`Samsung Electronic's Exhibit 1051
`Exhibit 1051, Page 1
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`
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`Gabon
`
`United Kingdom
`Georgia
`Guinea
`Greece
`Hungary
`Ireland
`Italy
`Japan
`Kenya
`Kyrgystan
`Democratic People’s Republic
`of Korea
`Republic of Korea
`Kazakhstan
`Liechtenstein
`Sri Lanka
`Luxembourg
`Latvia
`Monaco
`Republic of Moldova
`Madagascar
`Mali
`Mongolia
`
`AT
`AU
`BB
`BE
`BF
`BG
`31
`BR
`BY
`CA
`CF
`CG
`CH
`Cl
`CM
`CN
`CS
`CZ
`DE
`DK
`ES
`Fl
`FR
`GA
`
`Austria
`Australia
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`COte d’Ivoire
`Cameroon
`China
`Czechoalovakia
`Czech Republic
`Germany
`Denmark
`Spain
`Finland
`France
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`FOR THE PURPOSES OF INFORMATION ONLY
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`Codes used to identify States party to the PCI‘ on the front pages of pamphlets publishing international
`applications under the PCI‘.
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`Mauritania
`Malawi
`Niger
`Netherlands
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Federation
`Sudan
`Sweden
`Slovenia
`Slovakia
`Senegal
`Chad
`Togo
`Tajikistan
`Trinidad and Tobago
`Ukraine
`United States of America
`Uzbekistan
`Viet Nam
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`Ex. 1051, Page 2
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`Ex. 1051, Page 2
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`WO 96/06203
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`PCTIUS95]1059']
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`ELECTROCHROMIC MATERIALS AND DEVICES, AND METHOD
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`1. BACKGROUND OF THE INVENTION
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`A. Mauritian
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`The present invention relates to electrochromic and electrochromically active
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`materials and devices and to methods and processes for making such materials and
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`devices.
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`B. Description of the Related Technology
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`Electrochromic or electrochromically active (EC) materials change their refractive
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`index (real and imaginary) as the result of a voltage potential-induced injection (or
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`rejection) of ions induced by the application of an electric potential. Charge neutrality
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`is maintained by a balanced and oppositely directed flow of electrons from the potential
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`source. The change in refractive index results in a_ change in the transmission and/or the
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`reflection characteristics of the film, often resulting in a visible change of color. So-
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`called anodic and cathodic electrochromic materials/devices color when a positive or
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`negative voltage of appropriate magnitude and duration is applied.
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`Because ion transfer is required to induce the change in the index of refraction.
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`reversible electrochromic devices contain both a source of ions and a sink. Typically.
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`this necessitates a multiple-material. multi-layer structure comprising electrochromic and
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`ion conductive materials. See for example, Large Area gzhromggenics: Materials and
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`Devices for [ransmittance Control, Ed. C.M. Lampert and CG. Granqvist. SPIE 1990.
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`The typical device structure used and the associated electrochemical processes are
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`equivalent to those of a rechargeable battery for which the degree of color is an indication
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`of the state of charge. Consequently, many of the electrochromic materials, fabrication
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`methods and analysis techniques are similar or identical to those used for the manufacture
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`of batteries.
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`FIGS. 1A and IB (collectively, FIG. 1) schematically depict key components of
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`two common types of reversible EC devices. Please note, these figures are not to scale.
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`Layer thicknesses are chosen in part for ease of illustration and to help in distinguishing
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`adjacent layers. Furthermore, except as noted, the cross-hatching is selected primarily
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`merely to visually distinguish adjacent layers.
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`Referring initially to FIG. 1A. there is shown a typical laminated device 1 which
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`incorporates polymer ion conducting material. The laminated device 1 comprises
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`supportive substrates 2 and 8, of material such as glass. at the opposite ends or sides
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`Ex. 1051, Page 3
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`Ex. 1051, Page 3
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`thereof. Conductor layers 3 and 7 on the interior sides of the substrates apply voltage
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`from source 9 across the EC structure which is positioned therebetween. The EC
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`structure comprises an EC layer 6 next to the conductor layer 7, a so-called ion storage
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`layer 4 next to the conductor layer 3 and polymer ion conducting layer 5 sandwiched
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`between the EC and ion storage layers. Suitable ion conductor polymer materials include
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`proton conducting polymer such as polyAMPS (2-acrylamido-2-mcthylpropanesulfonic
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`acid) , and Li+ conducting polymer such as PMMA (poly methyl methacrylate) doped
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`with LiClO...
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`The EC layer 6 is the primary electrochromic layer in that most of the color
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`change occurs within this layer. The ion conducting layer 5 which separates the EC layer
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`and the ion storage layer functions both as an ion conducting layer and an electronic
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`insulator. Ion storage layer 4 fimctions as a sink and as a source of ions for the primary
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`EC layer 6. In fact, the ion storage layer 4 often is an EC material whose color change
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`augments that of the primary EC layer 6. This can be achieved using an EC layer 6 that
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`colors as the result of the injection of ions and an ion storage layer 4 of different EC
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`material that colors upon the loss of the transported ions.
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`FIG. 13 schematically illustrates a so-called solid state stack EC device 10. (This
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`device is of the greater interest here. because the components can be formed using the
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`techniques developed for forming optical thin film coatings.) The thin film device 10
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`comprises a substrate 12 of material such as glass; first conductor layer 13 on the
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`substrate; ion storage layer 14 formed next to the conductor 13'. electrochromic layer 16;
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`ion conducting layer 15 between the electrochromic layer and the ion storage layer:
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`second conductor 17; and a substrate 18 formed on the opposite end/side of the device
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`from the substrate 12. As indicated in the figure. one or both the substrates may be used.
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`Voltage source 19 is connected to the conductors l3 and 17 for supplying the required
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`voltage across the EC structure. The arrows (see also FIG. 1A) indicate a typical
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`potential-induced flow of electrons (e') and ions (M‘) during coloring. Examples of
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`suitable ion conductor thin film materials include TazOs, Mng, LiNbO3, etc.
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`In so-called window (optically transmissive) versions of the devices I and 10,
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`both conductors l3 and 17, FIG. 18 (also 3 and 7. FIG. 1A) . are transparent layers of
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`material such as tin oxide SnOz, indium tin oxide (In203:Sn or ITO), fluorine-doped tin
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`oxide (Sn022F) , aluminum-doped zinc-oxide (ZnO:Al), etc.
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`In mirror (reflective)
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`devices. one of the transparent conductors 13 or 17 (3 or 7) typically is replaced with a
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`reflective conductor layer, for example. a metal such as aluminum. In both window and
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`mirror devices, the other constituent layers preferably are transparent. Examples of
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`Ex. 1051, Page 4
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`suitable materials for the electrochromic (electrochromic and ion storage) layers 14 and
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`16 (4 and 6) include W03, M003, NbZOS, V205, Cr203, TiOz, IrOz, NiO, Rh203, etc.
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`One suitable construction for device 10 uses a glass substrate; an ITO
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`conductors); a nickel oxide (N10) ion storage layer; a tantalum pentoxide (Ta205) ion
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`conducting layer; and a tungsten oxide (W03 ) electrochromic layer.
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`Several processes are reported to have been used to manufacture electrochromic
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`materials, including the electrochromic components of the exemplary EC devices 1
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`and/or 10. These processes include sol-gel deposition, electrodeposition, and vacuum
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`deposition techniques such as plasma-enhanced chemical vapor deposition (PECVD),
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`electron beam evaporation, reactive ion plating, and reactive sputtering.
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`US. Patent No. 5,277,986 describes sol gel deposition of the tungsten oxide.
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`Reported advantages include low cost of operation, at least in part because the process
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`can be effected at ambient atmospheric pressures, thus eliminating the time and expensive
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`apparatus required for vacuum processing. However, sol gel deposition requires the use
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`of high temperatures to evaporate and decompose the solvent and organic materials.
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`respectively. As a result, this approach is unsuitable for temperature-sensitive materials
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`such as many plastics and for coating electrochromic layers/devices on plastics.
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`US. Patent No. 4,282,272 describes the use of reactive evaporation for forming
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`on a heated substrate a film of electrochromically active. amorphous W03 or of WO3
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`containing TiOg, Ta305. NbZOS, . V305. or B203. Reactive evaporation has the advantage
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`of high deposition rates, here about 5A/sec., but requires heating the substrate to elevated
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`temperatures ranging from about 250°C to 350°C , which prevents coating electrochromic
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`layers/devices on plastics.
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`Plasma-enhanced chemical vapor deposition of electrochromic transition metal
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`oxide materials is described in US. Patent No. 4,687,560. PECVD has the advantage of
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`being a very high deposition rate process. The '560 patent reports a deposition rate of
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`about 4.75A/sec. for tungsten trioxide, W03 using this technique. The '560 patent
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`suggests the PECVD process may be used to coat electrochromic materials on
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`temperature sensitive substrates such as plastics, because of the inherently low substrate
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`heating associated with the process. However, this capability is unlikely. Despite the
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`lack of need of "intentional" heating to deposit electrochromic materials, exothermic
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`reactions often occur in the deposition chamber during PECVD processing. causing
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`substrate heating. Perhaps the primary disadvantage of PECVD is the use of poisonous
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`and corrosive gases such as WFé, MOFO, and W(CO)6 whose gaseous byproducts are
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`hazardous and corrosive, and which thus present problems of equipment design and
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`maintenance and are subject to stringent safety regulations.
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`Ex. 1051, Page 5
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`Both RF and DC magnetron reactive sputtering from a metal target have been
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`used to form electrochromic films. However, to ensure proper film stoichiometry (for
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`example, a composition close to W03), high oxygen partial pressures are required, which
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`cause oxidation and poisoning of the target, thereby slowing film formation. Also, the
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`5
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`reported deposition rates of less than one Angstrom per second are too low for
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`commercially viability. See for example, H. Akram, M. Kitao, and S. Yamada in J. Appl.
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`Phys. 66(9), 1989 p. 4364.
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`.
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`US. Patent No. 4,451,498 describes the use of RF-excited reactive ion plating for
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`forming anodically coloring materials (materials which ”color" when a positive voltage
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`10
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`is applied) in oxygen and water vapor atmospheres. Examples of such materials are
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`iridium hydroxide and nickel hydroxide. The technique has not been shown to be viable
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`at producing the remaining layers of an electrochromic device such as the cathodically
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`coloring material, the conductive layers, etc.
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`US. Patent No. 5,189,550 reports the low temperature formation of crystalline
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`electrochromic W03 thin films on glass and plastic substrates by RF ion-assisted
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`evaporation. W03 powder is evaporated onto an unheated substrate that is being
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`bombarded with a stream of 200-300 eV oxygen ions. Crystalline W03 is known in the
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`art to show a large infrared reflection upon coloring and therefore is suitable for energy
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`efficient electrochromic device applications.
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`20
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`As should be evident from the above discussion. electrochromic and ion
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`conductive materials are not easily formed using the standard deposition processes.
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`In
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`part. this is the result of the fact that the structures of electrochromic and ion conductive
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`materials simply are not well suited to the standard deposition techniques.
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`2. SUMMARY OF THE INVENTION
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`In one aspect, the present invention is embodied in a process suitable for forming
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`electrochromic materials on one or more substrates, comprising traversing a substrate
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`through physically separated deposition and reaction zones; at the sputter deposition
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`zone, sputtering depositing at least one layer of material on the traversing substrate; at
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`the physically separate reaction zone, reacting the deposited material on the traversing
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`substrate, thereby converting the material to a thin coating of an electrochromic material
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`or a material useful in an electrochromic device; and repeating the depositing and
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`reacting steps to build up the thickness of the coating.
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`The process is well suited to the formation of composites or devices which
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`include temperature sensitive components such as plastic substrates.
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`Ex. 1051, Page 6
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`PCI‘IU595/10597
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`In another aspect, the present invention is embodied in a process for forming an
`electrochromic structure in situ in a vacuum processing chamber. The process comprises:
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`providing a plurality of deposition zones associated with a plurality of sputtering
`cathodes and at least one physically separate reaction zone associated with an ion source
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`device; selectively operating the sputtering cathodes for depositing selected materials;
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`selectively operating the ion source device for generating a reactive gas plasma for
`chemically reacting with selected ones of the deposited materials; and continuously
`traversing a substrate through the deposition zones and the at least one reaction zone for
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`forming a first of an ion storage layer and an EC layer, forming an ion conductor layer,
`and forming the second of the ion storage layer and the electrochromic layer. In another
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`aspect, a first conductor layer is formed in situ on the outside of said first layer; and a
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`second conductor layer is formed in situ on the outside of said second layer.
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`In an optically transmissive (window) embodiment, the conductor layer(s). are
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`indium tin oxide. said first and second layers are selected from nickel oxide and tungsten
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`oxide, and the ion conducting layer is tantalum oxide.
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`In a reflective (mirror)
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`embodiment, one of the conductor layers is reflective material such as the metal
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`aluminum.
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`Presently preferred process parameters using the throw distances described herein
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`and sputtering and reaction gases such as argon and oxygen. are: system pressure of 20-
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`20
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`80 mtorr (millitorr); and reactive gas partial pressure of 7—40 mtorr.
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`In other aspects, the present invention is embodied in a composite which is a solid
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`state stack electrochromic device, in a composite which is a stack of components suitable
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`for a solid state stack electrochromic device. and in a composite which is a stack of
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`components suitable for use in a laminated electrochromic device.
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`In one specific
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`embodiment. the composite comprises an ion storage layer and a conductor layer formed
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`on a substrate in situ. Another specific composite comprises an electrochromic layer and
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`a conductor formed on a substrate in situ. Another specific composite comprises a layer
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`of ion storage material. an ion conducting layer and an electrochromic layer formed in
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`situ. Still another specific composite comprises a layer of ion storage material. an ion
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`conducting layer and an electrochromic layer formed in situ. along with at least one
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`conducting layer.
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`3. BRIEF DESCRIPTION OF THE DRAWING
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`The above and other aspects of the invention are described with respect to the
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`accompanying drawing. in which:
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`Ex. 1051, Page 7
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`Ex. 1051, Page 7
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`PCT/US9SI10597
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`FIGS. 1A and 1B are simplified cross-sectional schematics of representative
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`electrochromic devices constructed respectively using polymer ion conducting material
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`and thin film ion conducting material.
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`' FIG. 2 depicts a magnetron-enhanced sputter system for forming electrochromic
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`materials and devices.
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`FIG. 3 depicts the optical characteristics (colored or clear) of as-deposited WO3
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`as a function of total pressure and oxygen partial pressure.
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`FIG. 4 depicts the change of optical density (OD) of as-deposited WO3 films at
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`633 nm (nanometers) as a function of total pressure.
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`FIG. 5 depicts the distribution of deposition rates for as-deposited W03 films
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`having different changes in optical densities. all measured at 633 nm.
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`FIG. 6 is a graph of the coloring and bleaching % transmission response at 633
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`nm for W0 films formed using either low pressure (8 mtorr, Table B l) or high pressure
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`(45 mtorr, Table B2). The response is determined from the injection of protons in a 0. lN
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`HCl solution and at the appropriate coloring and bleaching voltages of -0.5V and +1 .OV
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`respectively. Transmission measurements were taken while samples were still in acid.
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`The underlying ITO has a sheet resistance of 5 ohms per square. The area tested is <1
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`cm“.
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`FIG. 7 depicts the optical switching response ato550 nm of 3800 A thick W03
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`films prepared according to Example I. The area tested was 4 cm3; ITO sheet resistance
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`was 5 ohms per square. Protonation took place in O.lN HCl solution.
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`FIG. 8 depicts the % transmission of the films of FIG. 7 in air, for both colored
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`and the bleached states.
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`FIG. 9 illustrates the optical switching response at 550 nm of 3500 A thick MO
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`films prepared according to Example 2. The area tested was 4 cm2; the ITO sheet
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`resistance was 15 ohms per square. Testing took place in 1.0M KOH solution.
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`FIG. 10 depicts the % transmission of the sample of FIG. 9 in air, for both
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`colored and bleached states.
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`FIG. I 1 depicts the optical switching response at 550 nm of 4400 A Nb305 film
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`prepared according to Example 4. The area tested was 4 cm2; ITO sheet resistance was
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`5 ohms per square. Protonation/hydration took place in a 0.1N HCl solution.
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`FIGS. 12 and 13 are, respectively, a simplified schematic perspective view,
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`partially cut away, and a simplified schematic horizontal cross-sectional view of one type
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`of DC linear magnetron sputtering device used in the system and process of the present
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`invention.
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`FIGS. 14 and 15 are, respectively, an exploded perspective view and an end view,
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`partly in schematic, of one embodiment of a linear magnetron ion source device used in
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`the sputtering system and process of the present invention.
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`4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
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`A-W
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`The MetaMode® sputtering system and associated processes, which are described
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`in detail in commonly assigned US. Patent Nos. 4,851,095 and 5,225,057, have been
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`used to effect the controlled deposition and formation of refractory metal compounds
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`such as oxides, nitrides, carbides, etc. The '095 patent and the '057 patent are
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`incorporated by reference.
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`This section, Section A, discusses a specific example of a sputtering system,
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`constructed and operating in accordance with the present
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`invention, for formng
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`electrochromically active materials and devices. The next section, Section B, discusses
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`the typical process parameters used for forming optical thin films in the MetaMode®
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`sputtering system described in the incorporated '095 and '057 patents, and the
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`improvements and discoveries according to the present invention which specially adapt
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`the MetaMode® sputtering system for forming exemplary electrochromically active
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`materials, specifically W03, in situ. Section B includes process examples. Section C
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`describes additional examples of processes for forming electrochromically active
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`materials as well as electrochromically active devices. Sections D and E describe various
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`additional embodiments of the present
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`invention. Section F summarizes certain
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`advantages of the present invention. Sections G and H disclose details of sputter
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`deposition cathodes or devices and ion source devices which are described in the
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`incorporated US. Patent 4,851,095 and which are suitable for use in the present system
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`and process.
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`FIG. 2 is a schematic horizontal cross-sectional view of one suitable embodiment
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`30 of a magnetron-enhanced reactive sputtering system, which is derived from the
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`30
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`MetaMode® sputtering system and is used to form electrochromic coatings in accordance
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`with the present invention. FIG. 2 describes a sputtering system having a rotating drum
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`34. However, other system geometries can be used to practice the present invention,
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`including the in-line system, the disc system and possibly the planetary system described
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`in the incorporated '095 and '057 patents. Certainly the electrochromic fabrication
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`35
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`process can be practiced utilizing the planetary system geometry: the issue is whether
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`there is a need to form electrochromic devices on the non-planar substrate geometries
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`Ex. 1051, Page 9
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`such as convex and concave curves and tubes for which this systems are especially well
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`suited.
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`Referring further to FIG. 2, the vacuum system 30 comprises an octahedral
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`housing 32 having eight walls which define a vacuum chamber in which the drum 34 is
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`mounted for rotation, as shown by the arrow, by conventional drive means. For
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`convenient reference, we have designated the walls as #1-#8. Mounted in the walls of
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`the octahedral housing 32 are as many as five planar magnetron-enhanced sputter
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`deposition devices 38—46 or "cathodes" of the type described in detail in the incorporated
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`‘095 and '057 patents. Preferably, each such cathode comprises a housing equipped with
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`baffles 43 and with a magnet assembly 45, target 47, and a gas manifold 49 which
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`ensures a uniform distribution of the sputtering gas at the target surface and hence a
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`uniform coating. Each cathode also comprises a DC power supply capable of delivering
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`1-10 kW (kilowatts) power.
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`In the illustrated octahedral chamber arrangement, the sputter cathodes are
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`mounted at positions 1-4 and 6, and a reactive ion source 48 of the type described in
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`detail in the incorporated '095 and '057 patents is mounted in the housing at wall position
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`#7. A pair of vacuum source means, preferably turbomolecular vacuum pumps 50 and
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`52, backed by mechanical pumps (not shown), are connected into the vacuum chamber,
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`respectively, at position #5 (between the sputter cathodes at positions #4 and the ion
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`source device) and at position #8 (between the reaction ion source and the sputter cathode
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`at position #1). The vacuum source means maintain the desired vacuum level in the
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`chamber. Throttle valves facilitate control of the vacuum pumping process.
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`Please note, the sputtering cathode 46 is mounted at position #6, adjacent to the
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`ion source. This positioning facilitates sputtering using metal targets to produce metal
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`films, or using ceramic targets where no reaction zone is needed. An example of the
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`latter use is the formation of electrically conductive indium tin oxide using an indium tin
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`oxide target. which does not require ion source operation.
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`The region of the vacuum chamber of FIG. 2 adjacent the reaction ion source 48
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`is a reaction zone and will be referred to here as the ion source or the ion source zone or
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`the reaction zone. The chamber regions adjacent the sputter cathode in walls 1-4 and 6
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`are sputter deposition zones. With the exception of deposition zone #6, the deposition
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`zones are separated from the reaction zone by the intervening exhaust connections to the
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`vacuum pumps 50 and 52, which isolate adjacent regions from one another.
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`The rotating drum 34 mounts the substrates 36 and is rotated by motor means (not
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`shown) at 20-100 rpm in front of the sputtering target(s) and the ion source, that is,
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`- sequentially through the deposition and reaction zones. Reactive gas is injected in the
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`~ vicinity of two long positively biased anode bars mounted in the racetrack region of the
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`magnet assembly 45 to form a uniform plasma comprising electrons and ions in the
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`reactive gas. Positively charged ions from the plasma are accelerated away from the bars
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`and toward the drum 34 and the substrates 36 thereon and react with the metal layer
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`5
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`previously on the substrates. DC power within the approximate range 50-200 volts (V)
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`potential, 1-5 amperes (A) current is supplied by the power supply between the bar
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`anodes and system ground.
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`_
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`During the sequential passage of the substrates through deposition and reaction
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`zones, a few monolayer of metal are deposited onto the substrate, then the reactive
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`species in the ion source plasma chemically react with the freshly deposited metal.
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`Preferably, the thickness of the deposited material is completely reacted, for example, a
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`deposited layer of silicon or titanium is completely converted to silicon oxide or titanium
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`oxide. However, the process parameters can be adjusted to effect partial reaction of the
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`layer.
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`A major advantage of the present system and process reside in the separation of
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`the deposition zone formed in front of the sputtering target from the reaction zone by use
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`of differentially pumped regions. The plasma formed in the sputtering zone(s) in front
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`of the target(s) is non—reactive and allows sputtering from a metal target with high.
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`”metal-like“ deposition rates. An intense plasma containing energetic reactive species
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`is formed in the reaction zone using a relatively high reactive gas pressure. Film deposi-
`
`tion and reaction take place by continuously and repetitively traversing (rotating or
`
`translating) the substrate sequentially through the deposition and reaction zones until the
`
`desired film thickness is obtained. This repetitive metal deposition-metal reaction
`
`sequence is one of the main attributes of the MetaMode® sputtering system.
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`25
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`This method of deposition and reaction, although certainly not limited to the
`
`formation of oxides, is particularly advantageous in the formation of oxides. As is well
`
`known, the presence of oxide on the surface of a metal sputter target reduces the rate of
`
`metal sputtered from the target.
`
`In the system 30, minimal target oxidation occurs and
`
`therefore, high metal sputter rates are maintained. In addition, the substrate rotation and
`
`30
`
`the separation of the metal target from the reactive gas results in low deposition
`
`temperatures so that heat sensitive substrates such as plastics can be coated.
`
`In accordance with the present invention, a substrate-to-target distance of about
`
`3 in. (inches) is preferred.
`
`In a present embodiment, the two turbomolecular vacuum
`
`pumps each have 2200 liters/seconds pumping speed and, as mentioned, are backed by
`
`35
`
`a mechanical pump. With appropriate adjustment of pumping speeds, the system can
`
`produce electrochromic materials of excellent optical qualities. The working gas
`
`Ex. 1051, Page 11
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`Ex. 1051, Page 11
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`
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`W0 96/062033
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`PCTIUS95]10597
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`10
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`pressures vary over the range of about 20-80 mtorr, depending on the material to be
`
`deposited. Cathodic and anodic coloring materials have been successfully and
`
`reproducibly deposited. The deposition rates using this MetaMode® sputtering system-
`
`derived system are higher than with conventional reactive sputtering techniques.
`The system 30, FIG. 2, andthe process described herein can be used to form
`
`5
`
`individual layers, groups of layers and solid state stack devices such as the solid state
`
`stack device 10 in situ within the chamber without breaking vacuum, for example, by
`
`forming the constituent layers sequentially on the substrate. The solid state stack often
`
`comprises five layers (plus substrate(s)). As alluded to previously, for a transmissive EC
`
`10
`
`structure, the two conductor layers of the five layer stack (conductor/IS layer/1C layer/EC
`
`layer/conductor) can be the same transmissive material and therefore where the other
`
`three layers are different materials, four (sputter) targets of the different materials are
`
`used. If all layers are different materials. five (sputter) targets are needed. Furthermore,
`
`the system 30 and present process can be used to form individual layers and groups of
`
`15
`
`layers of laminated devices such as the device 1. For example, the ion storage layer and
`
`associated conductor can be formed in situ on the associated substrate, and/or the EC
`
`layer and associated conductor layer be formed in situ on their associated substrate,
`
`preparatory to forming the ion conducting layer using other techniques and assembling
`
`the device.
`
`20
`
`As alluded to above, up to five targets can be accommodated in the octagonal
`
`machine 30 shown in FIG. 2. A key aspect of the present invention is the ability to
`
`fabricate electrochromic layers of either of the above types using the modified
`
`MetaMode® sputtering technique. High switching speeds, high coloration efficiency.
`
`good adhesion, and high durability films can be obtained by the present system and
`
`25
`
`process.
`
`In addition,
`
`films show a long memory,
`
`i. e.,
`
`films remain in the
`
`electrochemically induced colored or bleached state for a long time, typically for 24
`
`hours with minimum loss in optical density.
`
`B. Evalu i
`
`f
`
`ract ri
`
`'c
`
`1'
`
`ss Param t rs forW
`
`30
`
`Typical process parameters used in the MetaMode® sputtering system to form
`
`optical thin films -- total pressure, P < 5 mtorr; oxygen partial pressure < 30%; and high
`
`ion (reaction) source current -- are not suitable for forming electrochromically active
`
`materials such as W03.
`
`It was difficult to obtain clear W03 films in the as-deposited
`
`state. Also, the W03 films colored and bleached poorly.
`
`35
`
`Unfortunately, the effects of total pressure. oxygen partial pressure, argon partial
`
`pressure, ion source current and other process parameters, such as power to the sputter
`
`Ex. 1051, Page 12
`
`Ex. 1051, Page 12
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`
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`WO 96/06203
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`PCT[US95]10597
`
`ll
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`target cathode, are interdependent. Changing one parameter to improve particular
`
`process or device characteristics may degrade other characteristics. For example, the
`
`clarity of the as-deposited film is enhanced by lowering the sputtering power and
`
`increasing the oxygen flow. However, lowering the sputtering power decreases the
`
`5
`
`deposition rate. Increasing the oxygen flow tends to poison the sputter target and thereby
`
`decrease the deposition rate.
`
`It has been discovered that the use of high total pressure, typically > 20 mtorr
`
`(typically measured in a deposition zone) , enables the use of relatively low ion gun
`
`source current and the combination of high oxygen flows and low oxygen partial
`
`10
`
`pressures, thereby obtaining (1) clear as-deposited films; (2) high deposition rates.
`
`because the target remains unpoisoned and operates in or near metal mode conditions;
`
`and (3) improved optical density.
`
`FIG. 3 summarizes the two critical parameters. total power and oxygen partial
`
`pressure, which affect the W03 formation process. The open squares represent W03
`
`15
`
`films that were "clear" as-deposited. The dark squares represent WO3 films that were
`
`colored blue as—deposited. The as-deposited coloring was the result of these films being
`
`substoichiometric tungsten oxide due to oxygen deficiency, not hydrated or protonated
`
`tungsten oxide due to residual water vapor in the coating system. These films showed
`
`poor to no optical modulation when proton injection/extraction was attempted.
`
`20
`
`FIG. 4 summarizes optical density values for all films. A normalized change in
`
`optical density calculation was used in which the optical density. OD, was divided by
`
`film thickness, d, to account for thickness: OD/d = (logI0 Tbkachcdffwmdyd. The data
`
`depicted in the figure illustrate that films deposited at total pressures of less than 10 mtorr
`
`have low values of OD/d, while those deposited at higher pressures. over the approximate
`
`25
`
`range 20 mtorr - 75 mtorr, have much higher normalized optical densities, on the order
`
`of 4.2-6.2.
`
`It is theorized that the pressure affects the structure of the films: the W atoms
`
`may be therrnalized at the high pressures (>20 mtorr total pressure), forming a more
`
`open,
`
`less dense structure than is attained at the lower pressures (<20 mtorr total
`
`pressure).
`
`30
`
`FIG. 5 summarizes the distribution of deposition rates for films of different
`
`optical densities, deposited at different (high and low) pressures, using typical process
`
`parameters which are shown below, in Tables B1 and B2. As indicated in this figure,
`
`high deposition rates still obtain at high pressures. The high total or system pressures
`
`allow the use of high oxygen flow rates in combination with relatively overall low
`
`35
`
`oxygen partial pressures. The high oxygen flows provide sufficient oxygen to completely
`
`react the deposited film, while the low oxygen partial pressures (high argon partial
`
`Ex. 1051, Page 13
`
`Ex. 1051, Page 13
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`
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`WO 96/06203
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`PCTIU595/10597
`
`12
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`pressures) allow the sputter target to operate unpoisoned, at or near the metal mode
`
`condition.
`
`The electrochromic properties listed in Tables BI and