Oxide buffer layer to promote TIO2 crystallinity and increase TIO2 refractive index for optical applications

Abstract

The disclosed and claimed methods provide a method for producing high refractive index rutile TiO2 at moderate process temperatures.

Description

background Technical Field

[0002] The disclosed and claimed subject matter relates to methods of producing high refractive index rutile TiO2 at moderate process temperatures. Background Art

[0003] TiO2 is widely used as a high refractive index material in a variety of optical coating applications, including anti-reflective coatings, LED components, display components, Bragg reflectors, lenses, etc. Among binary transition metal oxides, TiO2 exhibits one of the highest refractive indices while maintaining negligible optical absorption in the visible range. It is also an extremely stable oxide, which makes it attractive from an integration perspective. It is worth noting that a higher TiO2 refractive index will improve BDR (distributed Bragg reflector) or ODR (omnidirectional reflector) performance, which provides important value to optical coatings.

[0004] Unfortunately, deposition by known methods (such as sputtering or evaporation processes) produces TiO2 layers with a refractive index of only about 2.4-2.6 at 460nm. For example, TiO2 deposited at room temperature exhibits an amorphous structure with a relatively low refractive index (2.4 at 460nm). The anatase phase is formed at low process temperatures, but it also has a relatively low refractive index comparable to the amorphous phase. The rutile phase is the most attractive one for optical coating applications because it exhibits a very high refractive index (2.7-3 at 460nm), however it requires high temperature processing (600°C) to form. For applications using glass or plastic substrates, this requirement makes the application of rutile TiO2 very difficult and impractical from an integration perspective.

[0005] Preferably, the high refractive index TiO2 is deposited by conventional deposition processes, including physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), flowable CVD (FCVD), atomic layer deposition (ALD), and spin coating processes.

[0006] Films containing transition metals are used in semiconductor and electronic applications. CVD and ALD have been applied as the main deposition techniques for thin films used to produce semiconductor devices. These methods enable conformal films (metals, metal oxides, metal nitrides, metal silicides, etc.) to be achieved by chemical reactions of metal-containing compounds (precursors). The chemical reactions occur on surfaces that may include metals, metal oxides, metal nitrides, metal silicides, and other surfaces. In CVD and ALD, precursor molecules play a key role in achieving high-quality films with high conformality and low impurities. The substrate temperature in CVD and ALD processes is an important consideration for selecting precursor molecules. Higher substrate temperatures in the range of 150 to 500 degrees Celsius (°C) promote higher film growth rates. Preferred precursor molecules must be stable within this temperature range. Preferred precursors can be delivered to the reaction vessel in liquid phase. Liquid phase delivery of precursors generally provides more uniform delivery of precursors to the reaction vessel than solid phase precursors.

[0007] Unfortunately, CVD and ALD cannot deposit high refractive index materials at lower temperatures. For example, if CVD or ALD is performed at 600°C, a TiO2 rutile phase may be seen. Therefore, it is desirable to develop a method by which the rutile phase can be achieved at lower temperatures, thereby enabling deposition on sensitive substrates.

[0008] The disclosed and claimed PVD process solves the above-mentioned difficulties associated with CVD and ALD. PVD is a physical method for depositing films. The PVD system includes a vacuum chamber capable of maintaining a vacuum during deposition and allowing controlled insertion of different gases at typical pressures of 1 mTorr to 10 mTorr. One or more solid targets are inserted into the chamber to serve as a source of deposited material. In the case of magnetron sputtering deposition, an array of magnets is located behind the target surface to help maintain a plasma near it. The disclosed and claimed subject matter relates to a method for forming a high refractive index layer (i.e., high refractive index rutile TiO2) using a PVD process at low temperatures. Summary of the invention

[0009] The disclosed and claimed method addresses and largely eliminates these problems by providing a method for producing high refractive index rutile TiO2 at moderate process temperatures.

[0010] In another embodiment, the disclosed and claimed subject matter includes producing high refractive index rutile TiO2 in a PVD deposition process. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are included to provide a further understanding of the disclosed subject matter and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosed subject matter and together with the description serve to explain the principles of the disclosed subject matter. In the drawings:

[0012] Figure 1 An XRD scan corresponding to the TiO2 deposition of Example 2 is illustrated. DETAILED DESCRIPTION

[0013] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference was individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0014] Unless otherwise specified herein or clearly contradictory to the context, in the context of describing the disclosed and claimed subject matter (especially in the context of the following claims), the use of the terms "one" and "an" and "the" and similar references should be interpreted as covering the singular and plural. Unless otherwise specified, the terms "comprising", "having", "including" and "containing" should be interpreted as open terms (i.e., meaning "including but not limited to"). Unless otherwise specified herein, the description of the numerical range herein is intended only to be used as a shorthand method for individually referring to each individual value falling within the range, and each individual value is incorporated into this specification as if it is individually described herein. Unless otherwise specified herein or clearly contradictory to the context, all methods described herein can be performed in any suitable order. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended only to better illustrate the disclosed and claimed subject matter, and does not limit the scope of the disclosed and claimed subject matter, unless otherwise required. Any language in the specification should not be interpreted as indicating that any unclaimed element is essential to the practice of the disclosed and claimed subject matter. The use of the terms "comprising" or "including" in the specification and claims includes the narrower expressions "consisting essentially of" and "consisting of.

[0015] Embodiments of the disclosed and claimed subject matter are described herein, including the best mode known to the inventor for implementing the disclosed and claimed subject matter. After reading the foregoing description, changes in those embodiments may become apparent to those of ordinary skill in the art. The inventor expects that those skilled in the art will appropriately adopt these changes, and the inventor intends to practice the disclosed and claimed subject matter in a manner different from that specifically described herein. Therefore, the disclosed and claimed subject matter includes all modifications and equivalents of the subject matter described in the attached claims as permitted by applicable law. In addition, unless otherwise specified herein or clearly contradictory to the context, the disclosed and claimed subject matter covers any combination of the above-mentioned elements in all possible variations thereof.

[0016] The headings used herein are not limiting; rather, they are included for organizational purposes only.

[0017] PVD Process

[0018] As described above, the disclosed and claimed subject matter relates to methods for producing high refractive index rutile TiO2 at moderate process temperatures. When deposited, TiO2 is generally amorphous, even at substrate temperatures as high as 250°C. Therefore, the refractive index of thin film TiO2 is always low.

[0019] In the disclosed and claimed method, an appropriate buffer layer is applied to promote the formation of TiO2 crystallinity in a subsequent deposition step. When employed, the method produces TiO2 with a less favorable rutile crystal structure when using a template transition metal oxide layer buffer layer having the same (or substantially the same) crystal structure and similar lattice constant / spacing as TiO2. In one embodiment, the template layer includes one or more of SnO2, GeO2, TaO2, and TeO2. In one embodiment, the template layer includes SnO2. In one embodiment, the template layer includes GeO2. In one embodiment, the template layer includes TaO2. In one embodiment, the template layer includes TeO2. For example, SnO2 is a good candidate because it has a lattice constant very close to that of rutile TiO2 and crystallizes at low temperatures.

[0020] (Table 1).

[0021]

[0022] Table 1: Crystal structure and lattice constants of TiO2 and SnO2

[0023] The disclosed and claimed PVD process uses a mixture of oxygen and one or more inert gases. Exemplary purge gases include, but are not limited to, argon (Ar), nitrogen (N2), helium (He), neon (Ne), and mixtures thereof. In one embodiment, the inert gas comprises argon (Ar). In one embodiment, the inert gas comprises nitrogen (N2). In one embodiment, the intermediate gas comprises helium (He). In one embodiment, the inert gas comprises neon (Ne).

[0024] The disclosed and claimed subject matter includes films deposited by the disclosed and claimed PVD processes. The films have a thickness of about to about Thickness.

[0025] Process parameters

[0026] In one embodiment, the disclosed and claimed PVD process comprises, consists essentially of, or consists of the following steps:

[0027] (1) depositing a template layer on the surface of the substrate using a first target by the following steps, wherein the template layer comprises one or more metal oxides selected from SnO2, GeO2, TaO2, and TeO2:

[0028] (a) bringing the substrate to a temperature of about 100° C. to about 400° C.;

[0029] (b) introducing a mixture of oxygen (O) and one or more inert gases;

[0030] (c) performing reactive sputtering by applying a voltage to the first target to generate plasma, wherein the template layer has a thickness of about to about thickness; and

[0031] (2) Depositing a high refractive index layer of rutile TiO2 on the template layer using a second target by the following steps:

[0032] (a) bringing the substrate to a temperature of about 100° C. to about 400° C.;

[0033] (b) introducing a mixture of oxygen (O) and one or more inert gases;

[0034] (c) Pulsed DC reactive sputtering is performed by applying voltage to the second target to generate plasma.

[0035] In one aspect of this embodiment, the disclosed and claimed PVD process comprises step 1 and step 2. In one aspect of this embodiment, the disclosed and claimed PVD process consists essentially of step 1 and step 2. In one aspect of this embodiment, the disclosed and claimed PVD process consists of step 1 and step 2.

[0036] In one aspect of this embodiment, the first target comprises one or more of a metal oxide material and a metal (i.e., an elemental metal as opposed to a metal oxide). In one aspect of this embodiment, the first target and the second target are the same. In one aspect of this embodiment, the first target and the second target are different.

[0037] In one aspect of this embodiment, the first target comprises a metal oxide material. In another aspect of this embodiment, the first target comprises a metal oxide material comprising SnO2. In another aspect of this embodiment, the first target comprises a metal oxide material comprising GeO2. In another aspect of this embodiment, the first target comprises a metal oxide material comprising TaO2. In another aspect of this embodiment, the first target comprises a metal oxide material comprising TeO2.

[0038] In one aspect of this embodiment, the first target comprises a metal. In another aspect of this embodiment, the first target comprises a metal selected from Sn, Ge, Ta, and Te. In another aspect of this embodiment, the first target comprises a metal including Sn. In another aspect of this embodiment, the first target comprises a metal including Ge. In another aspect of this embodiment, the first target comprises a metal including Ta. In another aspect of this embodiment, the first target comprises Te. In another aspect of this embodiment, the first target comprises a metal including two or more of Sn, Ge, Ta, and Te. When the first target comprises a metal, the reactive sputtering in step 1(c) utilizes a mixture richer in oxygen than the oxygen mixture used for the first target comprising a metal oxide material.

[0039] In one aspect of this embodiment, the second target comprises one or more of a metal oxide material and a metal (i.e., an elemental metal as opposed to a metal oxide). In one aspect of this embodiment, the second target comprises a metal oxide material. In another aspect of this embodiment, the second target comprises TiO2. In one aspect of this embodiment, the second target comprises a metal. In another aspect of this embodiment, the second target comprises a metal including Ti. When the second target comprises a metal, the reactive sputtering in step 2(c) utilizes a mixture that is richer in oxygen than the oxygen mixture used for the template layer comprising the metal oxide material.

[0040] The disclosed and claimed PVD process includes step 1 and step 2.

[0041] In another aspect of this embodiment, the template layer comprises SnO2. In another aspect of this embodiment, the template layer comprises GeO2. In another aspect of this embodiment, the template layer comprises TaO2. In another aspect of this embodiment, the template layer comprises TeO2. In another aspect of this embodiment, the template layer comprises two or more of SnO2, GeO2, TaO2, and TeO2.

[0042] In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 125°C to about 375°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 150°C to about 375°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 175°C to about 375°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 200°C to about 375°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 225°C to about 375°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 250°C to about 350°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 275°C to about 325°C.

[0043] In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 100°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 125°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 150°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 175°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 200°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 225°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 250°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 275°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 300°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 325°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 350°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 375°C. In another aspect of this embodiment, in one or both of step 1(a) and step 2(a), the substrate is brought to a temperature of about 400°C.

[0044] In one aspect of this embodiment, step 1(a) and step 2(a) are performed at the same temperature. In one aspect of this embodiment, step 1(a) and step 2(a) are performed at substantially the same temperature. In one aspect of this embodiment, step 1(a) and step 2(a) are performed at different temperatures.

[0045] In another aspect of this embodiment, in one or both of step 1(b) and step 2(b), the inert gas comprises argon (Ar). In another aspect of this embodiment, in one or both of step 1(b) and step 2(b), the inert gas comprises nitrogen (N2). In another aspect of this embodiment, in one or both of step 1(b) and step 2(b), the inert gas comprises helium (He). In another aspect of this embodiment, in one or both of step 1(b) and step 2(b), the inert gas comprises neon (Ne). In another aspect of this embodiment, the inert gas of step 1(b) is the same as the inert gas of step 2(b). In another aspect of this embodiment, the inert gas of step 1(b) is different from the inert gas of step 2(b).

[0046] In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 1 mTorr to about 10 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 1 mTorr to about 5 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 5 mTorr to about 10 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 3 mTorr to about 7 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 1 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 2 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 3 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 4 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 5 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 6 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 7 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 8 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 9 mTorr. In one embodiment, one or both of step 1(b) and step 2(b) are performed at a pressure of about 10 mTorr.

[0047] In one aspect of this embodiment, step 1(b) and step 2(b) are performed at the same pressure. In one aspect of this embodiment, step 1(b) and step 2(b) are performed at substantially the same pressure. In one aspect of this embodiment, step 1(b) and step 2(b) are performed at different pressures.

[0048] In another aspect of this embodiment, the thickness of the template layer is about to about In another aspect of this embodiment, the thickness of the template layer is about to about In another aspect of this embodiment, the thickness of the template layer is about to about In another aspect of this embodiment, the thickness of the template layer is about to about In another aspect of this embodiment, the thickness of the template layer is about to about In another aspect of this embodiment, the thickness of the template layer is about to about In another aspect of this embodiment, the thickness of the template layer is about to about In another aspect of this embodiment, the thickness of the template layer is about to about

[0049] In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about In another aspect of this embodiment, the thickness of the template layer is about

[0050] In another aspect of this embodiment, the voltage for reactive sputtering in step 1(c) is generated by DC. In another aspect of this embodiment, the voltage for reactive sputtering in step 1(c) is generated by RF.

[0051] In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.70 to about 3.0 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.75 to about 3.0 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.80 to about 3.0 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.85 to about 3.0 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.90 to about 3.0 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.95 to about 3.0 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.70 to about 2.80 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.70 to about 2.75 at 460 nm.

[0052] In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.70 or more at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.75 or more at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.80 or more at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.85 or more at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.90 or more at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.95 or more at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 3.0 or more at 460nm.

[0053] In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.70 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.75 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.80 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.85 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.90 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 2.95 at 460nm. In another aspect of this embodiment, the high refractive index layer of rutile TiO2 has a refractive index of about 3.0 at 460nm.

[0054] Suitable substrates that can be used with the disclosed and claimed methods are not particularly limited and vary depending on the intended end use. For example, the substrate can be selected from transition metal oxides, rare earth oxide-based materials, ternary oxide-based materials, etc. or from nitride-based films. Other substrates may include solid substrates, such as metal substrates (e.g., Au, Pd, Rh, Ru, W, Al, Ni, Ti, Co, Pt, and metal silicides (e.g., TiSi2, CoSi2, and NiSi2); substrates containing metal nitrides (e.g., TaN, TiN, WN, TaCN, TiCN, TaSiN, and TiSiN); semiconductor materials (e.g., Si, SiGe, GaAs, InP, diamond, GaN, and SiC); insulators (e.g., SiO2, Si3N4, SiON, HfO2, Ta2O5, ZrO2, TiO2, Al2O3, and barium strontium titanate); plastic and flexible substrates (e.g., polymers); and combinations thereof. Preferred substrates include glass and silicon oxide-based substrates. In one embodiment, the substrate includes glass. In another embodiment, the substrate includes a silicon oxide-based material.

[0055] Example

[0056] Reference will now be made to more specific embodiments of the present disclosure and to experimental results that provide support for these embodiments.The following examples more fully illustrate the disclosed and claimed subject matter and should not be construed as limiting the disclosed subject matter in any way.

[0057] It is obvious to those skilled in the art that various modifications and variations may be made to the disclosed subject matter and the specific embodiments provided herein without departing from the spirit or scope of the disclosed subject matter. Therefore, the disclosed subject matter (including the description provided by the following embodiments) is intended to cover modifications and variations of the disclosed subject matter that fall within the scope of any claims and their equivalents.

[0058] Materials and methods:

[0059] All experiments described in the embodiment are carried out in a PVD sputtering chamber with a base pressure of 1E-7 mTorr. The chamber is equipped with two or more targets to allow deposition of multiple layers without destroying the vacuum. A mixture of gases (O, Ar, etc.) can be introduced into the chamber during processing. The susceptor temperature can be adjusted between room temperature and 600°C. Finally, voltage can be applied to different targets in a continuous manner (DC), pulsed (PDC) or RF frequency. Specific embodiments

[0061] Example 1: As shown in Table 1, different refractive index values ​​are obtained for different stacks with and without SnO2 template layer and also deposited at different temperatures. It is worth noting that when deposited without SnO2 template layer, no crystalline peaks are detected for TiO2 using X-ray diffraction (XRD) due to lack of crystallinity for deposition temperatures up to 350°C. In contrast, the introduction of SnO2 template layer promotes the crystal growth of TiO2 starting at a deposition temperature of about 150°C, with deposition at 350°C having an increased refractive index of up to 2.81 at 460nm.

[0062]

[0063] Table 1

[0064] Example 2: As shown in Table 2, process parameters can be adjusted to increase and / or adjust the refractive index of the deposited TiO2 (layer 2). For example, this is for a layer of TiO2 at 350°C with a thickness of 30 to 100 μm. The process parameters and results obtained when depositing TiO2 on a SnO2 (1st layer) template layer (deposited at 350°C) are demonstrated. Both the 1st and 2nd layer processes were performed with 12 sccm Argon flow. The SnO2 thickness was 0.17 W, and the highest refractive index was obtained. Figure 1 XRD scans corresponding to the same samples are shown, showing the growth of rutile TiO2 in all cases.

[0065]

[0066] The foregoing description is primarily for illustrative purposes. Although the disclosed and claimed subject matter has been shown and described with respect to exemplary embodiments of the disclosed and claimed subject matter, it will be understood by those skilled in the art that the foregoing and various other changes, omissions, and additions may be made in form and detail without departing from the spirit and scope of the disclosed and claimed subject matter.

Claims

1. A PVD process comprising the following steps: (1) depositing a template layer on the surface of the substrate using a first target by the following steps, wherein the template layer comprises one or more metal oxides selected from SnO2, GeO2, TaO2, and TeO2: (a) bringing the substrate to a temperature of about 100° C. to about 400° C.; (b) introducing a mixture of oxygen (O) and one or more inert gases; (c) performing pulsed DC reactive sputtering by applying a voltage to the first target to generate plasma, The template layer has about to about thickness; and (2) depositing a high refractive index layer of rutile TiO2 on the template layer using a second target by the following steps: (a) bringing the substrate to a temperature of about 100° C. to about 400° C.; (b) introducing a mixture of oxygen (O) and one or more inert gases; (c) Pulsed DC reactive sputtering is performed by applying a voltage to the second target to generate plasma.

2. The PVD process of claim 1, wherein the template layer comprises a metal oxide selected from the group consisting of SnO2, GeO2, TaO2, TeO2 and combinations thereof.

3. The PVD process according to claim 1, wherein the template layer comprises two or more of SnO2, GeO2, TaO2 and TeO2.

4. The PVD process of claim 1, wherein the template layer comprises SnO2.

5. The PVD process of claim 1, wherein the template layer comprises GeO2.

6. The PVD process of claim 1, wherein the template layer comprises TaO2.

7. The PVD process of claim 1, wherein the template layer comprises TeO2.

8. The PVD process of claim 1, wherein the first target comprises one or more of a metal oxide material and a metal.

9. The PVD process of claim 1, wherein the first target and the second target are the same.

10. The PVD process of claim 1, wherein the first target and the second target are different.

11. The PVD process of claim 1 , wherein the first target comprises a metal oxide material.

12. The PVD process of claim 1, wherein the first target comprises a metal oxide material including SnO2.

13. The PVD process of claim 1, wherein the first target comprises a metal oxide material including GeO2.

14. The PVD process of claim 1, wherein the first target comprises a metal oxide material including TaO2.

15. The PVD process of claim 1, wherein the first target comprises a metal oxide material including TeO2.

16. The PVD process of claim 1, wherein the first target comprises a metal.

17. The PVD process of claim 1, wherein the first target comprises a metal selected from the group consisting of Sn, Ge, Ta, and Te.

18. The PVD process of claim 1, wherein the first target comprises a metal including Sn.

19. The PVD process of claim 1, wherein the first target comprises a metal including Ge.

20. The PVD process of claim 1 wherein the first target comprises a metal including Ta.

21. The PVD process of claim 1, wherein the first target comprises a metal including Te.

22. The PVD process of claim 1, wherein the first target comprises a metal including two or more of Sn, Ge, Ta, and Te.

23. The PVD process of claim 1, wherein the second target comprises one or more of a metal oxide material and a metal.

24. The PVD process of claim 1 wherein the second target comprises a metal oxide material.

25. The PVD process of claim 1, wherein the second target comprises a metal oxide material including TiO2.

26. The PVD process of claim 1 wherein the second target comprises a metal.

27. The PVD process of claim 1, wherein the second target comprises a metal including Ti.

28. The PVD process of claim 1, wherein in one or both of step 1(a) and step 2(a), the substrate reaches a temperature of about 125°C to about 375°C.

29. The PVD process of claim 1, wherein in one or both of step 1(a) and step 2(a), the substrate reaches a temperature of about 150°C to about 375°C.

30. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 175°C to about 375°C.

31. The PVD process of claim 1, wherein in one or both of step 1(a) and step 2(a), the substrate reaches a temperature of about 200°C to about 375°C.

32. The PVD process of claim 1, wherein in one or both of step 1(a) and step 2(a), the substrate reaches a temperature of about 225°C to about 375°C.

33. The PVD process of claim 1, wherein in one or both of step 1(a) and step 2(a), the substrate reaches a temperature of about 250°C to about 350°C.

34. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 275°C to about 325°C.

35. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 100°C.

36. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 125°C.

37. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 150°C.

38. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 175°C.

39. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 200°C.

40. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 225°C.

41. The PVD process of claim 1 wherein in one or both of step 1(a) and step 2(a), the substrate reaches a temperature of about 250°C.

42. The PVD process of claim 1 wherein in one or both of step 1(a) and step 2(a), the substrate reaches a temperature of about 275°C.

43. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 300°C.

44. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 325°C.

45. The PVD process of claim 1 wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 350°C.

46. ​​The PVD process of claim 1 wherein in one or both of step 1(a) and step 2(a), the substrate reaches a temperature of about 375°C.

47. The PVD process of claim 1, wherein in one or both of steps 1(a) and 2(a), the substrate reaches a temperature of about 400°C.

48. The PVD process of claim 1, wherein step 1(a) and step 2(a) are performed at the same temperature.

49. The PVD process of claim 1, wherein step 1(a) and step 2(a) are performed at substantially the same temperature.

50. The PVD process of claim 1, wherein step 1(a) and step 2(a) are performed at different temperatures.

51. The PVD process of claim 1, wherein in one or both of step 1(b) and step 2(b), the inert gas comprises argon (Ar).

52. The PVD process of claim 1, wherein in one or both of step 1(b) and step 2(b), the inert gas comprises nitrogen (N2).

53. The PVD process of claim 1, wherein in one or both of step 1(b) and step 2(b), the inert gas comprises helium (He).

54. The PVD process of claim 1, wherein in one or both of step 1(b) and step 2(b), the inert gas comprises neon (Ne).

55. The PVD process of claim 1, wherein the inert gas in step 1(b) is the same as the inert gas in step 2(b).

56. The PVD process of claim 1, wherein the inert gas in step 1(b) is different from the inert gas in step 2(b).

57. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 1 mTorr to about 10 mTorr.

58. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 1 mTorr to about 5 mTorr.

59. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 5 mTorr to about 10 mTorr.

60. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 3 mTorr to about 7 mTorr.

61. The PVD process of claim 1 wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 1 mTorr.

62. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 2 mTorr.

63. The PVD process of claim 1 wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 3 mTorr.

64. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 4 mTorr.

65. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 5 mTorr.

66. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 6 mTorr.

67. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 7 mTorr.

68. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 8 mTorr.

69. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 9 mTorr.

70. The PVD process of claim 1, wherein one or both of step 1(b) and step 2(b) are performed at a pressure of about 10 mTorr.

71. The PVD process of claim 1, wherein step 1(b) and step 2(b) are performed at the same pressure.

72. The PVD process of claim 1, wherein step 1(b) and step 2(b) are performed at substantially the same pressure.

73. The PVD process of claim 1, wherein step 1(b) and step 2(b) are performed at different pressures.

74. The PVD process of claim 1, wherein the template layer has about to about Thickness.

75. The PVD process of claim 1, wherein the template layer has about to about Thickness.

76. The PVD process of claim 1, wherein the template layer has about to about Thickness.

77. The PVD process of claim 1, wherein the template layer has about to about Thickness.

78. The PVD process of claim 1, wherein the template layer has about to about Thickness.

79. The PVD process of claim 1, wherein the template layer has about to about Thickness.

80. The PVD process of claim 1, wherein the template layer has about to about Thickness.

81. The PVD process of claim 1, wherein the template layer has about to about Thickness.

82. The PVD process of claim 1, wherein the template layer has about Thickness.

83. The PVD process of claim 1, wherein the template layer has about Thickness.

84. The PVD process of claim 1, wherein the template layer has about Thickness.

85. The PVD process of claim 1, wherein the template layer has about Thickness.

86. The PVD process of claim 1, wherein the template layer has about Thickness.

87. The PVD process of claim 1, wherein the template layer has about Thickness.

88. The PVD process of claim 1, wherein the template layer has about Thickness.

89. The PVD process of claim 1, wherein the template layer has about Thickness.

90. The PVD process of claim 1, wherein the template layer has about Thickness.

91. The PVD process of claim 1, wherein the template layer has about Thickness.

92. The PVD process of claim 1, wherein the template layer has about Thickness.

93. The PVD process of claim 1, wherein the template layer has about Thickness.

94. The PVD process of claim 1, wherein the template layer has about Thickness.

95. The PVD process of claim 1, wherein the template layer has about Thickness.

96. The PVD process of claim 1, wherein the template layer has about Thickness.

97. The PVD process of claim 1, wherein the template layer has about Thickness.

98. The PVD process of claim 1, wherein the template layer has about Thickness.

99. The PVD process of claim 1, wherein the template layer has about Thickness.

100. The PVD process of claim 1, wherein the template layer has about Thickness.

101. The PVD process of claim 1, wherein the template layer has about Thickness.

102. The PVD process of claim 1, wherein the template layer has about Thickness.

103. The PVD process of claim 1, wherein the template layer has about Thickness.

104. The PVD process of claim 1, wherein the template layer has about Thickness.

105. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.70 to about 3.0 at 460 nm.

106. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.75 to about 3.0 at 460 nm.

107. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.80 to about 3.0 at 460 nm.

108. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.85 to about 3.0 at 460 nm.

109. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.90 to about 3.0 at 460 nm.

110. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.95 to about 3.0 at 460 nm.

111. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.70 to about 2.80 at 460 nm.

112. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.70 to about 2.75 at 460 nm.

113. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.70 or greater at 460 nm.

114. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.75 or greater at 460 nm.

115. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.80 or greater at 460 nm.

116. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.85 or greater at 460 nm.

117. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.90 or greater at 460 nm.

118. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.95 or greater at 460 nm.

119. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 3.0 or greater at 460 nm.

120. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.70 at 460 nm.

121. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.75 at 460 nm.

122. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.80 at 460 nm.

123. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.85 at 460 nm.

124. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.90 at 460 nm.

125. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 2.95 at 460 nm.

126. The PVD process of claim 1, wherein the high refractive index layer of rutile TiO2 has a refractive index of about 3.0 at 460 nm.

127. The PVD process of claim 1, wherein the substrate comprises one or more of a transition metal oxide, a rare earth oxide-based material, a ternary oxide-based material, and a nitride-based material.

128. The PVD process of claim 1, wherein the substrate comprises one or more of a solid metal substrate and a metal silicide.

129. The PVD process of claim 1, wherein the substrate comprises a metal substrate comprising one or more of Au, Pd, Rh, Ru, W, Al, Ni, Ti, Co, and Pt.

130. The PVD process of claim 1, wherein the substrate comprises a metal silicide, the metal silicide comprising one or more of TiSi2, CoSi2, and NiSi2.

131. The PVD process of claim 1 wherein the substrate comprises glass.

132. The PVD process of claim 1, wherein the substrate comprises a silicon oxide based material.

133. The PVD process of claim 1, wherein the substrate comprises one or more of a semiconductor material and an insulator.

134. The PVD process of claim 1, wherein the substrate comprises a semiconductor material comprising one or more of Si, SiGe, GaAs, InP, diamond, GaN, and SiC.

135. The PVD process of claim 1, wherein the substrate comprises an insulator comprising one or more of SiO2, Si3N4, SiON, HfO2, Ta2O5, ZrO2, TiO2, Al2O3, and barium strontium titanate.

136. The PVD process of claim 1, wherein the substrate comprises one or more of a plastic and a flexible substrate.

137. The PVD process of claim 1, wherein the substrate comprises one or more flexible substrates comprising a polymer.

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