereon,
wherein the barrier layer is resistant to transmission of moisture
and oxygen therethrough and has a water vapor transmission rate
(WVTR) at 25.degree. C. and 100% relative humidity of less than
about 2 g/m.sup.2-day and an oxygen transmission rate (OTR) at
25.degree. C. and 100% oxygen concentration of less than about 2
cc/m.sup.2-day, the method comprising the steps of: a) providing a
substrate; b) generating an thermal plasma, the thermal plasma
having an electron temperature of less than about 1 eV; c)
injecting at least one reagent into the thermal plasma; d) reacting
the at least one reagent in the thermal plasma to form at least one
deposition precursor; e) depositing the at least one deposition
precursor on the substrate at a rate of at least about 200 nm/min
to form the barrier layer on the substrate.
61. The method of claim 60, wherein the step of depositing the at
least one deposition precursor on the substrate at a rate of at
least about 200 nm/min to form a barrier layer on the substrate
comprises depositing the at least one deposition precursor on the
substrate at a rate of at least about 200 nm/min to form a barrier
layer comprising at least one of a metal oxide, a metal nitride, a
metal carbide, and combinations thereof on the substrate.
62. The method of claim 61, wherein each of the metal nitride, the
metal carbide, and the metal oxide contains at least one of
silicon, aluminum, zinc, indium, tin, a transition metal, and
combinations thereof.
63. The method of claim 61, wherein the transition metal is
titanium.
64. The method of claim 60, wherein the article is one of a light
emitting diode (LED), a liquid crystal display (LCD), a
photovoltaic article, a flat panel display device, an
electrochromic article, an organic integrated circuit, and an
organic electroluminescent device (OELD).
65. The method of claim 60, wherein the step of providing a
substrate comprises providing one of a glass substrate, a polymeric
substrate, a silicon substrate, a metallic web substrate, and a
fiberglass substrate.
66. The method of claim 65, wherein the polymeric substrate
comprises one of a polycarbonate, a polyethylene terephtalene, a
polyethylene naphthalene, a polyimide, a polyethersulfone, a
polyacrylate, a polynorbomene, and combinations thereof.
67. The method of claim 65, wherein the metallic web comprises one
of aluminum and steel.
68. The method of claim 60, wherein the step of generating a
thermal plasma comprises generating an expanding thermal
plasma.
69. The method of claim 60, wherein the step of injecting at least
one reagent into the thermal plasma comprises injecting a first
reagent into the thermal plasma, the first reagent comprising at
least one of a silane, a metal vapor, a metal halide, and an
organic compound of a metal, wherein the metal is one of titanium,
zinc, aluminum, indium, and tin, and combinations thereof.
70. The method of claim 69, wherein the silane is one of a
disilane, an aminosilane, and a chlorosilane.
71. The method of claim 69, wherein the organic compound is one of
titanium isopropoxide, diethyl zinc, dimethyl zinc, indium
isopropoxide, indium tert-butoxide, aluminum isopropoxide, and
combinations thereof.
72. The method of claim 69, wherein the metal halide is a metal
chloride.
73. The method of claim 69, further comprising the step of
injecting a second reagent into the plasma, the second reagent
comprising at least one of oxygen, nitrogen, hydrogen, water, and
ammonia.
74. The method of claim 60, further comprising the step of
depositing at least one layer on one of the barrier layer and the
substrate.
75. The method of claim 74, wherein the step of depositing at least
one layer on one of the barrier layer and the substrate comprises
depositing at least one layer of an organic material on one of the
barrier layer and the substrate, the organic material comprising at
least one of polymerized monomers, polymerized oligomers, a
polymer, an epoxide, an acrylate, an acrylonitrile, a xylene, a
styrene; and combinations thereof.
76. The method of claim 74, wherein the step of depositing at least
one layer on one of the barrier layer and the substrate comprises
depositing at least one layer of an inorganic material on one of
the barrier layer and the substrate, the inorganic material
comprising at least one of: a carbide of a metal, an oxycarbide of
said metal, an oxide of said metal, a nitride of said metal,
wherein said metal is one of silicon, aluminum, titanium,
zirconium, hafnium, tantalum, gallium, germanium, zinc, tin,
cadmium, tungsten, molybdenum, chromium, vanadium, and platinum;
amorphous carbon; a ceramic material, wherein said ceramic material
comprises at least one of glass, silica, alumina, zirconia, boron
nitride, boron carbide, and boron carbonitride.
77. The method of claim 74, wherein the step of depositing at least
one layer on one of the barrier layer and the substrate comprises
depositing at least one layer of an hybrid organic-inorganic
material on one of the barrier layer and the substrate, the hybrid
organic-inorganic material comprising at least one of a silicone, a
siloxane, and an organic-inorganic polymer.
78. The method of claim 60, wherein the step of depositing the at
least one deposition precursor on the substrate at a rate of at
least about 200 nm/min to form the barrier layer on the substrate
comprises depositing the at least one deposition precursor on the
substrate at a rate of at least about 600 nm/min to form the
barrier layer on the substrate.
79. The method of claim 78, wherein the step of depositing the at
least one deposition precursor on the substrate at a rate of at
least about 600 nm/min to form the barrier layer on the substrate
comprises depositing the at least one deposition precursor on the
substrate at a rate of at least about 3,000 nm/min to form the
barrier layer on the substrate.
80. The method of claim 60, wherein the step of depositing the at
least one deposition precursor on the substrate at a rate of at
least about 3,000 nm/min to form the barrier layer on the substrate
comprises depositing the at least one deposition precursor on the
substrate at a rate of at least about 10,000 nm/min to form the
barrier layer on the substrate.
81. A method of forming a barrier layer on a substrate, wherein the
barrier layer is resistant to transmission of moisture and oxygen
therethrough and has a water vapor transmission rate (WVTR) at
25.degree. C. and 100% relative humidity of less than about 2
g/m.sup.2-day and an oxygen transmission rate (OTR) at 25.degree.
C. and 100% oxygen concentration of less than about 2
cc/m.sup.2-day, and wherein the barrier layer comprises at least
one of a metal oxide, a metal nitride, a metal carbide, and
combinations thereof, wherein each of the metal nitride, the metal
carbide, and the metal oxide contains at least one of silicon,
aluminum, zinc, indium, tin, a transition metal, and combinations
thereof, the method comprising the steps of: a) generating a
thermal plasma, the thermal plasma having an electron temperature
of less than about 1 eV; b) injecting a first reagent into the
thermal plasma, the first reagent comprising at least one of
silicon, aluminum, zinc, indium, tin, a transition metal, and
combinations thereof; c) injecting a second reagent into the
thermal plasma, the second reagent comprising at least one of
oxygen, nitrogen, and ammonia; d) reacting the first reagent and
the second reagent in the thermal plasma to form at least one
deposition precursor; and e) depositing the at least one deposition
precursor on the substrate at a rate of at least about 200 nm/min,
thereby forming the barrier layer comprising at least one of a
metal oxide, a metal nitride, a metal carbide, and combinations
thereof on the substrate.
82. The method according to claim 81, wherein the step of
generating a thermal plasma comprises generating an expanding
thermal plasma.
83. The method according to claim 81, wherein the step of
depositing the at least one deposition precursor on the substrate
at a rate of at least about 200 nm/min comprises depositing the at
least one deposition precursor on the substrate at a rate of at
least about 600 nm/min.
84. The method according to claim 83, wherein the step of
depositing the at least one deposition precursor on the substrate
at a rate of at least about 600 nm/min comprises depositing the at
least one deposition precursor on the substrate at a rate of at
least about 3,000 nm/min.
85. The method according to claim 84, wherein the step of
depositing the at least one deposition precursor at a rate of at
least about 3,000 nm/min to form the barrier layer on the substrate
comprises depositing the at least one deposition precursor at a
rate of at least about 10,000 nm/ min on the substrate.
86. A method of forming a coated article, the coated article
comprising a substrate and a barrier layer disposed thereon,
wherein the barrier layer has a water vapor transmission rate
(WVTR) at 25.degree. C. and 100% relative humidity of less than
about 2 g/m.sup.2-day and an oxygen transmission rate (OTR) at
25.degree. C. and 100% oxygen concentration of less than about 2
cc/m.sup.2-day, and wherein the barrier layer comprises at least
one of at least one of a metal oxide, a metal nitride, a metal
carbide, and combinations thereof, wherein each of the metal
nitride, the metal carbide, and the metal oxide contains at least
one of silicon, aluminum, zinc, indium, tin, a transition metal,
and combinations thereof, the method comprising the steps of: a)
providing a substrate; b) generating a thermal plasma, the thermal
plasma having an electron temperature of less than about 1 eV; c)
injecting a first reagent into the thermal plasma, the first
reagent comprising at least one of silicon, aluminum, zinc, indium,
tin, a transition metal, and combinations thereof; d) injecting a
second reagent into the thermal plasma, the second reagent
comprising at least one of oxygen, nitrogen, water, and ammonia; e)
reacting the first reagent and the second reagent in the thermal
plasma to form at least one deposition precursor; and f) depositing
the at least one deposition precursor on the substrate at a rate of
at least about 200 nm/min, thereby forming the barrier layer
comprising at least one of a metal oxide, a metal nitride, a metal
carbide, and combinations thereof on the substrate.
87. The method of claim 86, wherein the transition metal is
titanium.
88. The method of claim 86, wherein the article is one of a light
emitting diode (LED), a liquid crystal display (LCD), a
photovoltaic article, a flat panel display device, an
electrochromic article, and an organic electroluminescent device
(OELD).
89. The method of claim 86, wherein the step of providing a
substrate comprises providing one of a glass substrate, a polymeric
substrate, a silicon substrate, a metallic web substrate, and a
fiberglass substrate.
90. The method of claim 86, wherein the polymeric substrate
comprises one of a polycarbonate, a polyethylene terephtalene, a
polyethylene naphthalene, a polyimide, a polyethersulfone, a
polyacrylate, a polynorbornene, and combinations thereof.
91. The method of claim 86, wherein the metallic web comprises one
of aluminum and steel.
92. The method of claim 86, wherein the step of generating a
thermal plasma comprises generating an expanding thermal
plasma.
93. The method of claim 86, wherein the step of injecting at least
one reagent into the thermal plasma comprises injecting a first
reagent into the thermal plasma, the first reagent comprising at
least one of a silane, a metal vapor, a metal halide, and an
organic compound of a metal, wherein the metal is one of titanium,
zinc, aluminum, indium, tin, and combinations thereof.
94. The method of claim 93, wherein the silane is one of a
disilane, an aminosilane, and a chlorosilane.
95. The method of claim 93, wherein the organic compound one of
titanium isopropoxide, diethyl zinc, dimethyl zinc, indium
isopropoxide, indium tert-butoxide, aluminum isopropoxide, and
combinations thereof.
96. The method of claim 93, wherein the metal halide is a metal
chloride.
97. The method of claim 86, wherein the second reagent comprises at
least one of oxygen, nitrogen, hydrogen, water, and ammonia.
98. The method of claim 86, further comprising the step of
depositing at least one layer on one of the barrier layer and the
substrate.
99. The method of claim 86, wherein the step of depositing at least
one layer on one of the barrier layer and the substrate comprises
depositing at least one layer of an organic material on one of the
barrier layer and the substrate, the organic material comprising at
least one of polymerized monomers, polymerized oligomers, a
polymer, an epoxide, an acrylate, an acrylonitrile, a xylene, a
styrene, and combinations thereof.
100. The method of claim 86, wherein the step of depositing at
least one layer on one of the barrier layer and the substrate
comprises depositing at least one layer of an inorganic material on
one of the barrier layer and the substrate, the inorganic material
comprising at least one of: a carbide of a metal, an oxycarbide of
the metal, an oxide of the metal, and a nitride of the metal,
wherein the metal is one of silicon, aluminum, titanium, zirconium,
hafnium, tantalum, gallium, germanium, zinc, tin, cadmium,
tungsten, molybdenum, chromium, vanadium, and platinum; amorphous
carbon; a ceramic material, wherein the ceramic material comprises
at least one of glass, silica, alumina, zirconia, boron nitride,
boron carbide, and boron carbonitride.
101. The method of claim 86, wherein the step of depositing the at
least one deposition precursor on the substrate at a rate of at
least about 200 nm/min comprises depositing the at least deposition
precursor on the substrate at a rate of at least about 600
nm/min.
102. The method of claim 101, wherein the step of depositing the at
least one deposition precursor on the substrate at a rate of at
least about 600 nm/min comprises depositing the at least one
deposition precursor on the substrate at a rate of at least about
3,000 nm/min.
103. The method of claim 102, wherein the step of depositing the at
least one deposition precursor on the substrate at a rate of at
least about 3,000 nm/min comprises depositing the at least one
deposition precursor on the substrate at a rate of at least about
10,000 nm/min.
Description
BACKGROUND OF INVENTION
[0001] The invention relates to a barrier layer that is resistant
to the transmission of moisture and oxygen. More particularly, the
present invention relates to an article having such a barrier layer
and methods of applying such a barrier layer to an article.
[0002] Different types of electronic devices such as, but not
limited to, light emitting diodes (also referred hereinafter as
"LEDs"), liquid crystal displays (also referred hereinafter as
"LCDs"), photovoltaic articles, flat panel display devices,
electrochromic articles, and organic electroluminescent devices
(also referred hereinafter as "OELDs") share a common architecture:
each device includes at least one substrate and at least one
"active" layer.
[0003] Many of the materials that are used in the active layers of
such devices are sensitive to environmental factors. Electrode
materials in LEDs and OELDs are sensitive to air and moisture, as
are the polymeric and organic compounds that are used in OELDs and
the liquid crystal materials in LCDs. Exposure to the
elements--particularly oxygen and water--may severely limit the
lifetime of such devices.
[0004] Selection of a substantially impermeable substrate, such as
glass, provides protection from environmental attack. Polymeric
substrates that are used in flexible versions of such devices,
however, do not provide adequate protection against oxygen and
moisture. Consequently, at least one coating that is substantially
impermeable to oxygen and water vapor must be applied to the
polymeric substrate to achieve the desired level of protection.
[0005] Barrier materials have been applied to substrates using a
variety of coating processes. Plasma enhanced chemical vapor
deposition (PECVD), for example, has been used to deposit barrier
materials. Typical PECVD processes, however, are relatively slow;
i.e. the barrier material is deposited on the substrate at a rate
of about 30 to 60 nm/min or less. In order to be commercially
viable, the barrier coating must be applied to the substrate at a
significantly higher deposition rate.
[0006] While barrier materials are needed to extend lifetimes of
flexible display devices such as LCDs, LEDs, and OELDs to
acceptable levels, the methods that are currently used to apply the
needed barrier materials to substrates are too slow. Therefore,
what is needed is a method of forming a barrier layer on a
substrate at a high rate of deposition. What is also needed is a
method of forming a barrier layer on a substrate to form an article
having acceptable water vapor and oxygen transmission rates. What
is further needed is an article having a barrier layer, the article
having acceptable water vapor and oxygen transmission rates.
SUMMARY OF INVENTION
[0007] The present invention meets these and other needs by
providing an article comprising a substrate having a barrier layer
disposed on the surface of the substrate and methods of depositing
such a barrier layer on the substrate, wherein the barrier layer is
resistant to transmission of moisture and oxygen therethrough. The
article may include additional layers, such as, but not limited to,
an adhesion layer, abrasion resistant layers, radiation-absorbing
layers, radiation-reflective layers, and conductive layers. Such
articles include, but are not limited to, light emitting diodes
(LEDs), liquid crystal displays (LCDs), photovoltaic articles,
electrochromic articles, organic integrated circuits, and organic
electroluminescent devices (OELDs).
[0008] Accordingly, one aspect of the invention is to provide an
article. The article comprises a substrate and at least one barrier
layer disposed on at least one surface of the substrate, wherein
the barrier layer comprises an inorganic material, and wherein the
barrier layer is resistant to transmission of moisture and oxygen
therethrough and has a water vapor transmission rate (WVTR) at
25.degree. C. and 100% relative humidity of less than about 2
g/m.sup.2-day and an oxygen transmission rate (OTR) at 25.degree.
C. and 100% oxygen concentration of less than about 2
cc/m.sup.2-day.
[0009] A second aspect of the invention is to provide a barrier
layer that is resistant to transmission of moisture and oxygen
therethrough. The barrier layer comprises at least one of a metal
oxide, a metal nitride, a metal carbide, and combinations thereof.
Each of the metal nitride, the metal carbide, and the metal oxide
contains at least one of silicon, aluminum, zinc, indium, tin, a
transition metal, and combinations thereof. The barrier layer has a
water vapor transmission rate (WVTR) at 25.degree. C. and 100%
relative humidity of less than about 2 g/m.sup.2-day and an oxygen
transmission rate (OTR) at 25.degree. C. and 100% oxygen
concentration of less than about 2 cc/m.sup.2-day.
[0010] A third aspect of the invention is to provide an article.
The article comprises a substrate and at least one barrier layer,
the at least one barrier layer comprising at least one of a metal
oxide, a metal nitride, a metal carbide, and combinations thereof,
wherein each of the metal nitride, the metal carbide, and the metal
oxide contains at least one of silicon, aluminum, zinc, indium,
tin, a transition metal, and combinations thereof, and wherein the
barrier layer is resistant to transmission of moisture and oxygen
therethrough and has a water vapor transmission rate (WVTR) at
25.degree. C. and 100% relative humidity of less than about 2
g/m.sup.2-day and an oxygen transmission rate (OTR) at 25.degree.
C. and 100% oxygen concentration of less than about 2
cc/m.sup.2-day.
[0011] A fourth aspect of the invention is to provide a method of
forming a coated article. The coated article comprises a substrate
and a barrier layer disposed thereon, wherein the barrier layer is
resistant to transmission of moisture and oxygen therethrough and
has a water vapor transmission rate (WVTR) at 25.degree. C. and
100% relative humidity of less than about 2 g/m.sup.2-day and an
oxygen transmission rate (OTR) at 25.degree. C. and 100% oxygen
concentration of less than about 2 cc/m.sup.2-day. The method
comprises the steps of: providing a substrate; generating a thermal
plasma, the thermal plasma having an electron temperature of less
than about 1 eV; injecting at least one reagent into the thermal
plasma; reacting the at least one reagent in the thermal plasma to
form at least one deposition precursor; and depositing the at least
one deposition precursor on the substrate at a rate of at least
about 200 nm/min to form the barrier layer on the substrate.
[0012] A fifth aspect of the invention is to provide a method of
forming a barrier layer on a substrate. The barrier layer is
resistant to transmission of moisture and oxygen therethrough and
has a water vapor transmission rate (WVTR) at 25.degree. C. and
100% relative humidity of less than about 2 g/m.sup.2-day and an
oxygen transmission rate (OTR) at 25.degree. C. and 100% oxygen
concentration of less than about 2 cc/m.sup.2-day, and comprises at
least one of at least one of a metal oxide, a metal nitride, a
metal carbide, and combinations thereof, wherein each of the metal
nitride, the metal carbide, and the metal oxide contains at least
one of silicon, aluminum, zinc, indium, tin, a transition metal,
and combinations thereof. The method comprises the steps of:
generating a thermal plasma, the thermal plasma having an electron
temperature of less than about 1 eV; injecting a first reagent into
the thermal plasma, the first reagent comprising at least one of
silicon, aluminum, zinc, indium, tin, a transition metal, and
combinations thereof; injecting a second reagent into the thermal
plasma, the second reagent comprising at least one of oxygen,
nitrogen, and ammonia; decomposing the first reagent and the second
reagent in the thermal plasma to form a plurality of decomposition
products; reacting the at least one reagent in the thermal plasma
to form at least one deposition precursor; and depositing the at
least one deposition precursor on the substrate at a rate of at
least about 200 nm/min to form the barrier layer comprising at
least one of a metal oxide, a metal nitride, a metal carbide, and
combinations thereof on the substrate.
[0013] A sixth aspect of the invention is to provide a method of
forming a coated article. The coated article comprises a substrate
and a barrier layer disposed thereon. The barrier layer is
resistant to transmission of moisture and oxygen therethrough and
has a water vapor transmission rate (WVTR) at 25.degree. C. and
100% relative humidity of less than about 2 g/m.sup.2-day and an
oxygen transmission rate (OTR) at 25.degree. C. and 100% oxygen
concentration of less than about 2 cc/m 2-day, and comprises at
least one of a metal oxide, a metal nitride, a metal carbide, and
combinations thereof, wherein each of the metal nitride, the metal
carbide, and the metal oxide contains at least one of silicon,
aluminum, zinc, indium, tin, a transition metal, and combinations
thereof. The method comprises the steps of: providing a substrate;
generating a thermal plasma, the thermal plasma having an electron
temperature of less than about 1 eV; injecting a first reagent into
the thermal plasma, the first reagent comprising at least one of
silicon, aluminum, zinc, indium, tin, a transition metal, and
combinations thereof; injecting a second reagent into the thermal
plasma, the second reagent comprising at least one of oxygen,
nitrogen, and ammonia; reacting the first reagent and the second
reagent in the thermal plasma to form at least one deposition
precursor; and depositing the at least one deposition precursor on
the substrate at a rate of at least about 200 nm/min, thereby
forming the barrier layer comprising at least one of a metal oxide,
a metal nitride, a metal carbide, and combinations thereof on the
substrate.
[0014] These and other aspects, advantages, and salient features of
the present invention will become apparent from the following
detailed description, the accompanying drawings, and the appended
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1 is a schematic representation of an article of the
present invention;
[0016] FIG. 2 is a schematic representation of a flexible liquid
crystal display of the present invention;
[0017] FIG. 3a is a schematic representation of a light emitting
diode of the present invention;
[0018] FIG. 3b is a schematic representation of a organic
electroluminescent device of the present invention;
[0019] FIG. 4 is a schematic representation of an expanding thermal
plasma deposition system; and
[0020] FIG. 5 is a plot of the water vapor transmission rate of a
silicon nitride barrier layer of the present invention as a
function of reagent flow rate.
DETAILED DESCRIPTION
[0021] In the following description, like reference characters
designate like or corresponding parts throughout the several views
shown in the figures. It is also understood that terms such as
"top," "bottom," "outward," "inward," and the like are words of
convenience and are not to be construed as limiting terms.
[0022] Several display devices such as, but not limited to, light
emitting diodes (also referred hereinafter as "LEDs"), liquid
crystal displays (also referred hereinafter as "LCDs"),
photovoltaic articles, flat panel display devices, electrochromic
articles, and organic electroluminescent devices (also referred
hereinafter as "OELDs") share a common architecture: each device
includes at least one substrate and at least one "active" layer.
Light emitting diodes and organic electroluminescent devices, for
example, may include a cathode layer, an electron transport layer,
an emission layer, a hole transport layer, and an anode layer
disposed on a substrate. Liquid crystal displays may include two
substrates, each having an electrically conductive layer disposed
thereon, and a liquid crystal layer sandwiched between the two
substrates.
[0023] Many of the materials that are used in these devices may be
adversely affected by environmental factors. Electrode materials in
LEDs and OELDs are sensitive to air and moisture, as are the
polymeric and organic compounds that are used in OELDs and the
liquid crystal materials in LCDs. Exposure to the
elements--particularly oxygen and water--may severely limit the
lifetime of such devices.
[0024] Selection of a substantially impermeable substrate, such as
glass, provides protection from environmental attack. Polymeric
substrates that are used in flexible versions of such devices,
however, do not provide adequate protection against oxygen and
moisture. Consequently, at least one barrier layer that is
substantially impermeable to oxygen and water vapor must be applied
to the polymeric substrate to achieve the desired level of
protection. Here, a coating, device, or coated substrate that is
described as being "substantially impermeable" is understood as
having a water vapor transmission rate (also referred hereinafter
as "WVTR") and an oxygen transmission rate (also referred
hereinafter as "OTR") of less than about 2 g/m.sup.2-day at
25.degree. C. and 100% relative humidity and less than about 2
cc/m.sup.2-day at 25.degree. C. and 100% oxygen concentration,
respectively.
[0025] Referring to the drawings in general and to FIG. 1 in
particular, it will be understood that the illustrations are for
the purpose of describing a preferred embodiment of the invention
and are not intended to limit the invention thereto. FIG. 1 is a
schematic representation of an article 100 of the present
invention. Article 100 comprises a substrate 102 and at least one
barrier layer 106 disposed on a surface of substrate 102. An
additional layer 104, such as, but not limited to, an adhesion
layer, may be optionally disposed between substrate 102 and the at
least one barrier layer 106. Substrate 102 may comprise one of
glass, a polymeric material, silicon, a metallic web, and
fiberglass. Where substrate 102 is a polymeric material, substrate
102 comprises at least one of a polycarbonate, a polyethylene
terephtalene, a polyethylene naphthalene, a polyimide, a
polyethersulfone, a polyacrylate, a polynorbomene, and combinations
thereof. In another embodiment, substrate 102 is a metallic web
comprising one of aluminum and steel.
[0026] The at least one barrier layer 106 comprises an inorganic
material and is resistant to the transmission of moisture and
oxygen therethrough. The at least one barrier layer 106 has a WVTR
of less than about 2 g/m.sup.2-day at 25.degree. C. and 100%
relative humidity and an OTR of less than about 2 cc/m.sup.2-day at
25.degree. C. and 100% oxygen concentration. In a second
embodiment, the at least one moisture layer 106 has a WVTR of less
than about 1.7 g/m.sup.2-day at 25.degree. C. and 100% relative
humidity and an OTR of less than about 0.21 cc/m.sup.2-day at
25.degree. C. and 100% oxygen concentration. In a third embodiment,
the at least one barrier layer 106 has a WVTR of less than about
0.157 g/m.sup.2-day at 25.degree. C. and 100% relative humidity and
an OTR of less than about 0.13 cc/m.sup.2-day at 25.degree. C. and
100% oxygen concentration. The at least one barrier layer 106
comprises at least one of a metal oxide, a metal nitride, a metal
carbide, and combinations thereof, wherein the metal is one of
silicon, aluminum, zinc, indium, tin, and a transition metal, such
as, but not limited to, titanium. In one embodiment, the at least
one barrier layer 106 comprises titanium oxide. In another
embodiment, the at least one barrier layer 106 comprises silicon
nitride. The at least one barrier layer 106 has a thickness in a
range from about 10 nm to about 10,000 nm. In one embodiment, the
at least one barrier layer has a thickness in a range from about 20
nm to about 500 nm.
[0027] Article 100 may further include at least one layer 110,
which is disposed adjacent to the at least one barrier layer 106.
Where article 100 is a LCD display, the at least one layer may
include at least one transparent electrically conductive layer
comprising an oxide of tin, cadmium, indium, zinc, magnesium,
gallium, and combinations thereof. Where article 100 is an LED or
OELD, the at least one layer may include, for example, a cathode
layer, an electron transport layer, an emission layer (in OELDs), a
hole transport layer, and an anode layer, wherein the electron
transport and hole transport layers may be either organic or
inorganic material, and wherein the emission layer comprises an
organic material.
[0028] FIG. 2 is a schematic representation of the structure of a
flexible liquid crystal display of the present invention. Flexible
LCD 200 comprises a center liquid crystal layer 212, a first and a
second conductive layer 214, 216, a first and a second barrier
layer 218, 220 and a first and a second polymeric substrate 222,
224. First polymeric substrate 222, first conductive layer 214 and
first barrier layer 218 combine to form a first plate 225 and
second polymeric substrate 224, second conductive layer 216 and
second barrier layer 220 combine to form a second plate 227. First
and second plates 225, 227 are disposed substantially parallel to
one another and liquid crystal layer 212 is interposed
therebetween. Flexible LCDs have been described in "A Transparent
Flexible Barrier for Liquid Crystal Display Devices and Method of
Making the Same," U.S. patent application Ser. No. 09/836,657, by
Argemiro Soares DaSilva Sobrinho, which is incorporated herein by
reference in its entirety.
[0029] FIGS. 3a and 3b are schematic representations of a light
emitting diode (LED) and an organic electroluminescent device
(OELD), respectively. In LED 300 (FIG. 3a), barrier layer 312 is
disposed on substrate 310. Anode 314 is disposed on barrier layer
312 opposite substrate 310. Hole transport layer 314, which
comprises at least one of the n-type (negative charge accepting)
semiconductors known in the art, such as, but not limited to,
silicon doped with phosphorous, is disposed on top of--and in
contact with--anode 314. Electron transport layer 316, comprising
at least one the p-type (positive hole) semiconductors known in the
art, such as, but not limited to, silicon doped with aluminum, is
disposed on top of and in contact with hole transport layer 314.
Cathode 318 is disposed on top of--and in contact with--electron
transport layer 316.
[0030] OELD 350 (FIG. 3b) also includes a substrate 360, barrier
layer 362, anode 364, hole transport layer 366, electron transport
layer 370, and cathode 372 in substantially the same relation as in
LED 300, with the exception that emission layer 368 is disposed
between hole transport layer 366 and electron transport layer 370.
Hole transport layer 366, emission layer 368, and electron
transport layer 370 each comprise an organic material in either
molecular or polymeric form. Electron transport layer 370 and
emission layer 368 may be combined into a single layer.
Alternatively, hole transport layer 366, emission layer 368, and
electron transport layer 370 may be combined into a single
layer.
[0031] In other embodiments, the at least one layer 110 may
comprise at least one of an adhesion layer, an abrasion-resistant
layer, an ultraviolet radiation-absorbing layer, and an infrared
radiation-reflecting layer. When the at least one layer 110
comprises an adhesion layer, which is intended to promote adhesion
of barrier layer 106 to substrate 102, the adhesion layer comprises
at least one of a metal in elemental form, a metal carbide, a metal
oxycarbide, a metal oxide, a metal nitride, a metal oxynitride, and
a metal carbonitride, wherein the metal is one of silicon,
aluminum, titanium, zirconium, hafnium, tantalum, gallium,
germanium, zinc, tin, cadmium, tungsten, molybdenum, chromium,
vanadium, and platinum. Alternatively, the adhesion layer may
comprise at least one of: amorphous carbon; a ceramic comprising at
least one of glass, silica, alumina, zirconia, boron nitride, boron
carbide, and boron carbonitride; a silicone; monomers; oligomers; a
siloxane; a polymer; an epoxide; an acrylate; an acrylonitrile; a
xylene; a styrene; and the like, as well as combinations thereof.
When included in the at least one layer 110, the ultraviolet
radiation-absorbing layer comprises at least one of titanium oxide,
zinc oxide, cerium oxide, an ultraviolet radiation-absorbing
organic material in either polymeric or molecular form, and
combinations thereof. The infrared radiation-reflecting layer, when
included in the at least one layer 110, comprises at least one of
silver, aluminum, indium, tin, indium tin oxide, cadmium stannate,
zinc, and combinations thereof.
[0032] In one embodiment, the at least one barrier layer 106 is
interposed between the at least one layer 110 and substrate 102. In
one embodiment, shown in FIG. 1, the at least one layer 110 may be
disposed between barrier layer 106 and a second barrier layer 105.
In addition, the at least one layer 110 need only be disposed
between a portion of barrier layer 106 and second barrier layer
105, as seen in FIG. 1. Such a configuration provides all-around
encapsulation and protection of the at least one layer 110 from
exposure to water vapor and oxygen. In another embodiment, the at
least one layer 110 is interposed between the at least one barrier
layer 106 and substrate 102 (as represented by 104 in FIG. 1). One
example of the latter embodiment is when the at least one layer 110
comprises an adhesion layer.
[0033] The present invention also includes a method of forming the
article 100 having barrier layer 106 disposed on substrate 102, as
described herein, and a method of forming barrier layer 106, which
is described herein, on substrate 102. Barrier layer 106 is formed
on substrate 102 by injecting at least one reactant gas into a
plasma, which is generated by at least one plasma source. The at
least one plasma source is preferably an expanding thermal plasma
(also referred to hereinafter as "ETP") source that produces an
expanding thermal plasma. Either a single plasma source or an array
of a plurality of plasma sources may be used to generate the
plasma. Systems having single and multiple plasma sources have been
described in: "Protective Coating by High Rate Arc Plasma
Deposition," U.S. Pat. No. 6,110,544, by Barry Lee-Mean Yang et
al.; "Apparatus and Method for Large Area Chemical Vapor Deposition
Using Expanding Thermal Plasma Generators," U.S. patent application
Ser. No. 09/681,820, by Barry Lee-Mean Yang et al.; "Large Area
Plasma Coating Using Multiple Expanding Thermal Plasma Sources in
Combination with a Common Injection Source," U.S. patent
application Ser. No. 09/683,149, by Marc Schaepkens; and "Apparatus
and Method for Depositing Large Area Coatings on Non-Planar
Surfaces," U.S. patent application Ser. No. 09/683,148, by Marc
Schaepkens, all of which are incorporated herein by reference in
their entirety.
[0034] A schematic representation of an ETP deposition system
having a single ETP source is shown in FIG. 4. ETP deposition
system 400 includes high pressure plasma chamber 410 and a low
pressure deposition chamber 420, the latter containing substrate
424. ETP source 402 includes a cathode 404, an anode 406, and a
plasma source gas inlet 408, of which the latter two are disposed
in plasma chamber 410. The plasma source gas is an inert gas, such
as a noble gas; i.e., argon, helium, neon, krypton, or xenon.
Alternatively, chemically reactive gases, such as, but not limited
to, nitrogen and hydrogen, may be used as the plasma source gas.
Preferably, argon is used as the plasma source gas. A plasma 412,
which is an expanding thermal plasma, is generated in ETP source
402 by striking an arc between cathode 404 and anode 406 while
introducing the plasma source gas into the arc through plasma
source gas inlet 408.
[0035] Plasma chamber 410 and deposition chamber 420 are in fluid
communication with each other through opening 418. Deposition
chamber 420 is in fluid communication with a vacuum system (not
shown), which is capable of maintaining the deposition chamber at a
pressure that is lower than that of plasma chamber 410. In one
embodiment, the deposition chamber 420 is maintained at a pressure
of less than about 1 torr (about 133 Pa) and, preferably, at a
pressure of less than about 100 millitorr (about 0.133 Pa), while
plasma chamber 410 is maintained at a pressure of at least about
0.1 atmosphere (about 1.01.times.10.sup.4 Pa).
[0036] At least one reactant gas injector 422 is located in
deposition chamber 420 for providing at least one reactant gas at a
predetermined flow rate into the plasma generated by plasma source
402. The at least one reactant gas is provided through at least one
reactant gas injector 422 to plasma 412 as the plasma 412 enters
deposition chamber 420 through opening 418. The at least one
reactant gas may comprise a single reactant gas or a mixture of
reactant gases. The at least one reactant gas may be provided from
a single reactant gas source or separate, multiple reactant gas
sources to either a single reactant gas injector system or separate
reactant gas injector systems.
[0037] In an ETP, a plasma is generated by ionizing the plasma
source gas in the arc generated between the cathode and anode to
produce a positive ion and an electron. The following reaction, for
example, occurs when an argon plasma is generated:
Ar.fwdarw.Ar.sup.++e.sup.-.
[0038] The plasma is then expanded into a high volume at low
pressure, thereby cooling the electrons and positive ions. In the
present invention, plasma 412 is generated in plasma chamber 410
and expanded into deposition chamber 420 through opening 418. As
previously described, deposition chamber 420 is maintained at a
significantly lower pressure than plasma chamber 410. Consequently,
the electrons in the ETP are too cold and thus have insufficient
energy to cause direct dissociation of the at least one reactant
gas within the ETP. Instead, the at least one reactant gas that is
introduced into the plasma may undergo charge exchange and
dissociative recombination reactions with the ions and electrons
within the ETP to form at least one deposition precursor. In the
expanded ETP, the positive ion and electron temperatures are
approximately equal and in the range of about 0.1 eV (about 1000
K). in contrast to an ETP, other types of plasmas produce electrons
having a sufficiently high temperature to substantially affect the
chemistry of the plasma. In such plasmas, the positive ions
typically have a temperature of greater than 0.1 eV, and the
electrons have a temperature of at least 1 eV, or about 10,000
K.
[0039] Once injected into plasma 412, the at least one reactant gas
undergoes a reaction within the ETP to form at least one deposition
precursor. Such reactions may include, but are not limited to,
charge exchange reactions, dissociative recombination reactions,
and fragmentation reactions. The at least one deposition precursor
that is formed within the ETP is then deposited on a surface of
substrate 424 to form the barrier layer 106 on substrate 424.
[0040] The at least one deposition precursor is deposited on
substrate 424 at a rate of at least about 200 nm/min to form the at
least one barrier layer 106 on substrate 424, although higher
deposition rates are within the scope of the invention. In one
embodiment, for example, the at least one deposition precursor is
deposited on substrate 424 at a rate of at least about 600 nm/min.
In yet another embodiment, the at least one deposition precursor is
deposited on substrate 424 at a rate of at least about 3,000
nm/min. in still yet another embodiment, the at least one
deposition precursor is deposited on a surface of substrate 424 at
a rate of at least about 10,000 nm/min.
[0041] As previously described, the at least one barrier layer 106
comprises at least one of a metal oxide, a metal nitride, a metal
carbide, and combinations thereof, wherein the metal is one of
silicon, aluminum, zinc, indium, tin, and a transition metal, such
as, but not limited to, titanium. In these instances, the at least
one reactant gas includes a first gaseous reagent comprising at
least one of a silane, a metal vapor, a metal halide, and an
organic compound of a metal, wherein the metal is one of titanium,
zinc, aluminum, indium, and tin. Exemplary silanes include
disilanes, aminosilanes, and chlorosilanes. Exemplary organic
compounds include titanium isopropoxide, diethyl zinc, dimethyl
zinc, indium isopropoxide, indium tert-butoxide, aluminum
isopropoxide, and combinations thereof. Exemplary metal halides
include the chlorides of titanium, tin, and aluminum. The at least
one reactant may also comprise elemental zinc, indium, tin, and
aluminum in vapor form. The first gaseous reagent is injected into
plasma 412 along with a second gaseous reagent comprising at least
one of oxygen, nitrogen, hydrogen, water, and ammonia. In one
particular embodiment, where the at least one barrier layer 106
comprises at least one of an oxide, a nitride, and a carbide of
titanium, a first gaseous reagent comprising at least one of
titanium chloride and titanium isopropoxide is injected into plasma
412 along with a second reagent, which, in addition to--or instead
of--oxygen, nitrogen, hydrogen, water, and ammonia, may include
propane, butane, acetylene, and the like, as well as combinations
thereof. In another embodiment in which the at least one barrier
layer 106 comprises at least one of an oxide, a nitride, and a
carbide of silicon, a first gaseous reagent comprising at least one
of a silane, a disilane, an aminosilane, and a chlorosilane is
injected into plasma 412 along with the second reagent. For
example, a silicon nitride barrier layer may be deposited by
injecting silane (SiH4), diluted in helium to a concentration of
about 2% and ammonia into an expanding thermal argon plasma.
[0042] As previously described, article 100 may further include at
least one layer 110 in addition to the at least one barrier layer
106. In such instances, the method of forming the article 100
having barrier layer 106 disposed on substrate 102, and the method
of forming barrier layer 106 on substrate 102, both of which are
described herein, may further include at least one step in which
the at least one layer 110 is applied to either substrate 102 or
barrier layer 106. It will be appreciated by those skilled in the
art that the method by which the at least one layer 110 is
deposited will depend upon the nature and properties (e.g.,
composition, desired physical properties, and the like) of the at
least one coating. The at least one layer 110 may be deposited
using the ETP plasma apparatus and method described herein.
Alternatively, the at least one layer 110 may be deposited using
methods such as, for example, sputtering, evaporation, ion beam
assisted deposition (IBAD), plasma enhanced chemical vapor
deposition (PEVCD), high intensity plasma chemical vapor deposition
(HIPCVD) using either an inductively coupled plasma (ICP) or
electron cyclotron resonance (ECR), and the like.
[0043] The following example serves to illustrate the salient
features and advantages of the present invention.
EXAMPLE 1
[0044] A polycarbonate substrate having a thickness of 30 mil
(about 0.76 mm) was placed in the deposition chamber of a plasma
deposition system similar to that described in the present
application and schematically shown in FIG. 4. The substrate was
positioned at a working distance (WD) ranging from about 25 cm to
about 60 cm from the expanding thermal plasma (ETP) source. The
vacuum vessel was evacuated to a pressure of less than about 100
mTorr (millitorr), argon gas was flowed through into the plasma
chamber and the ETP source at a rate in a range from about 2 slm
(standard liters per minute) to about 3 slm, and the plasma source
was ignited. The ETP operated at a current level in the range form
about 40 A to about 70 A. The pressure within the plasma chamber
was in the range from about 300 torr to about 800 torr, whereas the
pressure within the deposition chamber was in the range from about
45 mtorr to about 100 mtorr. The pressure differential caused the
argon thermal plasma to expand into the deposition chamber, where
reagents, comprising silane diluted in helium to a concentration of
about 2% and ammonia, were injected through a ring injector into
the expanding argon thermal plasma. The reagents reacted with the
ETP to form deposition precursors, which then combined to deposit a
silicon nitride material barrier layer on the polycarbonate
substrate at a deposition rate of at least 200 nm/min.
[0045] A plot of the water vapor transmission rate (WVTR) at
25.degree. C. and 100% relative humidity and 100% relative humidity
of the silicon nitride barrier layer as a function of reagent (in
this case, ammonia) flow rate is shown in FIG. 5. The WVTR for an
uncoated polycarbonate film having a thickness of 30 mil is also
shown in FIG. 5. As seen in FIG. 5, a single 350 nm thick silicon
nitride barrier layer deposited on a polycarbonate film having a
thickness of about 30 mil reduces the WVTR to less than 0.2
g/m.sup.2-day. The films are highly transparent and colorless; the
polycarbonate film with the silicon nitride barrier layer has a
transparency of at least 89% and a yellow-index of less than
0.7.
[0046] While typical embodiments have been set forth for the
purpose of illustration, the foregoing description should not be
deemed to be a limitation on the scope of the invention. For
example, articles, other than flexible LCD displays, LEDs and
OELDs, that comprise a substrate and a barrier having the
properties described herein are also considered to be within the
scope of the present invention. Such articles include, but are not
limited to, photovoltaic devices, electrochromic devices, x-ray
imaging devices, organic integrated circuits, and rigid-substrate
display devices. Accordingly, various modifications, adaptations,
and alternatives may occur to one skilled in the art without
departing from the spirit and scope of the present invention.
* * * * *