METALLIC STRUCTURES

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to and benefit from U.S. Provisional

Patent Application Serial No. 62/613,432 titled "Gas Phase Co-Deposition of

Hydrogen/Deuterium Loaded Metallic Structures", filed on January 4, 2018, the content of which is incorporated by reference herein.

TECHNICAL FIELD

[0002] The present invention relates generally to deposition methods for making a metallic film, and more specifically, to deposition methods in the presence of a partial hydrogen/deuterium pressure.

BACKGROUND

[0003] Deposition methods are widely used to make metallic coatings or films. Well- known deposition methods include physical vapor deposition (PVD), chemical vapor deposition (CVD), etc. In PVD, a piece of metal wire or plate is turned into vapor through a physical process, such as sputtering. In a sputter deposition process, an atom of an inert gas, such as argon, is accelerated toward a metal plate with sufficient energy to dislodge metal atoms from the plate. The dislodged metal atoms or ions are accelerated under a force field to reach a substrate and are deposited onto the substrate. In CVD, metal atoms are part of a molecule. Energy, such as a plasma or heat, acts to break up the molecule so that individual metal atoms may deposit on a substrate.

[0004] In either PVD or CVD, the deposition process takes place in a deposition chamber. The deposition chamber is under a vacuum and filled with one or more inert gases. Alternatively, the deposition chamber can also be filled with reactive gasses, e.g., oxygen, for creating a metallic compound, such as a metal oxide. The metallic compound is formed when the reactive gasses interact with the gas phase metal.

[0005] In PVD or CVD, a co-deposition process can be used to deposit metallic atoms and one or more other atoms onto the substrate. An example of existing co-deposition technologies include liquid phase co-deposition by electrolysis. Another example of a co deposition technique is cyclically exposing the reaction material or deposition material to a gas in between deposition processes.

SUMMARY

[0006] This summary is provided to introduce in a simplified form concepts that are further described in the following detailed descriptions. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it to be construed as limiting the scope of the claimed subject matter. [0007] The present disclosure relates to methods and apparatus for fabricating a metallic or alloy structure in the presence of a partial hydrogen/deuterium gas pressure such that the metallic or alloy structure is loaded with hydrogen/deuterium upon creation. Moreover, due to the presence of the hydrogen/deuterium gas, the number of vacancies in the fabricated metallic or alloy structure is increased.

[0008] In the present disclosure, a method of fabricating a hydrogen loaded metallic structure in a deposition chamber is disclosed. The deposition chamber comprises a substrate holder and the deposition chamber is evacuated to create a vacuum. The substrate holder holds a substrate. The method comprises introducing a deuterium gas to the deposition chamber to build a partial gas pressure. The method further comprises depositing a metallic material onto the substrate in the partial gas pressure to form a hydrogen loaded metallic structure. In some embodiments, two or more gases may be introduced into the deposition chamber. The two or more gases include a hydrogen/deuterium gas and the metallic material is deposited on the substrate in the presence of both a hydrogen/deuterium gas and a second gas. In one

embodiment, the second gas is fluorine. In another embodiment, the second gas is chlorine. In some embodiments, the metallic material is deposited onto the substrate via a vapor deposition method, for example, physical vapor deposition or chemical vapor deposition.

[0009] A deposition chamber for fabricating a hydrogen loaded metallic structure in the presence of a partial hydrogen/deuterium gas pressure is also disclosed. The deposition chamber comprises a substrate holder, a vacuum pump, a gas valve, and a target. The substrate holder is configured for holding a substrate onto which the metallic structure is deposited. The vacuum pump is configured for evacuating the deposition chamber. The gas valve is configured for introducing one or more gases into the deposition chamber, wherein the one or more gases include a hydrogen gas. The target is configured to sputter the metallic material onto the substrate. In some embodiments, a first power supply is applied to provide a voltage bias between the substrate holder and the ground, and a second power supply is applied to provide a voltage bias between the target and the ground. The substrate is in physical contact with the substrate holder. The substrate may or may not be in electrical contact with the substrate holder.

[0010] Disclosed herein is a method of fabricating a hydrogen loaded metallic structure in a deposition chamber. The deposition chamber includes a substrate and the deposition chamber is evacuated to form a vacuum. The method includes introducing a deuterium gas to the deposition chamber to build a partial gas pressure; and depositing a metallic material onto the substrate in the presence of the partial gas pressure to form the hydrogen loaded metallic structure.

[0011] According to one or more embodiments, the method includes introducing a second gas into the deposition chamber.

[0012] According to one or more embodiments, the second gas is fluorine.

[0013] According to one or more embodiments, the second gas is chlorine. [0014] According to one or more embodiments, the metallic material is deposited on the substrate in the presence of both the deuterium gas and the second gas.

[0015] According to one or more embodiments, the metallic material is deposited onto the substrate via a vapor deposition process.

[0016] According to one or more embodiments, the vapor deposition process is a chemical vapor deposition process.

[0017] According to one or more embodiments, the vapor deposition process is a physical vapor deposition process.

[0018] According to one or more embodiments, the metallic material is deposited onto the substrate via an electrolysis process.

[0019] According to one or more embodiments, the metallic material is deposited onto the substrate via an evaporation process.

[0020] According to one or more embodiments, the metallic material is deposited onto the substrate via a sputtering step. [0021] According to one or more embodiments, the method includes transferring the substrate into a glove box filled with a hydrogen gas of a pressure greater than an atmospheric pressure, and packaging the substrate in the presence of the pressurized hydrogen gas.

[0022] According to one or more embodiments, a deposition chamber configured for fabricating a hydrogen loaded metallic structure includes a substrate for on which the metallic structure is deposited, a vacuum pump for evacuating the deposition chamber, a gas valve for introducing one or more process gases into the deposition chamber, wherein the one or more process gasses comprise a hydrogen gas, and a target device configured to provide a metallic material to be deposited onto the substrate in a partial pressure of the one or more process gases.

[0023] According to one or more embodiments, the one or more process gases comprises a second gas.

[0024] According to one or more embodiments, the second gas is fluorine.

[0025] According to one or more embodiments, the second gas is chlorine.

[0026] According to one or more embodiments, the metallic material is deposited onto the substrate via a physical vapor deposition (PVD) process.

[0027] According to one or more embodiments, the metallic material is deposited onto the substrate via a chemical vapor deposition (CVD) process, wherein in the CVD process, the metallic material is introduced as molecules in a gas and deposited as a metal coating on the substrate.

[0028] According to one or more embodiments, the target device is a sputtering deposition device.

[0029] According to one or more embodiments, the deposition chamber includes one or more power supplies for providing a voltage bias between a substrate holder and ground.

[0030] According to one or more embodiments is a method for fabricating a hydrogen loaded metallic structure in a deposition chamber, wherein the deposition chamber includes a substrate holder and a target, and the target includes a metallic material. The method includes sputtering a metallic material onto the substrate, suspending the sputtering step, and introducing one or more process gases into the deposition chamber, wherein one of the one or more process gases is hydrogen. Then, after a pre-determined time period, evacuating the deposition chamber, re-introducing an argon gas, and resuming the sputtering step.

[0031] According to one or more embodiments, the one or more process gases comprise a second gas.

[0032] According to one or more embodiments, the second gas is fluorine.

[0033] According to one or more embodiments, the second gas is chlorine. [0034] According to one or more embodiments, during the pre-determined time period, a layer of hydrogen atoms is adsorbed on and absorbed into the metallic material sputtered onto the substrate, wherein the adsorbed and absorbed hydrogen atoms are of a desirable amount.

[0035] According to one or more embodiments, the sputtering step is suspended after the metallic material sputtered onto the substrate is of a desirable thickness.

[0036] According to one or more embodiments, the recited steps are performed cyclically.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The foregoing, as well as the following Detailed Description of preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purposes of illustration, there is shown in the drawings exemplary embodiments; however, the presently disclosed subject matter is not limited to the specific methods and instrumentalities disclosed.

[0038] The embodiments illustrated, described, and discussed herein are illustrative of the present invention. As these embodiments of the present invention are described with reference to illustrations, various modifications or adaptations of the methods and or specific structures described may become apparent to those skilled in the art. It will be appreciated that modifications and variations are covered by the above teachings and within the scope of the appended claims without departing from the spirit and intended scope thereof. All such modifications, adaptations, or variations that rely upon the teachings of the present invention, and through which these teachings have advanced the art, are considered to be within the spirit and scope of the present invention. Hence, these descriptions and drawings should not be considered in a limiting sense, as it is understood that the present invention is in no way limited to only the embodiments illustrated.

[0039] Figure 1 illustrates an exemplary deposition chamber, according to one or more embodiments of the presently disclosed subject matter.

[0040] Figure 2 illustrates an exemplary cyclical deposition process, according to one or more embodiments of the presently disclosed subject matter.

[0041] Figure 3 is a flow chart illustrating a first exemplary gas-phase co-deposition process, according to one or more embodiments of the presently disclosed subject matter.

[0042] Figure 4 is a flow chart illustrating a second exemplary gas-phase co-deposition process, according to one or more embodiments of the presently disclosed subject matter.

[0043] Figure 5 illustrates an exemplary packaging process of a hydrogen loaded metallic structure, according to one or more embodiments of the presently disclosed subject matter. DETAILED DESCRIPTION

[0044] These descriptions are presented with sufficient details to provide an

understanding of one or more particular embodiments of broader inventive subject matters.

These descriptions expound upon and exemplify particular features of those particular embodiments without limiting the inventive subject matters to the explicitly described embodiments and features. Considerations in view of these descriptions will likely give rise to additional and similar embodiments and features without departing from the scope of the inventive subject matters. Although the term“step” may be expressly used or implied relating to features of processes or methods, no implication is made of any particular order or sequence among such expressed or implied steps unless an order or sequence is explicitly stated.

[0045] Any dimensions expressed or implied in the drawings and these descriptions are provided for exemplary purposes. Thus, not all embodiments within the scope of the drawings and these descriptions are made according to such exemplary dimensions. The drawings are not made necessarily to scale. Thus, not all embodiments within the scope of the drawings and these descriptions are made according to the apparent scale of the drawings with regard to relative dimensions in the drawings. However, for each drawing, at least one embodiment is made according to the apparent relative scale of the drawing.

[0046] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter pertains. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the presently disclosed subject matter, representative methods, devices, and materials are now described.

[0047] Following long-standing patent law convention, the terms "a", "an", and "the" refer to "one or more" when used in the subject specification, including the claims. Thus, for example, reference to "a device" can include a plurality of such devices, and so forth.

[0048] Unless otherwise indicated, all numbers expressing quantities of components, conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the instant specification and attached claims are

approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.

[0049] As used herein, the term "about", when referring to a value or to an amount of mass, weight, time, volume, concentration, and/or percentage can encompass variations of, in some embodiments +/- 20%, in some embodiments +/-l0%, in some embodiments +/- 5%, in some embodiments +/- 1%, in some embodiments +/- 0.5%, and in some embodiments +/-0.l%, from the specified amount, as such variations are appropriate in the presently disclosed subject matter.

[0050] The present disclosure teaches advantageous methods and apparatus for fabricating a hydrogen loaded metallic structure using gas phase co-deposition techniques. [0051] Figure 1 illustrates an exemplary apparatus 100 configured for gas phase co deposition of a hydrogen loaded metallic structure. The exemplary apparatus 100 comprises a deposition chamber 102, a vacuum pump 116, a pressure gauge 112, and a process gas supply 114. The deposition chamber 102 comprises a target 104 and a substrate holder 106, which holds a substrate 118. The target 104 is made of a metallic material and can be used to produce free metal atoms/ions when a voltage bias is applied to the target. When a bias is applied to the substrate holder 106, the metal ions are accelerated from the target 104 to the substrate holder 106 and deposited onto the substrate 118. The substrate 118 is configured for deposition of the metallic material. The target 104 and the substrate holder 106 are each connected to power supplies 108 and 110 respectively. The voltage bias applied to the substrate holder 106 creates an electric field that accelerates metal ions that are dislodged from the target 104 toward the substrate holder 106 to form a metallic structure on the substrate 118.

[0052] In Figure 1, the vacuum pump 116 is connected to the deposition chamber 102.

The vacuum pump 116 is configured to evacuate any undesirable or residual gas from the deposition chamber 102 to create a high vacuum in the chamber 102. The deposition chamber 102 is also connected to a pressure gauge 112 and one or more gas supplies 114. The pressure gauge 112 is configured to measure the pressure of the deposition chamber 102. The one or more gas supplies 114 are configured to supply one or more process gases to the deposition chamber 102. In some embodiments, one of the process gases is hydrogen/deuterium gas. In some embodiments, two or more process gases may be introduced into the reaction chamber. The two or more process gases include a hydrogen/deuterium gas and a second gas. In some embodiments, the second gas is fluorine. In some embodiments, the second gas is chlorine.

[0053] The apparatus 100 shown in Figure 1 is configured to deposit some of the metallic material dislodged from the target 104 onto the substrate 118. The deposition process can be a physical vapor deposition (PVD) or a chemical vapor deposition (CVD) process. An exemplary PVD process is sputtering deposition, which is illustrated in Figure 2.

[0054] Figure 2 depicts a deposition chamber 102 that comprises the target 104 and the substrate holder 106. The deposition chamber 102 is filled with argon gas. The argon gas is of a pressure less than the atmospheric pressure and is in a plasma state due to a voltage bias created between the substrate holder 106 and the ground. Argon ions (Ar) 202 in a plasma state possess high kinetic energies. When argon ions (Ar) 202 bombard the target 104, their kinetic energies are transferred to the metallic material in the target 104. Metal ions (M ⁺ ) are dislodged from the target 104. The process of dislodging material from a target is known as sputtering. As shown in Figure 1, the target 104 and the substrate holder 106 are connected to different power supplies. The target power supply 108 can be used to enhance the sputtering of metallic material by creating a voltage bias between the target 104 and the ground. The voltage bias created by the power supply 110 induces an electric field that accelerates the metal ions (M ⁺ ) towards the substrate holder 106 and the substrate 118. Some portion of the metal ions (M ⁺ ) which hit the substrate 118, are deposited on the substrate 118 to form a metallic coating 210. After the metallic coating 210 has reached a desired thickness, the power supplies may be turned off for a period of time. [0055] During power off, the metallic coating 210 does not grow substantially, or not at all. In one embodiment, deuterium gas is introduced into the deposition chamber 102 via the gas supply 114. Plasma argon ions collide with deuterium gas molecules and break the molecules into deuterium ions (D ⁺ ). Deuterium ions (D ⁺ ) created by plasma argon ions will adsorb onto the metallic coating 210 to form a layer of deuterium 212. Some portion of the deuterium ions will diffuse into the metallic coating. When enough deuterium ions 212 have accumulated on and/or absorbed into the metallic coating 212, the vacuum pump 116 may be turned on and the deposition chamber 102 is evacuated. After both the deuterium and argon gases are evacuated, argon is reintroduced into the deposition chamber 102. The power supplies to the target 104 and the substrate holder 106 are turned on. The sputtering process is resumed and another layer of metallic coating 214 is deposited on the substrate 118. When the second layer of metallic coating 214 has reached a desired thickness, the sputtering process may be suspended and the deuterium gas may be introduced to the deposition chamber 102 once again. A second layer of deuterium is then adsorbed by and/or absorbed into the metallic coating 214. This gas-phase co-deposition process can be repeated for a number of times as needed. The final product deposited on the substrate 118 is a metallic structure loaded with hydrogen.

[0056] In some embodiments, the target 104 comprises palladium and the final product deposited on the substrate 118 is a deuterium loaded palladium. Hydrogen/deuterium loaded palladium has many industrial applications. However, in several of the industrial applications, it is desirable to achieve a high hydrogen loading ratio. Under normal conditions, the hydrogen loading ratio in palladium often cannot exceed 0.7 or 0.8. To attain a high hydrogen loading ratio, extraordinary conditions are often required. For example, ultra-high pressure (> 10,000 Pascal) or ultra-high temperature (>1000 °C) are often needed to achieve a hydrogen loading ratio exceeding 1.0.

[0057] The gas phase co-deposition process depicted in Figure 2 is a cyclical deposition process, which can be used to manufacture a hydrogen loaded metallic structure having a high hydrogen loading ratio. It is noted that in the metallic structure deposited on the substrate comprising the layers 210, 212, and 214, the amount of hydrogen/deuterium ions or atoms which absorb into the metallic structure can be varied by controlling the hydrogen/deuterium gas pressure inside the deposition chamber 102, and by controlling the time period between two consecutive sputtering processes. Increasing the time period between two sputtering processes allows more hydrogen/deuterium atoms to be absorbed by the metallic structure, thus attaining a higher hydrogen loading ratio in the final deposition product.

[0058] Figure 3 is a flow-chart illustrating an exemplary gas phase co-deposition process

300. The gas phase co-deposition process 300 takes place in the deposition chamber 102. The deposition chamber 102 comprises a (metal) target 104 and a substrate holder 106. In step 302 of the gas-phase co-deposition process 300, the deposition chamber 102 is evacuated to remove any undesirable gas, and an argon gas is then introduced to the deposition chamber 102. A voltage bias created between the substrate holder 106 and the ground is used to produce argon plasma. The deposition chamber 102 is now ready for gas phase co-deposition. [0059] In step 304 of the gas phase co-deposition process 300, the sputtering process starts when the argon plasma is created. During the sputtering process, a metallic structure is deposited onto the substrate 118 held by the holder 106. After the metallic structure has reached a desirable thickness, the sputtering process is turned off by removing the voltage bias between the substrate 106 and the ground (step 306). A hydrogen/deuterium gas is then introduced into the deposition chamber 102 (step 306). During the time period when the sputtering process is turned off, hydrogen/deuterium ions or atoms adsorb and, after some time, absorb into the metallic layer 212. After a desirable amount of hydrogen/deuterium has been adsorbed and/or absorbed into the metallic layer 212, the hydrogen/deuterium gas is evacuated from the deposition chamber 102 and an argon gas is re-introduced into the deposition chamber 102 (step 308). Afterwards, the sputtering process is turned on to deposit a second metallic layer 214 onto the substrate 118 (step 310).

[0060] In the gas phase co-deposition process 300 shown in Figure 3, deposition of the metallic layers 210, 214 and that of the hydrogen/deuterium layer 212 onto the substrate 118 are performed sequentially. In some embodiments, deposition of the metallic material may be performed in the presence of a partial hydrogen gas pressure, as illustrated in the gas phase co deposition process 400 in Figure 4.

[0061] In the gas phase co-deposition process 400, a deuterium gas is introduced into the deposition chamber 102 to build a partial deuterium gas pressure (step 402). In the presence of the partial deuterium gas pressure, a metallic material is deposited onto the substrate 118 to form a hydrogen loaded metallic structure (step 404). The metallic structure fabricated in the gas phase co-deposition process 400 comprises hydrogen/deuterium atoms/ions loaded within the metallic structure and a number of vacancies that are left in the metallic structure by escaped hydrogen/deuterium atoms/ions.

[0062] Figure 5 illustrates an exemplary packaging process 500 of the substrate 118 created in the gas co-deposition process 300 or 400. The substrate 118 is transferred into a glove box filled with a hydrogen gas of a pressure greater than one atmospheric pressure (step 502). The substrate 118 is packaged in the presence of the pressurized hydrogen gas (step 504) so that the hydrogen/deuterium atoms/ions adsorbed or absorbed in the substrate 118 are retained.

[0063] The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

[0064] Particular embodiments and features have been described with reference to the drawings. It is to be understood that these descriptions are not limited to any single embodiment or any particular set of features, and that similar embodiments and features may arise or modifications and additions may be made without departing from the scope of these descriptions and the spirit of the appended claims. [0065] These and other changes can be made to the disclosure in light of the above

Detailed Description. While the above description describes certain embodiments of the disclosure, and describes the best mode contemplated, no matter how detailed the above appears in text, the teachings can be practiced in many ways. Details of the system may vary

considerably in its implementation details, while still being encompassed by the subject matter disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the disclosure should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the disclosure with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the disclosure to the specific embodiments disclosed in the

specification, unless the above Detailed Description section explicitly defines such terms.

Accordingly, the actual scope of the disclosure encompasses not only the disclosed

embodiments, but also all equivalent ways of practicing or implementing the disclosure under the claims.