U.S. patent application number 11/125208 was filed with the patent office on 2005-09-15 for high rate deposition of titanium dioxide.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Gillette, Gregory Ronald, Iacovangelo, Charles, Schaepkens, Marc.
Application Number | 20050202250 11/125208 |
Document ID | / |
Family ID | 32592765 |
Filed Date | 2005-09-15 |
United States Patent
Application |
20050202250 |
Kind Code |
A1 |
Iacovangelo, Charles ; et
al. |
September 15, 2005 |
High rate deposition of titanium dioxide
Abstract
There is provided a structure. The structure comprises a
substrate, and a titanium oxide layer disposed over the substrate.
There is also provided a method of forming a titanium oxide coating
on a substrate. The method includes generating a plasma; providing
a first reactant, comprising titanium, and a second reactant,
comprising oxygen, into the plasma stream extending to the
substrate; and forming the titanium oxide coating on the
substrate.
Inventors: |
Iacovangelo, Charles;
(Clifton Park, NY) ; Gillette, Gregory Ronald;
(Clifton Park, NY) ; Schaepkens, Marc; (Ballston
Lake, NY) |
Correspondence
Address: |
FOLEY AND LARDNER
SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
GENERAL ELECTRIC COMPANY
|
Family ID: |
32592765 |
Appl. No.: |
11/125208 |
Filed: |
May 10, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11125208 |
May 10, 2005 |
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10248152 |
Dec 20, 2002 |
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6890656 |
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Current U.S.
Class: |
428/412 ;
427/453; 428/336; 428/701; 428/702 |
Current CPC
Class: |
Y10T 428/265 20150115;
Y10T 428/31507 20150401; Y10T 428/31855 20150401; C23C 16/513
20130101; C23C 16/405 20130101 |
Class at
Publication: |
428/412 ;
428/701; 428/702; 428/336; 427/453 |
International
Class: |
B32B 009/00 |
Claims
1-22. (canceled)
23. An apparatus for forming a titanium oxide film comprising: a
first reactant source containing TiCL.sub.4; a second reactant
source containing water vapor; a plasma stream generator; and a
substrate holder.
Description
BACKGROUND OF THE INVENTION
[0001] This invention is related generally to TiO.sub.x (titanium
oxide) or titanium oxide TiO.sub.2 (titanium dioxide) coatings or
films, products incorporating the TiO.sub.x coatings, methods for
making the coatings and products, and an apparatus for making the
coatings and products.
[0002] TiO.sub.2 is widely used in a number of applications. For
example, TiO.sub.2 is used for UV filters in glazing and opthalmic
applications, as a high index material in optical stacks, and as a
photocatalytic coating to degrade organics on the surface of
billboards and lighting fixtures. TiO.sub.2 is typically deposited
at high temperatures by chemical vapor deposition (CVD) techniques.
These CVD techniques, however, can not be used on low temperature
substrates such as plastics or polymers, because the deposition
temperatures will damage the substrate.
[0003] TiO.sub.2 has been deposited on low temperature substrates,
such as some plastics, by conventional physical vapor deposition
(PVD) techniques such as sputtering and e-beam evaporation. These
PVD techniques, however, suffer from being very low rate processes,
typically, 10-100 angstroms/minute. In addition, the TiO.sub.2
coatings tend to have a high tensile stress, thus limiting their
usefulness in applications requiring thicker deposits, multi-layer
stacks, and depositing on thin films where the stress may cause
curling of the substrate. Also, these coatings tend to be rough
with low absorbency per unit thickness (A/t) in the UV light range,
where A is the absorbency and t is the thickness.
[0004] More recently, workers have tried to overcome the problems
cited above by depositing TiO.sub.2 in plasma enhanced chemical
vapor deposition (PECVD) reactors with and without biasing. These
PECVD processes, however, have not overcome the limitations of the
classical PVD approaches, and still generate low rate, highly
stressed TiO.sub.2 coatings with low (A/t) in the UV light
range.
SUMMARY OF THE INVENTION
[0005] In accordance with one aspect of the present invention,
there is provided a structure comprising a substrate; and a
titanium oxide layer disposed over the substrate, wherein the
titanium oxide layer is characterized by a property, wherein the
property is at least one of an absorbency per unit thickness at an
optical wavelength of 330 nm of greater than 4/.mu.m, an absorbency
per unit thickness at an optical wavelength of 330 nm of greater
than 4/.mu.m which decreases by no more than 5% after the structure
is submerged for 3 days in distilled water at 65.degree. C., and a
haze increase of less than 1% after the structure is submerged for
3 days in distilled water at 65.degree. C.
[0006] In accordance with another aspect of the present invention,
there is provided a method of forming a titanium oxide coating on a
substrate, the method comprising: generating a plasma stream with
an expanding thermal plasma generator; providing a first reactant,
comprising titanium, and a second reactant, comprising oxygen, into
the plasma stream extending to the substrate; and forming the
titanium oxide coating on the substrate.
[0007] In accordance with another aspect of the present invention,
there is provided an apparatus for forming a titanium oxide film
comprising: a first reactant source containing TiCl.sub.4; a second
reactant source containing water vapor; a plasma stream generator;
and a substrate holder.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a side cross sectional view of a substrate coated
with a TiO.sub.2 layer according to an exemplary embodiment of the
invention.
[0009] FIG. 2 is side cross sectional view of an apparatus used to
manufacture the substrate coated with a TiO.sub.2 layer according
to an exemplary embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] The present inventors have realized that an expanding
thermal plasma (ETP) process can deposit TiO.sub.2 at low
temperatures while maintaining high deposition rates and still
provide high quality coatings with properties such as good clarity,
refractive index, UV absorbency, gas/moisture barrier and
hydrolytic stability.
[0011] Structure with TiO.sub.2 Coating
[0012] FIG. 1 illustrates a structure 10 incorporating an improved
TiO.sub.x coating according to one embodiment of the invention. The
TiO.sub.x coating may comprise a stoichiometric TiO.sub.2 coating
or a non-stoichiometric TiO.sub.x coating where x is not equal to
2. The structure includes a substrate 12 and a TiO.sub.x layer 14
disposed over the substrate. The structure 10 may optionally
include an interlayer 16 disposed between the substrate 12 and the
TiO.sub.x layer 14 depending upon the application. The interlayer
16 may function as an adhesion layer between the substrate 12 and
the TiO.sub.x layer 14 to promote adhesion between these layers, or
may function to reduce stress between the substrate 12 and
overlying layers, including the TiO.sub.x layer 14. The interlayer
16 may comprise sublayers where one sublayer functions to reduce
stress between the substrate 12 and the TiO.sub.x layer 14, and the
other sublayer functions to promote adhesion between the substrate
12 and the TiO.sub.x layer 14. Alternatively, the interlayer 16 may
provide both the functions of an adhesion layer and to reduce
stress. The structure 10 may also optionally include an abrasion
resistant layer 18 on the TiO.sub.x layer 14 to protect the
TiO.sub.x layer 14 from abrasion. The structure may optionally
incorporate IR reflecting or electrically conducting layers between
the TiO.sub.2 layer 14 and the abrasion layers (if any). The
structure 10 may optionally contain antireflecting layers on top of
layer 18. Alternatively, the structure of a stress
release/reduction layer and a TiO.sub.x layer 14 may be repeated a
number of times to form a multi-layer stack that has superior
barrier performance over single layer TiO.sub.x barrier
coatings.
[0013] The substrate 10 may be a low temperature substrate. In this
application low temperature substrate means a substrate that may be
damaged at temperatures slightly greater than about 150.degree. C.
The substrate 10 may alternatively be a high temperature substrate.
In this application high temperature substrate means a substrate
that is not expected to be damaged at temperatures slightly greater
than about 250.degree. C.
[0014] The substrate may comprise for example, a polymer resin. For
example, the substrate may comprise a polycarbonate. Polycarbonates
suitable for forming the substrate are well-known in the art.
[0015] Aromatic carbonate polymers may be prepared by methods well
known in the art as described, for example, in U.S. Pat. Nos.
3,161,615; 3,220,973; 3,312,659; 3,312,660; 3,313,777; 3,666,614;
3,989,672; 4,200,681; 4,842,941; and 4,210,699, all of which are
incorporated herein by reference.
[0016] The substrate may also comprise a polyestercarbonate which
can be prepared by reacting a carbonate precursor, a dihydric
phenol, and a dicarboxylic acid or ester forming derivative
thereof. Polyestercarbonates are described, for example, in U.S.
Pat. Nos. 4,454,275; 5,510,448; 4,194,038; and 5,463,013, all of
which are incorporated herein by reference.
[0017] The substrate may also comprise a thermoplastic or thermoset
material. Examples of suitable thermoplastic materials include
polyethylene, polypropylene, polystyrene, polyvinylacetate,
polyvinylalcohol, polyvinylacetal, polymethacrylate ester,
polyacrylic acids, polyether, polyester, polycarbonate, cellulous
resin, polyacrylonitrile, polyamide, polyimide, polyvinylchloride,
fluorine containing resins and polysulfone. Examples of suitable
thermoset materials include epoxy and urea melamine.
[0018] Acrylic polymers, also well known in the art, are another
material from which the substrate may be formed. Acrylic polymers
can be prepared from monomers such as methyl acrylate, acrylic
acid, methacrylic acid, methyl methacrylate, butyl methacrylate,
cyclohexyl methacrylate, and the like. Substituted acrylates and
methacrylates, such as hydroxyethyl acrylate, hydroxybutyl
acrylate, 2-ethylhexylacrylate, and n-butylacrylate may also be
used.
[0019] Polyesters can also be used to form the substrate.
Polyesters are well-known in the art, and may be prepared by the
polyesterification of organic polycarboxylic acids (e.g., phthalic
acid, hexahydrophthalic acid, adipic acid, maleic acid, terphthalic
acid, isophthalic acid, sebacic acid, dodecanedioic acid, and the
like) or their anhydrides with organic polyols containing primary
or secondary hydroxyl groups (e.g., ethylene glycol, butylene
glycol, neopentyl glycol, and cyclohexanedimethanol).
[0020] Polyurethanes are another class of materials which can be
used to form the substrate. Polyurethanes are well-known in the
art, and are prepared by the reaction of a polyisocyanate and a
polyol. Examples of useful polyisocyanates include hexamethylene
diisocyanate, toluene diisocyanate, MDI, isophorone diisocyanate,
and biurets and triisocyanurates of these diisocyanates. Examples
of useful polyols include low molecular weight aliphatic polyols,
polyester polyols, polyether polyols, fatty alcohols, and the
like.
[0021] Examples of other materials from which the substrate may be
formed include acrylonitrile-butadiene-styrene, glass, VALOX.RTM.
(polybutylenephthalate, available from General Electric Co.),
XENOY.RTM. (a blend of LEXAN.RTM. and VALOX.RTM., available from
General Electric Co.), and the like. Typically, the substrate
comprises a clear polymeric material, such as PC, PPC, PES, PEI or
acrylic.
[0022] The substrate can be formed in a conventional manner, for
example by injection molding, extrusion, cold forming, vacuum
forming, blow molding, compression molding, transfer molding,
thermal forming, solvent casting and the like. The article or
product may be in any shape and need not be a finished article of
commerce, that is, it may be sheet material or film which would be
cut or sized or mechanically shaped into a finished article. The
substrate may be transparent or not transparent. The substrate may
be rigid or flexible.
[0023] The substrate may be, for example, a vehicle window, such as
a car, truck, motorcycle, tractor, boat or air plane window. The
substrate may also comprise an eye glass lens, an optical stack, a
display screen or a component for a display screen, such as a
television screen, LCD screen, computer monitor screen, a plasma
display screen or a glare guard for a computer monitor.
[0024] The substrate is preferably a polymer substrate, which will
typically be a low temperature substrate.
[0025] The TiO.sub.x layer 14 is preferably formed by an Expanding
Thermal Plasma process (ETP), as discussed in more detail below.
ETP processes, such as arc plasma deposition, and systems
performing ETP, are generally known, and are described in U.S. Pat.
No. 6,420,032, for example, which is herein incorporated by
reference in its entirety. The TiO.sub.x layer 14 has UV absorption
properties and is typically about 10 to 10,000 nm thick.
[0026] The interlayer 16 may function to relieve stress between the
substrate 12 and the overlying layers. Stress may occur, for
example, due to different coefficients of thermal expansion,
different ductility, and different elastic moduli between the
substrate 12 and the overlying layers. Preferably, the interlayer
16 comprises a material which has a value of coefficient of thermal
expansion, ductility, and elastic modulus which is between the
corresponding values of the substrate and the overlying layers. One
example of a suitable interlayer material is a plasma polymerized
organosilicon, as described in the application Ser. No. 09/271,654,
entitled "Multilayer Article and Method of Making by Arc Plasma
Deposition" , which is incorporated by reference.
[0027] The abrasion resistant layer 18 prevents the TiO.sub.x layer
14 from being scratched during use. The abrasion resistant layer 18
may comprise any scratch or abrasion resistant and UV stable
material. The abrasion resistant layer 18 may comprise, for
example, a plasma polymerized organosilicon material, as described
in U.S. Ser. No. 09/271,654. The organosilicon material may
comprise, for example, octamethylcyclotetrasiloxane (D4),
tetramethyldisiloxane (TMDSO), hexamethyldisiloxane (HMDSO), or
other organosilicon, as described in the above application. The
organosilicon monomers are oxidized, decomposed, and polymerized in
an arc plasma deposition apparatus, to form an abrasion resistant
layer which comprises an oxidized D4, TMDSO, or HMDSO layer, for
example. Such an abrasion resistant layer may be referred to as a
SiO.sub.x layer. However, the SiO.sub.x layer may also contain
hydrogen and carbon atoms in which case it is generally referred to
as SiO.sub.xC.sub.yH.sub.z. Other examples of compounds and
materials suitable as the abrasion-resistant material include
silicon dioxide and aluminum oxide, for example.
[0028] Deposition System
[0029] The system for forming the TiO.sub.x layer 14 is preferably
an ETP system such as described in U.S. Pat. No. 6,420,032. FIG. 2
illustrates an example of an appropriate system 100 for forming a
TiO.sub.x layer 14 according to embodiments of the invention. The
system of FIG. 2 is similar to the system of FIG. 4 of U.S. Pat.
No. 6,420,032. However, in FIG. 2, only two reactant supply lines
are shown, although the system may have more than two reactant
supply lines. Other appropriate ETP systems are disclosed for
example in U.S. Pat. No. 6,397,776, entitled "APPARATUS FOR LARGE
AREA CHEMICAL VAPOR DEPOSITION USING MULTIPLE EXPANDING THERMAL
PLASMA GENERATORS", and U.S. patent application Ser. Nos.
09/683,148, 09/683,149 and 10/064,888, all of which are hereby
incorporated by reference in their entirety. These latter
disclosures illustrate features such as multiple injection rings,
one ring around several arcs, and/or an adjustable cathode to anode
distance, which may be preferable in some applications.
[0030] The system 100 comprises a plasma generation chamber 110 and
a deposition chamber 111. The deposition chamber 111 contains a
substrate 120 mounted on a temperature controlled support 122. The
substrate 120 may be a transparent glass or polymeric substrate,
for example, coated with the interlayer 16, shown in FIG. 1. The
deposition chamber 111 also contains a door (not shown) for loading
and unloading the substrate 120 and an outlet 123 for connecting to
a pump. The support 122 may be positioned at any position in volume
121 of deposition chamber 111. The substrate 120 may be positioned
10 to 50 cm, for example, and typically about 25.5 cm, from the
anode 119 of the plasma generator.
[0031] The deposition chamber 111 also optionally comprises a
retractable shutter 124. The shutter may be positioned, for
example, by a handle 125 or by a computer controlled positioning
mechanism. The shutter 124 may also contain a circular aperture to
control the diameter of the plasma that emanates from the plasma
generation chamber 110 towards the substrate 120. The deposition
chamber 111 may also optionally comprise magnets or magnetic field
generating coils (not shown) adjacent to chamber walls to direct
the flow of the plasma.
[0032] The deposition chamber 111 may also contain an optional
nozzle 118. The nozzle 118 provides improved control of the
injection, ionization and reaction of the reactants to be deposited
on the substrate 120. The nozzle 118 provides for the deposition of
a material such as the TiO.sub.x layer on the substrate 120 and
minimizes or even prevents formation of powdery reactant deposits
on the substrate 120. Preferably, the nozzle 118, if employed, has
a conical shape with a divergent angle of about 40 degrees and a
length of about 10 to 80 cm, preferably about 16 cm. However, the
nozzle 118 may alternatively have a variable cross section, such as
such as conical-cylindrical-conical or conical-cylindrical.
Furthermore, the nozzle 118 may have a divergent angle other than
40 degrees and a length other than 16 cm. The nozzle may also be
omitted entirely.
[0033] The deposition chamber 111 also contains at least one
reactant supply line. The number of reactant supply lines may be,
for example, two or more. For example, the deposition chamber 111
may contain a first reactant supply line 112 and a second reactant
supply line 114 to deposit the TiO.sub.x layer film on the
substrate 120. The supply lines 112 and 114 preferably communicate
with the nozzle 118 and supply reactants into the plasma flowing
through the nozzle. The deposition chamber 111 also generally
contains vacuum pumps (not shown) for evacuating the chamber
111.
[0034] The plasma generation chamber 110 contains at least one
cathode 113, a plasma gas supply line 117 and an anode 119. The
plasma generation chamber 110 typically comprises three cathodes
113. The cathodes 113 may comprise, for example, tungsten or
thorium doped tungsten tips. The use of thorium allows the
temperature of the tips to be maintained below the melting point of
tungsten, thus avoiding contamination of the plasma with tungsten
atoms.
[0035] The plasma generation chamber 110 generally includes at
least one plasma gas supply line 117. The plasma generation chamber
110 may also contain a purging gas supply line adjacent to the
carrier gas supply line 117 to supply a purging gas to chambers 110
and 111 prior to supplying the plasma gas.
[0036] To form a plasma in the plasma generation chamber 110, a
plasma gas is supplied through plasma gas supply line 117. The
plasma gas may suitably comprise a noble gas, such as argon or
helium, or a reactive gas, such as nitrogen, ammonia, carbon
dioxide or hydrogen or any mixture thereof. If there is more than
one plasma gas, then the plural gasses may be supplied through
plural supply lines, if desired. Preferably, for the TiO.sub.x
deposition, the plasma gas comprises argon. The plasma gas in
plasma generation chamber 110 is maintained at a higher pressure
than the pressure in the deposition chamber 111, which is
continuously evacuated by a pump. An arc voltage is then applied
between the cathode(s) 113 and the anode 119 to generate a plasma
in the plasma generation chamber 110. The plasma then extends
through the aperture of the anode 119 into the deposition chamber
111 due to the pressure difference between chambers 110 and 111.
The reactants are supplied into the plasma through supply lines 112
and 114.
[0037] Method of Forming the TiO.sub.x Coating
[0038] A method of forming a TiO.sub.x coating on a substrate
according to an embodiment of the present invention is now
described. The substrate may comprise, for example, a low
temperature substrate of polycarbonate with an interlayer formed on
the polycarbonate. The substrate is provided in the deposition
chamber 111 of the system 100 of FIG. 2. A plasma is generated
using a plasma gas supplied by plasma gas line 117. The plasma gas
may be, for example, a noble gas. Preferably the plasma gas is
Ar.
[0039] First and second reactants are then supplied to the plasma
via supply lines. The first reactant comprises titanium and the
second reactant comprises oxygen. Preferably the first reactant
comprises TiCl.sub.4 and the second reactant comprises water vapor.
The first and second reactants react and form a TiO.sub.x film on
the substrate.
[0040] For a first reactant comprising TiCl.sub.4 and a second
reactant comprising water, the preferred range of deposition would
be between 10 and 1000 nm and more preferably between 200 and 600
nm, the preferred reactant flow rate ranges are 0.1 to 1 slm for
TiCl.sub.4 and 0.4 to 4 slm for water. The preferred power range is
20 to 3000 W dc power, 1 to 100 Amps, and 20-30 V. High quality
TiO.sub.x films can be deposited at a rate greater than 1 .mu.m per
minute.
EXAMPLES
[0041] A polycarbonate substrate was provided as a substrate. A
TiO.sub.x layer was formed directly on the polycarbonate. All
depositions on the polycarbonate included a V-D4 layer deposited at
20 Amps, 1.65 Ipm of Ar and 0.03 Ipm V-D4 scanning past the Etp as
2.3 cm/second. The first reactant was TiCl.sub.4. The second
reactant was water vapor and Ar was used as the plasma gas. The
chamber pressure was 45 mT (milliTorr). The deposition parameters
are shown in Table 1. All of examples in Table 1 were for ETP
deposition except for sample 6.
[0042] As another example, TiO.sub.x layers were formed using an Ar
ETP with titanium isopropoxide as a first reactant and water vapor
as a second reactant. The deposition conditions are shown in Table
1.
[0043] As yet another example, a TiO.sub.x layer was formed using
an Ar ETP with titanium ethoxide or as a first reactant and water
vapor as a second reactant. The deposition conditions are also
shown in Table 1.
1TABLE 1 Change Ar Ox H.sub.2O Am Thick Haz A/t A WS # Source Ipm
Ipm Ipm Ipm p Abs (nm) e (/.mu.m) (%) 1 TiCl.sub.4 0.2 1.65 0.8 80
1.1 186 0.6 5.9 0 2 isopr 0.4 1.65 2.0 80 0.74 300 19 2.5 20 3
isopr 0.3 2.0 6.0 70 0.30 80 0.5 3.76 NA 4 isopr 0.3 2 2.5 80 0.89
558 1.5 1.6 5 5 ethoxi 0.3 2 2.5 90 0.75 500 2.2 1.5 NA de 6 isopr
* * * * * 0.78 506 11 1.5 delam 7 TiCl.sub.4 0.6 5 2.4 90 1.65 319
0.8 5.2 0
[0044] The samples 1 through 7 were prepared at a chamber pressure
of 45 mT, with a deposition time of .about.7 seconds for samples
other than sample 6. Sample 6 was a comparative PECVD run using
N.sub.2O at 100 sccm, TiPT at 5 sccm, for 14 minutes at 100 mT
pressure and 200 W power. The PECVD film delaminated under a water
soak treatment.
[0045] Table 1 lists the flow rates for the source gases
TiCl.sub.4, titanium isopropoxide and titanium ethoxide, and the
flow rates of Argon (Ar), oxygen (Ox), water (H.sub.2O). Table 1
also lists the current (Amp), absorbency (Abs), thickness (nm),
haze, and absorbency per unit thickness (A/t).
[0046] For the water soak treatment, the samples were immersed for
3 days at 65.degree. C. in distilled water and examined for extent
of delaminated areas and change in absorbency. The column labeled
Change A WS (%) shows the percent change in absorbency at 330 nm
after the water soak treatment. As can be seen in Table 1, only the
films formed using the source gase TiCl.sub.4 did not change
absorbency under the water soak treatment.
[0047] The samples formed using isopropoxide were relatively hazy
and of lower absorbency as compared to those formed using
TiCl.sub.4, unless the oxygen flow rate (for isopropoxide formed
films) was substantially increased relative to the water flow rate
(for TiCl.sub.4 formed films). The absorbency and thickness was
also better for the TiC.sub.4 formed films for the lower water flow
rate. The properties for the TiCl.sub.4 formed films was also
improved relative to the ethoxide formed films as can be seen in
Table 1.
[0048] Table 2 shows a number of samples of titanium oxide films
formed using TiCl.sub.4 where the titanium oxide film is part of a
multilayer film package, and where the multilayer package was
subjected to a water soak treatment.
2TABLE 2 Ar H.sub.2O Delaminate Change A # Temp Ipm Ipm Amp % area
WS (%) 8 75 1.6 1.8 80 30 60 5 9 100 1.6 1.8 80 35 40 5 10 120 1.6
1.8 80 35 5 5 11 130 1.6 1.8 80 30 0 5 12 120 2 1.8 80 10 2 13 120
3 1.8 80 5 0 14 120 3 0.8 80 0 0 15 PECV 50% D
[0049] In Table 2 all samples were prepared as follows with the
exceptions noted in the table. The polycarbonate substrate was
cleaned in IPA, rinsed, and dried at 80.degree. C. overnight. All
deposition and etching was done at a pressure of 45mT with an ETP
under the following conditions. The sample was preheated to varying
temperatures to achieve the deposition temperature (Temp) given in
table 2. An interlayer was deposited at deposition parameters 20A,
1.65 Ipm Ar, 0.03 Ipm V-D4, This interlayer layer was etched ar
40A, 1.65 Ipm Ar, 0.3 Ipm oxygen. Titanium oxide was deposited at
80A, 0.2 Ipm TiCl.sub.4, with varying Ar and water. This titanium
oxide layer was etched at 40A, 1.65 Ipm Ar, 0.3 Ipm oxygen. Then an
abrasion layer comprising 5 abrasion layers were deposited at 70A,
1.65 Ipm Ar, 0.19 Ipm D4, with oxygen at 0.2, 0.4, 0.6, and 0.8 Ipm
in layers 1-5 respectively. The samples were immersed for 3 days at
65.degree. C. in distilled water and examined for extent of
delaminated areas and change in absorbency. Some of the samples
exhibited multiple circular defects upon the water soak treatment
which could be seen in scanning electron micrograph (SEM) analysis.
As can be seen from table 2, the samples that were prepared at
higher Ar flow rate showed the least delamination.
[0050] Further, the titanium oxide layer density of the films
formed using TiCl.sub.4 and water can be sufficiently high and
porosity can be sufficiently low to significantly reduce the oxygen
and moisture permeation rates through coated polycarbonate film
substrate to less than 10 cc/m.sup.2/day at 100% O.sub.2 at room
temperature.
[0051] As can be seen from table 1 and 2, the titanium oxide films
themselves (table 1 ) and the multilayer package incorporating the
titanium oxide films both showed good delamination properties and
little change in absorbency for the water soak treatment in the
case that TiCl.sub.4 and water were used as reactant gases.
[0052] While the invention has been described in detail and with
reference to specific embodiments thereof, it will be apparent to
one skilled in the art that various changes and modifications can
be made therein without departing from the spirit and scope of the
invention. Thus, the breadth and scope of the present invention
should not be limited by any of the above-described exemplary
embodiments, but should be defined only in accordance with the
following claims and their equivalents.
* * * * *