Plasma-assisted carbon structure forming

Formation of Plasma-Assisted Carbon Structures CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the priority of the following U.S. provisional patent applications: No. 60/378,693 filed on May 8, 2002, No. 60 filed on December 4, 2002 /430,677, No. 60/435,278 filed on December 23, 2002, the entire content of which is hereby incorporated for reference.

TECHNICAL FIELD The present invention relates to methods and devices for plasma-assisted carbon structure formation, and more particularly to the formation of carbon structures using plasma excited by electromagnetic radiation in the presence of a plasma catalyst.

BACKGROUND Various methods can be used to achieve the formation of carbon structures (such as carbon nanotubes, C60 fullerenes, diamonds, etc.). For example, it is reported that when a large amount of heat source, such as flame or electric arc, is used to vaporize carbon materials, C60 molecules can be formed.

By heating a carbon source, such as graphite mixed with a metal catalyst by laser ablation, single-walled carbon nanotubes (SWCNTs) can also be formed _oUnlike the formation of fullerenes, the formation of SWCNTs may require a catalytic surface, such as a seed substrate or a small amount of metal catalyst (such as Ni and Co at about one atomic percent) to provide a place for the synthesis and growth of SWCNTs.

According to reports, multi-walled carbon nanotubes (MWCNTs) can also be formed by depositing MWCNTs on a substrate using a chemical vapor deposition (CVD) technique with a gasification catalyst. According to the latest report, a technique for growing nanotubes without a catalytic surface has been developed.

However, the traditional technology of growing carbon structures is often difficult to control because different carbon structures are formed at the same time, making it difficult to synthesize a given carbon structure optimally without being "contaminated" by other carbon structures (such as graphite particles during the synthesis of SWCNTs). / Formation and collection of molecules).

03810273.0 The problems encountered in the control of the formation and growth of carbon structures such as nanotubes and fullerenes may hinder the preferential growth of carbon structures. For example, if the carbon structure is required to be located on a complex or temperature-sensitive substrate, the heating process needs to place the entire substrate in a furnace to expose it to high temperatures for a long time. For example, MWCNTs need 600-800 degrees Celsius, and SWCNTs need 1200 degrees Celsius. Degrees Celsius. However, the aforementioned temperature adjustment may be difficult to accurately achieve and control.

As the devices incorporating the carbon structure shrink and the preparation of the carbon structure becomes more and more sensitive to environmental processing conditions, more flexible alternative manufacturing devices are needed, including methods to prevent damage during the heat treatment of high-temperature bodies.

SUMMARY OF THE INVENTION The present invention provides a method and device for synthesizing carbon atom structure. In one embodiment, the catalyzed plasma can be formed in the cavity by the following method, subjecting the gas to a certain amount of electromagnetic radiation in the presence of the plasma catalyst, adding carbon-containing materials to the plasma, and forming it on the surface of the substrate A predetermined structure is grown on it. Radiation can use any frequency less than about 333GHz.

In another embodiment, a plasma assist system for synthesizing a predetermined carbon structure on a substrate is provided. The system includes a container in which a cavity is formed, an electromagnetic radiation source configured to introduce radiation into the cavity during synthesis, and at least one gas source connected to the cavity so as to transport carbonaceous material can flow in during synthesis The cavity, and at least one plasma catalyst disposed in the electromagnetic radiation (eg, located in or near the cavity).

The present invention also provides a plasma catalyst for exciting, regulating and maintaining plasma. The plasma catalyst according to the present invention may be inert or active. The inert plasma catalyst according to the present invention may include any object that induces plasma by deforming a local electric field, such as an electromagnetic field, without applying additional energy. The active plasma catalyst may be any particle or high-energy wave packet that can transfer enough energy to a gaseous atom or molecule in the presence of electromagnetic radiation to cause the gaseous atom or molecule to lose at least one electron. In both cases of inertness and activity, the plasma catalyst can improve or relax the environmental conditions required to excite the coating plasma.

The present invention also provides other plasma catalysts, methods and devices for igniting, adjusting and maintaining plasma for synthesizing predetermined carbon structures.

03810273.0 Description of the Figures Other features of the present invention will become apparent through the following detailed description in conjunction with the accompanying drawings, where the same reference numerals represent the same components, in which: Figure 1 shows the plasma assist system of the synthetic carbon structure according to the present invention Schematic diagram; Figure 1A shows an embodiment of a part of the plasma assist system according to the present invention, the system is used to synthesize a carbon structure and by adding a powder plasma catalyst to the plasma chamber to excite, adjust or maintain the plasma in the chamber; Figure 2 shows According to the plasma catalyst fiber of the present invention, at least one component of the fiber has a concentration gradient along its length; FIG. 3 shows the plasma catalyst fiber of the present invention, and multiple components of the fiber are arranged along its length. Ratio change; Figure 4 shows another plasma catalyst fiber according to the present invention, which includes an inner core and a coating; Figure 5 shows the plasma catalyst fiber shown in Figure 4 according to the present invention along the line of Figure 4 A cross-sectional view of line 5-5; FIG. 6 shows an embodiment of another part of a plasma system according to the present invention, which includes an elongated plasma catalyst extending through an excitation port; FIG. 7 shows an embodiment according to the present invention. Invented an embodiment of the elongated plasma catalyst used in the system of FIG. 6; FIG. 8 shows another embodiment of the elongated plasma catalyst used in the system of FIG. 6 according to the present invention; and Figure 9 shows an embodiment of a partial plasma assist system according to the present invention for synthesizing a carbon structure and introducing an active plasma catalyst into the radiation chamber in the form of ionizing radiation; Figure 10 shows an additional optional plasma chamber according to the present invention 1 shows an embodiment of a partial plasma assist system for synthesizing a carbon structure; Fig. 11 shows an embodiment of a method for synthesizing a predetermined carbon structure according to the present invention; Fig. 12 shows an embodiment of a method for synthesizing a predetermined carbon structure according to the present invention; Figure 1 of the device that provides energy with materials

03810273.0 Another embodiment of the partial plasma assist system for synthesizing carbon structure; FIG. 13 shows another embodiment of the partial plasma assist system for synthesizing carbon structure through openings according to the present invention; and FIG. 14 shows another embodiment of the partial plasma assist system for synthesizing carbon structure according to the present invention Another embodiment of the partial plasma assist system of the synthetic carbon structure, wherein the plasma chamber has internal surface features for forming the patterned area of the carbon structure.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to methods and devices for exciting, regulating, and maintaining plasma for synthesizing various carbon structures, including, for example, the formation of carbon nanotubes and other carbon structures. Therefore, the present invention can be used to facilitate the control of the formation of plasma-assisted carbon structures, which can reduce energy consumption and improve the flexibility of synthesis, growth, and production of carbon structures.

A method for synthesizing a carbon structure according to the present invention may include adding gas, plasma catalyst and electromagnetic radiation into the cavity for catalyzing plasma. Any plasma with a plasma catalyst used here to form a carbon structure on one or more objects is a "catalyzed plasma" or simply "plasma". The catalyst can be inert or active. The inert plasma catalyst according to the present invention may include any object that induces plasma by deforming a local electric field (for example, an electromagnetic field) without applying additional energy to the catalyst, such as applying a voltage to cause an instantaneous discharge. On the other hand, the active plasma catalyst may be any particle or high-energy wave packet, which can transfer enough energy to a gaseous atom or molecule in the presence of electromagnetic radiation to cause the gaseous atom or molecule to lose at least one electron.

The entire contents of the following U.S. patent applications jointly owned and filed at the same time are hereby incorporated as reference: U.S. Patent Application

No.10/_,_ (Atty.Docket No.1837.0008 ),

No.10/_,_ (Atty.Docket No.1837.0009 ),

No.10/_,_ (Atty.Docket No.1837.0010 ),

No.l0/_,_ (Atty.Docket No.1837.0011 ),

No.l0/_,_ (Atty.Docket No.l837.0012 ),

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<td colspan="2">Description of the plasma system</td>

Fig. 1 shows a plasma-assisted carbon structure synthesis and growth system 10 according to one aspect of the present invention. In this embodiment, the cavity 12 is formed in a container located inside an electromagnetic radiation cavity (ie, an applicator) 14. In another embodiment (not shown), the cavity 12 and the electromagnetic radiation cavity 14 are the same, so that two separate components are not required. The container in which the cavity 12 is formed may include one or more electromagnetic radiation transmissive partitions to improve its thermal insulation performance so that the cavity 12 does not need to be significantly shielded from electromagnetic radiation.

In one embodiment, the cavity 12 is formed in a container made of ceramic. Since the plasma according to the present invention can reach very high temperatures, the upper limit of the processing temperature is only limited by the melting point of the ceramic used to make the container. For example, in an experiment, the ceramic used can withstand about 3000 degrees Fahrenheit. For example, the ceramic material may include 29.8% by weight of silicon, 68.2% of aluminum, 0.4% of iron oxide, 1% of titanium, 0.1% of calcium oxide, 0.1% of wedge oxide, and 0.4% of alkali metal.

03810273.0 The first ceramic material is Model No. LW-30, sold by New Castle Refractories of New Castle, Pennsylvania. However, those of ordinary skill in the art know that other materials can also be used according to the present invention, such as quartz and those materials different from the above-mentioned ceramic materials (such as those with higher or lower melting temperatures).

In a successful experiment, plasma was formed in a partially open cavity inside the first brick and capped by a second brick. The dimensions of the cavity are about 2 inches X about 2 inches X about 1.5 inches. There are at least two holes in the brick that communicate with the cavity: one for observing the plasma, and at least one for supplying gas. The size of the cavity depends on the plasma treatment that needs to be performed. In addition, the cavity should at least be configured to prevent the plasma from rising/drifting and leaving the main processing area, even though the plasma may not touch the substrate.

The cavity 12 can be connected to one or more gas sources 24 (such as nitrogen, nitrogen, hydrogen, fermented gas, nitrogen, carbon-containing gas (such as hydrocarbons), etc.) through a pipeline 20 and a control valve 22, and is provided by the power supply 28 energy. The pipeline 20 may be tubular (for example, between about 1/16 inch and about 1/4 inch, such as about 1/8 inch), but may also be any device capable of supplying air. Moreover, if necessary, a vacuum pump can be connected to the chamber to pump away any unnecessary gas generated during the plasma processing.

A radiation leak detector (not shown) is installed near the source 26 and the waveguide 30, and is connected to a safety interlock system. If the leakage exceeds a predetermined safety value, for example, by FCC and/or OSHA (for example, 5m\ V/cm2) the specified value, the electromagnetic radiation power supply is automatically turned off.

An electromagnetic radiation source 26 energized by a power source 28 introduces electromagnetic radiation into the cavity 14 through one or more waveguides 30. Those of ordinary skill in the art should understand that the electromagnetic radiation source 26 can be directly connected to the cavity 14 or the cavity 12, thereby eliminating the waveguide 30. The electromagnetic radiation entering the cavity 14 or the cavity 12 can be used to excite the plasma in the cavity. By combining additional electromagnetic radiation with the catalyst, the catalyzed plasma can be fully adjusted or maintained and confined in the cavity.

Electromagnetic radiation is provided through a circulator 32 and a tuner 34 (for example, a 3-stub tuner). The tuner 34 is used to minimize reflection energy as a function of changing excitation or processing conditions, especially before the formation of the catalyzed plasma, because electromagnetic radiation will be strongly absorbed by the plasma after the plasma is formed.

03810273.0 As explained in more detail below, if the cavity 14 supports multiple modes, especially when these modes are continuously or periodically mixed, the position of the electromagnetic radiation transmitting cavity 12 in the cavity 14 is not important. As described in more detail below, the motor 36 can be connected to the mode mixer 38 to make the time-averaged electromagnetic radiation energy distribution substantially uniform in the cavity 14. Moreover, a window 40 (for example, a quartz window) may be provided on a wall of the cavity 14 adjacent to the cavity 12 to enable a temperature sensor 42 (for example, an optical pyrometer) to observe the processing in the cavity 12. In one embodiment, the output value of the optical pyrometer may increase from 0 volts to within the tracking range value when the temperature rises. The pyrometer can be used to detect the radiation intensity of two or more wavelengths, and use Planck's law to fit these intensity values to determine the temperature of the workpiece.

The temperature of the plasma can also be estimated from the optical radiation intensity of one or more transitions in the atomic or molecular materials present in the plasma. The known probability of these transitions can be used to evaluate the density distribution of the excited state of atoms or molecules, and the temperature of the material can be calculated from this information using Boltzmann's law.

The sensor 42 is capable of generating an output signal as a function of the temperature of the relevant workpiece (not shown) in the cavity 12 or any other monitorable condition and supplying the signal to the controller 44. As described below, dual temperature induction and heating, as well as automatic cooling rate and airflow control can also be used. The controller 44 is used to control the operation of the power supply 28, and has an output terminal connected to the above-mentioned electromagnetic radiation source 26 and another output terminal connected to the valve 22 for controlling the air flow into the cavity 12.

Although any radiation less than about 333 GHz can be used, the present invention has achieved the same success with 915 MHz and 2.45 GHz electromagnetic radiation sources provided by the Communications and Energy Industry (CPI). The 2.45 GHz system continues to provide from about 0.5 kilowatts to about 5.0 Kilowatts of variable electromagnetic radiation energy. According to an embodiment of the present invention, the electromagnetic radiation energy density during the synthesis of the carbon structure can be approximately 0.05 W/cm³And approximately 100 W/cm³Between, for example, about 2.5W/cm³_o The 3-way stub tuner matches the impedance to the maximum energy transfer, and uses a two-way connector (not shown) that measures incident and reflected energy. An optical pyrometer is also used to remotely sense the temperature of the substrate.

As mentioned above, any radiation with a frequency less than about 333 GHz can be used in accordance with the present invention. For example, a frequency such as an energy line frequency (approximately 50 Hz to 60 Hz) may be used, although the pressure of the gas forming the plasma may be reduced to facilitate plasma excitation. In addition, according to the present invention, any radio frequency or microwave frequency can be used including frequencies greater than about 100 kHz.

03810273.0 First, in most cases, the gas pressure used for these relatively high frequencies does not need to be lowered in order to excite, adjust, or maintain the plasma, so a variety of plasma treatments can be achieved at and above atmospheric pressure.

The device is controlled by a computer using LabVIEW®6i software, which can provide real-time temperature monitoring and electromagnetic radiation energy control. LabVIEW® graphical development environment is used for automatic data acquisition, instrument control, measurement analysis and data display. LabVIEW® comes from National Instruments Corporation (National Instruments Corporation) in Austin, Texas.

Reduce noise by smoothing the average value of an appropriate number of data points. Moreover, in order to improve the speed and calculation efficiency, the number of data points stored in the buffer array is limited by the technical adjustment of the shift register and the buffer area size. The pyrometer measures the temperature of the sensitive area of approximately lcn? and is used to calculate the average temperature. The pyrometer is used to detect the radiation intensity of two wavelengths, and use Planck's law to fit these intensity values to determine the temperature. However, it should be understood that other devices and methods for monitoring and controlling temperature consistent with the present invention also exist and can be used. For example, US Patent Application No. 10/_,_ (Attorney Dorket No. 1837.0033), which is co-owned and filed at the same time, describes the control software that can be used according to the present invention, and the entire content thereof is incorporated herein by reference.

The cavity 14 has several glass cover observation ports with electromagnetic radiation shielding and a quartz window for inserting a pyrometer. Although it is not necessary to use it, it also has several ports connected to the vacuum pump and the gas source.

The system 10 also includes a closed-cycle deionized water cooling system (not shown) with an external heat exchanger cooled with tap water. In operation, the deionized water first cools the magnetron, then cools the loading and unloading parts in the circulator (used to protect the magnetron), and finally flows through the water channel welded on the outer surface of the cavity to cool the electromagnetic radiation cavity.

Plasma catalyst As described above, the plasma catalyst according to the present invention may include one or more different materials and may be inert or active. In the case where the gas pressure is lower than, equal to or greater than the atmospheric pressure, the plasma catalyst can excite, regulate and/or maintain plasma in other materials.

A method for forming plasma according to the present invention may include making the gas in the cavity inert plasma

03810273.0 The first sub-body catalyst is exposed to electromagnetic radiation with a frequency less than about 333GHz. The inert plasma catalyst according to the present invention includes any object that induces plasma by deforming a local electric field (for example, an electromagnetic field) according to the present invention, without applying additional energy to the catalyst, such as causing a flash discharge by applying a voltage.

The inert plasma catalyst of the present invention can also be nanoparticles or nanotubes. The term "nanoparticle" as used herein includes any particle that is at least semiconducting and has a largest physical dimension less than about 100 nm. Moreover, doped and undoped SWCNTs and MWCNTs are particularly effective for the excited plasma of the present invention due to their abnormal conductivity and elongated shape. The nanotube can have any suitable length and can be fixed on the substrate in powder form. If fixed, when the plasma is excited or maintained, the nanotubes can be arbitrarily oriented on the surface of the substrate or fixed to the substrate (for example, in some predetermined directions).

The inert plasma of the present invention can also be powder, and does not need to be made into nanoparticles or nanotubes. For example, it can be formed into fibers, dust particles, flakes, thin plates, and the like. In the powder state, the catalyst can be suspended in the gas at least temporarily. If necessary, by suspending the powder in the gas, the powder can be quickly dispersed throughout the cavity and more easily consumed.

In one embodiment, the powdered catalyst may be loaded into the cavity and suspended in the carrier gas at least temporarily. The carrier gas may be the same as or different from the gas forming the plasma. Moreover, the powder can be added to the gas before being introduced into the cavity. For example, as shown in FIG. 1A, the electromagnetic radiation source 52 may apply radiation to the electromagnetic radiation cavity 55 provided with the plasma cavity 60. The powder source 65 supplies the catalyst powder 70 to the air flow 75. In an alternative embodiment, the powder 70 may be added to the cavity 60 in bulk (for example, a pile) first, and then distributed in the cavity in any manner, including gas flowing through or over the bulk powder. In addition, the powder can be moved, transported, scattered, sprayed, blown or otherwise delivered or distributed in the cavity, and the powder can be added to the gas to excite, adjust or maintain the coating plasma.

In one experiment, plasma was excited in the cavity by placing a pile of carbon fiber powder in a copper tube extending into the cavity. Although sufficient electromagnetic (microwave) radiation is introduced into the cavity, the copper tube shields the radiation from the powder without plasma excitation. However, once the carrier gas starts to flow into the copper tube, the powder is forced to flow out of the copper tube and into the cavity, so that the powder is exposed to electromagnetic radiation, and the plasma in the cavity

03810273.0 The first is almost instantaneous.

The powder catalyst according to the present invention is basically incombustible, so that it does not need to include oxygen or burn in the presence of oxygen. As described above, the catalyst may include metals, carbon, carbon-based alloys, carbon-based composites, conductive polymers, conductive silicone rubber elastomers, polymer nanocomposites, organic-inorganic composites, and any combination thereof.

Moreover, the powder catalyst can be substantially uniformly distributed in the plasma cavity (for example, suspended in a gas), and the plasma excitation can be precisely controlled in the cavity. Uniform excitation is important in some applications, including applications that require a short plasma exposure time, such as in the form of one or more bursts. It also takes a certain amount of time to make the powder catalyst itself evenly distributed in the entire cavity, especially in a complex multi-cavity cavity. Therefore, according to another aspect of the present invention, the powder plasma can be introduced into the cavity through a plurality of excitation ports in order to form a more uniform catalyst distribution therein faster (see below).

In addition to powder, the inert plasma catalyst according to the present invention may also include, for example, one or more microscopic or macroscopic fibers, flakes, needles, threads, ropes, filaments, yarns, strings, shavings, splinters, fragments, dead Thread, tape, whiskers or any mixture thereof. In these cases, the plasma catalyst may have at least a portion of which one physical size is substantially larger than the other physical size. For example, the ratio between at least two vertical dimensions is at least about 1:2, and may also be greater than about 1:5, or even greater than about 1:10. Therefore, the inert plasma catalyst may include at least a portion that is relatively thin compared to its length. material. It is also possible to use catalyst bundles (e.g. fibers), which include, for example, a section of graphite tape. In an experiment, a section of tape with about 30,000 graphite fibers each having a diameter of about 2-3 microns was successfully used. The number of internal fibers and beam length are not important for igniting, regulating, or maintaining the plasma. For example, a section of graphite tape approximately 1/4 inch long gives satisfactory results. According to the present invention, a carbon fiber is successfully used as Model No. AS4C-GP3K under the trademark Magnamite® sold by Hexcel Company of Salt Lake City, Utah. In addition, silicon carbide fiber has been successfully used.

The inert plasma catalyst according to another aspect of the present invention may include one or more such as substantially spherical, annular, conical, cubic, planar, cylindrical, rectangular, or elongated portions.

03810273.0 The first point.

The aforementioned inert plasma catalyst includes at least one material that is at least semi-conductive. In a case of history, the material has a strong electrical conductivity. For example, the inert plasma catalyst according to the present invention may include metals, inorganic materials, carbon, carbon-based alloys, carbon-based composites, conductive polymers, conductive silicone rubber elastomers, polymeric nanocomposites, organic-inorganic composites, or any of them. combination. Some possible inorganic materials that can be included in the plasma catalyst include carbon, silicon carbide, filling, steel, lithium, sulphur, carbon nitride, and aluminum, although it is believed that other conductive inorganic materials can also be used.

In addition to one or more conductive materials, the inert plasma catalyst of the present invention may also include one or more additives (conductivity is not required). As used herein, the additive can include any material that the user wants to add to the plasma. For example, as described in detail below, one or more carbon-containing materials can be added to the plasma through a catalyst for growing predetermined carbon structures on semiconductors and other substrate materials. The catalyst may include the carbon-containing material itself, or a precursor material that can form a carbon source for synthesis after decomposition. Therefore, the plasma catalyst may include one or more additives and one or more conductive materials in any desired ratio depending on the final desired plasma composite and the treatment using the plasma.

The ratio of conductive components to additives in the inert plasma catalyst varies with the time it is consumed. For example, during excitation, the plasma catalyst may be required to include a larger percentage of conductive components to improve excitation conditions. On the other hand, if used while maintaining plasma, the catalyst may include a larger percentage of additives or carbonaceous materials. Those of ordinary skill in the art know that the composition ratio of the plasma catalyst used to excite and maintain the plasma can be the same, and the ratio can be formulated to deposit any desired carbon composition.

The predetermined ratio distribution can be used to simplify many plasma assisted carbon structure formation processes. In some conventional processes, the composition of the plasma is increased as needed, but such an increase generally requires a programmable device to add the composition according to a predetermined plan. However, according to the present invention, the component ratio in the catalyst is variable, and thus the component ratio of the plasma itself can be automatically changed. That is to say, the composition ratio of the plasma at any given time depends on the part of the catalyst currently consumed by the plasma. Therefore, the ratio of the catalyst components at different positions within the catalyst may be different. Also, the current plasma composition ratio depends on the current and/or pre-consumption catalysis

03810273.0 The first agent part, especially when the gas flow rate through the plasma chamber is slow.

The inert plasma catalyst according to the present invention may be uniform, non-uniform or gradual. Moreover, the plasma catalyst component ratio in the entire catalyst may be continuously or discontinuously changed. For example, in Figure 2, the ratio can be changed smoothly to form a gradient along the length of the catalyst 100. The catalyst 100 may include a material that contains a lower concentration of components in the section 105 and continuously increases the concentration to the section 110.

Optionally, as shown in FIG. 3, the ratio in each part of the catalyst 120 may be discontinuously changed, for example, including alternating sections 125 and 130 with different concentrations. It should be understood that the catalyst 120 may have more than two stages. Therefore, the ratio of the catalyst component consumed by the plasma can be changed in any predetermined form. In one embodiment, when the plasma is monitored and a special additive has been detected, further processing can be started or ended automatically.

Another method of changing the component ratio in the plasma to be maintained is by introducing multiple catalysts with different component ratios at different times and at different rates. For example, multiple catalysts can be introduced at approximately the same position or different positions in the cavity. When introduced at different positions, the plasma formed in the cavity will have a component concentration gradient determined by different catalyst positions. Therefore, the automated system may include means for mechanically inserting a consumable plasma catalyst before and/or during plasma ignition, conditioning, and/or maintenance.

The inert plasma catalyst according to the invention can also be coated. In one embodiment, the catalyst may include a substantially non-conductive coating deposited on the surface of a substantially conductive material. Alternatively, the catalyst may include a substantially conductive coating deposited on the surface of a substantially non-conductive material. For example, FIGS. 4 and 5 show a fiber 140 including an inner layer 145 and a coating 150. In one embodiment, in order to prevent oxidation of carbon, the plasma catalyst includes a carbon core coated with carbon.

A plasma catalyst may also include multilayer coatings. If the coating is consumed during exposure to plasma, the coating can continuously introduce plasma from the outer coating to the innermost coating, thereby forming a time-release mechanism. Therefore, the coated plasma catalyst may include any number of materials, as long as part of the catalyst is at least semi-conductive.

According to another embodiment of the present invention, in order to substantially reduce or prevent leakage of electromagnetic radiation energy, the plasma catalyst may be completely located in the electromagnetic radiation cavity. In this way, the plasma catalyst will not

03810273.0 The first electrical or magnetic connection to the radiation cavity, the container including the cavity, or any conductive object outside the cavity. This can prevent an instantaneous discharge at the excitation port and prevent electromagnetic radiation from leaking out of the cavity during the excitation and if the plasma is maintained thereafter. In one embodiment, the catalyst may be located at the end of a substantially non-conductive extension that extends into the excitation port.

For example, FIG. 6 shows an electromagnetic radiation cavity 160 in which a plasma cavity 165 may be provided. The plasma catalyst 170 may extend and extend into the excitation port 175. As shown in FIG. 7, the catalyst 170 according to the present invention may include a conductive tip part 180 (disposed in the cavity 160) and a non-conductive part 185 (basically disposed outside the cavity 160, but can slightly extend into the cavity). This structure prevents electrical connection (eg, flash discharge) between the tip portion 180 and the cavity 160.

In another embodiment as shown in FIG. 8, the catalyst is formed by a plurality of conductive segments 190 separated by a plurality of non-conductive segments 195 and mechanically connected thereto. In this embodiment, the catalyst can extend through the excitation port between one point in the cavity and another point outside the cavity, but its electrically discontinuous distribution effectively prevents instantaneous discharge and energy leakage.

Another method of forming plasma according to the present invention includes subjecting the gas in the cavity to electromagnetic radiation with a frequency of less than about 333 GHz in the presence of an active plasma catalyst to generate or include at least one ionized particle.

The active plasma catalyst according to the present invention may be any particle or high-energy wave packet capable of transferring sufficient energy to gaseous atoms or molecules to make the gaseous atoms or molecules lose at least one electron in the presence of electromagnetic radiation. Using a source, ionized particles can be introduced directly into the cavity in the form of a focused or collimated beam, or they can be sprayed, ejected, sputtered or otherwise introduced.

For example, FIG. 9 shows that the electromagnetic radiation source 200 introduces radiation into the electromagnetic radiation cavity 205. The plasma cavity 210 may be disposed in the cavity 205 and allow gas to flow through the ports 215 and 216. The source 220 can introduce ionized particles 225 into the cavity 210. The source 220 can be protected by a metal shield through which the ionized particles can pass, but also shields electromagnetic radiation to the source 220. If necessary, the source 220 can be water-cooled.

Examples of ionized particles according to the present invention may include x-ray particles, gamma-ray particles, alpha particles, beta particles, neutrons, protons, and any combination thereof. Therefore, ionized particle catalysts can be charged (for example, ions from an ion source) or uncharged and can be the product of a radioactive fission process. In one embodiment, the container in which the plasma cavity is formed can be fully or partially transparent

03810273.0 The first ionized particle catalyst. Therefore, when the radioactive fission source is located outside the cavity, the source can guide the fission product through the container to excite the plasma. In order to basically prevent the fission products (such as ionized particle catalysts) from causing safety hazards, the radioactive fission source can be located in the electromagnetic radiation cavity.

In another embodiment, the ionized particle may be a free electron, but it need not be emitted during radioactive decay. For example, electrons can be introduced into the cavity by exciting an electron source (such as a metal) so that the electrons have enough energy to escape from the source. The electron source can be located in the cavity, adjacent to the cavity, or even on the cavity wall. Those of ordinary skill in the art know that any combination of electron sources can be used. The common method of generating electrons is to heat the metal, and these electrons can be further accelerated by the application of an electric field.

In addition to electrons, free energy protons can also be used to catalyze plasma. In one embodiment, free protons can be generated by ionized hydrogen, and are selectively accelerated by an electric field.

Multimode electromagnetic radiation cavity The electromagnetic radiation waveguide, cavity or chamber is configured to support or facilitate the propagation of at least one electromagnetic radiation mode. As used herein, the term "module" refers to any special form of stagnant or propagating electromagnetic wave that satisfies Maxwell's equation and applicable boundary conditions (such as that of a cavity). Within the waveguide or cavity, the mode can be any of various possible forms of propagating or stagnating electromagnetic fields. Each mode is characterized by the frequency and polarization of its electric and/or magnetic field vector. The electromagnetic field form of the mode depends on the frequency, refractive index or permittivity, and the geometry of the waveguide or cavity.

The transverse electric (TE) mode is the mode where the electric field vector is perpendicular to the direction of propagation. Similarly, the transverse magnetic (TM) mode is the mode in which the magnetic field vector is perpendicular to the direction of propagation. The transverse electromagnetic (TEM) mode is a mode in which the electric and magnetic field vectors are perpendicular to the direction of propagation. Hollow metal waveguides generally do not support standard TEM modes for electromagnetic radiation propagation. Although the electromagnetic radiation seems to propagate along the length of the waveguide, it is only reflected at an angle through the inner wall of the waveguide. Therefore, according to the propagation mode, electromagnetic radiation has some electric field components or some magnetic field components along the waveguide axis (usually referred to as the z-axis).

The actual field distribution in the cavity or waveguide is the superposition of its modes. Each mode can be represented by one or more subscripts (such as TEio (Tee ee one zero"). The subscripts generally indicate how many "half waves" at the catheter wavelength are contained in the x and γ directions. Common techniques in the field The person knows that the wavelength of the waveguide is different from the wavelength of free space, because the electromagnetic radiation in the waveguide is reflected at a certain angle through the inner wall of the waveguide. In some cases, a third subscript can be added to define the edge

03810273.0 The number of half waves of the first Z axis in the standing wave form.

For a given frequency of electromagnetic radiation, the size of the waveguide can be selected to be small enough so that it can support a propagation mode. In this case, the system is called a single-mode system (such as a single-mode radiator). In the rectangular single-mode waveguide, the TE10 mode is usually dominant. In addition to waveguides, it should be understood that coaxial cables and radiating antennas can be used.

As the size of the waveguide (or the cavity to which the waveguide is connected) increases, the waveguide or radiator can sometimes support additional higher-order modes, forming a multi-mode system. When it can support multiple modes at the same time, the system is often expressed as highly moded.

A simple single-mode system has at least one maximum and/or minimum field distribution. The maximum magnitude largely depends on the amount of electromagnetic radiation applied to the system. Therefore, the field distribution of a single-mode system is drastically changed and substantially non-uniform.

Unlike a single-mode cavity, a multi-mode cavity can support several propagation modes at the same time, which forms a mixed field distribution form when superimposed. In this form, the field becomes blurred spatially, and therefore the field distribution usually does not show the same intensity type for the minimum and maximum field values in the cavity. In addition, as detailed below, a mode mixer can be used to "mix" or "redistribute" the modes (eg, using the mechanical motion of the electromagnetic radiation reflector). This redistribution is expected to provide a more uniform time-averaged field (and therefore plasma) distribution within the cavity.

The multi-mode cavity according to the present invention can support at least two dies, and can support multiple dies more than two. Each mode has a maximum electric field vector. Although there can be two or more modes, only one mode is dominant and has the largest electric field vector magnitude larger than the other modes. As used herein, the multi-mode cavity can be any cavity in which the ratio between the first and second modulus levels is less than about 1:10, or less than about 1:5, or even less than about 1:2. Those of ordinary skill in the art know that the smaller the ratio is, the smaller the electric field energy between the modes is, so that the electromagnetic radiation energy in the cavity is dispersed.

The distribution of plasma in the cavity is very dependent on the distribution of applied electromagnetic radiation. For example, in a pure single-mode system, there can only be one position of the maximum electric field. Therefore, strong plasma can only be generated in this one location. In many applications, such a strongly localized plasma can undesirably cause inhomogeneous plasma treatment or heating (ie, local overheating and underheating).

According to the present invention, whether single or multi-cavity is used to grow carbon structures, those of ordinary skill in the art

03810273.0 Members know that the cavity in which the plasma is formed can be completely closed or semi-closed. However, in other applications, it may be necessary to flow gas through the cavity, so that the cavity must be opened to some extent. In this way, the flow rate, type and pressure of the flowing gas can be changed over time. This is satisfactory because a specific gas such as nitrogen that facilitates plasma formation is easier to excite, but is not required in the subsequent plasma treatment.

In many applications of synthetic carbon structures, mold mixing requires a uniform plasma in the cavity. However, since electromagnetic radiation can have longer wavelengths (for example, tens of centimeters under microwave radiation), the phosphorus obtains a uniform distribution. As a result, according to one aspect of the present invention, the radiation modes in the multi-mode cavity can be mixed or redistributed within a period of time. Because the field distribution in the cavity must satisfy all the boundary conditions set by the inner surface of the cavity, these field distributions can be changed by changing the position of any part of the inner surface.

In one embodiment according to the present invention, the movable reflective surface is located in the electromagnetic radiation cavity. The shape and movement of the reflective surface will jointly change the inner surface of the cavity during the movement. For example, an L-shaped metal object (ie, "mode mixer") will change the position or direction of the reflective surface in the cavity when rotating around any axis, thereby changing the electromagnetic radiation distribution in it. Any other asymmetrically shaped objects can also be used (when rotating), but symmetrical shaped objects can also work, as long as relative movement (such as rotation, translation or a combination of the two) causes some changes in the position and direction of the reflective surface. In one embodiment, the mold mixer may be a cylinder that rotates around an axis that is not the longitudinal axis of the cylinder.

Each mode in a multi-mode cavity has at least one maximum electric field vector, but each vector periodically appears in the cavity. Generally, assuming that the frequency of electromagnetic radiation does not change, the maximum value is fixed. However, by moving the mode mixer to interact with electromagnetic radiation, it is possible to move the maximum position. For example, the mode mixer 38 may be used to optimize the field distribution in the cavity 12 in order to optimize the plasma excitation conditions and/or plasma maintenance conditions. Therefore, once the plasma is activated, for a uniform time-averaged plasma treatment (such as heating), the position of the mold mixer can be changed to move the maximum position.

Therefore, according to the present invention, mode mixing can be used during plasma excitation. For example, when conductive fibers are used as plasma catalysts, it has been known that the direction of the fibers can strongly influence the least

03810273.0 The first plasma excitation conditions. For example, it is reported that when such fibers are oriented to an electric field greater than 60. From a different perspective, the catalyst rarely improves or relaxes these conditions. However, by moving the reflective surface into or close to the cavity, the electric field distribution can change significantly.

For example, radiation can be injected into the radiator cavity through a rotating waveguide joint installed in the radiator cavity, and mode mixing can also be achieved. In order to effectively emit radiation in different directions in the radiation cavity, the rotary joint can be moved mechanically (such as rotating). As a result, a varying field form can be generated in the radiator cavity.

Radiation is injected into the radiation cavity through the flexible waveguide, and mode mixing can also be realized. In one embodiment, the waveguide may be fixed in the cavity. In another embodiment, the waveguide can extend into the cavity. In order to inject radiation (such as microwave radiation) into the cavity in different directions and/or positions, the position of the end of the flexible waveguide can be moved continuously or periodically (such as bending) in any suitable manner. This movement can also cause mode mixing and contribute to a more uniform plasma treatment (such as heating) on a time average basis. Optionally, this movement can be used to optimize the position of the excited plasma or other plasma-assisted processing, such as synthetic carbon structures.

If the flexible waveguide is rectangular, for example, a simple twist of the open end of the waveguide will cause the direction of the radiated electric and magnetic field vectors in the radiator cavity to rotate. Therefore, the periodic twisting of the waveguide can cause mode mixing and rotation of the electric field, which can be used to assist in exciting, regulating or maintaining the plasma.

Therefore, even if the initial direction of the catalyst is perpendicular to the electric field, the reorientation of the electric field vector can change the ineffective direction to a more effective direction. Those skilled in the art know that mode mixing can be continuous, periodic or pre-programmed.

In addition to plasma excitation, during subsequent plasma treatments, such as synthesis and growth of predetermined carbon structures, such as during the elimination of crystallization, mode mixing can be used to reduce or create (eg adjust) "hot spots" in the cavity. When the electromagnetic radiation cavity supports only a few modes (such as less than 5), one or more local electric field maximums can generate "hot spots" (such as in cavity 12). In one embodiment, these hot spots can be arranged to coincide with one or more separate but simultaneous plasma excitation or carbon structure growth treatments. Therefore, in one embodiment, the plasma catalyst may be placed on one or more of these excitation or coating locations.

03810273.0 The multi-position plasma excitation can use a variety of plasma catalysts in different positions to excite the plasma. In one embodiment, multiple fibers can be used to excite the plasma at different points in the cavity. This multi-point excitation is particularly beneficial when uniform plasma excitation is required. For example, when the plasma is adjusted at high frequency (ie, tens of Hz or higher), or excited in a larger space, or both, the substantially uniform transient impact and re-impingement of the plasma can be improved. Optionally, when the plasma catalyst is used at multiple points, the catalyst can be selectively introduced into these different locations, and the plasma catalyst can be used to continuously excite plasma at different locations in the plasma chamber. In this way, if necessary, a plasma excitation gradient can be controllably formed in the cavity.

Moreover, in a multi-mode cavity, the random distribution of catalysts at multiple positions in the cavity increases the possibility that at least one fiber or any other inert plasma catalyst according to the present invention is optimized for orientation along the line of power. However, even if the catalyst is not oriented optimally (essentially not aligned with the power line), the excitation conditions are improved.

Moreover, since the catalyst powder can be suspended in the gas, it can be considered that each powder particle has the effect of being located at a different physical position in the cavity, thereby improving the uniformity of excitation in the cavity.

Dual-cavity plasma excitation/maintenance The dual-cavity arrangement according to the present invention can be used to excite and maintain plasma. In one embodiment, as shown in FIG. 1B, the system includes at least an excitation chamber 280 and a plasma processing (for example, carbon structure synthesis) chamber 285 that are in fluid communication with each other. As shown in FIG. 1, the cavities 280 and 285 may be disposed in, for example, an electromagnetic radiation cavity (ie, a radiator) 14.

In order to form an excited plasma, the gas in the first excitation chamber 280 is selectively subjected to electromagnetic radiation with a frequency of less than about 333 GHz in the presence of a plasma catalyst. In this way, the proximity of the first and second cavities allows the plasma 600 formed in the cavity 280 to excite the plasma 610 in the cavity 285, which can be maintained by additional electromagnetic radiation. For example, the additional cavities 290 and 295 are optional and can be maintained in fluid communication with the cavity 285 through the channel 605. The substrate on which the carbon structure is desired to be synthesized and grown, such as the substrate 250, can be placed in any of the cavities 285, 290, or 295, and can be supported by any type of support device such as a support 260, which is used in the synthesis and The substrate 250 is selectively moved or rotated during the growth process.

03810273.0 First, in an embodiment of the present invention, the cavity 280 can be very small and mainly or only provided for plasma excitation. In this way, very little electromagnetic radiation energy is required to excite the plasma 600, which makes the excitation easier, especially when the plasma catalyst according to the present invention is used. It should also be understood that the cavity used in the plasma system of the present invention can have an indefinite size, and a controller can be used to control the size of the cavity.

In one embodiment, cavity 280 is substantially a single-mode cavity and cavity 285 is a multi-mode cavity. When the cavity 280 only supports a single mode, the electric field distribution in the cavity will change drastically, forming one or more accurately positioned electric field maximums. The maximum value is generally the first position where the plasma is excited, and it is taken as an ideal point for placing the plasma catalyst. However, it should be understood that when the plasma catalyst is used to excite the plasma 600, the catalyst does not need to be set at the maximum electric field, and in most cases, it does not need to be oriented in a specific direction.

Synthetic carbon structure FIGS. 1-14 show embodiments of the method and apparatus for synthesizing one or more predetermined carbon structures on one or more substrates according to the present invention. Here, the word "synthesis" refers to the formation and/or growth of structures including carbon and any other atoms or molecules with or without the use of catalytic surfaces or seeds.

As mentioned above, FIG. 10 shows how to use a dual-cavity system to excite plasma in one cavity and then use it to form plasma in the other cavity. Figure 10 also shows how to add additional cavities in sequence when needed. It should be understood that carbon structures can be formed in any cavity, or environmental conditions can be precisely adjusted to synthesize and grow multiple carbon structures in different cavities simultaneously in a continuous or periodic plasma treatment process.

FIG. 11 shows a flowchart of a plasma assisted method 645 for synthesizing a carbon structure using a catalyzed plasma according to the present invention. In this method, for example, in the presence of a plasma catalyst, a plasma is formed in step 650 by subjecting the gas to electromagnetic radiation. As mentioned above, the present invention can use any plasma catalyst, such as an inert plasma catalyst or an active plasma catalyst, to excite the plasma and then adjust or maintain the plasma.

In step 655, at least one carbonaceous material is added to the plasma. The carbon-containing material may be a final desired carbon structure or a precursor of a carbon-containing compound. For example, some precursor materials such as

03810273.0 Graphite or crucible (such as methane), introduced into the plasma in solid, liquid or gaseous form. These precursors will decompose in the plasma and leave the carbon element, as described in the previous example, synthesize one or more carbon structures. These carbon-containing materials can themselves be plasma catalysts, and thus will be consumed by the plasma during the addition process.

After the carbon-containing material is added to the plasma in step 655, one or more predetermined carbon structures (for example, on the surface of the substrate) can be synthesized in step 660. Those of ordinary skill in the art should know that almost any material can be used as a substrate, especially a material with a crystal structure. For example, the substrate can be a semiconductor, such as elemental semiconductors (such as C, Ge, Si&gt; α-Sn (gray tin), P, Se, Te, etc.) or compound semiconductors (such as GaAs, GaP, GaN, InP, SiGe, SiC) , GaAsP, GaAIAs, InGaAs, InGaP, ZnSe, ZnO, HgTe, etc.). Alternatively, the substrate may be an insulator or an insulating material containing one or more semiconductor layers (such as silicon-on-insulator "SOI"). Other materials including organic and inorganic compounds, alloys and structures can also be used as the substrate.

Different substrates can be used to synthesize different predetermined carbon structures. In addition, the substrate may be a special type of patterned structure, a catalytic surface, or any type of ordered or disordered seed crystal.

For example, arrays, pillars, or other surface features can be formed on the surface of a substrate (such as a semiconductor or oxide substrate) to form a surface for preferential synthesis of a given carbon structure. The specific predetermined carbon structure depends on the specific array or column size and crystal structure used. These surfaces can be catalytic (such as darts, diamonds, iron powder, particles including nano-sized powders or other seed materials), but not necessarily (such as nanotubes). Therefore, the crystal structure of the catalytic surface can determine the location and type of carbon structure synthesis. In this regard, a single surface may include multiple surface portions having different crystal structures and characteristics.

The carbon structure synthesis according to the present invention can be realized using the exemplary apparatus shown in FIG. 12. In this device, in the presence of the plasma catalyst 240, by subjecting the gas to electromagnetic radiation to excite plasma in the cavity 230, one or more carbon structures are synthesized on the substrate 250. However, it should be known that catalyzed or uncatalyzed plasma can be used to synthesize the carbon structure according to the present invention.

In the presence of the plasma catalyst 240, for example, it can be placed on the support 245

03810273.0 First, the plasma 615 is formed in the cavity 230 by subjecting the gas to a certain amount of electromagnetic radiation, and the carbon structure synthesis is realized on the first surface of the substrate 250. In addition, the laser 500 can provide a laser beam through the optical window 505 to excite (such as by evaporation, sublimation or sputtering) the carbonaceous material 510 in the kettle 515. Anything that can be evaporated, sublimated or sputtered when exposed to the laser 500 Solid or liquid materials can be used as the carbon-containing material 510, including the plasma catalyst 240. Therefore, the carbon-containing material 510 plays a dual role in synthesizing and growing a predetermined carbon structure, and can not only catalyze plasma but also provide a carbon source. Alternatively, gas may be injected into the path of the laser beam.

In addition to the laser 500, other types of energy sources, including, for example, particle beams, carrier gas, etc., can also be used to excite the carbon-containing material 510.

In one embodiment, the laser 500 generates a light beam with a wavelength of about 150 nm to 20 μm, although other convenient wavelengths can also be used. It should be understood that the laser 500 can also be replaced by an incoherent light source. The laser 500 can also be a pulsed laser beam with high peak energy, which can excite the carbon-containing material 510 continuously, periodically, or in a predetermined program. A carrier gas such as nitrogen (not shown) or any other carrier gas as described above The excited (eg evaporated) carbon-containing material may be introduced into the plasma 615 to form a predetermined carbon structure on the substrate 250. It should be understood that the substrate 250 can be moved by using a support 260 (such as a turntable), so that the uniformity of growth on the surface of the substrate 250 can be changed (such as increased). For example, if the substrate 250 contains one or more seed crystals or other catalytic surface structures 251, the moving surface 250 can be used to preferably increase the synthesis of one or more carbon structures 252.

Thus, the carbon-containing material 510 can be excited by the laser 500 to enhance the plasma 615 generated by using the plasma catalyst 240 to catalyze the gas. It should be understood that although FIG. 12 only shows a single cavity system, two or more cavity systems as shown in FIG. 10 may also be used in the present invention.

Those skilled in the art should understand that the plasma assist system for synthesizing carbon structures in the present invention may include any electronic or mechanical method for introducing the catalyst into the plasma chamber. For example, the fibers can be mechanically inserted before or during plasma formation. Those skilled in the art should also understand that the plasma 615 can also be excited by a cremation plug, a pulsed laser, or even a burning matchstick introduced into the cavity 230, and this process can be before, during, or after the supply of electromagnetic radiation.

It should also be understood that the carbonaceous material 510 can be separated from the plasma 615 during synthesis to improve

03810273.0 Better control the introduction of materials into the plasma. To achieve this, one or more walls or screens (not shown) can be placed between the carbonaceous material 510 and the plasma 615 in the pot 515. Other methods of shielding electromagnetic radiation or plasma can also be used.

The plasma 615 can absorb an appropriate amount of electromagnetic radiation energy to achieve any predetermined temperature distribution (such as any selected temperature). In another embodiment of the present invention, by adjusting the magnetic field distribution in the cavity 230, such as mode mixing, the temperature at any synthesis position can be controlled. In addition, by adjusting the plasma 615 in the cavity 230 using a fixed or variable duty cycle, the temperature can be controlled. The air pressure in the cavity 615 may be lower than, equal to, or greater than atmospheric pressure. At least one additional carbon-containing material (not shown) is added to the plasma 615, so that a multi-component or multi-level carbon structure can be formed on the surface of the substrate 250. The rate of gas flow through the cavity can also be used to control the temperature of the plasma.

Figure 13 shows another embodiment of the present invention in which the synthesis of the predetermined carbon structure takes place outside the plasma chamber. In this example, the cavity 292 has an opening 410 that may be located at or near the bottom of the cavity 292 in order to prevent the plasma 620 from escaping from the cavity 292. However, it should be understood that the opening 410 may be located anywhere in the cavity 292. The substrate 250 can be supported by the support 260 and can rotate arbitrarily or move with the opening 410. The plasma 620 in the cavity 292 may include one or more carbonaceous materials, which may be deposited on the surface of the substrate 250.

The plasma 620 in the cavity 292 may be maintained or adjusted, and the substrate 250 may be maintained at any desired temperature, for example, substantially lower than the temperature of the plasma 620 to increase the deposition rate and adhesion of the carbonaceous material. Then, by using the plasma 620 as a heat source or any other external heat source (not shown) to grow the deposited carbon-containing material, a predetermined carbon structure region 252 may be formed. The advantage of using the plasma 620 as the heat source is that the entire substrate does not need to be heated, so that the carbon structure can be selected spatially for synthesis. This is very useful when the prefabricated substrate contains other temperature-sensitive components. In addition, the support 260 may be heated or cooled by an external device (such as a heat exchanger) to maintain the substrate 250 at a desired temperature. For example, a cooled fluid (such as a gas) can be used to cool the substrate 250 before, during, or after the carbon growth process.

It should be understood that the carbonaceous material passing through the opening 410 may be combined with one or more other materials or gases (not shown) inside or outside the cavity 292 to obtain the desired carbon composition. Should also

03810273.0 It is understood that the material is in the form of plasma, such as the form of plasma spray, passing through the opening 410.

Although the plasma can be excited, adjusted, or maintained at atmospheric pressure (such as using a regulated carrier gas flow) according to the present invention, the plasma can be excited, adjusted, or maintained at the same or different pressures, including conditions lower than, equal to, or higher than atmospheric pressure. A predetermined carbon structure can be synthesized and grown on the bottom 250. Further, as described above, the pressure and temperature of the plasma can be adjusted as required. For example, using a system (as shown in Figure 10) allows the technician to adjust or maintain the plasma 610 in the chamber 285 at atmospheric pressure, and when it is above or below the atmospheric pressure, in another chamber (such as 285, 290 or 295) A predetermined carbon structure is synthesized and grown on the substrate 250. This flexibility can be very useful, for example, in large-scale manufacturing processes.

Figure 14 shows a cross-sectional view of the inner surface of the cavity 230 that includes surface features, such as one or more topographical features. These features can be used to form selective regions of the synthetic carbon structure on the conductive substrate 250. For example, by providing a sufficient gap between the surface of the substrate 250 and the inner surface of the cavity 230, the plasma 320 at a predetermined position on the surface of the substrate 250 can be adjusted or maintained. For example, when the gap is at least about /4 (for example, lower than the surface 320), where the input is the wavelength of the applied electromagnetic radiation, the plasma 320 can be formed and a predetermined carbon can be synthesized near the plasma 320, such as the seed region 253. structure. Conversely, when the void is less than approximately 1/4 (below the surface 300), little or no plasma is formed, so the carbonaceous material will not deposit. Thus, a predetermined carbon structure can be selectively synthesized and grown on the carbon structure seed region 253 near the plasma, but the synthesis and growth of the carbon structure where the plasma is inhibited is also selectively and sexually inhibited. It should be understood that the graph shown in Figure 14 is not the only possible graph.

It should be understood that the plasma formation depends on the wavelength caused by the boundary conditions imposed by the conductive surface, such as the inner metal surface of the cavity. When a non-metallic surface is used, the volume of the local plasma will be increased or decreased. For example, the reduction in volume can limit the intensity of the plasma and thus the energy flow near the catalytic surface.

Although FIG. 14 shows that the inner surface of the cavity 230 has protruding or recessed surface features, it should be understood that these features may also be located on the substrate 250, and the inner surface of the cavity 230 may be relatively flat or smooth.

03810273.0 First, the surface features on the substrate 250 can effectively act as a mask during the synthesis of the carbon structure to limit the locations where the structure is allowed to grow. This "mask" can be the substrate itself, or photoresist, such as the analog used in the semiconductor industry, or any other material used to change the geometry of the predetermined carbon structure grown on the seed region (such as Designed to prevent the synthesis and growth of a sacrificial film of carbon structure on certain areas such as semiconductor devices). For example, the mask may be a negative or positive photoresist, deposited metal, oxide, or other material used to form the desired carbon structure area in a permanent or temporary manner.

The advantage of using the catalytic plasma synthesis carbon structure according to the present invention is that during synthesis, even when the cavity is in a relatively high pressure state, a highly selective carbon-containing substance can be generated on the substrate 250 according to changes in the concentration and position of the carbonaceous material. Growth rate.

It should be understood that other single-element or multi-element carbon structures not discussed above can also be formed according to the present invention.

In the foregoing embodiments, in order to simplify the description, various features are grouped in a single embodiment. This method of disclosure does not mean that the claims of the present invention claim more features than those explicitly stated in each claim. Rather, as described in the following claims, the inventive aspect is less than all the features of the single embodiment disclosed above. Therefore, the following claims are added to this specific embodiment, and each claim itself serves as a separate preferred embodiment of the present invention.

03810273.0