Generation of reactive oxygen species

Abstract

A method and system for generating reactive oxygen species are disclosed. The photoreactor has a reaction chamber, the inlet to the reaction chamber is configured to be coupled to an oxygen source containing molecular oxygen. A photoexcitation source is optically coupled to the reaction chamber and is configured to generate synchrotron radiation in the ultraviolet wavelength range. The synchrotron radiation excites some of the molecular oxygen in the reaction chamber without using a plasma generator to form atomic oxygen, which then reacts with the molecular oxygen in the reaction chamber to form ozone. The outlet of the reaction chamber is configured to release a gas mixture containing atomic oxygen, molecular oxygen, and ozone.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to U.S. Provisional Application No. 63 / 508,068, filed on 14 June 2023, entitled “Generation of Reactive Oxygen Species,” the entirety of which is incorporated herein by reference. [Background technology]

[0002] The film deposition process for various materials, including those used in the manufacture of semiconductor materials, relies on the generation of precursor materials. These precursor materials bond at the deposition surface to form the desired compound layer. For oxide layer deposition, conventionally, a first source supplies non-oxide components in vapor form, while another source supplies one or more reactive oxygen species capable of donating a single oxygen atom (e.g., oxygen plasma, ozone, atomic oxygen) to form the oxide layer at the deposition surface. For the formation of more complex oxides, an additional source of non-oxide components may be used.

[0003] In one embodiment, ozone, which is a reactive oxygen species, may be formed using a dielectric barrier discharge (DBD) type ozone generator. Molecular oxygen is treated using a series of electrostatic plates to which a high voltage (e.g., 10kV) is applied to form ozone. In this embodiment, molecular oxygen is dissociated by electron collisions, and atomic oxygen is produced (i.e., O2+e - →2O * ). Next, ozone is formed by the reaction of molecular oxygen and atomic oxygen (i.e., O2 + O * →O3). However, this DBD process can only produce an ozone-oxygen mixture gas with an ozone concentration of about 1%. To obtain an ozone concentration suitable for the film deposition process, the output of the DBD ozone generator must be further processed by cryogenic distillation. This process is carried out at a temperature of about 4K, forming liquid ozone with a concentration of about 90%, which is then stored at cryogenic temperatures. Next, to obtain ozone for the film deposition process, a predetermined amount of the stored liquid ozone is "boiled" and vaporized.

[0004] In another example of a system that generates reactive oxygen species in the form of atomic oxygen, a selected flow rate of molecular oxygen is introduced through an inlet into a vacuum chamber that also has an outlet. A high-frequency (RF) microwave field is applied to the contents of the vacuum chamber, and a plasma is formed, thereby generating atomic oxygen from molecular oxygen. Generally, the inlet and outlet of the microwave vacuum chamber are 1 × 10⁻¹⁶, suitable for thin-film deposition. -6 Torr~100×10 -6 The Torr is configured to generate atomic oxygen at its outlet pressure. In these plasma-based processes, the atomic oxygen generation efficiency is typically around 1% to 5%.

[0005] As a further example of an existing system, a film deposition system forms an oxide thin film through a reaction with the surface of a substrate. In this embodiment, oxygen gas is introduced into a chamber, and an ultraviolet lamp is used to ionize the oxygen gas on the surface of the substrate (e.g., silicon). A separate laser light source is used to raise the temperature of the substrate and produce a thin film (e.g., a silicon oxide film). [Overview of the project] [Means for solving the problem]

[0006] In some embodiments, a system for generating reactive oxygen species has a reaction chamber, the inlet of which is configured to be coupled to an oxygen source containing molecular oxygen. A photoexcitation source is optically coupled to the reaction chamber and is configured to generate synchrotron radiation in the ultraviolet wavelength range. The synchrotron radiation is configured to excite some of the molecular oxygen in the reaction chamber without using a plasma generator to form atomic oxygen, which then reacts with the molecular oxygen in the reaction chamber to form ozone. The outlet of the reaction chamber is configured to release a gas mixture containing atomic oxygen, molecular oxygen, and ozone.

[0007] In some embodiments, a method for generating reactive oxygen species includes introducing molecular oxygen into the inlet of a reaction chamber and generating synchrotron radiation in the reaction chamber from a photoexcitation source to excite a portion of the molecular oxygen and form atomic oxygen. The synchrotron radiation is in the ultraviolet wavelength range. The method also includes reacting molecular oxygen and atomic oxygen present in the reaction chamber to form ozone without using a plasma generator, and releasing a gas mixture containing atomic oxygen, molecular oxygen, and ozone from the outlet of the reaction chamber.

[0008] In some embodiments, a system for forming an oxide film includes a material deposition system and a photoreactor. The photoreactor comprises a reaction chamber and an inlet to the reaction chamber, the inlet being configured to be coupled to an oxygen source containing molecular oxygen. A photoexcitation source is optically coupled to the reaction chamber and is configured to generate synchrotron radiation in the ultraviolet wavelength range. The synchrotron radiation is configured to excite some of the molecular oxygen in the reaction chamber without using a plasma generator to form atomic oxygen, which then reacts with the molecular oxygen in the reaction chamber to form ozone. The outlet of the reaction chamber is coupled to the material deposition system to deliver a gas mixture containing atomic oxygen, molecular oxygen, and ozone.

[0009] Embodiments of this disclosure will be described with reference to the accompanying drawings. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of a system for generating reactive oxygen species according to several embodiments. [Figure 2] Figure 1 is a schematic diagram of a photoreactor of the system shown in several embodiments. [Figure 3A] This graph shows the absorption spectra of molecular oxygen and ozone in the range from vacuum ultraviolet (VUV) to ultraviolet (UV) wavelengths. [Figure 3B]This graph shows the absorption spectra of molecular oxygen and ozone in the range from vacuum ultraviolet (VUV) to ultraviolet (UV) wavelengths. [Figure 4] This plot shows the absorption selectivity of ozone for molecular oxygen at three selected excimer wavelengths. [Figure 5] This graph shows the effective pathway length of molecular oxygen as a function of reaction chamber pressure at a selected excimer wavelength shown in Figure 4, according to several embodiments. [Figure 6] This is a flowchart of a method for generating reactive oxygen species according to several embodiments. [Figure 7] This is a reaction pathway diagram showing, according to several embodiments, the pathway through which molecular oxygen is formed from atomic oxygen, the pathway through which molecular oxygen and atomic oxygen combine to form ozone, and the pathway through which ozone dissociates to become molecular oxygen. [Figure 8A] Figure 7 is a graph showing the concentration changes of molecular oxygen, atomic oxygen, and ozone in a reaction chamber with a 172 nm excitation source, relating to the reaction pathway diagram shown. [Figure 8B] This graph shows the general dependence of ozone and atomic oxygen concentrations on the output of a photoexcitation source according to several embodiments. [Figure 9A] The following are various nozzle designs for use in the photoreactor of the present disclosure, according to several embodiments. [Figure 9B] The following are various nozzle designs for use in the photoreactor of the present disclosure, according to several embodiments. [Figure 9C] The following are various nozzle designs for use in the photoreactor of the present disclosure, according to several embodiments. [Figure 9D] The following are side views illustrating the exemplary angular distribution of a gas mixture emitted from a beamforming nozzle according to several embodiments. [Figure 9E] The following are side views illustrating the exemplary angular distribution of a gas mixture emitted from a beamforming nozzle according to several embodiments. [Figure 10A]This is a graph of the ozone absorption spectrum in the ultraviolet C (UVC) wavelength range, showing an absorption peak at approximately 250 nm for use as a probe wavelength, according to some embodiments. [Figure 10B] This is a graph of the deuterium emission spectrum according to several embodiments. [Figure 10C] This graph shows the transmittance of a photoreactor as a function of its absorption wavelength, according to several embodiments. [Figure 10D] This is a schematic diagram of a concentration monitoring system for measuring the concentration of ozone and / or atomic oxygen generated in the reaction chamber of a photoreactor, according to several embodiments. [Figure 10E] This is a schematic diagram of a concentration monitoring system for measuring the concentration of ozone and / or atomic oxygen generated in the reaction chamber of a photoreactor, according to several embodiments. [Figure 11A] Isometric and bottom views of photoreactors according to several embodiments are shown. [Figure 11B] Isometric and bottom views of photoreactors according to several embodiments are shown. [Figure 12A] The front and rear perspective views of the excitation source according to several embodiments are shown, respectively. [Figure 12B] The front and rear perspective views of the excitation source according to several embodiments are shown, respectively. [Figure 13A] Various diagrams of photoreactors according to several embodiments are shown. [Figure 13B] Various diagrams of photoreactors according to several embodiments are shown. [Figure 13C] Various diagrams of photoreactors according to several embodiments are shown. [Figure 13D] Various diagrams of photoreactors according to several embodiments are shown. [Figure 13E] Various diagrams of photoreactors according to several embodiments are shown. [Figure 14A] Two side views of a photoreactor equipped with a concentration monitor, according to several embodiments, are shown. [Figure 14B]Two side views of a photoreactor equipped with a concentration monitor, according to several embodiments, are shown. [Figure 15] This is a diagram of a film deposition configuration incorporating a reactive oxygen species generation system according to several embodiments. This is a conceptual diagram of a film deposition arrangement incorporating a reactive oxygen species generation system. [Modes for carrying out the invention]

[0011] In the following description, similar reference numerals indicate the same or corresponding parts throughout the drawings.

[0012] This disclosure relates to the generation of reactive oxygen species for processes requiring ozone species, etc. The reactive oxygen species generated by this system and method include ozone and atomic oxygen. Processes in which the system and method described herein can be used include, for example, material deposition processes for forming (manufacturing) layers of semiconductor materials. In some embodiments, this disclosure relates to the generation of reactive oxygen species for forming oxide-related layers in deposition processes.

[0013] While technologies exist for generating reactive oxygen species as described above, these technologies have drawbacks. For example, conventional processes using DBD ozone generators produce ozone in the form of liquid ozone. As is understood, liquid ozone is highly reactive, and because oxygen formation is an exothermic reaction, it can cause explosions, requiring strict hazard control procedures for safe use. Furthermore, any valve can react with ozone and be oxidized to form oxygen, which is also dangerous. In addition, the capital investment costs associated with generating ozone through a process combining DBD and cryogenic distillation are substantial. In another example, the technology of generating atomic oxygen by creating a plasma using an RF microwave field in a vacuum chamber also has drawbacks. This plasma-based reactive oxygen species generation process does not require cryogenic storage (unlike the ozone generation process described above) and can supply atomic oxygen "at the point of use," but its efficiency is usually extremely low, producing only 1% to 5% atomic oxygen at a time of atomic oxygen / molecular oxygen output. As those skilled in the art will understand, the presence of high concentrations of molecular oxygen not only inhibits the film deposition process but also risks causing oxidation of the heating elements involved in the film deposition process.

[0014] This disclosure provides various methods, apparatuses, and systems for the continuous and on-demand generation of reactive oxygen species. Unlike conventional configurations, the reactive oxygen generation methods and systems according to this disclosure can be configured to generate a continuous beam containing reactive oxygen species without requiring hazardous storage configurations. A continuous beam containing ozone (or reactive oxygen species) can be generated in minutes or hours, depending on the requirements of the film deposition process in which ozone is supplied. For example, a continuous beam containing ozone (or reactive oxygen species) can be generated for at least 1 minute, at least 10 minutes, at least 1 hour, up to 10 hours, or more than 10 hours, or in the range of 1 minute to 100 hours. In some examples, the concentration of ozone (or other reactive oxygen species) in the generated gas mixture is at least 5%, at least 6%, at least 7%, or at least 10%, and in other examples it may be more than 30% or more than 40%.

[0015] Aspects of this disclosure focus on the existence of reaction chamber sizes and pressure ranges that are favorable to both i) the generation of highly reactive atomic oxygen from molecular oxygen by photodissociation, and ii) the formation of ozone within the reaction chamber, in contrast to competing reactions that reduce ozone concentration. The trade-offs required to balance various factors in order to properly form ozone at an appropriate level for material deposition are complex and not easy to achieve. These trade-offs are addressed in this disclosure by leveraging unique insights into the interactions between these factors and special design features in the systems and methods for ozone generation. Embodiments enable the stable generation and supply of reactive oxygen species on demand, such as in a continuous flow.

[0016] Figure 1 is a block diagram of a system 100 for generating reactive oxygen species according to an embodiment. In this embodiment, system 100 comprises a molecular oxygen source 110 and a photoreactor 120 configured to emit reactive oxygen species as a beam, and possibly as a continuous beam, from a photoreactor 120 (i.e., a photoreaction chamber). System 100 may be coupled to a containment chamber 150 that utilizes the reactive oxygen species generated by the photoreactor 120. In some embodiments, the containment chamber 150 may be a chamber for a material deposition system, such as a molecular beam epitaxy system.

[0017] Figure 2 shows a schematic cross-sectional view of a photoreactor 200 corresponding to the photoreactor 120 of the reactive oxygen species generation system shown in Figure 1, as an example. In this embodiment, the photoreactor 200 comprises a reaction chamber 210, an inlet 220 to the reaction chamber 210, and an outlet 240 from the reaction chamber 210. The reaction chamber 210 has a volume V チャンバ It has pressure P チャンバ The pressure sensor 212 is coupled to the reaction chamber 210 as described throughout this disclosure, and operates at the pressure P inside the reaction chamber 210. チャンバ(i.e., the operating pressure, the operating pressure, the chamber pressure) is monitored before, during, and / or after the generation of reactive oxygen species. The inlet 220 (diameter D 流入口 ) is coupled to a source containing molecular oxygen (e.g., the molecular oxygen source 110 of FIG. 1) and is configured to introduce molecular oxygen into the reaction chamber 210 as the injection gas 225 at a flow rate F 流入口 . The outlet 240 having a diameter D 排出口 is configured to emit a beam 290 of reactive oxygen species in the form of a gas mixture containing atomic oxygen, molecular oxygen, and ozone (flow rate F 排出口 ).

[0018] The photoexcitation source 230a or 230b is optically coupled to the reaction chamber 210 such that the photoexcitation sources 230a and 230b transmit only the emitted light into the reaction chamber 210 without accompanying physical particles. In some embodiments, the photoreactor 200 may utilize the photoexcitation source 230a located inside the reaction chamber 210. In one embodiment, the photoexcitation source 230a may be located at the center within the reaction chamber 210 and may have a cylindrical shape that emits emitted light into the chamber. In some embodiments, the photoreactor 200 may utilize the photoexcitation source 230b located outside the reaction chamber. The photoexcitation source 230b is optically coupled to the inside of the reaction chamber through a window 235 that is optically transparent to the light emitted from the photoexcitation source 230b (i.e., the emitted light). In one of the illustrated embodiments, the photoexcitation source 230b may be a planar light source (not a cylindrical light source) that optically transmits the emitted light into the inside of the reaction chamber 210 through the window 235.

[0019] The photoexcitation sources 230a and 230b are configured to generate synchrotron radiation in the ultraviolet wavelength range. The wavelength range generated by the photoexcitation sources 230a and 230b may include the ultraviolet (UV) wavelength range of 110 nm to 400 nm, for example, the vacuum ultraviolet (VUV) wavelength range of 125 nm to 180 nm. The photoexcitation sources 230a and 230b have the function of optically exciting a portion of the molecular oxygen (derived from the injected gas 225) introduced into the reaction chamber to form atomic oxygen by photodissociation. The atomic oxygen then reacts with the molecular oxygen present in the reaction chamber 210 to form ozone. As a result, a gas mixture containing atomic oxygen, molecular oxygen, and ozone is formed in the reaction chamber 210. The gas mixture is fed with a beam profile as described herein, with a flow rate F as the beam 290 of reactive oxygen species. 排出口 It is then discharged from outlet 240.

[0020] Furthermore, the photoreactor 200 is equipped with a beamforming nozzle 245 at its outlet 240, and the nozzle 245 has an opening 246 through which the gas flow passes. The beam profile formation characteristics of the beamforming nozzle 245 are mainly determined by the characteristic length L of the nozzle in the direction of emission. ノズル , and mainly the representative diameter D of the nozzle opening ノズル Nozzle conductance Q ノズル This depends on the following: In this way, the beam profile of the photoreactor 200 and the operating pressure of the outlet can be configured according to the requirements of the film deposition process to which the beam 290 of reactive oxygen species is delivered.

[0021] This paper describes the configuration of photoreactor 200, which is uniquely designed to produce a gas mixture containing reactive oxygen species. Technical insights into the factors influencing the reactions between molecular oxygen, atomic oxygen, and ozone, as well as how to address the complex interactions between these factors, could not be easily derived from conventional practices and required a novel approach.

[0022] Referring to Figure 3A, Graph 300 shows experimental results for the absorption spectra of molecular oxygen and ozone. Absorption section α (a measure of the ability or probability of a molecule absorbing photons, in units of cm) 2The molecule ( / molecule) is plotted on the Y-axis as a function of wavelength λ (nanometers) on the X-axis. The spectrum extends from vacuum ultraviolet to ultraviolet wavelengths, and further beyond these ranges to approximately 700 nm. Graph 301 in Figure 3B shows similar experimental results to those in Figure 3A, but Graph 301 focuses on the VUV wavelength range, showing the spectrum in the wavelength range of 130 nm to 190 nm.

[0023] Figure 3A shows two absorption spectra for molecular oxygen; the first spectrum is in the 116 nm to 244 nm range, shown by curve 310, and the second spectrum is in the 235 nm to 389 nm range, shown by curve 315. Curves 310 and 315 correspond to two different datasets. Curve 320 is the absorption spectrum for ozone. As can be seen from Figures 3A and 3B, in the wavelength range of 136 nm to 172 nm, the absorption spectrum of molecular oxygen (curve 310) is approximately equivalent to or better than the absorption spectrum of ozone (curve 320).

[0024] The embodiments of this disclosure utilize the finding that molecular oxygen has higher synchrotron radiation absorption than ozone at certain VUV wavelengths. In some embodiments, the photoexcitation sources 230a and 230b of the photoreactor 200 generate synchrotron radiation in the VUV wavelength range, such as generating synchrotron radiation in the 125 nm to 180 nm wavelength band. In this way, molecular oxygen is excited by photodissociation to produce atomic oxygen. By carefully designing the photoreactor and balancing the reaction conditions using the technical knowledge described herein, a balance is reached between the photodissociation of molecular oxygen and competing reactions (see Figure 7), and ozone is produced.

[0025] In some embodiments, the photoexcitation sources 230a and 230b may include one or more light-emitting diodes, laser light sources, or gas discharge light sources. In some embodiments, the photoexcitation sources 230a and 230b are excimer lamps. Various excimer lamps have different emission wavelengths, as shown in Table 1, depending on the excimer molecule being operated on. As shown in Table 1, these wavelengths are in the VUV range and can be used in the photoreactor system if carefully designed with other reactants in mind, as described herein.

[0026] [Table 1]

[0027] Referring to Figure 4, Chart 400 shows the calculated absorption selectivity of molecular oxygen and ozone for three selected excimer wavelengths, which was derived based on the data in Figures 3A and 3B. The value on the Y axis represents the absorption selectivity of molecular oxygen at a specific excimer wavelength ("α(O2(λ)"). ex ))」) and the absorption selectivity of ozone at the relevant excimer wavelength ("α(O3(λ ex This is the inverse square root of the ratio of ))」」). Rod 410 shows the result at 146 nm (Kr2*), rod 420 shows 172 nm (Xe2*), and rod 430 shows 193 nm (ArF*). As shown, the absorption selectivity of molecular oxygen to ozone decreases as the wavelength increases.

[0028] Figure 5 shows Graph 500, modeled according to this disclosure, relating to the effective pathway length of molecular oxygen before photodissociation. For the selected excimer wavelengths shown in Figure 4, the penetration depth of molecular oxygen (centimeters) on the Y-axis is plotted as a function of the pressure of molecular oxygen in the reaction chamber (Torr) on the X-axis. Graph 500 has a cylindrical structure and is 0.02 m 3A reaction chamber with a constant volume V operating at ambient temperature T is assumed. Lines 510, 520, and 530 represent the penetration depth as a function of pressure when exposed to 146 nm, 172 nm, and 193 nm. As can be seen from Graph 500, the expected penetration depth before oxygen molecules are excited and form atomic oxygen by photodissociation decreases as the pressure in the reaction chamber increases. Furthermore, the expected penetration depth is wavelength-dependent, and within this range, the shorter the excitation wavelength, the lower the depth. This is consistent with Figure 3B, where the absorption cross-section increases as the wavelength decreases in this wavelength range (146-193 nm).

[0029] Using Graph 500, it is possible to determine the operating pressure of a reaction chamber having characteristic dimensions (e.g., diameter, width, and / or length of approximately 0.1m to 1m) for a selected wavelength. As an example, the pressure inside the photoreactor is 10, depending on the configuration of the photoreactor. -4 Torr~10 2 Torr (approximately 10 -2 Pascal ~10 4The pressure can be in the range of Pascals. The pressure, chamber size, and excitation wavelength are selected so that molecular oxygen is photodissociated in the reaction chamber to form atomic oxygen within a specific timescale, e.g., at least a few seconds or tens of seconds. These system configurations are further selected to preferentially select the formation of ozone by the bonding of molecular oxygen and atomic oxygen over the competing reaction of molecular oxygen formation by the reaction of ozone with atomic oxygen (see, e.g., Figure 7). A longer reaction timescale means that the residence time of molecular oxygen in the reaction chamber is long enough to allow the molecular oxygen to absorb light and produce ozone. The residence time is based on a balance of various design factors, including chamber pressure, chamber volume, wavelength of the photoexcitation source, and molecular oxygen flow rate. By achieving conditions suitable for the reaction chain to occur, the ozone concentration in the resulting gas mixture can be at least 5%, or at least 6%, or at least 7%, or at least 10%, or 10–15%, or at least 30%. In some cases, the chamber size is selected based on penetration depth to ensure that the majority of molecular oxygen is photodissociated. The proportion of molecular oxygen that photodissociates affects the rate of ozone production compared to competing reactions, and thereby can affect the reaction timescale and / or the residence time of ozone and other reactive oxygen species in the chamber.

[0030] In some embodiments, a xenon excimer lamp with an excitation wavelength of 172 nm is used as the photoexcitation source for the photoreactor. Xenon excimer lamps have the advantage of being commercially available and, as shown in Figure 4, also exhibit relatively good absorption selectivity for ozone. In some embodiments, the photoexcitation source may be configured to operate in an extended wavelength range. In such cases, the absorption selectivity of oxygen for ozone decreases significantly at wavelengths above 180 nm (see Figures 3B and 4), so the operation of the photoreactor may be adjusted accordingly.

[0031] Figure 6 shows a flowchart of a method 600 for generating a beam containing reactive oxygen species according to an embodiment. This method can be used in the manufacture of semiconductor materials such as oxide films. In some embodiments, method 600 may use the reactive oxygen species generation system 100 shown in Figure 1 and the photoreactor 200 shown in Figure 2, or systems of other embodiments disclosed herein. In some embodiments, the pressure in the reaction chamber 210 may be higher than the pressure in the containment chamber of the film deposition process (e.g., the containment chamber 150 in Figure 1), and the pressure in the containment chamber may be a vacuum environment. That is, the containment chamber may be a vacuum chamber. In some embodiments, the beam containing reactive oxygen species is supplied to a film deposition process such as molecular beam epitaxy, in which the discharge pressure at the outlet is 10 depending on the film deposition conditions. -5 Torr~10 -8 Torr (approximately 10 -3 Pa~10 -6 It may be required that the range be within Pa.

[0032] In block 610, molecular oxygen is introduced into the inlet 220 of the reaction chamber 210. In block 620, synchrotron radiation is generated from a photoexcitation source 230a (inside the reaction chamber) or a photoexcitation source 230b (outside the reaction chamber), and a portion of the molecular oxygen in the reaction chamber is excited. In some embodiments, the ultraviolet wavelength range of the synchrotron radiation generated by the photoexcitation source is 125 nm to 180 nm, 172 nm in one embodiment, or 146 nm or 193 nm in other embodiments. The excited molecular oxygen forms atomic oxygen, which then reacts with the molecular oxygen present in the reaction chamber in block 630 to form ozone. Therefore, blocks 620 and 630 include generating synchrotron radiation from a photoexcitation source inside or coupled to the reaction chamber, exciting a portion of the molecular oxygen to form atomic oxygen, wherein the synchrotron radiation is in the ultraviolet wavelength range, and reacting the molecular oxygen present in the reaction chamber with the atomic oxygen to form ozone. Ozone is formed without requiring a plasma source, as in the prior art. In some embodiments, Method 600 includes maintaining a pressure of less than 100 Torr (13332 Pascals) in the reaction chamber during ozone formation.

[0033] Block 640 includes releasing a gas mixture containing atomic oxygen, molecular oxygen, and ozone from an outlet 240 of the reaction chamber. In some embodiments, the release of block 640 involves the gas mixture being continuously released from the reaction chamber as a beam containing reactive oxygen species (containing at least one of atomic oxygen or ozone), for example, by continuous release. In some embodiments, the release of the gas mixture includes delivering the gas mixture as a beam containing reactive oxygen species to a containment chamber (e.g., containment chamber 150) using a nozzle (e.g., nozzle 245) connected to the outlet 240, the nozzle being configured to generate a desired beam distribution and a desired pressure difference between the reaction chamber and the containment chamber.

[0034] In Figure 6, blocks 610 to 640 are shown in order, but each block can be executed simultaneously and repeatedly by continuously supplying molecular oxygen to the reaction chamber, thereby continuously generating the gas mixture.

[0035] In various embodiments, the pressure inside the reaction chamber may be monitored using a pressure sensor to determine whether a predetermined pressure value has been reached or to maintain that predetermined pressure.

[0036] In some cases, the introduction of block 610 allows molecular oxygen to be continuously introduced into the reaction chamber, forming a continuous beam containing reactive oxygen species. In these cases, the flow rate F of molecular oxygen introduced at the inlet of the reaction chamber is 流入口 This refers to the beam flow rate F when the beam containing reactive oxygen species is emitted from the outlet 240 of the reaction chamber 210. 排出口 This is nearly equivalent. Method 600 operates to continuously generate reactive oxygen species, for example, as a beam containing such reactive oxygen species. Thus, the continuous photoreaction process can be characterized by a characteristic flow rate. In some embodiments, in the introduction of molecular oxygen in block 610, the flow rate of the molecular oxygen is 100 SCCM (standard cubic centimeters per minute) or less. In examples, the characteristic flow rate of the process may be 0.1 SCCM to 100 SCCM, or 1 SCCM to 10 SCCM, or 1 SCCM to 5 SCCM. As those skilled in the art will understand, a beam containing reactive oxygen species that is emitted at a relatively low flow rate but has a high ozone concentration may be advantageous in the film deposition process.

[0037] In other cases, the introduction of block 610 involves introducing molecular oxygen until the reaction chamber is pressurized to a predetermined pressure. In these cases, block 610 may include initial filling the reaction chamber 210 to a target pressure rather than injecting a continuous flow of molecular oxygen. In such a mode of operation, block 610 includes an initial injection of molecular oxygen to form a pressurized chamber (e.g., about 100 Torr as a predetermined / target pressure value). This amount of molecular oxygen in the reaction chamber is then used to generate ozone over a predetermined time. The volume of the reaction chamber is used to measure the amount of ozone generated from the pressurized chamber. The pressure may be replenished by subsequently filling with molecular oxygen as needed to reach the desired pressure. In this way, the gas mixture can still be generated continuously by introducing molecular oxygen in stages (e.g., periodically injecting molecular oxygen).

[0038] In some embodiments, Method 600 may optionally include a block 602 comprising a reaction chamber, such as by selecting the shape, dimensions, and / or volume of the reaction chamber. The configuration of block 602 is performed to provide a residence time for molecular oxygen sufficient to form (or preferentially produce ozone) ozone, and such configuration is based on factors including operating pressure, wavelength of synchrotron radiation, and flow rate of molecular oxygen introduced into the inlet of the reaction chamber. Block 602 may include configuring the reaction chamber and other system parameters to suitably select a formation reaction pathway in which molecular oxygen and atomic oxygen react to form ozone, rather than a loss reaction pathway in which ozone forms molecular oxygen (see, for example, Figure 7 and the relevant descriptions throughout this disclosure). The volume of the reaction chamber and the conductance of the nozzle outlet opening can be adjusted together with other parameters such as operating pressure, wavelength of synchrotron radiation, power intensity of synchrotron radiation, and / or flow rate of molecular oxygen introduced into the inlet of the reaction chamber to suitably select the formation reaction pathway.

[0039] Depending on the circumstances, the chamber volume can be adjusted along with other parameters such as flow rate and conductance of the outlet opening to provide desired residence times for atomic oxygen, molecular oxygen, and ozone. The residence time is related to which reaction occurs and whether the formation reaction pathway, in which molecular oxygen and atomic oxygen react to form ozone, is preferred over the loss reaction pathway, in which ozone forms molecular oxygen. The chamber volume affects the photon flux, and as the chamber size decreases, the probability of photons colliding with oxygen molecules increases. Block 602 includes configuring the reaction chamber volume to provide residence times for atomic oxygen, molecular oxygen, and ozone, for example, by setting or calculating a desired chamber volume, and preferentially selecting the formation reaction pathway, in which molecular oxygen and atomic oxygen react to form ozone, rather than the loss reaction pathway, in which ozone forms molecular oxygen, and the volume is based on one or more of the operating pressure, the wavelength of synchrotron radiation, the output intensity of synchrotron radiation, and / or the flow rate of molecular oxygen introduced into the reaction chamber inlet. In some embodiments, one or more of the operating pressure, the wavelength of the synchrotron radiation, the output power of the synchrotron radiation, and the flow rate of molecular oxygen introduced into the inlet of the reaction chamber are configured to provide residence times for atomic oxygen, molecular oxygen, and ozone in accordance with a given volume of the reaction chamber, thereby favorably selecting a formation reaction pathway in which molecular oxygen and atomic oxygen react to form ozone, rather than a loss reaction pathway in which the generated ozone forms molecular oxygen.

[0040] In any of these scenarios, the operating pressure may be within the range of operating pressures used, the synchrotron radiation wavelength may be within the range of wavelengths (e.g., a target wavelength having an operating tolerance range for the photoexcitation source), and the molecular oxygen flow rate may be within the flow rate range used during operation. In addition, in any of the embodiments, the operating temperature or temperature range may be configured to create favorable conditions. Considerations for generating these favorable conditions using the knowledge described herein are illustrated in Figure 7 and elsewhere in this disclosure.

[0041] In some embodiments, block 602 may also include optimizing the operating pressure with respect to the volume of the reaction chamber. As the pressure increases, the number of molecules per unit volume increases, resulting in a greater likelihood of photons interacting with oxygen molecules. The pressure level should also take into account the excitation wavelength, as shown in Figure 5, so that the reaction in which molecular oxygen reacts with atomic oxygen to form ozone is preferably selected, rather than a competitive reaction in which ozone reacts with atomic oxygen to form molecular oxygen, and preferably so that the gas molecules reside in the reaction chamber for at least several seconds, e.g., at least several tens of seconds. Another design consideration is that the flow rate of injected molecular oxygen and the flow rate of the resulting gas mixture will depend on the desired pressure difference between the reaction chamber and the system containing the gas mixture. All these factors for configuring the reaction chamber and its operating conditions must be considered, and trade-offs must be made to achieve the required photon flux (number of photons per area per second) at a given pressure and volume, and to allow sufficient residence time for O2 molecules to occur in the reaction chamber for photodissociation. Further details of the reactions of molecular oxygen, atomic oxygen, and ozone are shown in Figure 7.

[0042] Referring further to Figure 6, Method 600 may optionally include a block 604 that controls the flow rate of molecular oxygen introduced into the reaction chamber, which may be performed based on the ozone concentration in the reaction chamber measured by an ozone concentration monitor and / or the atomic oxygen concentration measured by an atomic oxygen concentration monitor (e.g., shown in Figures 10A-10E). In such a case, Method 600 may also include measuring the ozone and / or atomic oxygen concentrations in block 635. The measurement in block 635 may include emitting a probe beam from a light source through a first window provided in the wall of the reaction chamber, wherein the probe beam has a probe wavelength that is absorbed more strongly by ozone (or atomic oxygen) than by molecular oxygen (e.g., see Figure 10A), and receiving the probe beam by a detector after it has passed through a second window provided in the wall of the reaction chamber. The measurement in block 635 is used as feedback to adjust the flow rate of molecular oxygen to block 604, adjusting the flow rate if the ozone concentration is too low or too high. Block 604 may also include controlling the pressure within the reaction chamber using feedback from a pressure sensor connected to a pump coupled to the reaction chamber. Control of flow rate, output intensity of the photoexcitation source, pressure, or other parameters is performed using a controller equipped with a processor, and adjustments can be made to maintain desired conditions using feedback (e.g., measured values ​​of pressure, ozone concentration, temperature).

[0043] Next, we will explain the details of the reaction that forms ozone.

[0044] In one embodiment, without being bound by any particular theory, it is possible to characterize the performance of the system for generating reactive oxygen species according to the embodiment of the present disclosure by applying a reaction kinetics approach. According to this approach, a step comprising reactants A and B that form products P and Q having stoichiometric coefficients (a, b, p, q), respectively, can be expressed as follows:

[0045]

number

[0046] When the concentration of [X] changes, X, which is selected from one of A, B, P, or Q, is defined as follows:

[0047]

number

[0048] In the above equation, k i is the rate constant, m is the reaction order, and the sign "±" (plus or minus) indicates an increase or decrease in concentration, respectively.

[0049] In this approach, the coupled process of generating reactive, short-lived atomic oxygen by photodissociation of oxygen and the subsequent additional process for ozone formation can be understood by the bimolecular reaction pathways shown in Figure 7, which shows reaction pathway diagram 700 illustrating three main reaction pathways 710, 720, and 730 related to ozone formation. Reaction pathways 710, 720, and 710 and 720 are formation reaction pathways, while the loss reaction pathways include one or both of reaction pathways 730 and 735 that form molecular oxygen.

[0050] The first reaction pathway 710 involves photodissociation (photons hν) to produce molecular oxygen (O * (g) Atomic oxygen (O) from ) 2(g) ) is formed. O2 + hν → O * +O * (Formula 3)

[0051] In this embodiment, the first reaction pathway 710 is [s -1The reaction is characterized by a dimensional reaction rate k1 (i.e., rate per second). Facilitating the first reaction pathway 710 for the production of atomic oxygen from molecular oxygen is one of the objectives of the reactive oxygen system. The first reaction pathway 710 can be favored by adjusting the pressure in the reaction chamber (i.e., the likelihood and frequency of its occurrence increases, the probability of occurrence increases for other reactions, and / or the reaction rate increases). Since the mean free path of gas particles is inversely proportional to the pressure, higher pressures increase the likelihood of interactions occurring. Higher pressures also increase the likelihood of interactions occurring between excited photons and seeds in the chamber, for example, when photons interact with molecular oxygen to form atomic oxygen in the first reaction pathway 710. The first reaction pathway 710 can also be favored by adjusting the synchrotron radiation output of the photoexcitation source, with higher synchrotron radiation levels (outputs) supplying more photons to cause photodissociation.

[0052] The second reaction pathway 720 involves the addition reaction of molecular oxygen to atomic oxygen to produce ozone (O 3(g) This is another formation reaction pathway that forms ) O2 + O * →O3 (formula 4)

[0053] This second reaction pathway 720 (sometimes called the addition reaction pathway) has a reaction rate k2 of [cm²]. 6 molecule -2 s -1 It is characterized by having the dimension of ]. A second reaction pathway 720 that generates ozone is also desirable in the reactive oxygen system of this disclosure and can be advantageous by adjusting the pressure of the reaction chamber (the higher the pressure, the greater the likelihood of interaction occurring). Comparing reaction pathways 710 and 720, high pressure promotes ozone formation via the second reaction pathway 720, whereas low pressure promotes atomic oxygen generation via the first reaction pathway 710 because the first reaction pathway 710 also utilizes photodissociation.

[0054] The lower part of reaction pathway diagram 700 is the competitive loss reaction pathway for ozone, which includes two component reaction pathways 730 and 735. Of these, the first and most important component loss reaction pathway 730 is the reaction that forms molecular and atomic oxygen by the photodissociation of ozone. O3 + hν → O2 + O * (Formula 5)

[0055] This first loss reaction component pathway 730 is [s -1 The reaction is characterized by a reaction rate k3 having dimensionality. Increasing the output from the photoexcitation source increases the likelihood that ozone will be converted to molecular and atomic oxygen by photodissociation. However, as mentioned above, the desirable formation reaction pathway 710 can also be favored by increasing the output from the photoexcitation source. Therefore, in some cases, the output from the photoexcitation source is balanced with other parameters (e.g., flow rate and conductance of the exit port) to increase the ratio of total reactive oxygen to molecular oxygen. In some cases, the output from the photoexcitation source and other parameters (e.g., flow rate and conductance of the exit port) are set to increase the ratio of atomic reactive oxygen to ozone.

[0056] The second loss reaction component pathway 735 relates to the reaction between ozone and atomic oxygen (i.e., ozone decay), and is as follows: O3+O * →2O2 (formula 6)

[0057]

number

[0058] It is desirable that the reactive oxygen species source has conditions that favor the formation reaction pathway (a first reaction pathway 710 that generates atomic oxygen and a second reaction pathway 720 that generates ozone) over the loss reaction pathway (which may include one or both of component loss reaction pathways 730 and / or 735) that forms molecular oxygen.

[0059] Rate constant k for each reaction pathway i This depends physically on the number density of the relevant reactive species, one or more of the pressure P, temperature T, and volume V, as well as the photon flux and energy (power level and wavelength of synchrotron radiation from the photoexcitation source).

[0060] The ideal gas law states that in a reaction chamber with volume V, temperature T, and initial O2 pressure P, the initial O2 reactants

[0061]

number

[0062]

number

[0063] In the equation, R is the general gas constant. Next, the total light absorption cross-section of O2 is:

[0064]

number

[0065] Similarly, k3 for the competing first loss reaction component pathway 730 also depends on the photon flux, photon energy (e.g., VUV energy range), and the absorption cross-section of O3 at that photon energy (e.g., see Figures 3A and 3B). As discussed earlier, shorter excitation wavelengths reduce the amount of ozone depleted by photodissociation (e.g., see Figure 4 showing the absorption selectivity of O2 vs. O3 at wavelengths of 146 nm, 172 nm, and 193 nm).

[0066] In contrast to k1 and k3, which depend on photodissociation, reaction rates k2 and k4 directly depend on the number density of each molecular species involved in the reaction and the associated interaction cross-sections. For example, higher pressure in the reaction chamber at a fixed volume can be favorable to increasing the number density of the reactant O2.

[0067] Solar VUV-induced ozone production is associated with the Chapman cycle, which contains an O2 / N2 mixture, from the polar upper atmosphere to the upper atmosphere (stratosphere), and is altitude-dependent. The Chapman cycle, which is responsible for ozone production, typically has the following reaction rates to stratospheric gas and solar VUV irradiation:

[0068]

number

[0069] Unlike the upper atmosphere, the systems and methods for generating reactive oxygen species according to the embodiments of this disclosure, but which are not limited thereto, may be designed to operate based on parameters suitable for the generation of reactive oxygen species, including the use of a relatively high-purity O2 source, a reaction chamber having a finite reaction volume and capable of operating at a selected chamber pressure, the use of a specific excitation wavelength for a photoexcitation source operating at a selected power capable of dissociating molecular oxygen, and the ability to adjust the residence time of gaseous species within the reaction chamber by selecting the effective leakage rate of diffusive species released from the reaction chamber. The ability to balance these parameters is based on the unique insights described in this disclosure.

[0070] The proportion β of reactive oxygen species in the gas mixture released from the outlet of the reaction chamber can be defined as follows:

[0071]

number

[0072] In the formula, N 活性 (O * O3) is the number density or concentration of combinations of atomic oxygen and ozone species, N i (O2) is the number density or concentration of O2 molecules in the gas mixture released from the outlet of the reaction chamber.

[0073] As those skilled in the art will understand, a value of β ≤ 0.05 is typically obtained using dielectric barrier discharge and / or plasma excitation with a pure O2 source. That is, the desired reactive oxygen species are less than 5% in the gas mixture produced by these approaches. The remaining 95% of the gas mixture consists of neutral molecular oxygen, which in applications such as vacuum deposition imposes severe limitations on the standard capacity of the associated exhaust system and can lead to accelerated degradation of high-temperature surfaces and easily oxidizable electrical filaments.

[0074] The embodiments described herein are based on the finding that in various applications such as vacuum deposition of oxide layers, high mass flow rates of ozone are not required, and low flow rates are sometimes desirable for the film formation process.

[0075] The exemplary photoreaction pathway described above, defined as the simultaneous reactions of equations (3) to (6), can be reduced to the following coupled equation. The exemplary photoreaction pathway described above, defined as the simultaneous reactions of equations (3) to (6), can be reduced to the following coupled equation.

[0076]

number

[0077] In this embodiment, the steady-state output of the reaction chamber is the desired quantity of interest, and can be estimated by uniquely recognizing that this occurs when the concentration changes of ozone and reactive oxygen species components become zero.

[0078]

number

[0079] Next, atomic oxygen [O * ] ss and ozone [O3] ss The steady-state concentration of can be determined as follows:

[0080]

number

[0081] As is clear from the equations derived in this disclosure, the ozone concentration is determined by the addition reaction rate k2 (see Equation 4) and is inversely proportional to the reaction rate k3 (see Equation 5) corresponding to the photodissociation of ozone.

[0082] The range of concentration values ​​in these steady states includes, but is not limited to, the following:

[0083]

number

[0084] These parameters and rates can be used as guidelines when configuring the reaction chamber according to this disclosure to generate reactive oxygen species in the required concentration relative to O2, based on the findings described herein.

[0085] For a substantially pressurized chamber with an initial pure O2 composition and its composition (P0, V0, T0) maintained, the rate of change of [O2] relative to a closed system can be defined as follows:

[0086]

number

[0087] As described above, low flow rates are desirable in various applications, and therefore, the gas mixture released from the reaction chamber functions as a conductance-limiting opening and substantially corresponds to a minute leak through an outlet that can be coupled to the subsequent film deposition chamber, thus providing a good approximation with Equation 14.

[0088] In other applications, a higher "leak" rate (i.e., flow rate or photon flux) of the released gas mixture, which can change the pressure within the reaction chamber, can be balanced by actively flowing the raw material O2 into the reaction chamber. However, it should be noted that in these implementations, the residence time of the oxygen species within the reaction chamber is a factor in determining the photon absorption probability in the reaction chamber.

[0089] Next, the steady state reactive oxygen species [O3] for the entire mixture ss The ratio is given by the following formula:

[0090]

number

[0091] The reaction pathway diagram in Figure 7 illustrates the complexity involved in constructing conditions to restrict the reconversion of the generated ozone to molecular oxygen by reaction pathways 730 and 735 before it is released from the reaction chamber, while realizing reaction pathways 710 and 720 for the formation of atomic oxygen and ozone, respectively (i.e., corresponding to the three bond rate equations of Equations 9, 10, and 14). In other words, generating a stable, and especially continuous, ozone source is difficult and not easy to achieve without the inventive insights recognized in this disclosure. A stable level of generated reactive oxygen species refers, for example, to a situation where the reactive oxygen concentration in the output flow rate remains within 10% of the average amount for at least one hour (i.e., does not fluctuate beyond that), or within 5% of the average amount for at least 10 hours. The reactive oxygen system of this disclosure provides a stable, on-demand source of reactive oxygen species that can be generated in real time.

[0092] As those skilled in the art will understand, the reaction pathway diagram 700 is somewhat simplified because it represents a state of equilibrium where various chemical processes are in equilibrium, meaning that reactions occur in both directions. For example, in the case of dissociation from molecular oxygen to atomic oxygen (reaction pathway 710), there is a reverse reaction in which atomic oxygen combines to form molecular oxygen. This reverse reaction proceeds in the opposite direction to the arrow in reaction pathway 710 and has its own reaction rate. It should also be noted that in a closed system, 100% ozone cannot be obtained due to loss mechanisms. For example, a reaction similar to the reverse reaction of equation 3 (reverse of reaction pathway 710), in which two atomic (excited) oxygen atoms combine to form molecular oxygen and energy, can be a significant loss reaction if the concentration of excited atomic oxygen in the chamber is sufficiently high.

[0093] Figure 8A shows an example of a reaction occurring in a reaction chamber using exemplary photoreaction conditions relating to this disclosure. Graph 800 in Figure 8A shows the concentrations (expressed as percentages) of molecular oxygen, atomic oxygen, and ozone over time (in seconds) in a reaction chamber having an excitation source of 172 nm, according to the reaction pathway diagram 700 in Figure 7 and the bond rate equations 9, 10, and 14.

[0094] In the example shown in Graph 800, the excitation source operates at 172 nm and has a power output of 50 mW / cm². 2 Assuming it is a lamp, the reaction chamber operates at room temperature with an initial oxygen pressure of 100 mTorr and a volume of 200 cm³. 3 In particular, the reaction chamber operating according to the embodiments of this disclosure operates at a moderate temperature compared to the high temperature in DBD ozone generation configurations. As shown in Graph 800, the concentration of molecular oxygen 810 is initially high, but rapidly dissociates (in about 1 second) to form atomic oxygen. The concentration of atomic oxygen 820 initially increases, and then decreases due to ozone formation resulting from the reaction of atomic and molecular oxygen. In this embodiment, after an initial stabilization period of about 2 seconds, the gaseous mixture formed in the reaction chamber reaches a steady-state concentration of ozone 830 approaching 38%, a steady-state concentration of atomic oxygen 820 at about 7%, and a steady-state concentration of molecular oxygen 810 at about 55%. These ozone levels are significantly higher than those achievable with prior art.

[0095] Graph 800 shows that, in accordance with this disclosure, excitation energy, excitation wavelength, operating pressure, and other factors can be configured to stably generate (e.g., a continuous supply for several seconds, several minutes, or more) a gas mixture consisting of molecular oxygen, atomic oxygen, and ozone. The generation of reactive oxygen species, including atomic oxygen and / or ozone, is achieved by photoexcitation without the use of a plasma generator (e.g., an RF microwave generator or other plasma actuator / plasma source).

[0096] To achieve the generation of reactive oxygen species described herein (e.g., Figures 7 and 8A), the reaction conditions must be carefully considered and designed. For example, the operating pressure and volume of the reaction chamber determine the number density of oxygen molecules. The lamp output power density at a specific frequency (e.g., number of photons / cm³) is also important. 2 This determines the number of photons that can interact with oxygen or ozone molecules having an absorption cross-section per unit area. The above-described embodiment in Figure 8A is based on continuous photo excitation, but pulsed photo excitation is also possible, and although it involves a duty cycle, it may be possible to provide a high peak power photon flux.

[0097] Referring to Figure 8B, Graph 850 shows the general dependence of the steady-state concentrations of ozone 860 and atomic oxygen 870 on the output of the photoexcitation source. In this embodiment, Graph 850 assumes a 172 nm continuous excitation source as the photoexcitation source, as mentioned above. As shown, generally, the concentrations of ozone 860 and atomic oxygen 870 increase with increasing output of the photoexcitation source, and the concentration of ozone 860 is approximately 50 mW / cm³. 2 While approaching saturation in the vicinity, the concentration of atomic oxygen-870 continues to increase slowly.

[0098] For example, currently, high-power VUV light sources have a power output of approximately 50 mW / cm². 2 This is limited. As can be seen from Figure 8B, it is possible to use a low-power light source, but in this case, it may potentially affect the concentration of reactive oxygen species, and a longer integration time may be required to reach the steady-state concentration. It should be noted that high-power VUV light sources are also readily available and may enable a smaller reaction chamber. For example, in some embodiments, 50 mW / cm² 2 Photoexcitation sources with the above output intensities can be utilized. Theoretically, ultra-high-power extreme ultraviolet (EUV) light sources operating at 10-100 nm, designed for high-performance lithography, are available, but at present these light sources are not economically practical for this application.

[0099] From another perspective, ozone is a relatively stable molecule compared to atomic oxygen. When atomic oxygen interacts with the inner surface of the reaction chamber and / or the outlet and / or any nozzle coupled to the outlet, atomic oxygen may recombine, resulting in a decrease in concentration. In one embodiment, various surfaces that atomic oxygen is expected to interact with are coated with high-purity silica glass or other oxide-based coatings. In other embodiments, it is permissible to form oxide coatings on the inner surface during operation. For example, in the case of a reaction chamber made of aluminum, allowing the formation of an aluminum oxide coating during operation can advantageously reduce the recombination of atomic oxygen. These configurations can be utilized in any of the systems and methods described herein. As will be understood by those skilled in the art, polymers and plastic materials should generally be avoided in reaction chambers due to the potential for contamination by carbon, carbon fluoride, and hydrocarbons.

[0100] Other potential considerations when using a dielectric barrier excimer lamp as a photoexcitation source in a reaction chamber include the possibility of parasitic discharge occurring in the molecular oxygen within the reaction chamber instead of discharge in the lamp if the molecular oxygen pressure is within a certain range defined by the Paschen curve. Excessively high ozone pressure / concentration within the reaction chamber also poses safety hazards, given the high reactivity of ozone. While balancing all these factors is challenging, this disclosure provides insights and system designs that can achieve the necessary conditions.

[0101] In several embodiments, it has been empirically found that by reducing the oxygen pressure in the reaction chamber to well below atmospheric pressure of 1 bar (e.g., 100 Torr), the molecular oxygen is excited by a photoexcitation source in the ultraviolet wavelength range, which has a sufficient residence time for photon absorption in the reaction chamber, thereby increasing and forming ozone. In some embodiments, the reaction chamber is configured to maintain a pressure of less than approximately 100 Torr, for example, 1 to 100 Torr, 10 to 100 Torr, 1 to 80 Torr, or less than 10 Torr.

[0102] In particular, while conventional ozone generators aim to maximize flow rate (for example, operating at 100 liters / second for sterilization purposes), the system and method of this disclosure aim to improve the concentration of reactive oxygen species in a gas mixture discharged at low flow rates, and are suitable for operation in film deposition systems, such as ultra-high vacuum (UHV) film deposition systems.

[0103] In one embodiment, the flow rate of injected molecular oxygen is in the range of 0.1 SCCM to 1000 SCCM. In another embodiment, the flow rate is in the range of 1 SCCM to 100 SCCM. In yet another embodiment, the flow rate is in the range of 1 SCCM to 20 SCCM.

[0104] As a result of the low flow rate, the residence time of a given oxygen molecule in the photoreaction chamber is increased in this system, improving the probability of interaction between oxygen molecules and photons. In some embodiments, the residence time can be further improved and photon absorption in multiple paths can be promoted by incorporating a light reflector into the photoreactor (e.g., the inner wall of the reaction chamber). The light reflector (i.e., optical resonator) is made of a material that reflects the wavelength of synchrotron radiation generated by the photoexcitation source, for example, ultraviolet wavelengths of 125 nm to 180 nm. As an example, in any embodiment of the photoreactor described herein, part or all of the chamber wall may be made of aluminum. The optical resonator may be configured to reuse unabsorbed photons in the gas volume, for example, by covering the entire inner wall of the reaction chamber or by inserting a planar reflector along the longitudinal axis of the chamber. In other embodiments, the inner wall of the chamber may include a material composition that reduces the loss of active species on the surface of the chamber wall, for example by using polytetrafluoroethylene (PTFE) or molten SiO2 as the material.

[0105] In the exemplary configurations of the systems and methods of this disclosure, the conditions include:

[0106] The wavelength of the synchrotron radiation from the photoexcitation source is approximately 146 nm, 172 nm, or 193 nm.

[0107] At a predetermined flow rate, the synchrotron radiation input power required to generate at least 10% to 15% atomic oxygen or 10% to 15% ozone in the discharge (output) flow is 10 mW / cm². 2 ~50mW / cm 2 That is the case.

[0108] The volume of the reaction chamber is 150 cm³. 3 ~250cm 3 For example, 200cm 3 That is the case.

[0109] The pressure inside the reaction chamber (i.e., the operating pressure) is less than 100 Torr (13332 Pascals), for example, between 1 milliTorr (0.133 Pascals) and 100 Torr or between 1 milliTorr and 10 Torr (1333 Pascals).

[0110] The flow rate of molecular oxygen injected into the reaction chamber of the reactive oxygen system is 100 SCCM or less.

[0111] The residence times of atomic oxygen, molecular oxygen, and ozone are at least a few seconds.

[0112] These conditions are carefully designed to generate reactive oxygen species in accordance with the findings described herein. In a particular example, the photoexcitation source operates at a wavelength of 172 nm and has a power output of 50 mW / cm². 2 The lamp (i.e., average power intensity) and the volume of the reaction chamber of the reactive oxygen species system is approximately 200 cm³. 3 The pressure in the reaction chamber is 100 mTorr (0.133 Pascals) to 1 Torr (133 Pascals), and the flow rate of injected molecular oxygen is 1 SCCM to 10 SCCM. In a particular example, the photoexcitation source operates at a wavelength of 146 nm and has a flow rate of 10 mW / cm². 2 The lamp is a reactive oxygen species system, and the volume of the reaction chamber is 200 cm³. 3The pressure inside the reaction chamber of the reactive oxygen system is 1 Torr to 10 Torr, and the flow rate of the injected molecular oxygen is 1 SCCM to 10 SCCM.

[0113] In some embodiments, the reactive oxygen system is configured to favor the formation reaction pathway that generates reactive oxygen species (i.e., atomic oxygen and / or ozone) by photodissociating molecular oxygen to form atomic oxygen (first reaction pathway 710, Equation 3) and by the reaction of molecular oxygen with atomic oxygen to form ozone (second reaction pathway 720, Equation 4), rather than the loss reaction pathway (e.g., by photodissociating ozone to form molecular oxygen and atomic oxygen via reaction pathway 730 (Equation (5)), and / or by the reaction of the formed ozone with atomic oxygen to form molecular oxygen via a second loss reaction component pathway 735 (Equation (6))). In some embodiments, the volume of the reaction chamber of the reactive oxygen system may be configured based on the operating pressure, the wavelength of the synchrotron radiation, the output power of the synchrotron radiation, and the flow rate of molecular oxygen to the inlet of the reaction chamber (optionally including other system parameters that affect residence time). In some embodiments, one or more of the operating pressure, synchrotron radiation wavelength, synchrotron radiation output, and molecular oxygen flow rate to the reaction chamber inlet (optionally including other system parameters that affect residence time) are configured to suit a given reaction chamber volume. In various embodiments, the above configuration may be set to favorably promote the formation of reactive oxygen species over a loss reaction pathway that produces molecular oxygen from ozone and / or atomic oxygen.

[0114] In some embodiments, the volume of the reaction chamber is configured (i.e., set, determined, and designed) to provide residence times for atomic oxygen, molecular oxygen, and ozone, thereby favorably selecting the formation reaction pathway in which ozone is formed by the reaction of molecular oxygen with atomic oxygen, rather than the loss reaction pathway in which formed ozone reacts with atomic oxygen to form molecular oxygen.

[0115] In embodiments of this disclosure, the gas mixture is emitted from the outlet of the reaction chamber as a beam containing reactive oxygen species (e.g., block 640 in Figure 6). For example, as mentioned in the description of Figure 6, the beam containing reactive oxygen species is used in UHV film deposition processes such as molecular beam epitaxy (MBE). -5 Torr~10 -8 Torr can be released at its operating pressure. In some embodiments, the system and method may include a nozzle designed to create a desired pressure difference between the reaction chamber and the containment chamber (e.g., the chamber of the material deposition system). Thus, the beam profile of the photoreactor and the operating pressure of the outlet can be configured according to the requirements of the deposition process.

[0116] As shown in the side cross-sectional view of Figure 9A, the outlet 940 may incorporate a beamforming nozzle 945 similar to the outlet 240 and beamforming nozzle 245 in Figure 2. In some embodiments, the nozzle 945 is coupled to the outlet 940 by being attached to the end of the outlet 940 or positioned within it. The beamforming nozzle 945 is mainly characterized by the nozzle's characteristic length L in the discharge direction. ノズル It has beam profile formation characteristics that depend on conductance Q ノズル This is mainly the representative diameter D ノズル The design of the beamforming nozzle 945 affects the operating pressure and beam profile of the exhaust gas mixture 941.

[0117] The photoreactor system described herein can operate in a molecular flow manner or an atomic flow manner. The first function of the beamforming nozzle 945 is to induce a pressure drop. Therefore, the effective conductance of the beamforming nozzle 945 is the characteristic diameter D ノズル The effective opening is determined by the effective opening having a diameter D and the differential pressure across that opening. The effective opening may be configured as a plurality of smaller openings (each having an associated opening size) or as a single opening. In this embodiment of Figure 9A, the beamforming nozzle 945 has a plurality of openings 946, each of which has a diameter D nIt has a representative diameter D of the opening. ノズル This is achieved by combining multiple holes in a manner that takes into account the losses incurred by using them instead of one larger hole of equivalent size, thereby reducing the individual diameter D n It can be calculated from the nozzle length. The nozzle length also affects the conductance of the opening(s), and generally the nozzle length L ノズル The more Q increases, the higher the conductance Q ノズル The value decreases. In some embodiments, the nozzle 945 (Figures 9A to 9C) has an effective opening diameter D (i.e., D ノズル ) and length L (that is, L ノズル The system has an aspect ratio L / D configured to create a desired pressure difference between the reaction chamber and the containment chamber, and the beam containing reactive oxygen species is delivered from the outlet 940 through a nozzle to the containment chamber.

[0118] The nozzle 945 may include one or more openings 946, for example 1 to 10, or 2 to 100, or 2 to 500, or up to 1000 individual openings, each of which has a diameter D in the range of, for example, 20 to 200 microns. n It has a representative diameter D of the opening. ノズル The diameter of the opening 946 is designed such that the pressure inside the reaction chamber is higher than that of the downstream system (e.g., the vacuum chamber of the deposition system). In one embodiment, the beamforming nozzle 945 has a characteristic length or thickness L ノズル The diameter can be 0.5 mm to 1 mm. In the plan view of the nozzle 945 in Figure 9B, seven openings 946 are shown as an example. In Figures 9A and 9B, the openings 946 are shown to be the same size as one another, but in other embodiments, the openings 946 may be of different sizes as one another.

[0119] Referring to FIG. 9C, a plan view of a beam forming nozzle 947 of another embodiment is shown. In this embodiment, the beam forming nozzle 947 has a single opening 948 having an effective diameter equivalent to the case where the openings 946 of the beam nozzle 945 shown in FIG. 9B are combined. In this embodiment, both the beam forming nozzles 945 and 947 are configured to have the same representative length or thickness L ノズル such that. As a result, the aspect ratio L / D of the single opening 948 is significantly lower than the aspect ratio of the individual openings 946.

[0120] In some embodiments, the nozzle is configured to provide a cosine n theta photon beam distribution to a containment chamber to which a gas mixture is delivered. For example, the aspect ratio (L / D) of the nozzle 945 can be selected to provide an angular beam distribution at a film formation surface located at a distance "d" from the opening plate. This distribution is generally in the form of a cosine n theta photon beam distribution, and as n increases with an increase in the aspect ratio (defined above), a more directional beam can be formed.

[0121] This effect is shown in FIGS. 9D and 9E, which schematically show the angular distributions 980 and 990 of the gas mixtures emitted from the beam forming nozzles 945 and 947, respectively (side views of the nozzles). As shown, due to the effect that the individual openings 946 of the nozzle 945 have a higher aspect ratio, the angular distribution 980 of the gas mixture emitted from the combination of the openings 946 is a more directional angular distribution 980 compared to the angular distribution 990 of the gas mixture emitted from the single opening 948 of the nozzle 947 (i.e., n is large in the cosine nθ beam distribution).

[0122] In some embodiments, the photoreaction chamber of the present disclosure has an available volume of 200 cm 3 ~250 cm 3 containing oxygen at an initial pressure of 100 mTorr, and 10 -10 Torr~l0 -5It may be equipped with a beamforming nozzle with an effective aperture diameter of 1 mm to 10 mm for supplying reactive oxygen species to a UHV system operating in the Torr range.

[0123] The generation of reactive oxygen species (ozone and / or atomic oxygen) can be monitored using a custom probe configuration described in relation to Figures 10A to 10E (block 635 in Figure 6). The monitoring system is described primarily for monitoring ozone concentration, but the system may also be applied to monitoring atomic oxygen concentration (in place of or in addition to ozone).

[0124] Figure 10A shows the absorption cross-section (cm²) for each wavelength (nm). 2 Graph 1000 shows the molecular oxygen absorption spectrum. Graph 1000 shows the ozone absorption spectrum 1010 in the UVC wavelength range, with an absorption peak 1011 around 250 nm. Also shown is the molecular oxygen absorption spectrum 1020, which is negligible at wavelengths above 200 nm compared to the ozone absorption spectrum 1010. In some examples, the system and method are used to measure the wavelength λ that is absorbed by ozone but not (or is absorbed very little) by molecular oxygen. プローブ By using a probe (monitoring system) that operates in this manner, the insights obtained from Graph 1000 can be effectively applied. As those skilled in the art will understand, other probe wavelengths may be used to measure ozone levels and make them distinguishable from molecular oxygen, and / or other probe wavelengths may be used to measure atomic oxygen levels and monitor them in a way that makes them distinguishable from molecular oxygen (for example, using absorption wavelengths for singlet and triplet atomic oxygen).

[0125] Figure 10B is graph 1001, which shows an example of an ozone concentration monitor using a deuterium lamp as the light source for the probe wavelength and using a wavelength band around 240 nm. Graph 1001 shows a stabilized deuterium lamp spectrum 1012 in which the deuterium emission intensity (relative percentage to reference peak 1014) is plotted against the emission wavelength (nm). As shown, the emission intensity is high in the band 1013 centered at 240 nm. Spectrum 1012 has another high-intensity peak (reference peak 1014) around 660 nm. In some examples, the system and method effectively utilize these findings regarding synchrotron radiation properties to provide a probe wavelength of approximately 240 nm using deuterium, which is strongly absorbed by ozone but not by molecular oxygen. Some examples also utilize an additional reference peak 1014 as a reference or control peak, since this reference wavelength of approximately 660 nm is not absorbed by ozone. Having the reference wavelength in the same spectrum as the probe wavelength provides an efficient method for calibrating the measurement.

[0126] Figure 10C is graph 1002, which shows the transmittance (relative percentage to reference peak 1014) of the photoreactor as a function of the absorption wavelength (nm) and indicates measured ozone concentrations generated in the photoreactor. Specifically, graph 1002 shows spectra representing different concentrations of ozone in the reaction chamber, as detected by a monitoring system with an optical path passing through the reaction chamber. As shown in Figure 10B, the deuterium lamp spectrum 1012 is shown as emitted from a probe light source, having a probe wavelength band 1013 and a reference peak 1014. Spectra 1015 and 1016, showing synchrotron radiation detected after passing through the reaction chamber, are also shown. Spectrum 1015 shows that much of the synchrotron radiation in the probe wavelength band 1013 around 240 nm is still transmitted, although it is less than the original lamp spectrum 1012 due to some absorption by ozone in the reaction chamber. Spectrum 1015 may represent, for example, a 20% ozone concentration in the gas mixture generated in the reaction chamber. Spectrum 1016 shows less transmission than spectrum 1015 in the probe wavelength band 1013, which may represent, for example, a higher 50% ozone concentration in the gaseous mixture produced in the reaction chamber. Both spectra 1015 and 1016 show complete transmission at the reference peak 1014, indicating that the measurements are accurately calibrated.

[0127] Ozone concentration monitoring can replace or complement atomic oxygen monitoring by utilizing (or adding) probe wavelengths that correspond to singlet and triplet atomic oxygen absorption lines.

[0128] Figure 10D shows a schematic diagram of a concentration monitoring system 1003 for measuring the concentration of ozone and / or atomic oxygen in the reaction chamber of a photoreactor using synchrotron radiation, for example, at the ozone absorption peak 1011 in Figure 10A or the band 1013 in Figure 10B. In Figure 10D, the concentration monitoring system 1003 measures the wavelength λ プローブ(For example, in some embodiments, it includes a narrowband light source 1030 that emits radiation light 1032 having a probe wavelength band in the vicinity of 240 nm to 250 nm as shown in FIGS. 10A to 10B). The probe radiation light 1032 is incident on the reaction chamber 210 through the first window 1040 (which may also be referred to as an access window or a viewport). The probe radiation light 1032 then passes through the gas mixture 1050 containing molecular oxygen, atomic oxygen, and ozone, and is emitted through the second window 1045 (i.e., the access window or the viewport). The first window 1040 and the second window 1045 are optically transparent with respect to the probe wavelength λ プローブ ). λ プローブ is selected to be absorbed more by ozone and / or atomic oxygen than by molecular oxygen (e.g., a probe wavelength for ozone and other probe wavelengths for atomic oxygen), so that a part of the probe radiation light 1032 is absorbed by the ozone and / or atomic oxygen in the gas mixture 1050. As a result, the intensity of the emitted probe beam 1034 is lower compared to the probe radiation light 1032.

[0129] After passing through the reaction chamber 210, the emitted probe beam 1034 has a wavelength λ プローブThe intensity of synchrotron radiation is measured by a wavelength-selective detector 1060 that operates to measure the intensity of synchrotron radiation having [specific characteristics]. The change in synchrotron radiation intensity between the probe synchrotron radiation 1032 and the emitted probe beam 1034 is directly related to the concentration of ozone and / or atomic oxygen in the reaction chamber 210. The concentration of the active species (ozone and / or atomic oxygen) can be determined by a processor 1070 that compares the original probe intensity (probe synchrotron radiation 1032) with the emitted probe beam 1034. This determined concentration can then be used as feedback to a controller 1072 that can generate control signals to control parameters such as the flow rate of oxygen entering the reaction chamber 210, the pressure inside the reaction chamber 210, and / or the output photon flux intensity of the excitation source 230a or 230b (shown in Figure 2) (e.g., block 604 in Figure 6). When the flow rate is changed in response to feedback from the ozone or atomic oxygen concentration monitor, a pressure sensor (e.g., pressure sensor 212 in Figure 2) can monitor the chamber pressure. For example, both the concentration monitoring system 1003 and the pressure sensor 212 are used in a feedback loop, and by controlling the flow rate, desired ozone and / or atomic oxygen concentration levels and pressure values ​​can be achieved in the reaction chamber, which are suitable conditions for generating a stable output of reactive oxygen species, including at least one of atomic oxygen or ozone (e.g., a gas mixture containing atomic oxygen, molecular oxygen, and ozone).

[0130] In some embodiments, the controller 1072 is configured to control the flow rate of molecular oxygen into the reaction chamber using measurements of the ozone or atomic oxygen concentration in the reaction chamber 210 from a concentration monitor (e.g., concentration monitoring system 1003 in Figure 10D). The ozone or atomic oxygen concentration monitor is coupled to the reaction chamber and includes a light source 1030 configured to emit a probe beam through a first window 1040 provided in the wall of the reaction chamber, the probe beam of the probe synchrotron radiation 1032 is absorbed more strongly by ozone or atomic oxygen than by molecular oxygen at a probe wavelength λ プローブThe concentration monitor also includes a detector 1060 positioned to receive the probe beam 1034 through a second window 1045 provided in the wall of the reaction chamber after it has passed through the reaction chamber. The probe wavelength for detecting ozone (the wavelength of the incident probe beam's synchrotron radiation 1032 and the emitted probe beam 1034) is, for example, 200 nm to 300 nm, and may be, for example, about 240 nm, or about 250 nm, or 240 nm to 250 nm. The method may include controlling the flow rate of molecular oxygen introduced into the reaction chamber based on the concentration of ozone and / or atomic oxygen in the reaction chamber measured by the concentration monitor. The method further includes measuring the concentration of ozone and / or atomic oxygen by emitting a beam of probe synchrotron radiation 1032 from a light source 1030 through a first window 1040 provided in the wall of the reaction chamber, wherein the probe beam has a probe wavelength that is absorbed more strongly by ozone or atomic oxygen than by molecular oxygen, and the probe beam 1034 is received by a detector 1060 after passing through a second window 1045 provided in the wall of the reaction chamber.

[0131] Figure 10E is a schematic diagram of the concentration monitoring system 1004, showing details of the detector 1060 in several embodiments. In this figure, the probe beam is oriented horizontally, rather than vertically as in Figure 10D. The light source 1030, for example, a deuterium lamp, emits a probe wavelength λ プローブThe probe emits synchrotron radiation 1032 having the following characteristics: The probe synchrotron radiation 1032 passes through the first window 1040 and enters the reaction chamber 210 (i.e., the photoreactor), where synchrotron radiation 1055 from a photoexcitation source (not shown, e.g., excitation source 230a or 230b in Figure 2) excites molecular oxygen injected into the reaction chamber 210, producing a gas mixture 1050 containing molecular oxygen, atomic oxygen, and ozone. In this figure, the synchrotron radiation 1055 is shown at a wavelength of 172 nm, but other wavelengths disclosed herein may be used. The probe synchrotron radiation 1032 then passes through the reaction chamber and is absorbed by ozone or atomic oxygen in the gas mixture 1050. The emitted probe beam 1034, with reduced intensity compared to the initial synchrotron radiation 1032, then passes through the second window 1045 and enters the detector 1060.

[0132] Both the first window 1040 and the second window 1045 are transparent to the probe wavelength band. In some embodiments, the materials of the first window 1040 and the second window 1045 may be selected to transmit the probe wavelength band and absorb the photoexcitation wavelength. In a specific example, the material of the ozone concentration monitor viewport (first window 1040 and second window 1045) may be transparent to the probe wavelength band around 240 nm and optically absorbent to wavelengths above 200 nm (excluding the probe wavelength band around 240 nm), thereby absorbing adjacent photoexcitation wavelengths. In some embodiments, the first window 1040 and the second window 1045 may be composed of sapphire, magnesium oxide, or calcium fluoride.

[0133] Detector 1060 includes a diffraction grating 1062. The emitted probe beam 1034 strikes the diffraction grating 1062 and is then guided to a charge-coupled device (CCD) diffraction grating spectrometer 1064, where the intensity of the emitted probe beam 1034 is measured. By comparing the intensity measured by the CCD diffraction grating spectrometer 1064 with the intensity of known synchrotron radiation 1032 generated by the light source 1030, the concentrations of ozone and / or atomic oxygen in the gas mixture 1050 can be calculated. The CCD diffraction grating spectrometer 1064 can also be used to calibrate the concentration monitoring system 1004 by measuring the intensity of a reference wavelength (e.g., corresponding to peak 1014 in Figures 10A-10B).

[0134] In some embodiments, the concentrations of reactive oxygen species (atomic oxygen and / or ozone) can be monitored using a residual gas monitor or residual gas analyzer (RGA) within a deposition chamber coupled to the reactive oxygen species generation system. For example, a residual gas monitor coupled inside the growth chamber is used to determine the amount of atomic oxygen, ozone, and / or molecular oxygen received from the reactive oxygen species source. Feedback on the concentrations of these various species can be used to control parameters of the reactive oxygen species source, such as operating pressure, molecular oxygen injection flow rate, or photoexcitation power intensity.

[0135] Figure 11A is a schematic isometric view of a photoreactor 1100 according to an exemplary embodiment. As described above, the photoreactor 1100 comprises a reaction chamber 1110, which in this embodiment is configured as a water-cooled four-way conflat (CF) cross member 1105, with four openings arranged at 90 degrees to each other and each provided with a mounting flange. The cross member 1105 may include a water-cooling jacket. In this embodiment, the left-side opening 1112 of the cross member 1105 forms an inlet 1120 for introducing an injection gas 1125 into the reaction chamber 1110. The injection gas 1125 may be, for example, molecular oxygen from an ultra-high pressure O2 supply source. The left-side opening 1112 is in fluid communication with the right-side opening 1114 of the reaction chamber 1110, and the right-side opening 1114 is connected to an outlet 1140. In this embodiment, the outlet 1140 is a T-shaped flange member that receives the gas mixture after the reaction in the reaction chamber 1110. A pressure sensor 1142 (e.g., a vacuum gauge) is connected to the stem of the T-shaped flange member of the outlet 1140 to monitor the pressure of the exhaust gas. A nozzle (not shown, but depicted in Figures 9A to 9C) may be connected to the outlet 1140 to set the characteristics of the exhaust gas 1150 (e.g., a beam containing reactive oxygen species) emitted from the photoreactor 1100.

[0136] A cylindrical extension member 1136 is attached to the upper opening 1113 of the reaction chamber 1110, configured to receive a photoexcitation source 1130. For illustrative purposes, the photoexcitation source 1130 is shown partially inserted into the cylindrical extension member 1136. In this embodiment, the photoexcitation source 1130 is a commercially available xenon excimer lamp, which can be housed within the KF50 flange of the extension member 1136 so that the excimer lamp extends into the central region of the reaction chamber 1110. An exhaust configuration 1160 (i.e., a pump) is connected to the lower opening 1115 and functions to regulate the pressure inside the reaction chamber 1110. In this embodiment, the photoreactor 1100 also incorporates a valve configuration, such as a reactor pressure throttle valve 1165, for separating the various gas flow stages. Measurements from the pressure sensor 212 (Figure 2) and the concentration monitoring system 1003 can be used as feedback to control the exhaust configuration 1160 to adjust the pressure in the reaction chamber 1110 (e.g., to compensate for fluctuations in the inflow of molecular oxygen into the chamber and / or fluctuations in the gas flow out of the chamber). For example, one or more of 1) the flow rate of molecular oxygen, 2) the pump valve for controlling the pressure in the reaction chamber, and 3) the output of the photoexcitation source may be controlled based on feedback from the pressure sensor 212 and / or the concentration monitoring system to enable the achievement of a desired ozone (and / or atomic oxygen) concentration level in the exhausted gas mixture and / or a desired exhaust pressure of the gas mixture.

[0137] In some embodiments, the chamber volume and operating parameters (e.g., chamber pressure, injection molecular oxygen flow rate, excitation source wavelength and output) are determined or set to at least an initial level before the system is operated. In some embodiments, feedback is monitored during the operation of the system and method, and the operating parameters are manually adjusted in response to this feedback. In other embodiments, a controller with a processor is used during the operation of the system and method to automatically control the parameters (e.g., chamber pressure, injection molecular oxygen flow rate, excitation source output) based on feedback from measuring sensors such as the pressure sensor 212 and a concentration monitoring system.

[0138] Figure 11B is a bottom view of the reaction chamber 1110 shown in Figure 11A, looking upward through the lower opening 1115. This figure confirms that the photoexcitation source 1130 is installed inside the reaction chamber 1110. Figure 11B also shows the introduction of molecular oxygen (i.e., injection gas 1125) through the left opening 1112 of the reaction chamber 1110, and the release of a gas mixture containing atomic oxygen, molecular oxygen, and ozone (i.e., exhaust gas 1150) from the right opening 1114 after the reaction in the reaction chamber 1110. In this embodiment, the flow of injection gas 1125 is divided to traverse around the excitation source 1130 located inside the reaction chamber 1110. By traversing around the excitation source 1130, the residence time of oxygen particles (i.e., species, molecules) within the reaction chamber 1110 is increased compared to a linear movement through the chamber, allowing the reaction of oxygen molecules shown in Figure 7 to proceed favorably.

[0139] Other photoreaction chambers in other embodiments are described in relation to Figures 12A-12B, 13A-13E, and 14A-14B, and are configured to accommodate an ozone concentration monitor (e.g., shown in Figures 10D-10E). Figures 12A-12B show front and rear perspective views, respectively, of an example of an excitation source 1130. In this embodiment, the excitation source 1130 is an excimer 172 nm lamp comprising a lamp section 1131, a connector 1132 for connecting to a power supply for the lamp, and an electronics area 1133 for housing electronics for generating synchrotron radiation. The lamp section 1131 is the region from which the generated synchrotron radiation is emitted, and in this figure it is configured as a cylinder made of quartz glass or the like. The connection end of the excitation source 1130 is located on the opposite side of the lamp section 1131 of the excitation source 1130 and is positioned on an adapter 1134 for mounting the lamp to the photoreactor. In this embodiment, adapter 1134 is a conical adapter compatible with KF50 and CF4.5.

[0140] Figure 13A is a perspective view of frame 1310, which functions as a structure supporting the reaction chamber of photoreactor 1300. Figure 13B is similar to Figure 13A, but is shown as an exploded view with added adapter plates and fittings for photoreactor 1300. In one embodiment, frame 1310 may be a 6-inch cubic frame. The reaction chamber is the space enclosed by frame 1310 and plates 1322, 1323, 1324, 1325, 1326, and 1327 (i.e., the internal space of the frame and plates). The excitation source 1130 in Figures 12A-12B is located within frame 1310. Plate 1322 is on the inlet side of photoreactor 1300 and is configured with fittings for connection to a molecular oxygen injection source. Plate 1324, on the opposite side of plate 1322, is connected to a pump (e.g., exhaust configuration 1160) to control the pressure within the reaction chamber. Plate 1323 holds the power connector end (connector 1132) of the excimer lamp (photoexcitation source 1130). Plate 1325 is on the opposite side of plate 1323 and is configured to be an outlet for the gas mixture produced by the photoreactor 1300. Side plates 1326 and 1327 have viewports (i.e., windows) for connecting ozone concentration monitors. For example, a light source for emitting a probe wavelength may be connected to side plate 1326, and a detector for detecting the probe wavelength may be connected to side plate 1327. A window 1345 of plate 1327 is shown in Figure 13B. In this embodiment, the light source is located in the center of the reaction chamber, but in other embodiments it may be located offset from the center of the chamber. Similarly, in this embodiment the viewport (e.g., window 1345) is located in the center of the side plate, but in other embodiments it may be located offset from the center of the chamber while providing an optical path for the probe beam to pass through the gas mixture produced in the reaction chamber.

[0141] Figure 13C is an assembly diagram of the photoreactor 1300, with the side plate 1327 shown in the front, and a window 1345 provided which functions as a viewport for the detector of an ozone concentration monitor (e.g., transparent to wavelengths with a wavelength band center of approximately 240 nm to 250 nm). The plate 1322 located on the upper side of the photoreactor 1300 in this figure is configured with an inlet 1352 (e.g., a "VCR" connector) for connection to a molecular oxygen source, thereby allowing a gas stream 1360 of molecular oxygen to be injected into the reaction chamber. The plate 1325 located on the right side in this figure is configured with an outlet 1355 for discharging a gas mixture 1365 consisting of ozone, atomic oxygen, and molecular oxygen from the reaction chamber. A nozzle 1356 may be connected to the outlet 1355 and is used to impart a desired beam profile characteristic to the discharged gas mixture 1365. The nozzle 1356 may also include openings or orifice plates (not shown) as described herein (e.g., opening 246 in Figure 2, opening 946 in Figure 9B, or opening 948 in Figure 9C).

[0142] As shown in Figure 13C, in this embodiment, the flow directions of the inlet 1352 and the outlet 1355 are at an angle of approximately 90 degrees to each other, and a curved channel 1357 including a curved section is formed between the inlet 1352 and the outlet 1355. The curved channel 1357 exemplifies a typical gas flow path from the inlet to the outlet. Actual gas molecules are likely to travel through a more complex path within the reaction chamber than the path shown by channel 1357, reacting with other gas molecules and photons, reflecting off the walls of the reaction chamber, and finally being discharged through the outlet 1355. This nonlinear channel 1357, formed due to the nonlinear orientation of the flow directions of the inlet 1352 and the outlet 1355, favorably increases the residence time of molecular oxygen in the reaction chamber of the photoreactor 1300 compared to a linear channel, thereby improving the ozone generation capacity. In various embodiments, the reaction chamber may be configured such that the gas flow path between the inlet and outlet has a bend at an angle greater than or less than 90 degrees, for example, between 30 and 180 degrees. The bend (i.e., the curved flow path) may be formed by arranging the inlet 1352 and outlet 1355 in adjacent walls rather than on opposing sides of the reaction chamber.

[0143] The plate 1323 on the left side of Figure 13C is equipped with a spacer 1353 in this figure to properly position the active region of the excitation source (i.e., the ramp section 1131) within the reaction chamber. For example, the active region of the excitation source may be located approximately in the center of the reaction chamber or approximately in the center of the gas flow path (e.g., so that the gas flows around the excitation source). In one embodiment, the spacer 1353 may be a zero-length 4.5” CF spacer. The connector 1132 and conical adapter 1134 of the excitation source can be seen in this figure as extending from the plate 1323 and spacer 1353.

[0144] An optional elbow tube 1354 is connected to plate 1324 and can help protect a pressure gauge (not shown, e.g., pressure sensor 212 in Figure 2) connected to plate 1324. A pump controlling the pressure in the reaction chamber (e.g., exhaust configuration 1160) is also coupled to plate 1324 and configured, for example, so that the pump is connected to a pressure gauge, which is connected to the elbow tube 1354. Vacuum pressure gauges often include a film to protect the sensitive electronic components inside the gauge. VUV radiation can degrade the film, which can damage the pressure gauge. The elbow tube 1354 can help protect the pressure gauge by keeping it out of the line of fire of the VUV radiation source. Therefore, in some embodiments, the photoreactor 1300 may include an elbow tube (or other non-linear conduit) between the excitation source in the reaction chamber and the pressure gauge (e.g., pressure sensor and associated components).

[0145] Figures 13D and 13E are diagrams of the photoreactor 1300, using the same reference numerals as in Figures 13A to 13C. Figure 13D is a rear view of Figure 13C, with the side plate 1326 positioned at the front. The side plate is provided with a window 1340 (for example, transparent to a wavelength band centered around approximately 240 nm to 250 nm) that functions as a viewport for the light source of the ozone concentration meter monitor. Figure 13E is similar to Figure 13D, but with the side plate 1326 removed to show the inside of the reaction chamber. Arrow 1362 indicates a gas flow path, showing that in this embodiment, the gas flows along a curved path and changes direction by approximately 90 degrees from the flow direction of the inlet 1352 to the flow direction of the outlet 1355. In this embodiment, this curved flow path is formed by the inlet 1352 being located in a first wall and the outlet 1355 being located in a second wall adjacent to the first wall. This differs from the case where the inlet and outlet are located on opposing side walls of the reaction chamber, forming a linear flow path across the reaction chamber. In some cases, the flow within the reaction chamber is non-turbulent. The flow path can be further lengthened depending on the location of the excitation source. For example, if the excitation source 1130 is located within the reaction chamber, the gas must flow around the excitation source 1130, which in this embodiment is cylindrical and penetrates the center of the reaction chamber. By forming a non-linear flow path between the inlet 1352 and outlet 1355 of the reaction chamber, where they are oriented in offset directions or at non-linear angles, and where gas molecules must flow around the excitation source, the residence time is advantageously increased compared to a linear flow path, and reactions such as the generation of atomic oxygen by excitation of molecular oxygen and the formation of ozone from atomic and molecular oxygen can occur, as shown in Figures 7 to 8B.

[0146] Figures 14A and 14B are similar to Figures 13A to 13E, and the same reference numerals are used for components similar to those of the photoreactor 1300, but they are oriented to show components of an ozone concentration monitor according to several embodiments. Figure 14A shows that side plate 1326 is located on the left side and side plate 1327 is located on the right side. Window 1340 is coupled to side plate 1326, and window 1345 is coupled to side plate 1327. The ozone concentrator monitor includes an optical light source 1430 and a detector 1460. The optical light source 1430 has a probe wavelength λ プローブ Synchrotron radiation 1432 having λ is emitted, and the detector 1460 detects the emitted synchrotron radiation 1434 that has passed through the reaction chamber to determine the amount of synchrotron radiation absorbed by ozone in the reaction chamber. In one embodiment, the light source 1430 has λ プローブ (λ プローブ It emits synchrotron radiation in a narrow band around approximately 240 nm. Windows 1340 and 1345 are transparent to the probe wavelength, and the lamp portion of the excitation source 1130 is also transparent to the probe wavelength.

[0147] Figure 14B is similar to Figure 14A, except that the plate 1323, which has a power connector 1132 for the excitation source, is rotated to face forward. The inlet 1352 for the gas flow 1360 is shown on the upper side of the photoreactor 1300. The optical light source 1430 emits synchrotron radiation 1432 through the window 1340, and the detector 1460 receives the synchrotron radiation 1434 that exits through the window 1345. In this figure, a pressure gauge 1410 is shown coupled to an L-shaped tube 1354, which is coupled to the plate 1324. A pump (not shown) is coupled to the pressure gauge, which is located between the pump and the L-shaped tube 1354.

[0148] Figure 15 is a schematic diagram of a system 1500 in which a photoreactor disclosed herein supplies ozone to a containment chamber such as a vacuum deposition chamber or other material deposition chamber (e.g., a deposition system). In Figure 15, the system 1500 has a deposition configuration that incorporates a deposition chamber 1550 (e.g., a vacuum deposition chamber) and an active oxygen species generation system 1501 according to the disclosure. The vacuum deposition chamber 1550 is configured to deposit a material on a substrate 1560. The active oxygen species generation system 1501 comprises a molecular oxygen source 1510 and a photoreactor system 1520 configured to emit a beam 1590 containing active oxygen species into the deposition chamber 1550, and in this embodiment, the deposition chamber 1550 is 10 -4 Torr~10 -10 It operates within the Torr pressure range. In other embodiments, the deposition chamber 1550 is 10 -5 Torr~10 -8 It operates within Torr's pressure range.

[0149] In one embodiment shown in Figure 15, the molecular oxygen source 1510 includes a bottled supply source 1511 containing ultra-high pressure 7N molecular oxygen. A mass flow controller 1515 is coupled to the oxygen source, i.e., the supply source 1511. Molecular oxygen from the supply source 1511 passes through an optional filter 1512, the mass flow controller 1515, and an output valve 1517, and is supplied to the inlet 220 of the photoreactor 200 of the photoreactor system 1520. A controller 1530, including a processor, may communicate with an ozone concentration monitoring system 1525, pressure sensors (e.g., pressure sensor 212 and / or pressure gauge 1410), the molecular oxygen source 1510, and / or the photoreactor 200. In some embodiments, the controller 1530 is coupled to the oxygen source and configured to control the flow rate of molecular oxygen into the reaction chamber using a measurement of the ozone concentration in the reaction chamber obtained from an ozone concentration monitor. In some embodiments, a pressure sensor is connected to a pump, which is coupled to a reaction chamber, and the pressure in the reaction chamber is controlled using feedback from the pressure sensor to the pump. In some embodiments, the system comprises a pump coupled to a reaction chamber, a pressure sensor configured to measure the pressure in the reaction chamber, and a controller coupled to the pump and the pressure sensor, the controller configured to control the pump and the pressure in the reaction chamber based on feedback from the pressure sensor.

[0150] The photoreactor 200 functions to generate a beam 1590 of reactive oxygen species. The reactive oxygen species contains at least 5%, or at least 6%, or at least 7%, or at least 10%, or at least 30% ozone, has a predetermined beam profile 1591, a beam flow rate of 1 SCCM to 5 SCCM, and a beam pressure of 10 -5 Torr~10 -8The beam is within the Torr range and is used for deposition on the substrate 1560. The beam profile 1591 may be formed by a nozzle 245 as described herein (e.g., Figures 9A-9E), which may include an orifice plate and a beamforming member. The beam 1590 is supplied to the deposition chamber 1550 on demand and may be supplied continuously for several minutes or several hours as needed for the deposition process in the deposition chamber 1550. The photoreactor system 1520 may also include an ozone concentration monitoring system 1525 including a probe light source and a detector, as described herein (e.g., Figures 10A-10E).

[0151] In various embodiments, the systems disclosed herein (e.g., System 1500) are systems for generating reactive oxygen species, comprising a reaction chamber and an inlet to the reaction chamber, the inlet being configured to be coupled to an oxygen source containing molecular oxygen. A photoexcitation source is optically coupled to the reaction chamber and is configured to generate synchrotron radiation in the ultraviolet wavelength range, which is configured to excite a portion of the molecular oxygen in the reaction chamber to form atomic oxygen without the use of a plasma generator, and which reacts with the molecular oxygen in the reaction chamber to form ozone. The outlet of the reaction chamber is configured to release a gas mixture containing atomic oxygen, molecular oxygen, and ozone.

[0152] In one embodiment of the system, the ultraviolet wavelength range of the synchrotron radiation generated by the photoexcitation source is 125 nm to 180 nm. The photoexcitation source may be located inside or outside the reaction chamber, and may optionally be optically coupled to the inside of the reaction chamber. The photoexcitation source may be, for example, an excimer lamp emitting the photoexcitation wavelengths described herein.

[0153] In some embodiments, one or more of the reaction chamber volume, operating pressure, synchrotron radiation wavelength, synchrotron radiation output intensity, and flow rate of molecular oxygen to the reaction chamber inlet (i.e., a combination of at least one of these parameters and one or more other parameters) are configured to favorably select a formation reaction pathway in which molecular oxygen forms atomic oxygen and ozone, rather than a loss reaction pathway in which ozone forms molecular oxygen.

[0154] In some embodiments, the volume of the reaction chamber is configured to provide residence times for atomic oxygen, molecular oxygen, and ozone, thereby favorably selecting the formation reaction pathways (pathways 710 and 720) in which molecular oxygen forms atomic oxygen and ozone, rather than the loss reaction pathway (pathways 730 and / or 735) in which ozone forms molecular oxygen, and the volume is configured based on the operating pressure, the wavelength of the synchrotron radiation, the output intensity of the synchrotron radiation, and the flow rate of molecular oxygen to the inlet of the reaction chamber.

[0155] In some embodiments, one or more of the operating pressure, the wavelength of the synchrotron radiation, the output intensity of the synchrotron radiation, and the flow rate of molecular oxygen to the inlet of the reaction chamber are configured to provide residence times for atomic oxygen, molecular oxygen, and ozone in accordance with a given volume of the reaction chamber, thereby favorably selecting the formation reaction pathway in which molecular oxygen forms atomic oxygen and ozone, rather than the loss reaction pathway in which ozone forms molecular oxygen.

[0156] In some embodiments, the volume of the reaction chamber, the operating pressure, the output intensity of the synchrotron radiation from the photoexcitation source, and the flow rate of molecular oxygen to the inlet of the reaction chamber are configured to favorably select the formation reaction pathway in which molecular oxygen forms atomic oxygen and ozone, rather than the loss reaction pathway in which ozone forms molecular oxygen. The ultraviolet wavelength range of the synchrotron radiation produced by the photoexcitation source may be 125 nm to 180 nm, for example, 146 nm, 172 nm, or 193 nm.

[0157] In some embodiments, the reaction chamber is configured to maintain a pressure of less than 100 Torr (13332 Pascals). In some embodiments, the photoexcitation source operates at a wavelength of 172 nm and has a power output of 50 mW / cm². 2 The light source is 200 cm³, and the volume of the reaction chamber is 200 cm³. 3 The pressure inside the reaction chamber is 100 mTorr (0.133 Pascals) to 1 Torr (133 Pascals), and the flow rate of molecular oxygen from the oxygen source is 1 SCCM to 10 SCCM.

[0158] In some embodiments, the system may also include a controller coupled to an oxygen source and configured to control the flow rate of molecular oxygen into the reaction chamber using measurements of the ozone or atomic oxygen concentration in the reaction chamber from a concentration monitor. The system may also include a pump coupled to the reaction chamber and a pressure sensor configured to measure the pressure in the reaction chamber, and the controller may be coupled to the pump and the pressure sensor and configured to control the pump based on feedback from the pressure sensor, thereby controlling the pressure in the reaction chamber.

[0159] In some embodiments, the system includes a concentration monitor configured to monitor atomic oxygen or ozone and coupled to a reaction chamber, comprising a light source configured to emit a probe beam having a probe wavelength that is absorbed more strongly by atomic oxygen or ozone than by molecular oxygen through a first window in the wall of the reaction chamber, and a detector positioned to receive the probe beam through a second window in the wall after the probe beam has passed through the reaction chamber. The probe wavelength may be, for example, 200 nm to 300 nm for monitoring ozone.

[0160] In some embodiments, a gaseous mixture is emitted from a reaction chamber as a beam containing reactive oxygen species, the reactive oxygen species containing at least one of atomic oxygen or ozone. A nozzle is coupled to an outlet and has an effective aperture diameter D and a length L, and the aspect ratio L / D is configured to create a desired pressure difference between the reaction chamber and the containment chamber, and the beam containing the reactive oxygen species is delivered through the nozzle from the outlet to the containment chamber. The containment chamber may be a vacuum chamber, such as for manufacturing semiconductor materials. The nozzle may be configured to provide a cosine-n-theta photon flux distribution. The nozzle may include an orifice plate configured with an effective aperture diameter D and a beamforming member configured to generate a desired beam distribution.

[0161] In some embodiments, the system may include a light reflector on the inner wall of the reaction chamber. In some embodiments, the inlet and outlet are located on adjacent walls of the reaction chamber, so that a curved gas flow path is formed between the inlet and outlet. In some embodiments, the system is for forming an oxide film, and further includes a material deposition system coupled to the outlet of the reaction chamber that receives a gas mixture containing atomic oxygen, molecular oxygen, and ozone.

[0162] In some embodiments of the system, the ultraviolet wavelength range of the synchrotron radiation generated by the photoexcitation source is 125 nm to 180 nm, and the volume of the reaction chamber, the operating pressure, the output intensity of the synchrotron radiation from the photoexcitation source, and the flow rate of molecular oxygen to the inlet of the reaction chamber are configured to provide residence times for atomic oxygen, molecular oxygen, and ozone, thereby favorably selecting the formation reaction pathway in which molecular oxygen forms atomic oxygen and ozone, rather than the loss reaction pathway in which ozone forms molecular oxygen.

[0163] In some embodiments, the systems described herein (e.g., system 1500 in Figure 15) are systems for forming oxide films, and the system includes a material deposition system (e.g., deposition chamber 1550) and a photoreactor (e.g., photoreactor system 1520). The photoreactor (e.g., photoreactor 200 and embodiments described herein) comprises a reaction chamber, an inlet to the reaction chamber, a photoexcitation source, and an outlet from the reaction chamber. The inlet is configured to be coupled to an oxygen source containing molecular oxygen. The photoexcitation source may be located inside or outside the reaction chamber and may be configured to generate synchrotron radiation in the ultraviolet wavelength range. The synchrotron radiation is configured to excite some of the molecular oxygen in the reaction chamber to form atomic oxygen, which then reacts with the molecular oxygen in the reaction chamber to form ozone. The outlet is coupled to the material deposition system and delivers a gas mixture containing atomic oxygen, molecular oxygen, and ozone. Accordingly, System 1500 includes any of the photoreactors and embodiments thereof described herein, the system being for forming oxide films, and further, the system may include a material deposition system coupled to the outlet of a reaction chamber that receives a gas mixture containing atomic oxygen, molecular oxygen, and ozone.

[0164] In some embodiments, the deposition chamber 1550 may be a material deposition system for forming epitaxial oxides, such as thin films for semiconductor structures. The semiconductor structure may be for devices such as electronic or optoelectronic devices. The film may be, for example, a binary, ternary, or quaternary oxide composition. In some embodiments, the epitaxial oxide may be a metal oxide. For example, the metal oxide may be A x B 1-x O nIt may be a ternary metal oxide in the form of (where 0 < x < 1.0). The metal species A may be Al or Ga, and the metal species B may be selected from the group consisting of Zn, Mg, Ga, Ni, rare earths, Ir, Bi, and Li. Examples of other oxide materials and structures that can be produced by the methods and systems described herein include U.S. Patent No. 11,342,484, "Metal Oxide Semiconductor-Based Light Emitting Device", U.S. Patent No. 11,502,223, "Epitaxial Oxide Materials, Structures, and Devices", and U.S. Patent No. 11,522,103, "Epitaxial Oxide Materials, Structures, and Devices". All of these are owned by the assignee of the present application and are incorporated herein by reference in their entirety.

[0165] The present disclosure describes a system for generating reactive oxygen species. The system includes a reaction chamber, an inlet to the reaction chamber configured to be coupled to an oxygen source containing molecular oxygen, a photoexcitation source optically coupled to the reaction chamber, and an outlet from the reaction chamber. The photoexcitation source is configured to generate radiation light in the ultraviolet wavelength range, which excites a portion of the molecular oxygen in the reaction chamber to form atomic oxygen, and the atomic oxygen is configured to react with the molecular oxygen in the reaction chamber to form ozone. The outlet is configured to discharge a gas mixture containing atomic oxygen, molecular oxygen, and ozone.

[0166] As will be understood by those skilled in the art, the present method and system are operable to provide a supply of reactive oxygen species generated on demand at the time of use. In this regard, the method according to the present disclosure has some similarities with the RF plasma method, but the concentration ratio of the reactive oxygen species generated is substantially higher than that generated by any RF plasma-based system.

[0167] The components of the embodiments and their variations shown in each figure of this specification can be used in different combinations. For example, any photoreactor described herein can utilize either the photoexcitation source 230a inside the reaction chamber or the photoexcitation source 230b outside the reaction chamber. In other embodiments, the nozzles shown in Figure 2, Figures 9A to 9C, and elsewhere in this disclosure can be used in any photoreactor described herein. In other embodiments, the ozone concentration monitor can be used in any photoreactor described herein. In other embodiments, the reactive oxygen species concentration monitor can be used in any photoreactor described herein. In other embodiments, the wavelengths described for the excitation source and the probe wavelengths described for the ozone concentration monitor can be used in any photoreactor described herein. Similarly, in addition to the photoexcitation source 1130 shown in Figures 12A to 12B, other suitable excitation sources that meet the conditions described herein (e.g., satisfying the absorption characteristics described in Figures 3A to 3B) can be used. In further embodiments, the L-shaped tube 1354 can be used in the photoreactor 1100 or other photoreactors described herein.

[0168] In some cases, a single embodiment may combine multiple features for brevity and / or to aid in understanding the scope of this disclosure. In such cases, it should be understood that these multiple features may be provided separately (in separate embodiments) or in any other suitable combination. Alternatively, where separate features are described in separate embodiments, these separate features may be combined into a single embodiment unless otherwise specified or implied. This also applies to claims that can be recombined in any combination; that is, a claim may be modified to include features specified in any other claim. Furthermore, the phrase "at least one" from the list of items refers to any combination of those items that contain a single element. For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc.

[0169] While embodiments of the disclosed invention have been described in detail, one or more examples of these are shown in the accompanying drawings. Each example is provided for illustrative purposes and is not intended to limit the Art. Indeed, although this specification describes in detail specific embodiments of the Invention, it will be understood that those skilled in the art, with an understanding of the foregoing, will readily devise modifications, variations, and equivalents to these embodiments. For example, features illustrated or described as part of one embodiment may be used in another embodiment to bring about yet another embodiment. Thus, this subject matter is intended to encompass all such modifications and variations within the scope of the appended claims and their equivalents. These and other modifications and variations of the Invention can be practiced by those skilled in the art without departing from the scope of the Invention as more specifically described in the appended claims. Furthermore, as will be apparent to those skilled in the art, the foregoing description is merely an example and is not intended to limit the Invention.

Claims

1. A system for generating reactive oxygen species, Reaction chamber and An inlet to the reaction chamber, configured to bind to an oxygen source containing molecular oxygen, A photoexcitation source is optically coupled to the reaction chamber and configured to generate synchrotron radiation in the ultraviolet wavelength range, wherein the synchrotron radiation is configured to excite a portion of the molecular oxygen in the reaction chamber to form atomic oxygen without using a plasma generator, and the atomic oxygen reacts with the molecular oxygen in the reaction chamber to produce ozone. The system includes an outlet of the reaction chamber configured to release a gas mixture comprising atomic oxygen, molecular oxygen, and ozone.

2. The system according to claim 1, wherein the ultraviolet wavelength range of the synchrotron radiation generated by the photoexcitation source is 125 nm to 180 nm.

3. The system according to any one of claims 1 to 2, wherein the photoexcitation source is located inside the reaction chamber.

4. The system according to any one of claims 1 to 3, wherein the photoexcitation source is an excimer lamp.

5. The volume of the reaction chamber is configured to provide residence time for the atomic oxygen, molecular oxygen, and ozone, thereby favorably selecting a formation reaction pathway in which molecular oxygen forms ozone with atomic oxygen, rather than a loss reaction pathway in which ozone forms molecular oxygen. The system according to any one of claims 1 to 4, wherein the volume is configured based on the operating pressure, the wavelength of the synchrotron radiation, the output intensity of the synchrotron radiation, and the flow rate of molecular oxygen to the inlet of the reaction chamber.

6. The system according to any one of claims 1 to 4, wherein one or more of the operating pressure, the wavelength of the synchrotron radiation, the output intensity of the synchrotron radiation, and the flow rate of the molecular oxygen to the inlet of the reaction chamber are configured to provide residence times for the atomic oxygen, the molecular oxygen, and the ozone in accordance with a given volume of the reaction chamber, thereby favorably selecting a formation reaction pathway in which the molecular oxygen forms the atomic oxygen and the ozone, rather than a loss reaction pathway in which the ozone forms the molecular oxygen.

7. The aforementioned photoexcitation source operates at a wavelength of 172 nm and has a power output of 50 mW / cm². ２ The light source is 200 cm³. ３ The system according to any one of claims 1 to 6, wherein the pressure in the reaction chamber is 100 mTorr (0.133 Pascals) to 1 Torr (133 Pascals), and the flow rate of molecular oxygen from the oxygen source is 1 SCCM to 10 SCCM.

8. The system according to any one of claims 1 to 7, further comprising a controller coupled to the oxygen source and configured to control the flow rate of molecular oxygen into the reaction chamber using a measurement of the ozone concentration or atomic oxygen concentration in the reaction chamber from a concentration monitor.

9. A pump coupled to the reaction chamber, The system further includes a pressure sensor configured to measure the pressure inside the reaction chamber, The system according to claim 8, wherein the controller is coupled to the pump and the pressure sensor and is configured to control the pump based on feedback from the pressure sensor, thereby controlling the pressure in the reaction chamber.

10. A concentration monitor configured to monitor the atomic oxygen or ozone, and coupled to the reaction chamber, A light source configured to emit a probe beam through a first window provided in the wall of the reaction chamber, wherein the probe beam has a probe wavelength that is absorbed more strongly by atomic oxygen or ozone than by molecular oxygen, The system according to any one of claims 1 to 9, further comprising a concentration monitor, the detector positioned to receive the probe beam after it has passed through the reaction chamber, through a second window provided in the wall of the reaction chamber.

11. The system according to claim 10, wherein the probe wavelength is 200 nm to 300 nm.

12. The system according to any one of claims 1 to 11, wherein the gas mixture is emitted from the reaction chamber as a beam containing the reactive oxygen species, and the reactive oxygen species contains at least one of atomic oxygen or ozone.

13. The present invention further includes a nozzle coupled to the discharge port, having an effective opening diameter D and a length L, and configured such that its aspect ratio L / D creates a desired pressure difference between the reaction chamber and the containment chamber. The system according to claim 12, wherein the beam containing the reactive oxygen species is delivered through the nozzle from the outlet to the containment chamber.

14. The system according to claim 13, wherein the containment chamber is a vacuum chamber for manufacturing semiconductor materials.

15. The system according to claim 13, wherein the nozzle is configured to provide a cosine-n-theta photon flux distribution.

16. The aforementioned nozzle is An orifice plate configured with the effective opening diameter D, The system according to claim 13, further comprising beamforming components configured to generate a desired beam distribution.

17. The system according to any one of claims 1 to 16, further comprising a light reflector on the inner wall of the reaction chamber.

18. The system according to any one of claims 1 to 17, wherein the inlet and outlet are located on adjacent walls of the reaction chamber, thereby forming a curved gas flow path between the inlet and the outlet.

19. The system according to any one of claims 1 to 18, wherein the system is for forming an oxide film and further comprises a material deposition system coupled to the outlet of the reaction chamber that receives the gas mixture comprising atomic oxygen, molecular oxygen, and ozone.

20. The ultraviolet wavelength range of the synchrotron radiation generated by the photoexcitation source is 125 nm to 180 nm. The system according to claim 1, wherein the volume of the reaction chamber, the operating pressure, the output intensity of the synchrotron radiation from the photoexcitation source, and the flow rate of molecular oxygen to the inlet of the reaction chamber are configured to favorably select a formation reaction pathway in which molecular oxygen forms atomic oxygen and ozone, rather than a loss reaction pathway in which ozone forms molecular oxygen.

21. A method for generating reactive oxygen species, Introducing molecular oxygen from an oxygen source containing molecular oxygen into the inlet of the reaction chamber, The process involves generating synchrotron radiation from a photoexcitation source optically coupled to the reaction chamber, exciting a portion of the molecular oxygen to form atomic oxygen, wherein the synchrotron radiation is within the ultraviolet wavelength range, and the process involves generating the synchrotron radiation. Without using a plasma generator, ozone is formed by reacting the atomic oxygen with the molecular oxygen present in the reaction chamber. The method comprising releasing a gas mixture containing atomic oxygen, molecular oxygen, and ozone from the outlet of the reaction chamber.

22. The method according to claim 21, wherein the ultraviolet wavelength range of the synchrotron radiation generated by the photoexcitation source is 125 nm to 180 nm.

23. The method according to any one of claims 21 to 22, wherein the photoexcitation source is located inside the reaction chamber.

24. The method according to any one of claims 21 to 23, wherein, in the emission, the gas mixture is emitted from the reaction chamber as a beam containing the reactive oxygen species, and the reactive oxygen species contains at least one of atomic oxygen or ozone.

25. The method according to claim 24, wherein the beam containing the reactive oxygen species is continuously emitted.

26. The method according to any one of claims 21 to 25, wherein, in the introduction of molecular oxygen, the molecular oxygen is continuously introduced into the reaction chamber.

27. The method according to any one of claims 21 to 26, wherein, in the introduction of the molecular oxygen, the flow rate of the molecular oxygen is 100 SCCM or less.

28. The method according to any one of claims 21 to 25, wherein, in the introduction of molecular oxygen, the molecular oxygen is introduced until the reaction chamber is pressurized to a predetermined pressure.

29. The volume of the reaction chamber is configured to provide residence time for the atomic oxygen, the molecular oxygen, and the ozone, and further includes favorably selecting a formation reaction pathway in which the molecular oxygen forms the ozone with the atomic oxygen, rather than a loss reaction pathway in which the ozone forms the molecular oxygen. The method according to any one of claims 21 to 28, wherein the volume is configured based on the operating pressure, the wavelength of the synchrotron radiation, the output intensity of the synchrotron radiation, and the flow rate of the molecular oxygen introduced into the inlet of the reaction chamber.

30. The method according to any one of claims 21 to 28, wherein one or more of the operating pressure, the wavelength of the synchrotron radiation, the output intensity of the synchrotron radiation, and the flow rate of the molecular oxygen to the inlet of the reaction chamber are configured to provide residence times for the atomic oxygen, the molecular oxygen, and the ozone in accordance with a given volume of the reaction chamber, thereby favorably selecting a formation reaction pathway in which the molecular oxygen forms the atomic oxygen and the ozone, rather than a loss reaction pathway in which the ozone forms the molecular oxygen.

31. The method according to any one of claims 21 to 30, further comprising maintaining a pressure of less than 100 Torr (13,332 Pascals) in the reaction chamber while the ozone is being formed.

32. The aforementioned photoexcitation source operates at a wavelength of 172 nm and has a power output of 50 mW / cm². ２ The light source is 200 cm³. ３ The method according to any one of claims 21 to 31, wherein the pressure in the reaction chamber is 100 mTorr (0.133 Pascals) to 1 Torr (133 Pascals), and the flow rate of molecular oxygen from the oxygen source is 1 SCCM to 10 SCCM.

33. The method according to any one of claims 21 to 32, further comprising using a controller to control the flow rate of molecular oxygen introduced into the reaction chamber based on the ozone concentration or atomic oxygen concentration in the reaction chamber measured by a concentration monitor.

34. The method according to claim 33, further comprising using a controller to control the pressure in the reaction chamber using feedback from a pressure sensor connected to a pump coupled to the reaction chamber.

35. The measurement further includes measuring the ozone concentration or the atomic oxygen concentration, and the measurement is The method involves emitting a probe beam from a light source through a first window provided in the wall of the reaction chamber, wherein the probe beam has a probe wavelength that is absorbed more strongly by ozone or atomic oxygen than by molecular oxygen, The method according to claim 33, comprising receiving the probe beam after it has passed through a second window provided in the wall of the reaction chamber using a detector.

36. The method according to any one of claims 21 to 35, wherein the discharge of the gas mixture comprises delivering the gas mixture as a beam containing the reactive oxygen species to a containment chamber using a nozzle connected to the discharge port, the nozzle being configured to generate a desired beam distribution and a desired pressure difference between the reaction chamber and the containment chamber.

37. The method according to claim 36, wherein the containment chamber is a vacuum chamber.

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