U.S. patent application number 10/301912 was filed with the patent office on 2003-11-06 for transparent conductive layer forming method, transparent conductive layer formed by the method, and material comprising the layer.
Invention is credited to Itoh, Hiroto, Kiyomura, Takakazu, Tsuji, Toshio.
Application Number | 20030207093 10/301912 |
Document ID | / |
Family ID | 19178005 |
Filed Date | 2003-11-06 |
United States Patent
Application |
20030207093 |
Kind Code |
A1 |
Tsuji, Toshio ; et
al. |
November 6, 2003 |
Transparent conductive layer forming method, transparent conductive
layer formed by the method, and material comprising the layer
Abstract
A transparent conductive layer forming method is disclosed which
comprises the steps of introducing a reactive gas to a discharge
space, exciting the reactive gas in a plasma state by discharge at
atmospheric pressure or at approximately atmospheric pressure, and
exposing a substrate to the reactive gas in a plasma state to form
a transparent conductive layer on the substrate, wherein the
reactive gas comprises a reducing gas.
Inventors: |
Tsuji, Toshio; (Tokyo,
JP) ; Itoh, Hiroto; (Tokyo, JP) ; Kiyomura,
Takakazu; (Tokyo, JP) |
Correspondence
Address: |
MUSERLIAN AND LUCAS AND MERCANTI, LLP
600 THIRD AVENUE
NEW YORK
NY
10016
US
|
Family ID: |
19178005 |
Appl. No.: |
10/301912 |
Filed: |
November 22, 2002 |
Current U.S.
Class: |
428/209 |
Current CPC
Class: |
C23C 16/50 20130101;
C23C 16/45595 20130101; Y10T 428/24917 20150115; C23C 16/407
20130101 |
Class at
Publication: |
428/209 |
International
Class: |
B32B 017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 3, 2001 |
JP |
368412/2001 |
Claims
What is claimed is:
1. A transparent conductive layer forming method comprising the
steps of: introducing a reactive gas to a discharge space; exciting
the reactive gas in a plasma state by discharge at atmospheric
pressure or at approximately atmospheric pressure; and exposing a
substrate to the reactive gas in a plasma state to form a
transparent conductive layer on the substrate, wherein the reactive
gas comprises a reducing gas.
2. The transparent conductive layer forming method of claim 1,
wherein the reducing gas is hydrogen.
3. The transparent conductive layer forming method of claim 1,
wherein the reactive gas comprises at least one gas selected from
gases derived from organometallic compounds.
4. The transparent conductive layer forming method of claim 1,
wherein the method comprises the step of introducing a mixed gas of
the reactive gas and inert gas to the discharge space, the inert
gas comprising argon or helium.
5. The transparent conductive layer forming method of claim 4,
wherein the content of the reducing gas in the mixed gas is 0.0001
to 5.0% by volume.
6. The transparent conductive layer forming method of claim 4,
wherein the mixed gas to be introduced to the discharge space
contains no oxygen.
7. The transparent conductive layer forming method of claim 1,
wherein an output density of not more than 100 W/cm.sup.2 is
applied at a frequency of not less than 0.5 kHz across the
discharge space.
8. The transparent conductive layer forming method of claim 7,
wherein an output density of not less than 1 W/cm.sup.2 is applied
at a frequency exceeding 100 kHz across the discharge space.
9. The transparent conductive layer forming method of claim 1,
wherein temperature of the surface of the substrate, on which the
transparent conductive layer is formed, is not more than
300.degree. C.
10. A transparent conductive layer, wherein the transparent
conductive layer is formed on a substrate by introducing a reactive
gas to a discharge space, exciting the reactive gas in a plasma
state by discharge at atmospheric pressure or at approximately
atmospheric pressure, and exposing the substrate to the reactive
gas in a plasma state, wherein the reactive gas comprises a
reducing gas.
11. The transparent conductive layer of claim 10, wherein the
transparent conductive layer has a resistivity of not more than
1.times.10.sup.-3 .OMEGA..multidot.cm.
12. The transparent conductive layer of claim 10, having a mobility
of carrier of not less than 10 cm.sup.2/V.multidot.sec.
13. The transparent conductive layer of claim 10, wherein the
transparent conductive layer has a density of carrier of not less
than 1.times.10.sup.19 cm.sup.-3.
14. The transparent conductive layer of claim 10, having a density
of carrier of not less than 1.times.10.sup.20 cm.sup.-3.
15. The transparent conductive layer of claim 10, wherein the
transparent conductive layer contains any of indium oxide, tin
oxide, zinc oxide, fluorine doped tin oxide, aluminum doped zinc
oxide, antimony doped tin oxide, ITO, and In.sub.2O.sub.3--ZnO as
the main component.
16. The transparent conductive layer of claim 15, wherein the
transparent conductive layer is an ITO layer having an atomic ratio
In/Sn of from 100/0.1 to 100/15.
17. The transparent conductive layer of claim 15, wherein the
transparent conductive layer has a carbon content of from 0 to 5.0
atomic %.
18. A material comprising a substrate and provided thereon, a
transparent conductive layer, wherein the transparent conductive
layer has a resistivity of not more than 1.times.10.sup.-3
.OMEGA..multidot.cm.
19. The material of claim 18, wherein the transparent conductive
layer has a mobility of carrier of not less than 10
cm.sup.2/V.multidot.sec.
20. The material of claim 18, wherein the transparent conductive
layer has a density of carrier of not less than 1.times.10.sup.19
cm.sup.-3.
21. The material of claim 18, wherein the transparent conductive
layer has a density of carrier of not less than 1.times.10.sup.20
cm.sup.-3.
22. The material of claim 18, wherein the transparent conductive
layer contains any of indium oxide, tin oxide, zinc oxide, fluorine
doped tin oxide, aluminum doped zinc oxide, antimony doped tin
oxide, ITO, and In.sub.2O.sub.3--ZnO as the main component.
23. The material of claim 22, wherein the transparent conductive
layer is an ITO layer having an atomic ratio In/Sn of from 100/0.1
to 100/15.
24. The material of claim 22, wherein the transparent conductive
layer has a carbon content of from 0 to 5.0 atomic %.
25. The material of claim 22, wherein the substrate is a
transparent resin film.
26. The material of claim 25, wherein the transparent resin film is
a substrate for a touch panel, a substrate for a liquid crystal
element, a substrate for an organic EL element, a substrate for a
PDP, a substrate for an electromagnetic wave shielding material, or
a substrate for an electronic paper.
27. The material of claim 18, wherein the critical radius of
curvature of the transparent conductive layer is not more than 8
mm.
28. The material of claim 22, wherein the transparent conductive
layer is an electrode formed by patterning.
29. A material comprising a substrate and provided thereon, a
transparent conductive layer, wherein the transparent conductive
layer has a coefficient of variation in the thickness direction of
the ratio H/M of not more than 5%, wherein H represents peak
intensity of a hydrogen ion in the thickness direction of the
transparent conductive layer measured according to dynamic SIMS,
and M represents peak intensity of a metal ion derived from the
main metal oxide in the thickness direction of the transparent
conductive layer measured according to dynamic SIMS.
30. The material of claim 29, wherein the transparent conductive
layer is formed on a substrate by introducing a reactive gas to a
discharge space, exciting the reactive gas in a plasma state by
discharge at atmospheric pressure or at approximately atmospheric
pressure, and exposing the substrate to the reactive gas in a
plasma state.
31. The material of claim 30, wherein the reactive gas comprises a
reducing gas.
32. The material of claim 30, wherein an output density if not less
than 1 W/cm.sup.2 is applied at a frequency exceeding 100 kHz
across the discharge space.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a method of forming a
transparent conductive layer suitably used for various electronic
elements such as a liquid crystal displaying element, an organic
electroluminescence element (hereinafter referred to as an organic
EL element), a plasma display panel (hereinafter referred to as
PDP), an electronic paper, a touch panel and a solar battery, a
transparent conductive layer formed according to the method, and a
material comprising the transparent conductive layer.
BACKGROUND OF THE INVENTION
[0002] The transparent conductive layer has been widely used, for
example, in a liquid crystal displaying element, an organic EL
element, a solar battery, a touch panel, an electromagnetic
radiation shielding material, and an infrared ray reflection film.
Examples of the transparent conductive layer include a layer of
metal such as Pt, Au, Ag or Cu, a layer of an oxide or a complex
oxide doped with a dopant such as SnO.sub.2, In.sub.2O.sub.3, CdO,
ZnO, SnO.sub.2:Sb, SnO.sub.2:F, ZnO:Al, or In.sub.2O.sub.3:Sn, and
a layer of a nonoxide such as chalcogenide, LaBe, TiN, or TiC. Of
these, a layer of a tin doped indium oxide (hereinafter referred to
also as ITO) has been widely used in its excellent electric
properties or its ease of processability such as etching. These
layers are formed according to a vacuum evaporation method, a
sputtering method, an ion plating method, a vacuum plasma CVD
method, a spray pyrolysis method, a thermal CVD method or a sol-gel
method.
[0003] In recent years, a flat panel display employing a liquid
crystal device or an organic EL element with a large area and high
precision has been developed, and a transparent conductive layer
with high performance is required. In order to obtain an element or
apparatus with quick response to electric field in the liquid
crystal device, a transparent conductive layer with high mobility
of electrons is required. Since an electric current driving method
is applied in the organic EL element, a transparent conductive
layer with lower resistivity is required.
[0004] A vacuum deposition method or sputtering method of the
transparent conductive layer forming methods provides a transparent
conductive layer with lower resistivity. Industrially, a DC
magnetron sputtering apparatus provides an ITO layer with high
conductivity having a resistivity of approximately 10.sup.-4
.OMEGA..multidot.cm order.
[0005] However, these physical vapor deposition methods (PVD
method) form a layer by depositing a predetermined material on a
substrate in a vapor phase, and require a vacuum chamber.
Accordingly, an apparatus employing the methods is large,
expensive, and poor in efficiency in use of materials, resulting in
low productivity. Further, it is difficult to manufacture a large
sized layer employing the apparatus. Since it is necessary to heat
a substrate at 200 to 300.degree. C. in order to form on the
substrate a transparent conductive layer with low resistivity, it
is difficult to form a transparent conductive layer with low
resistivity on a plastic substrate as the substrate.
[0006] In the sol-gel method (coating method), many procedures such
as preparation of a dispersion solution, coating and drying are
necessary to form a layer. Further, adhesion of the formed layer to
a substrate is low, and a binder resin is necessary, which lowers
transparency of the product. Further, electric properties of the
resulting transparent conductive layer are poor as compared with
those of the layer obtained by a PVD method.
[0007] The thermal CVD method is a method in which a precursor of a
coated substance is coated on a substrate according to a spin coat
method, a dip coat method, or a printing method, and baked
(thermally decomposed) to form a layer. This method has advantages
in that a device used is simple, productivity is excellent, and a
layer of a large area can be easily formed, but has problem in that
a substrate used is limited, since it requires baking treatment at
a high temperature of from 400 to 500.degree. C. It is difficult to
form a layer particularly on a plastic film substrate.
[0008] As a method for overcoming the demerits in that the sol-gel
method (coating method) is difficult to provide a layer with high
function or use of the vacuum chamber results in lowering of
productivity, a method is proposed which comprises subjecting a
reactive gas to discharge treatment at atmospheric pressure or
approximately atmospheric pressure, exciting the reactive gas to a
plasma state and forming a layer on a substrate (hereinafter
referred to also as an atmospheric pressure plasma CVD method).
Japanese Patent O.P.I. Publication No. 2000-303175 discloses
technique which forms a transparent conductive layer employing the
atmospheric pressure plasma CVD method. However, the formed
transparent conductive layer has a high resistivity, approximately
10.sup.-2 .OMEGA..multidot.cm, which is insufficient as a
transparent conductive layer for a flat panel display of a liquid
crystal device, an organic EL element, a PDP or an electronic
paper, the transparent conductive layer being required to have a
resistivity of not more than 10.sup.-3 .OMEGA..multidot.cm.
Further, the CVD method employs, as a material, triethylindium,
which may ignite and explode at ordinary temperature in ambient
air, and therefore, has a question of safety.
SUMMARY OF THE INVENTION
[0009] The present inventors have made an extensive study on a
transparent conductive layer, and as a result, have found that a
transparent conductive layer with good optical and electric
properties can be formed with a high productivity according to an
atmospheric pressure plasma CVD method employing a reducing
reactive gas as a reactive gas.
[0010] An object of the invention is to provide a method of forming
a transparent conductive layer with good optical and electric
properties, a method of forming a transparent conductive layer with
good critical radius of curvature on a substrate, and a method of
forming a transparent conductive layer with high safety and with
high productivity. Another object of the invention is to provide a
transparent conductive layer formed according to the
above-mentioned method and a material comprising the transparent
conductive layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows a schematic drawing of one embodiment of the
plasma discharge vessel equipped in a plasma discharge apparatus
used in the manufacturing method in the invention.
[0012] FIG. 2 shows a schematic drawing of another embodiment of
the plasma discharge vessel equipped in a plasma discharge
apparatus used in the manufacturing method of the invention.
[0013] FIGS. 3(a) and 3(b) show a schematic drawing of embodiment
of a cylindrical roll electrode used for plasma discharge in the
invention.
[0014] FIGS. 4(a) and 4(b) show a schematic drawing of embodiment
of a fixed, cylindrical electrode used for plasma discharge in the
invention.
[0015] FIGS. 5(a) and 5(b) show a schematic drawing of embodiment
of a fixed, prismatic electrode used for plasma discharge in the
invention.
[0016] FIG. 6 shows a schematic drawing of one embodiment of a
plasma discharge treatment apparatus used in the layer forming
method of the invention.
[0017] FIG. 7 shows a schematic drawing of one embodiment of a
planar plasma discharge treatment apparatus with planar electrodes
used in the layer forming method of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The above object of the invention can be attained by each of
the following constitutions:
[0019] 1. A transparent conductive layer forming method comprising
the steps of introducing a reactive gas to a discharge space,
exciting the reactive gas in a plasma state by discharge at
atmospheric pressure or at approximately atmospheric pressure, and
exposing a substrate to the reactive gas in a plasma state to form
a transparent conductive layer on the substrate, wherein the
reactive gas comprises a reducing gas.
[0020] 2. The transparent conductive layer forming method of item 1
above, wherein the reducing gas is hydrogen.
[0021] 3. The transparent conductive layer forming method of item 1
above, wherein the reactive gas comprises at least one gas selected
from gases derived from organometallic compounds.
[0022] 4. The transparent conductive layer forming method of item 1
above, wherein the method comprises the step of introducing a mixed
gas of the reactive gas and inert gas to the discharge space, the
inert gas comprising argon or helium.
[0023] 5. The transparent conductive layer forming method of item 4
above, wherein the content of the reducing gas in the mixed gas is
0.0001 to 5.0% by volume.
[0024] 6. The transparent conductive layer forming method of item 4
above, wherein the mixed gas to be introduced to the discharge
space contains no oxygen.
[0025] 7. The transparent conductive layer forming method of item 1
above, wherein an output density of not more than 100 W/cm.sup.2 is
applied at a frequency of not less than 0.5 kHz across the
discharge space.
[0026] 8. The transparent conductive layer forming method of item 7
above, wherein an output density of not less than 1 W/cm.sup.2 is
applied at a frequency exceeding 100 kHz across the discharge
space.
[0027] 9. The transparent conductive layer forming method of item 1
above, wherein temperature of the surface of the substrate, on
which the transparent conductive layer is formed, is not more than
300.degree. C.
[0028] 10. A transparent conductive layer, wherein the transparent
conductive layer is formed on a substrate by introducing a reactive
gas to a discharge space, exciting the reactive gas in a plasma
state by discharge at atmospheric pressure or at approximately
atmospheric pressure, and exposing the substrate to the reactive
gas in a plasma state, wherein the reactive gas comprises a
reducing gas.
[0029] 11. The transparent conductive layer of item 10 above,
wherein the transparent conductive layer has a resistivity of not
more than 1.times.10.sup.-3 .OMEGA..multidot.cm.
[0030] 12. The transparent conductive layer of item 10 above,
having a mobility of carrier of not less than 10
cm.sup.2/V.multidot.sec.
[0031] 13. The transparent conductive layer of item 10 above,
wherein the transparent conductive layer has a density of carrier
of not less than 1.times.10.sup.19 cm.sup.-3.
[0032] 14. The transparent conductive layer of item 10 above,
having a density of carrier of not less than 1.times.10.sup.20
cm.sup.-3.
[0033] 15. The transparent conductive layer of item 10 above,
wherein the transparent conductive layer contains any of indium
oxide, tin oxide, zinc oxide, fluorine doped tin oxide, aluminum
doped zinc oxide, antimony doped tin oxide, ITO, and
In.sub.2O.sub.3--ZnO as the main component.
[0034] 16. The transparent conductive layer of item 15 above,
wherein the transparent conductive layer is an ITO layer having an
atomic ratio In/Sn of from 100/0.1 to 100/15.
[0035] 17. The transparent conductive layer of item 15 above,
wherein the transparent conductive layer has a carbon content of
from 0 to 5.0 atomic %.
[0036] 18. A material comprising a substrate and provided thereon,
a transparent conductive layer, wherein the transparent conductive
layer has a resistivity of not more than 1.times.10.sup.-3
.OMEGA..multidot.cm.
[0037] 19. The material of item 18 above, wherein the transparent
conductive layer has a mobility of carrier of not less than 10
cm.sup.2/V.multidot.sec.
[0038] 20. The material of item 18 above, wherein the transparent
conductive layer has a density of carrier of not less than
1.times.10.sup.19 cm.sup.-3.
[0039] 21. The material of item 18 above, wherein the transparent
conductive layer has a density of carrier of not less than
1.times.10.sup.20 cm.sup.-3.
[0040] 22. The material of item 18 above, wherein the transparent
conductive layer contains any of indium oxide, tin oxide, zinc
oxide, fluorine doped tin oxide, aluminum doped zinc oxide,
antimony doped tin oxide, ITO, and In.sub.2O.sub.3--ZnO as the main
component.
[0041] 23. The material of item 22 above, wherein the transparent
conductive layer is an ITO layer having an atomic ratio In/Sn of
from 100/0.1 to 100/15.
[0042] 24. The material of item 22 above, wherein the transparent
conductive layer has a carbon content of from 0 to 5.0 atomic
%.
[0043] 25. The material of item 22 above, wherein the substrate is
a transparent resin film.
[0044] 26. The material of item 25 above, wherein the transparent
resin film is a substrate for a touch panel, a substrate for a
liquid crystal element, a substrate for an organic EL element, a
substrate for a PDP, a substrate for an electromagnetic wave
shielding material, or a substrate for an electronic paper.
[0045] 27. The material of item 18 above, wherein the critical
radius of curvature of the transparent conductive layer is not more
than 8 mm.
[0046] 28. The material of item 22 above, wherein the transparent
conductive layer is an electrode formed by patterning.
[0047] 29. A material comprising a substrate and provided thereon,
a transparent conductive layer, wherein the transparent conductive
layer has a coefficient of variation of the ratio H/M in the
thickness direction of not more than 5%, wherein H represents peak
intensity of a hydrogen ion in the thickness direction of the
transparent conductive layer measured according to dynamic SIMS,
and M represents peak intensity of a metal ion derived from the
main metal oxide in the thickness direction of the transparent
conductive layer measured according to dynamic SIMS.
[0048] 30. The material of item 29 above, wherein the transparent
conductive layer is formed on a substrate by introducing a reactive
gas to a discharge space, exciting the reactive gas in a plasma
state by discharge at atmospheric pressure or at approximately
atmospheric pressure, and exposing the substrate to the reactive
gas in a plasma state.
[0049] 31. The material of claim 30 above, wherein the reactive gas
comprises a reducing gas.
[0050] 32. The material of item 30 above, wherein an output density
of not less than 1 W/cm.sup.2 is applied at a frequency exceeding
100 kHz across the discharge space.
[0051] 101. A transparent conductive layer forming method
comprising the steps of introducing a reactive gas to a discharge
space, exciting the reactive gas in a plasma state by discharge at
atmospheric pressure or at approximately atmospheric pressure, and
exposing a substrate to the reactive gas in a plasma state to form
a transparent conductive layer on the substrate, wherein the
reactive gas comprises a reducing gas.
[0052] 102. The transparent conductive layer forming method of item
101 above, wherein the reducing gas is hydrogen.
[0053] 103. The transparent conductive layer forming method of item
101 or 102 above, wherein the reactive gas comprises at least one
gas selected from gases derived from organometallic compounds.
[0054] 104. The transparent conductive layer forming method of any
one of items 101 through 103 above, wherein the method comprises
the step of introducing a mixed gas of the reactive gas and inert
gas to the discharge space, the inert gas comprising argon or
helium.
[0055] 105. The transparent conductive layer forming method of item
104 above, wherein the content of the reducing gas in the mixed gas
is 0.0001 to 5.0% by volume.
[0056] 106. The transparent conductive layer forming method of item
104 or 105 above, wherein the mixed gas to be introduced to the
discharge space contains no oxygen.
[0057] 107. The transparent conductive layer forming method of any
one of items 101 through 104 above, wherein an output density of
not more than 100 W/cm.sup.2 is applied at a frequency of not less
than 0.5 kHz across the discharge space.
[0058] 108. The transparent conductive layer forming method of item
107 above, wherein an output density of not less than 1 W/cm.sup.2
is applied at a frequency exceeding 100 kHz across the discharge
space.
[0059] 109. The transparent conductive layer forming method of any
one of items 101 through 108 above, wherein temperature of the
surface of the substrate, on which the transparent conductive layer
is formed, is not more than 300.degree. C.
[0060] 110. A transparent conductive layer formed according to the
transparent conductive layer forming method of any one of items 101
through 109 above.
[0061] 111. The transparent conductive layer of item 110, wherein
the transparent conductive layer has a resistivity of not more than
1.times.10.sup.-3 .OMEGA..multidot.cm.
[0062] 112. The transparent conductive layer of item 110 or 111
above, having a mobility of carrier of not less than 10
cm.sup.2/V.multidot.sec.
[0063] 113 The transparent conductive layer of any one of items 110
through 112 above, wherein the transparent conductive layer has a
density of carrier of not less than 1.times.10.sup.19
cm.sup.-3.
[0064] 114. The transparent conductive layer of any one of items
110 through 113 above, having a density of carrier of not less than
1.times.10.sup.20 cm.sup.-3.
[0065] 115. The transparent conductive layer of any one of items
110 through 114 above, wherein the transparent conductive layer
contains any of indium oxide, tin oxide, zinc oxide, fluorine doped
tin oxide, aluminum doped zinc oxide, antimony doped tin oxide,
ITO, and In.sub.2O.sub.3--ZnO as the main component.
[0066] 116. The transparent conductive layer of item 115 above,
wherein the transparent conductive layer is an ITO layer having an
atomic ratio In/Sn of from 100/0.1 to 100/15.
[0067] 117. The transparent conductive layer of item 115 or 116
above, wherein the transparent conductive layer has a carbon
content of from 0 to 5.0 atomic %.
[0068] 118. A material comprising a substrate and provided thereon,
a transparent conductive layer, wherein the transparent conductive
layer has a resistivity of not more than 1.times.10.sup.-3
.OMEGA..multidot.cm.
[0069] 119. The material of item 118 above, wherein the transparent
conductive layer has a mobility of carrier of not less than 10
cm.sup.2/V.multidot.sec.
[0070] 120. The material of any one of item 118 or 119 above,
wherein the transparent conductive layer has a density of carrier
of not less than 1.times.10.sup.19 cm.sup.-3.
[0071] 121. The material of any one of items 118 through 120 above,
wherein the transparent conductive layer has a density of carrier
of not less than 1.times.10.sup.20 cm.sup.-3.
[0072] 122. The material of any one of items 118 through 121 above,
wherein the transparent conductive layer contains any of indium
oxide, tin oxide, zinc oxide, fluorine doped tin oxide, aluminum
doped zinc oxide, antimony doped tin oxide, ITO, and
In.sub.2O.sub.3--ZnO as the main component.
[0073] 123. The material of item 122 above, wherein the transparent
conductive layer is an ITO layer having an atomic ratio In/Sn of
from 100/0.1 to 100/15.
[0074] 124. The material of item 122 or 123 above, wherein the
transparent conductive layer has a carbon content of from 0 to 5.0
atomic %.
[0075] 125. The material of any one of items 122 through 124 above,
wherein the substrate is a transparent resin film.
[0076] 126. The material of item 125, wherein the transparent resin
film is a substrate for a touch panel, a substrate for a liquid
crystal element, a substrate for an organic EL element, a substrate
for a PDP electromagnetic wave shielding material, or a substrate
for an electronic paper.
[0077] 127. The material of any one of items 118 through 126 above,
wherein the critical radius of curvature of the transparent
conductive layer is not more than 8 mm.
[0078] 128. The material of any one of items 122 through 127 above,
wherein the transparent conductive layer is an electrode formed by
patterning.
[0079] 129. A material comprising a substrate and provided thereon,
a transparent conductive layer, wherein the transparent conductive
layer has a coefficient of variation of the ratio H/M in the
thickness direction of not more than 5%, wherein H represents peak
intensity of a hydrogen ion in the thickness direction of the
transparent conductive layer measured according to dynamic SIMS,
and M represents peak intensity of a metal ion derived from a main
metal in the thickness direction of the transparent conductive
layer measured according to dynamic SIMS.
[0080] 130. The material of item 129 above, wherein the transparent
conductive layer is formed on a substrate by introducing a reactive
gas to a discharge space, exciting the reactive gas in a plasma
state by discharge at atmospheric pressure or at approximately
atmospheric pressure, and exposing the substrate to the reactive
gas in a plasma state.
[0081] 131. The material of item 130 above, wherein the reactive
gas comprises a reducing gas.
[0082] 132. The material of item 130 or 131, wherein an output
density of not less than 1 W/cm.sup.2 is applied at a frequency
exceeding 100 kHz across the discharge space.
[0083] The present invention will be explained in detail below.
[0084] In the invention, a transparent conductive layer referred to
is a transparent layer well known as industrial material, which
does not absorb visible light (with a wavelength of from 400 to 700
nm), and is conductive. Since the transparent conductive layer is
transparent, has in the visible wavelength region high
transmissivity of free carrier, which transports electricity, is
transparent, and has a high electric conductivity, it is used as a
transparent electrode or an antistatic film.
[0085] The transparent conductive layer herein referred to may be a
layer formed on a substrate to such an extent that it can function
depending on its usage, but is not necessarily a continuous layer
with which parts or the whole of the substrate surface are covered.
Examples of the transparent conductive layer include a layer of
metal such as Pt, Au, Ag or Cu, a layer of an oxide or a complex
oxide doped with a dopant such as SnO.sub.2, In.sub.2O.sub.3, CdO,
ZnO, SnO.sub.2:Sb, SnO.sub.2:F, ZnO:Al, or In.sub.2O.sub.3:Sn, and
a layer of a nonoxide such as chalcogenide, LaBe, TiN, or TiC. Of
these, a layer of a tin doped indium oxide (hereinafter referred to
also as ITO) has been widely used in its excellent electric
properties or its ease of processability such as etching.
[0086] Next, the atmospheric pressure plasma CVD method, which is
the transparent conductive layer forming method of the invention,
will be explained.
[0087] The present invention is a transparent conductive layer
forming method comprising the steps of introducing a reactive gas
to a discharge space, exciting the reactive gas in a plasma state
by discharge at atmospheric pressure or at approximately
atmospheric pressure, and exposing a substrate to the reactive gas
in a plasma state to form a transparent conductive layer on the
substrate, wherein the reactive gas comprises a reducing gas.
[0088] In the atmospheric pressure plasma CVD in the invention,
power (output density) of not more than 100 W/cm.sup.2 is supplied
at a high frequency voltage exceeding 0.5 kHz across a gap between
opposed electrodes to excite a reactive gas in the gap and generate
plasma.
[0089] In the invention, the upper limit of the frequency of the
high frequency voltage applied across the gap between opposed
electrodes is preferably 150 MHz, and more preferably not more than
15 MHz. The lower limit of the frequency of the high frequency
voltage is preferably 0.5 kHz, more preferably 10 kHz, and still
more preferably 100 kHz.
[0090] The lower limit of the power supplied across the gap between
opposed electrodes is preferably 0.1 W/cm.sup.2, and more
preferably 1 W/cm.sup.2. The upper limit of the power supplied
across the gap between opposed electrodes is preferably 100
W/cm.sup.2, and more preferably 60 W/cm.sup.2. The discharge
surface area (cm.sup.2) refers to the surface area of the electrode
at which discharge occurs.
[0091] The high frequency voltage applied to the electrodes may be
a continuous sine wave or a discontinuous pulsed wave. The
continuous sine wave is preferred in securing the effects of the
invention.
[0092] It is necessary in the invention that a plasma discharge
apparatus be installed with electrodes which are capable of
maintaining uniform glow discharge even when such a voltage is
applied.
[0093] Such electrodes are preferably those in which a dielectric
is coated on the surface of a metal base material. A dielectric is
coated on at least one of a voltage application electrode and a
ground electrode opposed to each other, and preferably on both
electrodes. The dielectric used in the dielectric coated electrode
of the invention is preferably an inorganic compound having a
dielectric constant of from 6 to 45. Examples thereof include
ceramic such as alumina or silicon nitride, and a glass lining
material such as silicate glass or borate glass.
[0094] When a substrate placed or transported between the
electrodes is exposed to plasma, one of the electrodes is
preferably a roll electrode, the substrate being transported while
directly contacting the roll electrode. The dielectric layer of the
dielectric coated electrode, when the layer has been surface
finished by polishing treatment so as to obtain a surface roughness
Rmax (according to JIS B 0601) of not more than 10 .mu.m, can
maintain the dielectric layer thickness or a gap between the
electrodes constant, provide stable discharge, and further,
coverage of non-porous inorganic dielectric layer with high
precision and without strain or cracks due to thermal shrinkage
difference or residual stress can provide an electrode with greatly
increased durability.
[0095] In preparing a dielectric coated electrode by coating a
dielectric layer on a metal base material at high temperature, it
is necessary that at least the dielectric layer surface of the
dielectric coated electrode on the side contacting a substrate be
surface finished by polishing treatment and the difference in
thermal expansion between the dielectric layer and the metal base
material be reduced, and a metal base material is preferably lined
with an inorganic material layer, in which a foam content is
controlled, as a stress absorbing layer. The inorganic material for
lining is preferably glass produced according to a melting method,
which is known as enamel etc. It is preferred that the foam content
of the lowest layer which contacts the conductive metal base
material is 20 to 30% by volume, and the foam content of the layer
or layers provided on the lowest layer is not more than 5% by
volume, which provides a good electrode with high density and
without cracks.
[0096] Another preferred method for coating a dielectric on a metal
base material is a method in which a ceramic is thermally splayed
on the metal base material to form a ceramic layer with a void
content of not more than 10% by volume, and sealed with an
inorganic material capable of being hardened by a sol-gel reaction.
In order to accelerate the sol gel reaction, heat hardening or UV
irradiation is preferably carried out. Sealing treatment, in which
coating of diluted sealing solution and hardening are alternately
repeated several times, provides an electrode with improved
inorganic property, with high density and without any
deterioration.
[0097] A plasma discharge apparatus employing such an electrode
will be explained below employing FIGS. 1 through 6.
[0098] A plasma discharge apparatus is one which induces discharge
in the gap between a roll electrode, which is a ground electrode,
and plural fixed electrodes, which are voltage application
electrodes and face the roll electrode, introduces a reactive gas
to the gap to excite the reactive gas in a plasma state, and
exposes a long length substrate provided on the roll electrode to
the reactive gas excited in a plasma state to form a layer on the
substrate. A plasma discharge apparatus carrying out the layer
forming method of the invention is not limited to that described
above, but may be any one as long as a stable glow discharge is
maintained and a reactive gas used for forming the layer is excited
into a plasma state. As another method, there is a jetting method
in which a substrate is provided or transported to the vicinity of
electrodes but not between the electrodes, and then generated
plasma is jetted to the substrate to form a layer on the
substrate.
[0099] FIG. 1 shows a schematic drawing of one embodiment of the
plasma discharge vessel equipped in a plasma discharge apparatus
used in the layer forming method of the invention.
[0100] In FIG. 1, substrate F with long length is transported while
wound around roll electrode 25 rotating in the transport direction
(clockwise in FIG. 1). Electrodes 26, which are fixed, are composed
of plural cylinders and opposed to the roll electrode 25. The
substrate F, which has been wound around the roll electrode 25, is
pressed with nip rollers 65 and 66, transported into a discharge
space in the plasma discharge vessel 31 through guide roller 64,
subjected to discharge plasma treatment, and then transported into
the next process through guide roller 67. Blade 54 is provided at
the vicinity of the nip rollers 65 and 66, and prevents air
accompanied by the transported substrate F from entering the plasma
discharge vessel 31.
[0101] The volume of the accompanied air is preferably not more
than 1% by volume and more preferably not more than 0.1% by volume,
based on the total volume of air in the plasma discharge vessel 31,
which can be attained by the nip rollers 65 and 66 above.
[0102] A mixed gas used in the discharge plasma treatment
(containing both inert gas and a reactive gas, a reducing gas
and/or an organometallic compound) is introduced into the plasma
discharge vessel 31 from supply port 52, and exhausted from exhaust
port 53 after discharge treatment.
[0103] As in FIG. 1, FIG. 2 shows a schematic drawing of another
embodiment of the plasma discharge vessel equipped in a plasma
discharge apparatus used in the layer forming method of the
invention. However, electrodes 26 in FIG. 1, which are fixed and
opposed to the roll electrode 25, are cylindrical, while electrodes
36 in FIG. 2 are prismatic.
[0104] As compared with cylindrical electrodes 26 shown in FIG. 1,
prismatic electrodes 36, as shown in FIG. 2, broaden the discharge
region (discharge surface area), and are preferably used in the
layer forming method of the invention.
[0105] FIG. 3(a) and FIG. 3(b) each show a schematic drawing of
embodiment of the cylindrical roll electrode described above, FIG.
4(a) and FIG. 4(b) each show a schematic drawing of embodiment of a
cylindrical, fixed electrode, and FIG. 5(a) and FIG. 5(b) each show
a schematic drawing of embodiment of a prismatic, fixed
electrode.
[0106] In FIG. 3(a), roll electrode 25c, which is a ground
electrode, is an electrode in which a conductive base roll 25a such
as a metal roll is coated with ceramic to form a ceramic dielectric
layer 25b as a dielectric layer, the coating being carried out by
thermally spraying ceramic on the base roll to form a ceramic
layer, and sealing the ceramic layer with sealing materials such as
inorganic compounds. The roll electrode is prepared to have a
ceramic dielectric layer with a thickness of 1 mm and a roll
diameter of 200.phi., and is grounded. In FIG. 3 (b), the roll
electrode 25C may be an electrode in which a conductive base roll
25A such as a metal roll is lining coated with inorganic materials
to form a lined dielectric layer 25B as a dielectric layer.
Examples of the materials for lining include silicate glass, borate
glass, phosphate glass, germanate glass, tellurite glass, aluminate
glass, and vanadate glass. Among these, borate glass is preferably
used in view of easy processability. Examples of a metal used in
the conductive base roll 25a or 25A include metals such as silver,
platinum, stainless steel, aluminum, and iron. Stainless steel is
preferable in view of processability. The ceramic material used for
thermal spraying is preferably alumina, silicon nitride, and more
preferably alumina in view of easy processability. In one
embodiment carried out in the invention, a base roll for the roll
electrode employs a stainless steel jacket roll having therein a
cooling means (not illustrated in the Figs.) employing chilled
water.
[0107] FIG. 4(a), FIG. 4(b), FIG. 5(a) and FIG. 5(b) show fixed
electrodes 26c, 26C, 36c, and 36C, respectively, which are voltage
application electrodes, and the electrodes have the same
constitution as that of the roll electrode 25c or 25C, described
above. That is, the same dielectric layer as above is coated on a
hollow stainless steel pipe, and the resulting electrode is
constructed so as to be cooled with chilled water during discharge.
The fixed roll electrodes having a ceramic dielectric layer are
prepared to give a roll diameter of 12.phi. or 15.phi.. Fourteen of
the fixed electrodes are arranged around the circumference of the
roll electrode described above.
[0108] Power sources for applying voltage to the voltage
application electrode are not specifically limited. As the power
sources, a high frequency power source (200 kHz) produced by Pearl
Kogyo Co., Ltd., a high frequency power source (800 kHz) produced
by Pearl Kogyo Co., Ltd., a high frequency power source (13.56 MHz)
produced by Nippon Denshi Co., Ltd., and a high frequency power
source (150 MHz) produced by Pearl Kogyo Co., Ltd. can be used.
[0109] FIG. 6 shows a schematic view of one embodiment of the
plasma discharge apparatus used in the invention. In FIG. 6, plasma
discharge vessel 36 has the same construction as that of FIG. 2,
and in addition, a gas generating device 51, a power source 41, and
an electrode cooling device 60 and so on are further provided. As a
cooling agent used in the electrode cooling device 60, insulating
materials such as distilled water and oil are used. Electrodes 25
and 36 shown in FIG. 6 are the same as those illustrated in FIGS.
3, 4, and 5. The gap distance between the opposed electrodes is,
for example, approximately 1 mm.
[0110] The gap distance described above is determined considering
thickness of a dielectric layer provided on the electrode base
roll, applied voltage level, or an object of employing plasma. When
one of the opposed electrodes described above has a dielectric
layer or both opposed electrodes described above have a dielectric
layer, the minimum gap distance between the electrode and the
dielectric layer or between the both dielectric layers is
preferably 0.5 to 20 mm, and more preferably 1.+-.0.5 mm, in
carrying out uniform discharge.
[0111] A mixed gas generated in the gas generating device 51 is
introduced from supply port 52 in a controlled amount into a plasma
discharge vessel 31, in which roll electrode 25 and fixed electrode
36 are arranged at a predetermined position, whereby the plasma
discharge vessel is charged with the mixed gas, and thereafter, the
gas is exhausted from the exhaust port 53. Subsequently, the roll
electrode 25 being grounded, voltage is applied to electrodes 36 by
power source 41 to generate discharge plasma. From stock roll 61 in
which substrate F is wounded, substrate F is transported to a gap
between the electrodes in the plasma discharge vessel 31 through
guide roller 64 (so that the one side of the substrate contacts the
surface of the roll electrode 25), subjected to discharge plasma
treatment while transporting in the device, and then transported to
the next processing through guide roller 67. In the above, only the
surface of the substrate opposite the surface contacting the roll
electrode is subjected to discharge treatment.
[0112] The level of voltage applied to the fixed roll 36 by power
source 41 is optionally determined. For example, the voltage is 0.5
to 10 kV, and frequency of power source is adjusted to the range of
from 0.5 kHz to 150 MHz. Herein, as a power supply method, either a
continuous oscillation mode (called a continuous mode) with a
continuous sine wave or a discontinuous oscillation mode (called a
pulse mode) carrying ON/OFF discontinuously may be used, but the
continuous mode is preferred in obtaining a uniform layer with high
quality.
[0113] The vessel used in the plasma discharge vessel 31 is
preferably a vessel of pyrex (R) glass, but a vessel of metal may
be used if insulation from the electrodes is secured. For example,
the vessel may be a vessel of aluminum or stainless steel laminated
with a polyimide resin or a vessel of the metal which is thermally
sprayed with ceramic to form an insulation layer on the
surface.
[0114] In order to minimize an influence on the substrate during
the discharge plasma treatment, the substrate temperature during
the plasma discharge treatment is adjusted to a temperature of
preferably from ordinary temperature (15 to 25.degree. C.) to
300.degree. C., and more preferably from ordinary temperature to
200.degree. C., and still more preferably from ordinary temperature
to 100.degree. C. In order to adjust to the temperature within the
range described above, the substrate or the electrodes are
optionally cooled with a cooling means during the discharge plasma
treatment.
[0115] In the invention, the discharge plasma treatment is carried
out at atmospheric pressure or at approximately atmospheric
pressure. Herein, approximately atmospheric pressure herein
referred to implies a pressure of 20 kPa to 110 kPa. In order to
obtain the effects as described in the invention, the pressure is
preferably 93 kPa to 104 kPa.
[0116] In the electrodes for electric discharge used in the layer
forming method of the invention, the maximum surface roughness Rmax
of the surface of the electrode on the side contacting the
substrate is adjusted to preferably not more than 10 .mu.m in
obtaining the effects as described in the invention, and adjusted
to more preferably not more than 8 .mu.m, and still more preferably
not more than 7 .mu.m. Herein, the maximum surface roughness is one
defined in JIS B 0161.
[0117] Further, the center-line average surface roughness (Ra) as
defined in JIS B 0161 is preferably not more than 0.5 .mu.m, and
more preferably not more than 0.1 .mu.m.
[0118] FIG. 7 shows a schematic drawing of one embodiment of a
planar plasma discharge treatment apparatus with planar electrodes
used in the layer forming method of the invention.
[0119] The plasma discharge treatment apparatus shown in FIG. 6 is
applied to a substrate F, which can be bent as a flexible film.
When the substrate is a substrate L with some thickness or a hard
substrate L such that it is difficult to wind around the roll
electrode, for example, a glass plate or lens, a planar plasma
discharge treatment apparatus 100 installed with planar electrodes,
shown in FIG. 7, is applied.
[0120] The plasma discharge treatment apparatus 100 comprises a
power source 110 and an electrode 120 comprised of an upper planar
electrode group 121 and a lower planar electrode 122 opposed to
each other.
[0121] The upper planar electrode group 121 is comprised of plural
rectangular electrodes 121a arranged to laterally form a line, and
intervals between any adjacent two of the electrodes constitute gas
paths. Gas supply inlets 123 are arranged so as to face a substrate
L. A gas generation device 124 is provided over the upper planar
electrode group 121. A reactive gas and inert gas are supplied to
the gas supply inlets 123 from the gas generation device 124, and
jetted to a space between the upper electrode group 121 and the
lower electrode 122.
[0122] The substrate L is placed on the lower planar electrode 122,
which is grounded, to face the gas supply inlets 123, and the lower
planar electrode 122 is laterally reciprocated as shown by an arrow
in FIG. 7. The lower electrode 122 moves as described above, and
the substrate L is exposed to a gas in plasma state in a space
between the upper planar electrode group 121 and the lower planar
electrode 122 to form a layer on the surface of the substrate L.
Since the substrate L also moves laterally, a layer is formed on a
substrate L having an area larger than the discharge area of the
electrode, and a uniform layer without unevenness is formed.
[0123] A mixed gas used in the transparent conductive layer forming
method of the invention will be explained below.
[0124] A gas, used when the transparent conductive layer forming
method of the invention is carried out, is basically a mixed gas of
inert gas as a carrier gas for inducing discharge and a reactive
gas for forming the transparent conductive layer, although it
varies due to kinds of a transparent conductive layer formed on the
substrate.
[0125] The reactive gas in the invention comprises a reducing gas.
The reducing gas is preferably an inorganic gas with chemical
reducibility containing no oxygen in the molecule. Examples of the
reducing gas include hydrogen and hydrogen sulfide. The reducing
gas is preferably hydrogen. In a mixed gas of the reducing gas and
inert gas, the reducing gas content is preferably 0.0001 to 5.0% by
volume, and more preferably 0.001 to 3.0% by volume.
[0126] The reducing gas is considered to act on the reactive gas
forming a transparent conductive layer and to have an effect of
forming a transparent conductive layer with good electric
properties.
[0127] It is preferred in the invention that a mixed gas,
introduced into a discharge space in which plasma is generated,
does not substantially contain an oxygen gas. The sentence "a mixed
gas does not substantially contain an oxygen gas" implies that a
mixed gas does not contain an oxygen gas in such an extent
canceling the above-described effects of forming a transparent
conductive layer with good electric properties. In the transparent
conductive layer forming method of the invention, an oxygen gas has
a tendency to deteriorate electric properties of the transparent
conductive layer, but an oxygen gas in a small amount may be
present as long as it does not deteriorate the electric properties.
In order to form an atmosphere that does not substantially contain
an oxygen gas in the invention, inert gas with high purity is
suitably used as inert gas used.
[0128] The reactive gas content of the mixed gas is preferably 0.01
to 10% by volume. The transparent conductive layer to be formed has
a thickness of 1 nm to 1000 nm.
[0129] The inert gas herein referred to implies an element
belonging to group XVIII in the periodic table, and is typically
helium, neon, argon, krypton, xenon, or radon. In order to obtain
the effects of the invention, helium or argon is preferably
used.
[0130] The reactive gas, which is a gas excited to plasma state at
discharge space, contains a component for forming a transparent
conductive layer, for example, an organometallic compound such as a
.beta.-diketone metal complex, a metal oxide or a metal alkyl. As
kinds of the reactive gas, there are a reactive gas providing a
main component of the transparent conductive layer, a reactive gas
used in a small amount for the purpose of doping, and a reactive
gas used in order to adjust electric resistance of the transparent
conductive layer.
[0131] The transparent conductive layer formed according to the
transparent conductive layer forming method of the invention has a
feature in that it has high carrier mobility. As is well known,
electric conductivity of a transparent conductive layer is
represented by the following formula (1): formula (1)
.sigma.=ne.mu.
[0132] wherein .sigma. represents electric conductivity, n
represents carrier density, e represents quantity of electricity of
electrons, and .mu. represents carrier mobility.
[0133] It is necessary to increase carrier density or carrier
mobility in order to increase electric conductivity. However, when
carrier density increases, reflectance increases at a carrier
density of not less than approximately 2.times.10.sup.21 cm.sup.-3,
and degree of transparency decreases. Accordingly, it is necessary
to increase carrier mobility in order to increase electric
conductivity. The carrier mobility of a transparent conductive
layer formed according to the DC magnetron sputtering method
available on the market is approximately 30
cm.sup.2/V.multidot.sec. It has been found that when the
transparent conductive layer forming method of the invention is
used under optimum conditions, it is possible to form a transparent
conductive layer having carrier mobility higher than that formed
according to the DC magnetron sputtering.
[0134] Since the transparent conductive layer forming method of the
invention provides high carrier mobility, it can provide a
transparent conductive layer with a low resistance having a
specific resistance of not more than 1.times.10.sup.-3
.OMEGA..multidot.cm without doping. The resistance of the
transparent conductive layer can be further reduced by carrying out
doping and increasing a carrier density. A transparent conductive
layer with a high resistance having a specific resistance of not
less than 1.times.10.sup.-2 .OMEGA..multidot.cm can be also formed
by optionally employing a reactive gas increasing resistance.
[0135] The transparent conductive layer formed according to the
transparent conductive layer forming method of the invention has a
carrier mobility of not less than 10 cm.sup.2/V.multidot.sec.
[0136] The transparent conductive layer formed according to the
transparent conductive layer forming method of the invention has a
carrier density of not less than 1.times.10.sup.19 cm.sup.-3, and
preferably of not less than 1.times.10.sup.20 cm.sup.-3.
[0137] The transparent conductive layer of the invention may
contain carbon in a small amount, since an organometallic compound
is optionally used as a reactive gas. In this case, the carbon
content of the transparent conductive layer is preferably from more
than 0 to 5.0 atomic %, and more preferably from 0.01 to 3.0 atomic
%.
[0138] The transparent conductive layer of the invention has a
coefficient of variation in the thickness direction of the ratio
H/M of preferably not more than 5%, in which H represents peak
intensity of a hydrogen ion in the thickness direction and M
represents peak intensity of a metal ion derived from the main
metal oxide in the thickness direction, each being measured
according to dynamic SIMS. As a method of preparing such a
transparent conductive layer, there is mentioned of the atmospheric
pressure plasma discharge treatment as described above, in which a
hydrogen gas is used as the reducing gas.
[0139] When the transparent conductive layer of the invention is
analyzed according to dynamic SIMS to obtain peak intensity in the
thickness direction of a hydrogen ion and peak intensity in the
thickness direction of a metal ion derived from the main metal
oxide, variation in the thickness direction of the ratio H/M is not
more than a specific value (wherein H represents peak intensity in
the thickness direction of a hydrogen ion and M represents peak
intensity in the thickness direction of a metal ion derived from
the main metal oxide). Degree of the variation is preferably
represented by coefficient of variation in the thickness direction
of the ratio H/M. The coefficient of variation in the thickness
direction of the ratio H/M in the transparent conductive layer of
the invention is preferably not more than 5%, more preferably not
more than 3%, and still more preferably not more than 1%. Regarding
dynamic secondary ion-mass spectrography (hereinafter referred to
as dynamic SIMS including a spectrometer), JITSUYO HYOMEN BUNSEKI
NIJIION SITSURYO BUNSEKI edited by HYOMEN KAGAKUKAI (2001, MARUZEN)
is referred to.
[0140] In the invention, preferred dynamic SIMS measurement
conditions are as follows.
[0141] Spectrometer used: ADEPT 1010 produced by Physical
Electronics Co., Ltd. Or TYPE 6300 secondary ion mass
1 spectrometer Primary ion used: Cs Primary ion energy: 5.0 KeV
Primary ion current: 200 nA Area radiated by primary ion: 600 .mu.m
square Absorption rate of secondary ion: 25% Secondary ion
polarity: Negative Secondary ions to be detected: H.sup.- and
M.sup.- (M represents a metallic element.)
[0142] Mass analysis is carried out under the above-described
conditions while sputtering the metal-containing layer in the
thickness direction. The ratio H/M of peak intensity of a hydrogen
ion to peak intensity of a metal ion from the main metal oxide is
determined from the resulting depth profile. The ratio H/M is
determined preferably at not less than 50 points, and more
preferably at not less than 75 points, per a 100 nm thickness of
the transparent conductive layer. The ratios H/M at portions from
15 to 85% of the thickness are determined, and their average and
standard deviation are obtained. The standard deviation is divided
by the average and multiplied by 100 to obtain coefficient of
variation of H/M in the thickness direction, which shows degree of
variation of H/M.
[0143] In the invention, the ratio H/M is in the range of
preferably from 0.001 to 50, and more preferably from 0.01 to 20.
In the invention, the ratio H/M in the thickness direction is
determined according to the above-mentioned, and the ratios H/M in
the thickness direction at portions from 15 to 85% of the thickness
are determined. The average of the resulting ratios H/M is defined
as the ratio H/M in the invention.
[0144] The hydrogen concentration of the transparent conductive
layer of the invention is preferably 0.001 to 10 atomic %, more
preferably 0.01 to 5 atomic %, and still more preferably 0.5 to 1
atomic %. The hydrogen concentration is determined according to the
dynamic SIMS under the conditions as described above. Firstly,
based on the hydrogen concentration of a standard transparent
conductive layer, which is determined according to a Rutherford
back scattering spectrography, and intensity of the hydrogen ion of
the standard transparent conductive layer obtained according to the
dynamic SIMS, relative sensitivity coefficient is obtained. Next,
based on the intensity of the hydrogen ion of a transparent
conductive layer of a sample to be measured obtained according to
the dynamic SIMS and the relative sensitivity coefficient obtained
above, the hydrogen concentration of the sample is computed. In the
invention, a hydrogen concentration of the transparent conductive
layer is measured through the entire thickness thereof to obtain a
depth profile of the hydrogen concentration. Hydrogen
concentrations are obtained at portions from 15 to 85% of the
thickness from the depth profile obtained above, and the average
thereof is defined as the hydrogen concentration in the
invention.
[0145] Methods of preparing a transparent conductive layer having a
coefficient of variation in the thickness direction of the ratio
H/M of not more than 5%, (wherein H represents peak intensity of a
hydrogen ion and M represents peak intensity of a metal ion from
the main metal oxide each being measured according to dynamic
SIMS), are not specifically limited, and include the atmospheric
pressure plasma discharge treatment as described above, that is, a
method comprising the steps of introducing a reactive gas to a
discharge space at atmospheric pressure or at approximately
atmospheric pressure, exciting the reactive gas in a plasma state
by discharge, and exposing a substrate to the reactive gas in a
plasma state to form a transparent conductive layer on the
substrate. It is preferred that the reactive gas be a reducing gas,
which makes it easy to obtain not more than 5% of the above
coefficient. It is more preferred that an output density of not
less than 1 W/cm.sup.2 be applied across the discharge space at a
frequency exceeding 100 kHz, which similarly makes it easy to
obtain not more than 5% of the above coefficient. The reason is not
apparent, but the above reducing atmosphere or high power electric
field as described above is considered to be conditions which can
provide uniformity of the transparent conductive layer and reduce
variation in the thickness direction of peak intensity of a
hydrogen ion and peak intensity of a metal ion from the main metal
oxide in the transparent conductive layer.
[0146] The reactive gas used for constituting a main component of
the transparent conductive layer in the invention is preferably an
organometallic compound having an oxygen atom in the molecule. The
organometallic compound has, in the chemical structure, preferably
a metal belonging to a group, Ib, IIb, IIIb, IVb, Vb, VIb, or VIII
of the periodic table. Preferred examples of the organometallic
compound include indium hexafluoropentanedionate, indium methyl
(trimethyl)acetylacetonate- , indium acetylacetonate, indium
isopropoxide, indium trifluoropentanedionate,
tris(2,2,6,6-tetramethyl-3,5-heptanedionato)indi- um,
di-n-butylbis(2,4-pentanedionato)tin, di-n-butyldiacetoxytin,
di-t-butyldiacetoxytin, tetraisopropoxytin, tetrabutoxytin, and
zinc acetylacetonate. Of these, indium acetylacetonate,
tris(2,2,6,6-tetramethyl-3,5-heptanedionato)indium, zinc
acetylacetonate, and di-n-butyldiacetoxytin are preferred.
[0147] Examples of the reactive gas for doping include aluminum
isopropoxide, nickel acetylacetonate, manganese acetylacetonate,
boron isopropoxide, n-butoxyantimony, tri-n-butylantimony,
di-n-butylbis(2,4-pentanedionato)tin, di-n-butyldiacetoxytin,
di-t-butyldiacetoxytin, tetraisopropxytin, tetrabutopxytin,
tetrabutyltin, zinc acetylacetonate, hexafluoropropylene,
octafluorocyclobutane, and carbon tetrafluoride.
[0148] Examples of the reactive gas used for adjusting resistivity
of the transparent conductive layer include titanium
triisopropoxide, tetramethoxysilane, tetraethoxysilane, and
hexamethyldisiloxane.
[0149] When a transparent conductive layer is formed, the amount of
a first reactive gas providing the main component of the layer and
a second reactive gas in a small amount for doping differs due to
the kinds of the transparent conductive layer. For example, when an
ITO layer comprised of indium oxide doped with tin is formed, the
amount of reactive gases used is adjusted so that an atomic ratio
In/Sn of the ITO layer falls within the range of from 100/0.1 to
100/15, and preferably from 100/0.5 to 100/10. The atomic ratio
In/Sn is obtained by measurement according to XSP.
[0150] When a transparent conductive layer (hereinafter referred to
as FTO layer) comprised of tin oxide doped with fluorine is formed,
the amount of reactive gases used is adjusted so that an atomic
ratio Sn/F of the ITO layer falls within the range of from 100/0.01
to 100/50. The atomic ratio Sn/F is obtained by measurement
according to XSP.
[0151] When an In.sub.2O.sub.3--ZnO amorphous transparent
conductive layer is formed, the amount of reactive gases used is
adjusted so that an atomic ratio In/Zn of the ITO layer falls
within the range of from 100/50 to 100/5. The atomic ratio In/Zn is
obtained by measurement according to XSP.
[0152] The substrate used in the invention may be in the form of
film, in the form of sheet or in the form of stereoscopic body, for
example, in the form of lens, as long as it can form a transparent
conductive layer on its surface. When the substrate is one capable
of being provided between electrodes, a transparent conductive
layer can be formed by placing the substrate in plasma generated
between the electrodes, and when the substrate is one incapable of
being provided between the electrodes, a transparent conductive
layer can be formed by spraying the generated plasma onto the
substrate.
[0153] Materials constituting the substrate are not specifically
limited, but resins are preferred in that discharge is a low
temperature glow discharge, and is carried out at atmospheric
pressure or at approximately atmospheric pressure.
[0154] For example, a film of cellulose ester such as cellulose
triacetate, polyester, polycarbonate or polystyrene, or one, in
which a gelatin layer, a polyvinyl alcohol (PVA) layer, an acryl
resin layer, a polyester resin layer or a cellulose resin layer is
coated on the above described film, is used as the substrate.
Further, a substrate obtained by coating an anti-glare layer, a
clear hard coat layer, a backing layer or an anti-static layer on a
support can be used as the substrate.
[0155] Examples of the support (which can be also used as the
substrate) include a polyester film such as a polyethylene
terephthalate or polyethylene naphthalate film, a polyethylene
film, a polypropylene film, a cellophane film, a film of a
cellulose ester such as cellulose diacetate, cellulose acetate
butyrate, cellulose acetate propionate, cellulose acetate
phthalate, cellulose triacetate, cellulose nitrate or their
derivative, a polyvinylidene chloride film, a polyvinyl alcohol
film, an ethylene-vinyl alcohol film, a syndiotactic polystyrene
film, a polycarbonate film, a norbornene resin film, a
polymethylpentene film, a polyetherketone film, a polyimide film, a
polyethersulfone film, a polysulfone film, a polyetherketoneimide
film, a polyamide film, a fluorine-containing resin film, a nylon
film, a polymethyl methacrylate film, an acryl film, and a
polyarylate film.
[0156] These materials can be used singly or as a mixture of two or
more kinds thereof. Commercially available materials such as
Zeonecks (produced by Nippon Zeon Co., Ltd.) or ARTON (produced by
Nippon Gosei Gomu Co., Ltd.) can be preferably used. Materials such
as polycarbonate, polyacrylate, polysulfone and polyethersulfone,
which have a high specific birefringence, can be also used by
properly controlling a solution casting condition, a melt extrusion
condition, or a stretching condition in the transverse or
mechanical direction. The substrate in the invention is not
specifically limited to those described above. The substrate in the
invention has a thickness of preferably 10 to 1000 .mu.m.
[0157] In the invention, the transparent conductive layer is formed
on a substrate such as a glass plate or a plastic film, but an
adhesion layer may be optionally provided between the substrate and
the transparent conductive layer in order to increase adhesion
between them. Further, an anti-reflection layer may be provided on
the surface of the substrate opposite the transparent conductive
layer in order to improve optical properties. An anti-stain layer
may be provided as an outermost layer. Another layer such as a gas
barrier layer or a solvent resistant layer can be also
provided.
[0158] A method of forming these layers is not specifically
limited, and for example, a coating method, a vacuum deposition
method, a sputtering method, or an atmospheric pressure plasma CVD
method can be used. The atmospheric pressure plasma CVD method is
preferred.
[0159] As the atmospheric pressure plasma CVD method, a method can
be used which is disclosed as an anti-reflection layer forming
method, for example, in Japanese Patent O.P.I. Publication No.
2000-021573.
[0160] In the invention, the transparent conductive layer is
provided on a substrate so that a deviation of the layer thickness
from the average thickness falls within preferably .+-.10%, more
preferably .+-.5%, and still more preferably .+-.1%.
EXAMPLES
Example 1
[0161] A glass plate (50 mm.times.50 mm.times.1 mm) on which an
approximately 50 nm thick silica film was formed as an alkali
barrier coat was used as a substrate.
[0162] A planar plasma discharge treatment apparatus shown in FIG.
7 was used in which two kinds of flat electrodes were opposed in
parallel with each other. The above-described glass plate was
placed in a space between the opposed electrodes and a mixed gas
was introduced to the space. A layer was formed on the glass plate
according to the following.
[0163] The electrodes as described below were used.
[0164] A stainless steel plate having a size of 200 mm.times.200
mm.times.2 mm was coated with an alumina thermal spray layer with
high density and high adhesion to obtain an electrode, and then a
solution prepared by diluting tetramethoxysilane with ethyl acetate
was coated on the resulting electrode, dried and hardened by UV ray
irradiation to carry out sealing treatment. Thus, a dielectric
layer coated electrode was obtained. The dielectric layer surface
of the electrode was polished, smoothed, and processed to give an
Rmax of 5 .mu.m. The resulting electrode was grounded.
[0165] The same dielectric layer as above was coated on hollow,
prismatic pure titanium pipes under the same condition as above.
Thus, plural electrodes were prepared as a group of voltage
application electrodes, and were provided opposed to the electrode
obtained above.
[0166] As a power supply for generating plasma, a high frequency
power supply JRF-10000 (13.56 MHz) produced by Nihon Denshi Co.
Ltd. was used, and power of 5 W/cm.sup.2 was supplied at a
frequency of 13.56 MHz.
[0167] A gas having the composition as shown below was supplied to
the gap between the opposed electrodes.
2 Inert gas: helium 98.5% by volume Reactive gas 1: hydrogen 0.25%
by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
[0168] The glass plate prepared above was subjected to atmospheric
pressure plasma treatment under the above conditions employing the
above gas to form a tin doped indium oxide layer. The formed indium
oxide layer was evaluated according to the following methods.
[0169] <Measurement of Transmittance>
[0170] Transmittance was measured according to JIS-R-1635,
employing a spectrophotometer TYPE 1U-4000 (produced by Hitachi
Seisakusho Co., Ltd.). The wavelength of light used was 550 nm.
[0171] <Measurement of Layer Thickness and Layer Forming
Speed>
[0172] The thickness of the indium oxide layer was measured
employing Spectral Reflectance Thickness Monitor FE-3000 produced
by Photal Co. The layer forming speed was obtained by dividing the
thickness by the plasma treatment time.
[0173] <Resistivity>
[0174] Resistivity was measured according to JIS-R-1637, employing
a four terminal method. The measurement was carried out employing
Loresta GP, MCP-T600 produced by Mitsubishi Chemical
Corporation.
[0175] <Hall Effect>
[0176] Hall effect was measured according to a van der Pauw's
method employing M1-675 system of Sanwa Musen Sokki Kenkyusho, and
density of carrier and mobility of carrier were determined.
[0177] <Composition of Indium Oxide Layer>
[0178] The indium oxide layer on the glass plate was dissolved with
hydrochloric acid, and the content of indium and tin in the layer
was determined employing an inductive coupling plasma emission
spectrometer SPS-4000 produced by Seiko electric Co.
[0179] <Measurement of Carbon Content>
[0180] The carbon content was measured employing an XPS surface
analyzer. The XPS surface analyzer used is not specifically
limited, and any kinds of surface analyzers can be used, but in the
examples, ESCALAB-200R produced by V G Scientifics Co., Ltd. was
employed. Measurement was made at an output of 600 W (an
acceleration voltage of 15 kV, and emission current of 40 mA),
employing Mg as an X ray anode. Energy dissolution regulated to a
peak width at half height of clean Ag 3d5/2 was set to be 1.5 to
1.7 eV. In order to eliminate an influence due to contamination, it
is necessary that before measurement, a surface layer corresponding
to 10 to 20% of the formed layer thickness be removed by etching.
The surface layer is preferably removed employing an ion gun
capable of using a rare gas ion. Examples of the ion include an ion
of He, Ne, Ar, Xe, or Kr. In this example, the surface layer was
removed employing argon ion etching.
[0181] Measurement was made at a measurement interval of 1.0 eV in
the bond energy range of 0 to 1100 eV, and firstly, an element to
be detected was examined.
[0182] Next, measurement was made at a measurement interval of 0.2
eV on each of the detected elements except for the element for
etching, and a narrow scanning of the photo-electron peak providing
a maximum intensity was carried out. Thus, the spectrum of each
element was obtained. In order to eliminate variation of the carbon
content obtained due to kinds of analyzers or computers employed,
the resulting spectrum was transferred to COMMON DATA PROCESSING
SYSTEM (preferably Version 2.3 or Versions thereafter) produced by
VAMAS-SCA-JAPAN Co., Ltd., and processed with its software to
obtain a carbon content in terms of atomic concentration (at atomic
%). The tin to indium ratio was also represented in terms of atomic
concentration ratio.
[0183] Before quantitative processing, calibration of Count Scale
on each element detected was carried out, and 5 point smoothing
processing was carried out. In the quantitative processing, the
peak area intensity (cps.multidot.eV) except for the background was
employed. The background processing was carried out employing a
Shirley method.
[0184] The Shirley method was described in D. A. Shirley, Phys.
Rev., B5, 4709 (1972).
Example 2
[0185] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below.
3 Inert gas: helium 98.65% by volume Reactive gas 1: hydrogen 0.10%
by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Example 3
[0186] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
4 Inert gas: helium 98.25% by volume Reactive gas 1: hydrogen 0.5%
by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Example 4
[0187] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
5 Inert gas: helium 98.75% by volume Reactive gas 1: hydrogen 1.00%
by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Example 5
[0188] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
6 Inert gas: helium 98.5% by volume Reactive gas 1: hydrogen
sulfide 0.25% by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Example 6
[0189] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
7 Inert gas: argon 98.5% by volume Reactive gas 1: hydrogen 0.25%
by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Example 7
[0190] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
8 Inert gas: argon 98.65% by volume Reactive gas 1: hydrogen 0.10%
by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Example 8
[0191] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was used changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
9 Inert gas: helium and argon (helium to argon ratio by 98.5% by
volume Volume of 70/30) Reactive gas 1: hydrogen 0.25% by volume
Reactive gas 2: 1.2% by volume tris(2,4-pentanedionato)indium
Reactive gas 3: dibutyltin diacetate 0.05% by volume
Example 9
[0192] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
10 Inert gas: mixed gas of helium and argon 98.65% by volume
(helium to argon ratio by volume of 70/30) Reactive gas 1: hydrogen
0.10% by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Example 10
[0193] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
11 Inert gas: nitrogen 98.5% by volume Reactive gas 1: hydrogen
0.25% by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Comparative Example 1
[0194] The glass plate prepared in example 1 was placed in a vacuum
chamber of a DC magnetron sputtering apparatus, and the pressure in
the chamber was reduced to less than 1.times.10.sup.-3 Pa. As the
sputtering target, a composition comprised of indium oxide and tin
oxide (indium oxide:tin oxide=95:5) was used. After that, a mixed
gas of argon and oxygen (Ar:O.sub.2=100:3) was introduced in the
vacuum chamber till pressure reached 1.times.10.sup.-3 Pa, and a
sputtering output of 100 W was applied at 100.degree. C. of the
plate to form a layer on the plate. The formed indium oxide layer
was evaluated in the same manner as in Example 1.
Comparative Example 2
[0195] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
12 Inert gas: helium 98.5% by volume Reactive gas 1: oxygen 0.25%
by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Comparative Example 3
[0196] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
13 Inert gas: helium 98.70% by volume Reactive gas 1: oxygen 0.05%
by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Comparative Example 4
[0197] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
14 Inert gas: helium 98.5% by volume Reactive gas 1: oxygen 0.25%
by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Comparative Example 5
[0198] The glass plate was subjected to atmospheric pressure plasma
treatment to form a tin doped indium oxide layer in the same manner
as in Example 1 above, except that the composition of the gas used
was changed as shown below. The formed indium oxide layer was
evaluated in the same manner as in Example 1.
15 Inert gas: a mixed gas of helium and argon 98.5% by volume
(helium to argon ratio by volume 70/30) Reactive gas 1: oxygen
0.25% by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: dibutyltin diacetate
0.05% by volume
Comparative Example 6
[0199] Monoethanolamine of 0.4 g, 3.8 g of indium acetate and 0.16
g of Sn(OC.sub.4H.sub.9).sub.4 was added to 22.2 g of
2-methoxymethanol, and stirred for 10 minutes. The resulting
solution was dip coated on the glass plate prepared in Example 1 at
a speed of 1.2 cm/minute, and dried in an electric furnace at
500.degree. C. for one hour.
[0200] The evaluation results of Examples 1 through 10 and
comparative examples 1 through 6 are collectively shown in Table
1.
16 TABLE 1 Concen- Density tration of Layer Resis- of Mobility
reactive forming Trans- tivity carrier of Carbon Inert Reactive gas
1 speed mittance (10.sup.-4 (10.sup.19 carrier SN/In content gas
gas 1 (volume %) (nm/min) (%) .OMEGA. .multidot. cm) cm.sup.-3)
(cm.sup.2/Vsec) ratio (atomic %) Ex. He H2 0.25 12 91 3.4 20 90 7.2
0.4 1 Ex. 2 He H2 0.10 11 89 3.8 19 85 7.5 0.5 Ex. 3 He H2 0.50 11
91 3.9 27 60 7.4 0.4 Ex. 4 He H2 1.00 10 89 4.2 46 32 7.3 0.6 Ex. 5
He H2S 0.25 9 86 4.8 52 25 7.4 0.6 Ex. 6 Ar H2 0.25 10 87 3.9 21 76
7.1 0.6 Ex. 7 Ar H2 0.10 14 86 3.8 21 78 7.6 0.5 Ex. 8 Ar/He H2
0.25 12 91 3.7 20 83 7.9 0.4 Ex. 9 Ar/He H2 0.10 14 88 3.8 24 68
7.3 0.7 Ex. N2 H2 0.25 9 86 4.7 44 30 7.2 0.5 10 Comp. -- -- -- 0.3
86 4.0 55 30 7.1 0.2 Ex. 1 Comp. He O2 0.25 8 84 34 9.3 20 7.6 0.5
Ex. 2 Comp. He O2 0.05 7 86 73 8.5 10 7.2 0.6 Ex. 3 Comp. Ar O2
0.25 9 87 36 16 11 7.3 0.8 Ex. 4 Comp. Ar/He O2 0.25 9 85 35 18 10
7.3 0.6 Ex. 5 Comp. -- -- -- -- 81 160 3.0 13 7.3 1.1 Ex. 6 Ex.:
Example, Com. Ex.: Comparative example
Example 11
[0201] The glass plate was subjected to atmospheric pressure plasma
treatment to form a layer in the same manner as in Example 1 above,
except that the composition of the gas used was changed as shown
below.
17 Inert gas: helium 98.65% by volume Reactive gas 1: hydrogen
0.15% by volume Reactive gas 2: 1.2% by volume
bis(2,4-pentanedionato)zinc
Example 12
[0202] The glass plate was subjected to atmospheric pressure plasma
treatment to form a layer in the same manner as in Example 1 above,
except that the composition of the gas used was changed as shown
below.
18 Inert gas: helium 98.65% by volume Reactive gas 1: hydrogen
0.15% by volume Reactive gas 2: di-n-butyltin diacetate 1.2% by
volume
Example 13
[0203] The glass plate was subjected to atmospheric pressure plasma
treatment to form a layer in the same manner as in Example 1 above,
except that the composition of the gas used was changed as shown
below.
19 Inert gas: argon 98.65% by volume Reactive gas 1: hydrogen 0.15%
by volume Reactive gas 2: 1.2% by volume
bis(2,4-pentanedionato)tin
Example 14
[0204] The glass plate was subjected to atmospheric pressure plasma
treatment to form a layer in the same manner as in Example 1 above,
except that the composition of the gas used was changed as shown
below.
20 Inert gas: helium 98.65% by volume Reactive gas 1: hydrogen
0.14% by volume Reactive gas 2: 1.2% by volume
bis(2,4-pentanedionato)tin Reactive gas 3: carbon tetrafluoride
0.01% by volume
Example 15
[0205] The glass plate was subjected to atmospheric pressure plasma
treatment to form a layer in the same manner as in Example 1 above,
except that the composition of the gas used was changed as shown
below.
21 Inert gas: helium 98.65% by volume Reactive gas 1: hydrogen
0.10% by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: 0.5% by volume
bis(2,4-pentanedionato)zinc
Example 16
[0206] The glass plate was subjected to atmospheric pressure plasma
treatment to form a layer in the same manner as in Example 1 above,
except that the composition of the gas used was changed as shown
below.
22 Inert gas: helium 98.65% by volume Reactive gas 1: hydrogen
0.10% by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: 0.5% by volume
bis(2,4-pentanedionato)tin
Example 17
[0207] The glass plate was subjected to atmospheric pressure plasma
treatment to form a layer in the same manner as in Example 1 above,
except that the composition of the gas used was changed as shown
below.
23 Inert gas: helium 98.65% by volume Reactive gas 1: hydrogen
0.10% by volume Reactive gas 2: tris(2,2,6,6-tetramethyl-3,5- 1.2%
by volume heptanedionato)indium Reactive gas 3: 0.5% by volume
bis(2,4-pentanedionato)tin
Example 18
[0208] The glass plate was subjected to atmospheric pressure plasma
treatment to form a layer in the same manner as in Example 1 above,
except that the composition of the gas used was changed as shown
below.
24 Inert gas: helium 98.65% by volume Reactive gas 1: hydrogen
0.10% by volume Reactive gas 2: 1.2% by volume
tris(2,4-pentanedionato)indium Reactive gas 3: tetrabutyltin 0.5%
by volume
Example 19
[0209] The glass plate was subjected to atmospheric pressure plasma
treatment to form a layer in the same manner as in Example 1 above,
except that the composition of the gas used was changed as shown
below.
25 Inert gas: helium 98.65% by volume Reactive gas 1: hydrogen
0.10% by volume Reactive gas 2: triethylindium 1.2% by volume
Reactive gas 3: di-n-butyltin diacetate 0.5% by volume
Comparative Example 7
[0210] A layer was formed on the glass plate prepared in Example 1
in the same manner as in Comparative example 1, except that zinc
oxide was used as the sputtering target.
Comparative Example 8
[0211] A layer was formed on the glass plate prepared in Example 1
in the same manner as in Comparative example 1, except that tin
oxide was used as the sputtering target.
Comparative Example 9
[0212] A layer was formed on the glass plate prepared in Example 1
in the same manner as in Comparative example 1, except that indium
oxide and zinc oxide (indium oxide:zinc oxide=95:5) were used as
the sputtering target.
Comparative Example 10
[0213] A layer was formed on the glass plate prepared in Example 1
in the same manner as in Example 11, except that hydrogen was
changed to oxygen.
Comparative Example 11
[0214] A layer was formed on the glass plate prepared in Example 1
in the same manner as in Example 12, except that hydrogen was
changed to oxygen.
Comparative Example 12
[0215] A layer was formed on the glass plate prepared in Example 1
in the same manner as in Example 13, except that hydrogen was
changed to oxygen.
Comparative Example 13
[0216] A layer was formed on the glass plate prepared in Example 1
in the same manner as in Example 14, except that hydrogen was
changed to oxygen.
Comparative Example 14
[0217] A layer was formed on the glass plate prepared in Example 1
in the same manner as in Example 15, except that hydrogen was
changed to oxygen.
Comparative Example 15
[0218] A layer was formed on the glass plate prepared in Example 1
in the same manner as in Example 16, except that hydrogen was
changed to oxygen.
Comparative Example 16
[0219] A layer was formed on the glass plate prepared in Example 1
in the same manner as in Example 17, except that hydrogen was
changed to oxygen.
[0220] Examples 11 through 19 and Comparative examples 7 through 16
were evaluated for layer forming speed, transmittance and
resistivity in the same manner as in Example 1. The results are
shown in Table 2.
[0221] In Table 2, In(AcAc).sub.3 represents
tris(2,4-pentanedionato)indiu- m Zn(AcAc).sub.2 represents
bis(2,4-pentanedionato)zinc, DBTDA represents di-n-butyltin
diacetate, tris(2,4-pentanedionato)indium, Sn(AcAc).sub.2
represents bis(2,4-pentanedionato)tin, In(C.sub.2H.sub.5).sub.3
represents triethylindium, TBT represents tetrabutyltin,
In(TMHD).sub.3 represents
tris(2,2,6,6-tetramethyl-3,5-heptanedionato)indium.
26 TABLE 2 Layer forming Resistivity Reactive Reactive Reactive
speed Transmittance (10.sup.-4 gas 1 gas 2 gas 3 (nm/min) (%)
.OMEGA. .multidot. cm) Ex. 11 H2 Zn(AcAc).sub.2 -- 13 89 13 Ex. 12
H2 DBTDA -- 10 87 14 Ex. 13 H2 Sn(AcAc).sub.2 -- 12 88 9.7 Ex. 14
H2 Sn(AcAc).sub.2 CF.sub.4 12 87 6.9 Ex. 15 H2 In(AcAc).sub.3
Zn(AcAc).sub.2 13 90 4.2 Ex. 16 H2 In(AcAc).sub.3 Sn(AcAc).sub.2 14
92 3.2 Ex. 17 H2 In(TMHD).sub.3 Sn(AcAc).sub.2 13 91 2.8 Ex. 18 H2
In(AcAc).sub.3 TBT 9 85 5.1 Ex. 19 H2 In(C.sub.2H.sub.5).sub.3
DBDTA 8 86 5.8 Comp. -- -- -- 0.4 88 16 Ex. 7 Comp. -- -- -- 0.3 86
19 Ex. 8 Comp. -- -- -- 0.3 89 6.2 Ex. 9 Comp. O2 Zn(AcAc).sub.2 --
13 72 111 Ex. 10 Comp. O2 DBDTA -- 12 77 42 Ex. 11 Comp. O2
Sn(AcAc).sub.2 -- 14 74 36 Ex. 12 Comp. O2 Sn(AcAc).sub.2 CF.sub.4
12 71 28 Ex. 13 Comp. O2 In(AcAc).sub.3 Zn(AcAc).sub.2 12 79 42 Ex.
14 Comp. O2 In(AcAc).sub.3 Sn(AcAc).sub.2 15 92 38 Ex. 15 Comp. O2
In(TMHD).sub.3 Sn(AcAc).sub.2 15 91 24 Ex. 16 Ex.: Example, Com.
Ex.: Comparative example
Example 20
[0222] The same procedures as Example 1 was carried out, except
that an amorphous cyclopolyolefin resin film with a thickness of
100 .mu.m (ARTON film produced by JSR Co., Ltd.) was used as the
substrate and a plasma discharge treatment apparatus as shown in
FIG. 6 was used. Thus, a tin doped indium oxide layer was formed on
the amorphous cyclopolyolefin resin film, and evaluated for layer
forming speed, transmittance and resistivity in the same manner as
in Example 1.
[0223] Critical radius of curvature was measured according to the
following procedures:
[0224] <Measurement of Critical Radius of Curvature)
[0225] Sample 20 with a tin doped indium oxide layer as prepared in
Example 1 was cut into a 10 cm square specimen. Surface resistance
RO of the resulting specimen was measured at 20.degree. C. and 60%
RH employing Loresta-GP, MCP-T600 produced by Mitsubishi Chemical
Corporation. Next, the specimen was closely wound around a
stainless steel rod with a diameter of 10 mm, and allowed to stand
for 3 minutes. After that, the specimen was unwound and surface
resistance R thereof was measured in the same manner as above.
Surface resistance R was measured in the same manner as above,
except that a rod with a radius reduced 1 cm by 1 cm was used. The
radius of a rod giving a ratio R/R0 exceeding 1 was defied as
critical radius of curvature.
Example 21
[0226] The same procedures as Example 20 were carried out, except
that Zeonor ZF16 with a thickness of 100 .mu.m produced by Nippon
Zeon Co., Ltd. was used as the substrate. Thus, a tin doped indium
oxide layer was formed on the Zeonor ZF16, and evaluated in the
same manner as in Example 20.
Example 22
[0227] The same procedures as Example 20 were carried out, except
that a polycarbonate film with a thickness of 100 .mu.m, Pureace
produced by Teijin Co., Ltd. was used as the substrate. Thus, a tin
doped indium oxide layer was formed on the film, and evaluated in
the same manner as in Example 20.
Example 23
[0228] The same procedures as Example 20 were carried out, except
that an acetylcellulose film with a thickness of 100 .mu.m, Pureace
produced by Teijin Co., Ltd. was used as the substrate. Thus, a tin
doped indium oxide layer was formed on the film, and evaluated in
the same manner as in Example 20.
Comparative Example 17
[0229] A tin doped indium oxide layer was formed on a polyethylene
terephthalate film employing a take-up type magnetron sputtering
apparatus in which a vacuum chamber, a sputtering target and an air
introducing tube were provided. The film was introduced in the
vacuum chamber of the apparatus, and the pressure in the chamber
was reduced to 4.times.10.sup.-4 Pa. As the sputtering target, a
composition comprised of indium oxide and tin oxide (indium
oxide:tin oxide=95:5) was used. After that, the film was rewound
and the chamber was degassed. Subsequently, a mixed gas of argon
and oxygen (Ar:O.sub.2=98.8:1.2) was introduced in the vacuum
chamber till pressure in the chamber reached 1.times.10.sup.-3 Pa,
and a power density of 1 W/cm.sup.2 was applied at a film
transporting speed of 0.1 m/min and at a main roll temperature of
100.degree. C. to form a layer on the film. The formed layer was
evaluated in the same manner as in Example 20.
[0230] The evaluation results of Examples 20 through 23 and
comparative example 17 are collectively shown in Table 3.
27 TABLE 3 Layer Critical forming Trans- radius of speed mittance
Resistivity curvature (nm/min) (%) (10.sup.-4 .OMEGA. .multidot.
cm) (mm) Ex. 20 12 87 4.0 6 Ex. 21 13 86 4.6 5 Ex. 22 12 84 4.9 6
Ex. 23 11 87 4.2 5 Comp. Ex. 17 0.3 84 4.9 7 Ex.: Example, Com.
Ex.: Comparative example
[0231] Transparent conductive layers of examples 24, 25 and 26 were
prepared according to the following procedures.
Example 24
[0232] Employing a planar plasma discharge treatment apparatus
shown in FIG. 7, a transparent conductive layer was formed on the
substrate in the same manner as in Example 1, except that
conditions as shown below were used.
[0233] Electric Field Conditions
[0234] frequency: 13.56 MHz, output density: 5W/cm.sup.2
28 Gas composition Inert gas: helium 98.74% by volume Reactive gas
1: hydrogen 0.15% by volume Reactive gas 2: 1.2% by volume Indium
acetylacetonate Reactive gas 3: dibutyltin diacetate 0.5% by
volume
Example 25
[0235] A transparent conductive layer (ITO layer) was formed on the
substrate in the same manner as in Example 24, except that the gas
composition as shown below was used.
29 Gas composition Inert gas: helium 98.60% by volume Reactive gas
1: hydrogen 0.15% by volume Reactive gas 2: 1.2% by volume Indium
acetylacetonate Reactive gas 3: dibutyltin diacetate 0.5% by
volume
Example 26
[0236] A transparent conductive layer was formed on a substrate
employing the atmospheric pressure plasma discharge treatment
disclosed in Example 3 of Japanese Patent O.P.I. Publication No.
2000-303175, except that the substrate and electrodes in Examples
24 and 25 were used, and electric field conditions and the gas as
shown below were used.
[0237] Electric Field Conditions
[0238] frequency: 10 kHz, output density: 0.8 W/cm.sup.2 (PHF-4K
produced by Heiden Kenkyusho)
[0239] Gas Composition
30 Inert gas: helium 98.75% by volume Reactive gas 1: hydrogen 0.5%
by volume Reactive gas 2: 1.2% by volume Indium acetylacetonate
Reactive gas 3: dibutyltin diacetate 0.05% by volume
[0240] Regarding the resulting transparent conductive layers,
coefficient of variation of H/M in the thickness direction and the
hydrogen concentration were determined according to the dynamic
SIMS as described above. Further, resistivity and light
transmittance were measured. The results are shown in Table 4.
31 TABLE 4 Concen- tration Co- of efficient Hydrogen reactive of
concen- gas 1 variation tration Resis- Trans- Inert Reactive (% by
of ratio (atomic tivity mittance gas gas 1 volume) H/M (%) %)
(.OMEGA. .multidot. cm) (%) Ex. 24 He H.sub.2O 0.01 2.8 1.0 2
.times. 10.sup.-4 90 Ex. 25 He H.sub.2 0.15 1.5 0.8 2 .times.
10.sup.-4 91 Ex. 26 He H.sub.2 0.5 5.3 1.3 3.9 .times. 10.sup.-4 80
Ex.: Example
[0241] As is apparent from Table 4 above, it has been confirmed
that the transparent conductive layer having a coefficient of
variation of ratio H/M in the thickness direction of not more than
5% further improves performances of the transparent conductive
layer.
[0242] The present invention provides a method of forming a
transparent conductive layer with good optical and electric
properties, a method of forming a transparent conductive layer with
good critical radius of curvature on a substrate, and a method of
forming a transparent conductive layer with high safety and with
high productivity, and provides a transparent conductive layer
formed according to the above-mentioned method and a material
comprising the transparent conductive layer.
* * * * *