High-brightness primary X-ray source for in-line XPS and XRF metrology

Abstract

A method for evaluating a sample, the method comprising: (a) irradiating a liquid metal jet alloyed with aluminum with an electron beam to provide a first X-ray beam; (b) spectrally filtering the first X-ray beam with a filtering unit to provide a second X-ray beam; (c) irradiating a sample with the second X-ray beam; and (d) detecting X-ray radiation emitted from the sample as a result of irradiating the sample.

Description

[Technical Field]

[0001] (cross reference) This application claims priority from U.S. Provisional Patent Application No. 63 / 376,770, filed September 22, 2022, which is incorporated herein by reference. [Background technology]

[0002] The most common X-ray energy utilized in XPS is AlKα (1486.7 eV), which is typically delivered and focused onto the wafer surface through a monochromator to narrow the natural linewidth of the emission line for chemical state identification.

[0003] The kinetic energy of the photoelectrons produced by AlKα radiation is up to 1486 eV (~1486 eV), which limits the analytical depth to a maximum of 10 nm and also restricts the range of secondary X-ray fluorescence lines that can be detected simultaneously, with independent input of the total dose of the analyzed material.

[0004] It may be desirable to utilize intense higher energy primary x-rays to increase the overall analytical depth and the range of excited fluorescent x-ray lines.

[0005] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification, although the invention, together with its objects, features, and advantages, both as to use and method of operation, may best be understood by reference to the following detailed description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0006] [Figure 1] A phase diagram is shown. [Figure 2] An example of generating a high-brightness X-ray beam is shown. [Figure 3]An example of generating a high-brightness X-ray beam is shown. [Figure 4] An example of a quasi-continuously variable single wavelength X-ray source is shown. [Figure 5] An example of the method is shown below. DETAILED DESCRIPTION OF THE INVENTION

[0007] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, those skilled in the art will understand that the present invention may be practiced without these specific details. Additionally, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.

[0008] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification, although the invention, together with its objects, features, and advantages, both as to use and method of operation, may best be understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

[0009] It will be understood that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements.

[0010] Because the illustrated embodiments of this invention can, for the most part, be implemented using electro-optical components known to those skilled in the art, details will not be described beyond the extent deemed necessary for the purposes of illustration as set forth above in order to enhance understanding and appreciation of the concepts underlying this invention and so as not to obfuscate or detract from the teachings of this invention.

[0011] Any reference in this specification to a method should apply mutatis mutandis to a system capable of carrying out that method.

[0012] Any reference in this specification to a system should apply mutatis mutandis to a method that can be performed by that system.

[0013] A system for evaluating a sample is provided, the system including: (a) a source of a liquid metal jet alloyed with aluminum; (b) an electron beam source having electron optics configured to irradiate the liquid metal jet alloyed with aluminum with an electron beam to provide a first X-ray beam; (c) a filtering unit configured to spectrally filter the first X-ray beam to provide a second X-ray beam; (d) electron optics configured to irradiate the sample with the second X-ray beam; and (e) a detector configured to detect x-ray radiation emitted from the sample as a result of irradiating the sample.

[0014] It is capable of producing X-ray beams in the range of approximately 1 keV and above, providing a high-brightness primary X-ray source for in-line XPS and XRF metrology that enables wafer composition analysis and thickness metrology using medium and high energy X-ray beams.

[0015] An X-ray source is provided that can (e.g., simultaneously) produce high-intensity AlKα (hv=1486.7 eV) and continuous high-energy radiation produced from Al alloys such as Al-Ga, Al-In, or other low-melting-point metal combinations.

[0016] The continuum radiation generated can also be selected in the second, third and fourth Bragg reflections at photon energies of 2973.4 eV, 4460.1 eV and 5946.8 eV, respectively, and transported and collected by a focusing quartz monochromator, thus generating and selecting four or more different high brightness / high intensity X-ray energies that can be focused onto the wafer.

[0017] The first, second, etc. orders of X-ray radiation for material composition analysis on small targets using a combination of XPS and XRF provide distinctly different and independent material information.

[0018] To increase throughput while reducing the measurement spot size required for in-line XPS / XRF measurements, a high brightness X-ray source combined with an efficient monochromator is required.

[0019] A bright x-ray source reduces the divergence angle, concentrating a high flux into a smaller spot, and the use of a smaller monochromator reduces the risk of crystal misalignment and reduces costs.

[0020] The smaller size of the monochromator improves spot size as well as energy resolution, making it less susceptible to slight alignment errors. The use of a monochromator allows for photoelectron energy resolution to resolve various bonding states of elements for excitation X-ray energies of <1500 eV, with a final X-ray energy spread at the target of <0.5 eV. The higher brightness of the primary X-ray allows for a 2x reduction in the footprint of the monochromator crystal, and the 10x higher X-ray flux of the X-ray source results in an overall 5x improvement in spot size and t-put.

[0021] Furthermore, the availability of higher energy X-rays from higher Bragg diffraction orders is also useful for tuning the photon energy of XPS and XRF to provide optimal excitation conditions for material characterization (composition, contamination, thickness) depending on the material thickness and composition.

[0022] The primary X-ray beam can be excited in the following manner: a. An intense e-beam that irradiates a liquid, solid, or gas jet. b. The electron beam source can be a focused conventional LaB6 electron source or equivalent. c. Instead of a conventional electron source, the electron beam can also be generated via a photocathode source illuminated by a focused light / laser source of high brightness and appropriate wavelength. d. Light-assisted x-ray emission from the target in conjunction with the electron beam

[0023] The excitation of the primary source X-rays can also be achieved by a focused high-intensity laser beam. The preferred excitation mode is continuous X-ray beam generation, but pulsed X-ray source operation is also conceivable with appropriate adjustment of the measurement system.

[0024] An Al-Ga liquid metal alloy is provided as an X-ray target that generates high-brightness AlKα (1486.7 eV) and Ga (9251.67 eV).

[0025] The phase diagram of Al-Ga alloys (see Figure 1) shows that Al-Ga alloys are in the liquid phase at temperatures slightly above room temperature for various stoichiometries.

[0026] Interestingly, Al-Ga liquid metal alloys have been used as catalysts for the decomposition of H2O to produce hydrogen, and their properties have been evaluated (Y. Yu et al., Jeffrey T. Ziebarth et al.).

[0027] Al x Ga 1-x At mass ratios of (x=10, 20, 30, 40, 50), Al was uniformly dispersed in the liquid metal above room temperature.

[0028] It was found that the presence of Ga in liquid Al-Ga alloys prevents the formation of an Al2O3 passivation layer, which is not observed in solid Al. 70 G 30 and Al 80 Ga 20In this study, the elements Ga and Al were not uniformly distributed, and traces of Al2O3 were detected. The brightness of AlKα X-rays produced from an Al-Ga liquid metal jet (or other suitable liquid metal jet alloyed with Al) is estimated to be at least one order of magnitude higher than that of a conventional solid target. By using a monochromator that efficiently collects a large solid angle from such a source, the flux fall on the measurement target is estimated to be one to two orders of magnitude higher than that of a solid Al target in an analysis area of ​​<50 μm × 50 μm.

[0029] Since Al-Ga alloys become liquid at high temperatures, they can be used as jet X-ray targets. By directing a high-power, high-brightness electron beam at a fast-moving liquid metal alloy jet, bright AlKα and GaKα X-ray sources can be generated.

[0030] The system employs liquid metal Al-Ga alloy as the X-ray source anode, which can generate high-brightness AlKα and GaKα for combined XPS and XRF systems. The weight x in AlxGa100-x can range from x<60 to x=0.

[0031] High brightness X-ray sources using Al-Ga alloys can be incorporated into XPS and XRF in-line measurement systems (such as those disclosed in U.S. Pat. No. 9,240,254, incorporated herein by reference) and, when used with a monochromator, can produce high brightness monochromatized AlKα at 1486.7 eV, along with GaKα at 9251.67 eV, and higher harmonic photon energies up to the fourth order (2973.4 eV, 4460.1 eV, and 5946.8 eV) for high-energy XPS and XRF applications. GaKα can be used with another monochromator to generate alternative high brightness monochromatized X-rays for material composition analysis using XPS, XRF, and XPS-XRF combo techniques.

[0032] When Al-Ga alloys, Al-In alloys, or other suitable metal alloys are used as X-ray targets and excited by a high-energy, high-brightness electron beam produced by a photocathode, characteristic AlKα and InKα lines are emitted, which are superimposed on the continuous X-ray spectrum and form the so-called Bremsstrahlung background.

[0033] In general, Bremsstrahlung radiation is most efficiently generated when small, high-energy particles interact with elements with high atomic numbers. Specifically, in the context of this disclosure, Bremsstrahlung radiation generation from In, Sn, or Ga is much higher than that from Al, and the yield increases with electron energy and electron beam power. Due to the fast heat dissipation of the LMJ target, the source can sustain higher electron source energy and power, resulting in higher Bremsstrahlung radiation. This Bremsstrahlung radiation can be selected by a monochromator to provide high-energy X-rays suitable for XRF and XPS at deeper analytical depths.

[0034] A high-brilliance (bright) electron beam is a prerequisite for generating a high-brilliance X-ray beam from a liquid metal jet, but is not a guaranteed condition.

[0035] A high brightness electron beam source coupled with a liquid metal jet anode improves x-ray performance. Those skilled in the art know that increasing the electron beam input to the x-ray anode increases x-ray intensity.

[0036] However, to generate high-brilliance X-rays, a high-power density and high-brightness electron source must be combined with an anode target. It is known that simply increasing the brightness and power density of the electron beam can cause catastrophic destruction of the X-ray source in solid anode X-ray targets. In the case of liquid metal targets, due to the circulation and replenishment nature of the liquid metal jet, higher electron beam power and power density can be used to generate high-brilliance X-ray beams. The most common electron source used in X-ray sources consists of a LaB6 cathode and electron focusing optics.

[0037] However, another method for generating a high brightness, high power density electron beam for a high brightness liquid metal jet X-ray source is to use a laser-driven photocathode, where the characteristic emission spot size is determined by the size of the illumination source (disclosed in U.S. Patent Application No. 63 / 365,414, which is incorporated herein by reference).

[0038] 2 is a schematic diagram of a high-intensity electron beam generated by a photocathode operating in transmission mode using the disclosed anode material to generate a first X-ray beam, which, coupled to a monochromator, is converted into a second X-ray beam that serves as an excitation source for XPS and XRF.

[0039] 2, the transmission X-ray source includes a radiation source, such as, but not limited to, a laser, photon beam source 20, configured to direct radiation (such as light beam 11) toward a transparent substrate 30 that mechanically supports a photocathode 40. Light beam 11 strikes one side of photocathode 40, causing electrons to be emitted from the opposite side of the photocathode to form electron beam 12. Electron beam 12 is attracted to control grid 50 (biased relative to photocathode 40 by bias circuit 70, which can determine the energy of the electrons emitted from the control grid) and passes through a liquid metal jet (LMJ) to provide first X-ray beam 13, which strikes monochromator 80 to provide second X-ray beam 13A, which irradiates sample 90 and causes the generation of fluorescent X-rays 14 that can be detected by detector 88.

[0040] 3, the transmission X-ray source includes a radiation source, such as, but not limited to, a laser, photon beam source 20, configured to direct radiation (such as light beam 11) toward a photocathode 40. The photocathode 40 is supported by a substrate 31. The light beam 11 strikes one side of the photocathode 40, causing electrons to be emitted from the same side to form an electron beam 12. The electron beam 12 is attracted to a control grid 50 (biased relative to the photocathode 40 by a bias circuit 70, the bias can determine the energy of the electrons emitted from the control grid), passes through a liquid metal jet (LMJ) to provide a first X-ray beam 13, which strikes a monochromator 80 to provide a second X-ray beam 13A, which irradiates a sample 90 and causes the generation of fluorescent X-rays 14 detectable by a detector 88.

[0041] The X-ray source of Figure 3 can be substituted with a gas chamber or liquid jet that provides a continuous X-ray spectrum over a wide X-ray energy range to provide a second X-ray beam 13A that strikes a monochromator 80 and irradiates a sample 90, and a first X-ray beam 13A that causes the generation of fluorescent X-rays 14 that can be detected by a detector 88.

[0042] In both Figures 2 and 3, if the electron beam 12 is of high quality, it can also be shaped and focused to a very small spot size using electron beam optics (located between the photocathode and the x-ray material).

[0043] The electron optical system that can be provided in both Figures 2 and 3 can include at least some components of an electron beam column, such as one or more apertures, and / or one or more deflectors, and / or one or more scan coils, and / or one or more electromagnetic lenses, and / or one or more magnetic lenses, and / or one or more detectors.

[0044] Additionally, any suitable X-ray optics and monochromator, such as an X-ray beam collimator combined with a flat monochromator and subsequent focusing optics, can also be used with the high brightness liquid metal jet source disclosed herein. The emitted photoelectrons are collected by a focusing electron lens and sent to an energy analyzer in XPS, while fluorescent X-rays are also generated from the material and collected by EDS or WDS in XRF.

[0045] The high-brightness, high-intensity continuum radiation produced by LMJ X-rays, combined with appropriate non-dispersive X-ray collection optics and X-ray energy selection via a movable (or angle-adjustable) monochromator crystal, can provide a quasi-continuously tunable single-wavelength X-ray source for XPS and XRF in situ. Using a fixed-crystal collection monochromator to deliver the X-ray beam to the wafer, multiple different diffraction orders of increasing energy can be delivered and collected.

[0046] FIG. 4 is a schematic diagram of a quasi-continuously tunable single-wavelength X-ray source, in which single wavelength turning can be achieved by rotating a flat monochromator 100 and then adjusting two polycapillary, or other suitable reflective achromatic collimating and focusing optics 101 and 102 to satisfy the Bragg condition.

[0047] In the continuous X-ray wavelength rotation described above, the crystal is rotated relative to the incident X-rays (crystal rotation), collimated with a primary polycapillary or reflection optical system, and the reflected beam is focused onto the sample to satisfy the Bragg angle of the crystal monochromator, serving as an excitation source for XPS and XRF. A first X-ray beam 13 is incident on the crystal 100, which diffracts a second X-ray beam 13A, which then enters the sample 90. The wavelength of the second X-ray beam follows nλ' = 2d sin(θ').

[0048] Figure 4 also shows a quasi-continuously tunable single-wavelength X-ray source, which can be rotated by translating a flat monochromator and then adjusting two polycapillary or reflective collimating and focusing optics to satisfy the Bragg condition. Single X-ray wavelength selection from a broadband LMJ source is achieved by translating a crystal monochromator and then adjusting the first and second polycapillary (or reflective) optics to satisfy the Bragg condition. The wavelength selection capability, combined with the sample orientation defined by the single-wavelength X-ray incidence angles (φ and φ'), can provide great flexibility in sample probing depth in XPS and XRF.

[0049] When an Al-Ga liquid metal anode is combined with a suitable high-brightness electron beam source, calculations using published chemistry papers (Malte Wansleben et al., Journal of Analytical Atomic Spectrometry, 2019) estimate that an X-ray brightness at least one order of magnitude greater than that of a solid target anode X-ray source can be obtained.

[0050] This system enables miniaturization of measurement targets in inline XPS (and XRF) without compromising the signal-to-noise ratio and XPS energy resolution. Due to the increased brightness of the source, signal contamination outside the measurement spot is suppressed, improving the accuracy of composition measurements. Furthermore, this method can take full advantage of the monochromator, which delivers and focuses high-energy X-rays generated via second- and higher-order Bragg reflections onto the wafer. This broadens the inline metrology applications of XPS / XRF and addresses a variety of application scenarios: extending the analytical depth of photoelectron escape in combination with the expanded suite of X-ray fluorescence that can be simultaneously detected via XRF using the same tool.

[0051] By taking advantage of higher X-ray source brightness, smaller monochromators can be used, reducing the risk of crystal misalignment and also reducing costs. Smaller monochromators offer improved spot size as well as energy resolution and are slightly less sensitive to small alignment errors.

[0052] Furthermore, instead of using two different X-ray sources, it would be very beneficial to use a single X-ray source operating under different conditions for XPS and XRF measurements.

[0053] The high brightness X-ray source can generate AlKα, bremsstrahlung, and GaKα (or other suitable liquid jet material radiation) using the same electron beam power source and the same X-ray source.

[0054] The proposed high-brilliance X-ray source is continuously tunable or tunable to several times the design wavelength (eg, AlKα energy), and offers the following capabilities: a.Increase or decrease the depth of analysis of XPS. b. Increasing or decreasing the number of characteristic fluorescent X-rays produced and available for detection.

[0055] FIG. 5 illustrates an example method 200 for evaluating a sample.

[0056] In one embodiment, the method 200 includes step 210 of irradiating a liquid metal jet alloyed with aluminum with an electron beam to provide a first x-ray beam.

[0057] In one embodiment, step 210 is followed by step 220, in which the first X-ray beam is spectrally filtered by a filtering unit to provide a second X-ray beam.

[0058] In one embodiment, step 220 is followed by step 230, which irradiates the sample with a second X-ray beam.

[0059] In one embodiment, step 230 is followed by step 240, which detects X-ray radiation emitted from the sample as a result of irradiating the sample.

[0060] In one embodiment, the electron beam is a continuous electron beam.

[0061] In one embodiment, in the above method, the electron beam is a pulsed electron beam.

[0062] In one embodiment, the second X-rays include photoelectrons produced by AlKα radiation energy of about 1486 electron volts.

[0063] In one embodiment, the second X-rays include (i) a second order Bragg reflection with an energy of about 2973.4 electron volts, (ii) a third order Bragg reflection with an energy of about 4460.1 electron volts, and (iii) a fourth order Bragg reflection with an energy of about 5946.8 electron volts.

[0064] In one embodiment, the second X-rays include photoelectrons generated by GaLa radiation energy of about 1097.92 electron volts.

[0065] In one embodiment, the second X-rays include photoelectrons produced by GaKα radiation of energy about 9251.74 electron volts.

[0066] In one embodiment, the aluminum alloyed liquid metal jet is an aluminum-gallium alloy.

[0067] In one embodiment, the aluminum alloyed liquid metal jet is different from an aluminum gallium alloy.

[0068] In one embodiment, the method includes varying parameters of the second X-ray beam, such as wavelength, varying the concentration ratio of aluminum to other metal in the aluminum-alloyed liquid metal jet, etc., from one measurement (at least one iteration of steps 210, 220, 230, and 240) to another measurement (at least one other iteration of steps 210, 220, 230, and 240), as shown in step 250.

[0069] In one embodiment, the method includes setting the second bandwidth by setting an angular relationship between the first X-ray beam and a crystal of the filtering unit.

[0070] In one embodiment, the spectral filtering (frequency filtering) is performed by a monochromator.

[0071] In one embodiment, the spectral filtering is performed by a crystal.

[0072] In one embodiment, the spectral filtering is performed by a single or multiple monochromators.

[0073] In one embodiment, the method includes performing a set of x-ray photoelectron spectroscopy (XPS) measurements, varying at least one parameter of the second x-ray beam, and performing a set of x-ray fluorescence (XRF) measurements.

[0074] In the foregoing specification, the invention has been described with reference to specific embodiments thereof. However, it will be evident that various modifications and changes can be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims.

[0075] References to "comprising" or "having" or "including" shall apply mutatis mutandis to "consisting of" and / or "consisting essentially of".

[0076] Furthermore, terms such as "front," "back," "top," "bottom," "over," and "under" used in this specification and in the claims are used for descriptive purposes and are not necessarily used to describe permanent relative positions. It is understood that terms so used are interchangeable under appropriate circumstances, such that the embodiments of the invention described herein are operable in orientations other than those illustrated or otherwise described herein.

[0077] An arrangement of components to achieve the same functionality is substantially "associated" such that the desired functionality is achieved. Thus, for purposes of this specification, two components combined to achieve a particular function may be considered to be "associated" with each other such that the desired functionality is achieved, regardless of architecture or intervening components. Likewise, any two components so associated may also be considered to be "operably connected" or "operably coupled" to each other to achieve the desired functionality.

[0078] Furthermore, those skilled in the art will recognize that the boundaries between the operations described above are merely illustrative. Multiple operations may be combined into a single operation, a single operation may be distributed among additional operations, and operations may be performed with at least partial overlap in time. Furthermore, alternative embodiments may include multiple instances of a particular operation, and the order of operations may be changed in various other embodiments.

[0079] Also, for example, in one embodiment, the illustrated examples may be implemented as circuits located on a single integrated circuit or within the same device, or the illustrated embodiments may be implemented as any number of separate integrated circuits or separate devices interconnected with each other in any suitable manner.

[0080] However, other modifications, variations, and alternatives are possible. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

[0081] In the claims, reference signs placed between parentheses shall not be construed as limiting the scope of the claim. The word "comprising" does not exclude the presence of other elements or steps than those recited in the claim. Furthermore, as used in this specification, the words "a" or "an" are defined as one or more. Also, the use of introductory phrases such as "at least one" and "one or more" in a claim shall not be construed as implying that the introduction of another claim element with the indefinite article "a" or "an" limits a particular claim containing such introduced claim element to an invention containing only one such element, even if the same claim also contains the introductory phrases "one or more" or "at least one" and an indefinite article such as "a" or "an." The same applies to the use of definite articles. Unless otherwise specified, terms such as "first" and "second" are used to arbitrarily distinguish between elements described by such terms. Accordingly, these terms are not necessarily intended to indicate any chronological or other priority of such elements. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

[0082] While certain features of the invention have been illustrated and described in this specification, many modifications, substitutions, changes, and equivalents will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

[0083] Although the described embodiment of an alloyed liquid metal jet X-ray source can serve as an example of a broadband X-ray source, other X-ray sources that provide a broadband continuous X-ray spectrum can also be considered with this invention, including X-ray sources that use a gas or liquid jet excited by an electron beam.

Claims

1. irradiating the aluminum alloyed liquid metal jet with an electron beam, a laser beam, or a combination of a laser beam and an electron beam, or a plurality of laser beams, to provide a first X-ray beam; spectrally filtering the first X-ray beam with a filtering unit to provide a second X-ray beam; irradiating the sample with a second X-ray beam; detecting X-ray radiation emitted from the sample as a result of irradiating the sample; Sample evaluation method.

2. providing a first X-ray beam by irradiating a gas or liquid jet or medium that provides a broadband continuous high-power X-ray beam with an electron beam, a laser beam, or a combination of a laser beam and an electron beam, or multiple laser beams; spectrally filtering the first X-ray beam with a filtering unit to provide a second X-ray beam; irradiating the sample with a second X-ray beam; Detecting X-rays emitted from the sample as a result of irradiating the sample; Sample evaluation method.

3. 2. The method of claim 1, wherein the electron beam is a continuous electron beam.

4. 2. The method of claim 1, wherein the electron beam is a pulsed electron beam.

5. 2. The method of claim 1, wherein the laser beam is a continuous laser beam.

6. 2. The method of claim 1, wherein the electron beam is a pulsed laser beam.

7. 2. The method of claim 1, wherein the laser beam has a wavelength of 100 nm to 5 μm.

8. 10. The method of claim 1, wherein the liquid metal jet target produces a broadband x-ray source in the x-ray energy range of 1 keV to 10 keV.

9. 10. The method of claim 1, wherein the second x-ray beam comprises photoelectrons produced by AlKα radiation of energy about 1486.7 electron volts.

10. 2. The method of claim 1, wherein the second X-ray beam includes (i) a second order Bragg reflection at an energy of about 2973.4 electron volts, (ii) a third order Bragg reflection at an energy of about 4460.1 electron volts, and (iii) a fourth order Bragg reflection at an energy of about 5946.8 electron volts.

11. 10. The method of claim 1, wherein the second x-ray beam comprises photoelectrons generated by GaLa radiation of energy equivalent to approximately 1097.92 electron volts.

12. 10. The method of claim 1, wherein the second x-ray beam comprises photoelectrons generated by GaKa radiation of approximately 9251.74 electron volts.

13. 2. The method of claim 1, wherein said liquid metal jet alloyed with aluminum is an aluminum gallium alloy.

14. 10. The method of claim 1, wherein said liquid metal jet alloyed with aluminum is different from an aluminum gallium alloy.

15. 10. The method of claim 1, further comprising varying the concentration ratio of aluminum to the other metal in the aluminum-alloyed liquid metal jet between measurements.

16. 2. The method of claim 1, wherein the second bandwidth is set by setting an angular relationship between the first X-ray beam and a crystal of a filtering unit.

17. The method of claim 1 , wherein the spectral filtering is performed by a monochromator.

18. The method of claim 1 , wherein the spectral filtering is performed by a crystal.

19. 10. The method of claim 1, wherein the spectral filtering is performed by one or more monochromators.

20. 10. The method of claim 1, further comprising: performing a set of X-ray photoelectron spectroscopy (XPS) measurements; varying at least one parameter of the second X-ray beam; and performing a set of X-ray fluorescence (XRF) measurements.

21. Aluminum-alloyed liquid metal jet source an electron beam source having electron optics configured to direct an electron beam at the liquid metal jet alloyed with aluminum to provide a first x-ray beam; a filtering unit configured to spectrally filter the first X-ray beam to provide a second X-ray beam; an electron-optical system configured to irradiate a sample with the second X-ray beam; and a detector configured to detect X-ray radiation emitted from the sample as a result of irradiating the sample; Sample evaluation system.

22. 22. The system of claim 21, wherein the second x-ray beam comprises photoelectrons generated by AlKα radiation of energy about 1486 electron volts.

23. 22. The system of claim 21, wherein the second X-ray beam includes (i) a second Bragg reflection at an energy of about 2973.4 electron volts, (ii) a third Bragg reflection at an energy of about 4460.1 electron volts, and (iii) a fourth Bragg reflection at an energy of about 5946.8 electron volts.

24. 22. The system of claim 21, wherein the second x-ray beam comprises photoelectrons generated by GaLa radiation energy of approximately 1097.92 electron volts.

25. 22. The system of claim 21, wherein the second x-ray beam comprises photoelectrons generated by GaKα radiation of energy about 9251.74 electron volts.

26. 22. The system of claim 21, wherein the liquid metal jet alloyed with aluminum is an aluminum gallium alloy.

27. 22. The system of claim 21, wherein the liquid metal jet alloyed with aluminum is different from an aluminum gallium alloy.

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