Secondary electron detector for ion beam system

Abstract

Two-beam charged particle microscopy systems, sensors, and techniques are disclosed. A charged particle microscope system may include a vacuum chamber, a sample stage disposed in the vacuum chamber, a first beam source operable to direct a first particle beam into the vacuum chamber, a second beam source operable to direct a second particle beam into the vacuum chamber, a first charged particle sensor, and a second charged particle sensor. The first charged particle sensor may include a detector unit having a semiconductor layer characterized by a band gap equal to or greater than about 2.0 eV oriented to detect secondary electrons generated based on interaction between the first particle beam or the second particle beam and a sample. The second charged particle sensor may include a scintillator detector configured to saturate from electrons generated based on an interaction between the second particle beam and the sample.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. non-provisional application No. 18 / 475,637, filed on September 27, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to electron microscopy components, systems and methods. More particularly, the present disclosure describes sensor components for improved detection of secondary electrons. Background Art

[0004] In charged particle microscopy, secondary electrons are generated by inelastic scattering of the electron beam as it interacts with the atoms of the sample. The secondary electrons originate near the surface of the sample material and can therefore be used to determine properties of the sample surface. In particular, secondary electrons can be used to image the surface of a sample with high resolution. Secondary electrons can also be generated by the interaction of other types of beams used in microscope systems, including ion beams and laser beams used, for example, to mill or etch the surface of a sample.

[0005] Conventionally, secondary electrons are detected using a scintillator detector (e.g., an Everhart-Thornley detector). Such detectors operate by collecting secondary electrons with a low-level electric field, converting the secondary electrons into photons with a scintillator medium, and then converting the photons into detectable electrical signals via a photomultiplier tube. Because the scintillator in such a detector continues to phosphoresce (e.g., produce photons) for up to several seconds after interacting with the collected electrons, the scintillator detector can be saturated with sufficient electron flux from the sample. Therefore, there is a need for improved detection techniques for secondary electrons in dual-beam electron microscope systems. Summary of the invention

[0006] The technology described herein relates to systems, detector devices, and methods for detecting secondary electrons in a charged particle microscope system. One embodiment relates to a charged particle microscope system. The charged particle microscope system may include a vacuum chamber, a sample stage disposed in the vacuum chamber and configured to accommodate a sample to be tested in the vacuum chamber, a first beam source operable to direct a first particle beam toward the sample stage into the vacuum chamber, a second beam source operable to direct a second particle beam toward the sample stage into the vacuum chamber, a first charged particle sensor, and a second charged particle sensor. The first charged particle sensor may be disposed at a first position in the vacuum chamber and may include a detector unit. The detector unit may have a semiconductor layer that spans and is characterized by a band gap equal to or greater than about 2.0 eV with a first level of electrical bias. The first charged particle sensor may be oriented to detect secondary electrons generated based on an interaction between the first particle beam or the second particle beam and a sample disposed on the sample stage. The second charged particle sensor may be disposed at a second position in the vacuum chamber and may include a scintillator detector electrically biased at a second level greater than the first level. The second charged particle sensor may be configured to be saturated from electrons generated based on an interaction between the second particle beam and a sample disposed on the sample stage.

[0007] The charged particle microscope system may further include: the first level is approximately 1 kV.

[0008] The charged particle microscope system may further include: the second level is approximately 10 kV.

[0009] The charged particle microscope system may also include: the first position is closer to the sample stage than the second position.

[0010] The charged particle microscope system may also include: a distance between the first position and the sample stage of about 7 mm to about 10 cm.

[0011] The charged particle microscope system may further include: a distance between the second position and the sample stage is about 10 cm.

[0012] The charged particle microscope system may also include a semiconductor layer having one or more materials selected from the group consisting of silicon carbide, single crystal diamond, polycrystalline diamond, gallium nitride, gallium phosphide, cadmium sulfide, aluminum phosphide, zinc selenide, zinc sulfide, and aluminum nitride.

[0013] The charged particle microscope system may also include that the first particle beam is an electron beam.

[0014] The charged particle microscope system may further comprise: the second particle beam is an ion beam, or wherein the second particle beam is a laser beam. The ion beam may be configured for milling or polishing.

[0015] Another embodiment relates to a charged particle sensor. The charged particle sensor includes a housing configured to be incorporated into a charged particle microscope system and a detector unit mechanically coupled to the housing. The detector unit may include a semiconductor layer characterized by a band gap equal to or greater than about 2.0 eV. The housing may be configured to be mechanically coupled to the charged particle microscope system such that when the housing is mechanically coupled to the charged particle microscope system, the charged particle sensor is disposed in a chamber of the charged particle microscope system and is oriented to detect secondary electrons from a sample.

[0016] The charged particle sensor may further include: the housing may be configured to mechanically couple with an end of the ion beam column, and wherein the housing and the detector unit form an annular configuration at the end of the ion beam column.

[0017] The charged particle sensor may further include a housing configured to mechanically couple with the charged particle microscope system at a position where an angle between an axis of the electron beam and a line from the sample to the detector unit is about 45°.

[0018] The charged particle sensor may further include the detector cell being electrically biased across the semiconductor layer at a voltage of about 0.01 V to about 10 kV.

[0019] Yet another embodiment relates to a method of operating a charged particle microscope system. The method may include: causing emission of an electron beam to be directed onto a sample positioned in a sample chamber. The electron beam may generate a first flux of detectable particles. The method may also include: causing emission of an ion beam to be directed onto the sample in the sample chamber. The ion beam may generate a second flux of detectable particles greater than the first flux. The method may also include: stopping emission of a second particle beam and detecting a signal at a charged particle sensor in the sample chamber. The charged particle sensor may include a detector unit having a semiconductor layer characterized by a band gap equal to or greater than about 2.0 eV. The signal may be generated by the first flux of detectable particles associated with the first particle beam.

[0020] The method may further include: detecting the signal at the charged particle sensor occurs after desaturation of the charged particle sensor. The desaturation may occur within about 100 μs after cessation of emission of the second particle beam.

[0021] The method may further include detecting the signal at the charged particle sensor omitting use of a conductive collector mesh coupled to the charged particle sensor.

[0022] The method may further include causing emission of the first particle beam to occur within about 100 μs after cessation of emission of the second particle beam.

[0023] The method may further include that detecting a signal at the charged particle sensor may include detecting secondary electrons generated based on an interaction between the first particle beam and a sample in the sample chamber.

[0024] The method may further include that detecting a signal at the charged particle sensor may include detecting backscattered electrons generated from a sample in the sample chamber by scattering of the first particle beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The foregoing aspects of the present disclosure and many of the attendant advantages will become more readily appreciated when the following detailed description is taken in conjunction with the accompanying drawings.

[0026] Figure 1 is a schematic diagram of an example dual-beam charged-particle microscope, according to some embodiments.

[0027] Figure 2A is an example of a scanning electron microscope including various detectors according to some embodiments. Figure 1 Schematic diagram of an example of the operation of a dual-beam charged-particle microscope.

[0028] Figure 2B is an example of a method according to some embodiments comprising Figure 2A The ion beam of various detectors is activated Figure 1 Schematic diagram of an example of the operation of a dual-beam charged-particle microscope.

[0029] Figure 3 is a schematic diagram of an example charged particle sensor according to some embodiments.

[0030] Figure 4 Shown are two image sequences from two scintillator detectors illustrating saturation and recovery of the scintillator after application of an ion beam to a sample, according to some embodiments.

[0031] Figure 5A is an image from a scintillator detector generated when an ion beam is first applied to a sample, then stopped and an electron beam is applied to the sample, according to some embodiments.

[0032] Figure 5B is an image from a wide bandgap detector generated when an ion beam is first applied to a sample, then stopped and an electron beam is applied to the sample, according to some embodiments.

[0033] Figure 6 is a schematic diagram of a wide bandgap detector in a dual-beam charged-particle microscope system positioned close to a sample, according to some embodiments.

[0034] Figure 7is a schematic diagram of a wide bandgap detector in a dual-beam charged-particle microscope positioned at the end of an ion beam column, according to some embodiments.

[0035] Figure 8 is a flow chart of an example process for operating a dual-beam charged-particle microscope system with a wide bandgap detector, according to some embodiments.

[0036] In the accompanying drawings, unless otherwise specified, the same reference numerals represent the same components in various views. Where appropriate, not all instances of components need to be labeled to reduce clutter in the drawings. The drawings are not necessarily drawn to scale, with emphasis instead on illustrating the principles being described. DETAILED DESCRIPTION

[0037] While exemplary embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the disclosure.

[0038] Charged particle microscopy can generate secondary electrons from the interaction of the electron beam with the atoms of the sample, especially the inelastic collisions of the electrons in the beam with the atoms of the sample. Secondary electrons can be detected to determine the surface characteristics of the sample, including imaging of the topography of the sample surface. Backscattered electrons (BSE) are generated from deeper in the sample by elastic scattering of electrons in the beam, and secondary electrons generally have much lower energy (up to about 50eV) in comparison. Due to the lower energy, conventional detectors for secondary electron detection use charged collection grids to guide the emitted secondary electrons toward the detector. Because BSE are generally backscattered near the axis of the incident electron beam, the positioning of the secondary electron detector is generally away from the beam axis and the sample. BSE can be detected with solid-state detectors (such as doped silicon) with narrow band gaps (e.g., 1.1eV to 2.0eV). In recent years, detectors with wide band gaps greater than 2.0eV have been used to improve noise reduction from thermal photons for detection of BSE. The application of such wide band gap materials to the detection of secondary electrons is the focus of the following description.

[0039] Systems used with charged particle microscopy may include a "dual beam" system having an electron beam for scanning electron microscopy (SEM), transmission electron microscopy (TEM), and / or scanning transmission electron microscopy (STEM) and another particle beam for milling, polishing, etching, ablation, surface preparation, field analysis, deposition, and other techniques. The other particle beam may include an ion beam or a laser beam, including a focused ion beam (FIB). For example, a dual beam system may include a plasma focused ion beam (PFIB), which may direct an ion beam to a sample to remove material from the sample surface to prepare a thin slice. In order to verify the milling process, an electron beam may be used to image the sample. These beams may be operated alternately to mill and verify, thereby ensuring accurate removal of material. For example, an electron beam may be activated to produce an image of the surface of a sample. Based on the image, the PFIB may be precisely targeted and activated to remove material from the sample. The PFIB may then be deactivated, and the electron beam reactivated to obtain another image of the sample, thereby verifying the previous milling operation. The PFIB may then be reactivated to continue milling, and the process may be repeated. Although the following description refers primarily to dual-beam systems, charged particle microscopy may include multi-beam systems having an electron beam, an ion beam, and a laser beam or a second ion beam.

[0040] A conventional detector for detecting secondary electrons is the Everhart-Thornley detector (ETD). The ETD includes a scintillator coupled to a photomultiplier tube. A charged collection grid in front of the ETD can guide the secondary electrons toward the scintillator. A high voltage potential (about 10 kV) can then accelerate the captured electrons to sufficient energy within the scintillator to cause phosphorescence and emission of photons, which are then directed to the photomultiplier tube to amplify into an electrical signal that can be detected. The collected signal is coordinated with the grating pattern of the electron beam to produce an image of the sample surface.

[0041] Unfortunately, operation of a focused ion beam like the PFIB produces a large flux of electrons (and other particles) from the sample. Since phosphorescence in the scintillator in the ETD may take some time to relax (several milliseconds to several seconds, depending on the material), the high flux from the operation of the PFIB may saturate the scintillator of the ETD. When operated as a SEM, in the case of saturation, the captured signal cannot be used to produce a useful image from the electron beam. Therefore, operating the PFIB and then switching to the electron beam while the ETD scintillator relaxes may take several seconds to obtain a usable image of the sample surface. Given the alternating operation of the electron beam and ion beam in a dual beam system, the delays caused by the saturation of the ETD may introduce substantial limitations to the throughput of sample preparation via milling with the PFIB.

[0042] To avoid saturation of the ETD detector in a dual beam charged particle microscopy system (e.g., a SEM-(P)FIB system), embodiments of the present disclosure include secondary electron detectors having semiconductor materials with a band gap higher than about 2 eV. Such semiconductor materials may include sp with a band gap of about 5.5 eV. 3 -hybridized carbon (e.g., diamond or diamond-like carbon). These wide bandgap detectors can be used as a supplement or alternative to conventional ETD in a dual beam system. Incident electrons (e.g., secondary electrons) can interact with wide bandgap semiconductor materials to produce electron-hole pairs in the material. Electron-hole pairs can be separated by a bias voltage applied across the material to generate a current that can be detected. For wide bandgap detectors, in some examples, the bias voltage can be about 1 kV, while the semiconductor material can be sensitive to secondary electrons with energies less than 50 eV. Therefore, the wide bandgap detector can be placed closer to the sample during electron beam and / or ion beam operation in a dual beam system without affecting (e.g., deflecting) the charged particle beam. In some other examples, the bias voltage can be up to 10 kV. In addition, the wide bandgap detector can be used with or without a charge collection grid, allowing more options for positioning the detector in the sample chamber of a dual beam system. Advantageously, this flexibility, especially given the typically limited space in a charged particle microscope sample chamber, allows additional measurement modalities to be implemented simultaneously without sacrificing secondary electron imaging, which may be useful for visual assessment of surface conditions and location on the sample. When a wide bandgap detector is used with a charged collection grid, the grid voltage may be set in conjunction with a bias voltage across the semiconductor material to improve the collected signal.

[0043] By using a wide bandgap detector in a dual beam system, a number of advantages are obtained over conventional systems that employ ETD or other scintillator detectors. For example, a wide bandgap detector is not saturated when exposed to a higher particle flux caused by a particle beam used for milling. Therefore, a dual beam system can switch from an ion beam used for milling to an electron beam used for secondary electron imaging, and a usable SEM imaging signal can be obtained immediately (e.g., in less than about 100 μs) from a wide bandgap detector, compared to several seconds for a scintillator detector. The speed at which milling, etching, polishing, and other sample preparation operations can be performed can be greatly accelerated (on the order of several minutes faster for thin section preparation), thereby allowing a corresponding increase in the throughput of sample preparation operations. As another example, a lower bias voltage of a wide bandgap detector can allow the detector to be placed closer to the sample, which can allow secondary electrons to be detected without the use of a charged collection grid. In some examples, the wide bandgap detector can be positioned in a position more obliquely oriented relative to the sample surface (e.g., at a greater angle to the electron beam axis A) without affecting the electron beam, thereby improving the imaging of certain surface features based at least in part on low-angle shadowing effects.

[0044] Figure 1 2 is a schematic diagram of an example dual beam charged particle microscope 100 according to some embodiments. The charged particle microscope 100 includes multiple sections, including an electron source, a beam column 105, and a vacuum chamber 110. The electron source includes a high voltage supply component, a vacuum system component, and an electron emitter configured to generate an electron beam accelerated into the beam column 105. The beam column 105 in turn includes an electromagnetic lens element configured to shape and form the electron beam from the electron source into a generally circular beam having a generally uniform profile transverse to the beam axis A, and adjust the beam to be focused onto a sample 125 through an objective lens, as described in more detail with reference to FIG.

[0045] Electron beams are typically characterized by the beam current and the accelerating voltage applied to generate the beam, among other parameters. The range of beam current and accelerating voltage can vary between instruments and is typically selected based on the material properties of the sample or the type of analysis being performed. However, typically, electron beams are characterized by energies ranging from about 0.1 keV (e.g., for an accelerating voltage of 0.1 kV) to about 60 keV and beam currents ranging from picoamperes to microamperes.

[0046] The vacuum chamber 110 and / or the beam column 105 may include multiple detectors for various signals, including but not limited to secondary electrons generated by the interaction of the electron beam with the sample, BSE, x-ray photons (e.g., EDAX), other photons (e.g., visible light and / or IR cameras), and / or molecular species (e.g., TOF-SIMS). The vacuum chamber 110 may also include a sample stage 120 that may be operably coupled to a multi-axis translation / rotation control system so that the sample 125 may be repositioned relative to the beam axis A as a means of investigating and / or imaging the sample 125. The sample stage 120 may include a window that allows electrons or other charged particles to be transmitted through the sample and the sample stage. In some embodiments, the charged particle microscope 100 may include detectors within the electron beam column 105, detectors arranged in an annular configuration at the end of the electron beam column 105 (for detecting BSE), and / or detectors below the sample stage 120 (for detecting transmitted electrons from the electron beam in the TEM / STEM). According to several embodiments of the present disclosure, the charged particle microscope 100 may include a wide bandgap detector 130 configured to detect secondary electrons, as described below with respect to Figure 2A and Figure 2B The wide bandgap detector 130 may include a semiconductor layer 135 characterized by a bandgap greater than about 2.0 eV. Figure 3 Additional details regarding semiconductor layer 135 are provided.

[0047] Charged particle microscope 100 can be combined with an ion beam system (e.g., a focused ion beam or FIB, a plasma focused ion beam or PFIB, a wide ion beam, or other ion source) that is suitable, for example, for modifying a sample or for microanalysis. Although the following description refers to the FIB as an ion beam system, the description should not be construed as limiting the embodiments of the present disclosure to only FIB systems. Other ion beams, including PFIB and wide ion beams, can also be used in charged particle microscopes. In addition, other particle beams, including laser beams, can be used in such systems.

[0048] like Figure 1 As shown, the charged particle microscope 100 may include a FIB 115. The charged particle sensor of the present disclosure including a wide bandgap detector 130 may be configured to generate secondary electron data (e.g., images, line scans, etc.) in coordination with a FIB and an electron source for modification and / or microanalysis of a sample. For example, an ion source (e.g., a PFIB, etc.) may be operably coupled to the vacuum chamber 110 and configured to incrementally remove portions of a sample 125 in a layer-by-layer manner. Between increments, secondary electron imaging of the sample 125 (in combination with BSE imaging) may show the surface morphology, material contrast, channel contrast, or charge contrast of the sample 125. Such imaging with a wide bandgap detector may be used to verify proper removal of material (e.g., during sample / thin section preparation), quality assurance in semiconductor applications, and other areas.

[0049] The FIB 115 may be configured to generate an ion beam directed along a beam axis B. As with an electron beam, the ion beam may be characterized by parameters including an accelerating potential and a beam current, as well as the type of ions provided by the source (e.g., gallium, gold, silicon, germanium in a liquid metal ion source, or oxygen, nitrogen, argon, xenon in a plasma ion source for a PFIB). The FIB 115 may include electromagnetic elements to focus the ion beam into a suitable uniform profile transverse to the beam axis B, and select the ion species (e.g., a Wiener filter) in the system if the selection is appropriate. The ion beam may be characterized by an accelerating voltage of several hundred volts (e.g., 100 V to 500 V) to several kilovolts (e.g., 30 kV), while the beam current may be in the range of about one picoampere to several microamperes (e.g., 0.8 pA to 2.5 μA).

[0050] In some examples, charged particle microscope 100 may include additional particle beams for milling or other operations, including a second ion beam source or a laser beam source. In certain embodiments that perform laser ablation / milling, the laser beam may be used in addition to or in place of FIB 115.

[0051] Figure 2Ais a schematic diagram illustrating the operation of a dual-beam charged particle microscope 200 configured as a scanning electron microscope including various detectors according to some embodiments of the present disclosure. The dual-beam charged particle microscope 200 may be Figure 1 An example of a charged particle microscope 100. Detectors include a wide bandgap detector 130 and an Everhart-Thornley detector (ETD) 230. Not shown are other detectors and sources that can be coupled to the vacuum chamber 110 to enhance the capabilities of the charged particle microscope 100, as an approach that focuses on the description of the configuration of the wide bandgap detector 130 and the ETD 230, which are configured to detect secondary electrons 244, 246. To this end, embodiments of the present disclosure include a charged particle microscope that includes an x-ray source, an x-ray detector, an ion beam source, a mass spectrometer, a light source (e.g., a laser source), or other sources that may be included in a supplement to an analytical instrument that may be used for SEM microanalysis. A configuration of a detector for detecting BSE 242 may be included in a dual beam charged particle microscope 200, including a detector surrounding the end of the electron beam column 105.

[0052] Figure 2A The dual beam charged particle microscope 200 shown includes both the ETD 230 and the wide bandgap detector 130. In many cases, it may be preferred to include the wide bandgap detector 130 in the dual beam charged particle microscope 200 without including the ETD 230. For example, the space within a vacuum chamber (e.g., vacuum chamber 110) may be limited, so that fewer detectors are preferred. In some cases, the wide bandgap detector 130 may be used in conjunction with the ETD 230. The ETD 230 may include a collection grid 235. The collection grid 235 may be charged to a low positive voltage (e.g., 250V) to attract relatively low energy secondary electrons 246 to the ETD 230. In some embodiments, the wide bandgap detector 130 may also include a collection grid to attract secondary electrons 244. In other embodiments, the wide bandgap detector 130 may omit the collector grid. In this configuration, the wide bandgap detector 130 can be placed in a position in the vacuum chamber of the dual-beam charged particle microscope 200 that is more favorable for detection of secondary electrons, including, for example, closer to the sample surface or at various angular positions relative to the electron beam 240.

[0053] When operating as a SEM, the dual beam charged particle microscope 200 can emit an electron beam 240 toward the sample 125. The interaction of the electron beam 240 can produce BSE 242 and secondary electrons 244, 246. The flux of secondary electrons 244, 246 can depend on the parameters of the electron beam 240 (e.g., beam current, accelerating potential) and the sample 125, but is generally less than the flux of secondary electrons produced during operation of the FIB 115.

[0054] Figure 2B is an example of a method according to some embodiments comprising Figure 2A Schematic diagram of the operation of the dual beam charged particle microscope 250 with various detectors of the ion beam 260 being activated. The dual beam charged particle microscope 250 may be Figure 2A An example of a dual-beam charged particle microscope 200. The FIB 115 can generate an ion beam 260 and focus it toward a sample 125 to perform any of a number of operations including milling, deposition, etc. When ions of the ion beam interact with atoms of the sample 125, secondary electrons 262, 264 are emitted from the sample 125. The flux of secondary electrons 262, 264 can be greater than the flux of secondary electrons 244, 246 emitted during operation of the electron source that generates the electron beam 240. The higher flux of secondary electrons 262 can saturate the ETD 230. When saturated, the ETD 230 may not be able to produce a usable signal for imaging the sample 125. In contrast, the wide bandgap detector 130 may not be saturated by the flux of secondary electrons 264, and may produce a usable signal for imaging the sample 125. Refer to the following Figure 4 , Figure 5A and Figure 5B Exemplary sample images during operation of a PFIB produced by ETD and a wide bandgap detector are discussed.

[0055] Figure 3 is a schematic diagram of an example charged particle sensor 300 according to some embodiments. The charged particle sensor 300 may be an example of a sensor element of a wide bandgap detector, including the above-mentioned Figure 1 The wide bandgap detector 130 is described. The example charged particle sensor 300 includes a detector unit 310 having a receptor layer 315, a first conductive layer 320, and a second conductive layer 325, which is mechanically coupled to a housing 305. The housing 305 can be configured to be incorporated into a charged particle microscopy system, such as Figure 1The dual beam charged particle microscope 100. The housing 305 may include mechanical accessories, couplings, and / or features corresponding to a given charged particle microscope system. For example, the detector may be configured as a pole piece mounted detector (PMD) in which the housing 305 may include one or more through holes disposed in the housing at positions corresponding to threaded holes of the pole piece, thereby facilitating mechanical coupling of the housing 305 with the pole piece. The pole piece may be configured differently in different dual beam charged particle microscope systems. For example, some manufacturers may omit some features in favor of other features, so that the configuration of the housing 305 may be based at least in part on the charged particle microscope into which the housing 305 is to be incorporated. In some examples, the housing 305 may be configured for mechanical coupling with a support (e.g., a retractable support) that may allow the charged particle sensor 300 to be positioned to collect secondary electrons or other particles (e.g., photons, BSEs, etc.). In these examples, the support may include tilt / rotation and / or linear translation.

[0056] The detector unit 310 can be mechanically coupled to the housing 305, for example, by an adhesive, a retaining clip, etc. The first conductive layer 320 can be disposed on a first surface of the receptor layer 315. The second conductive layer 325 can be disposed on a second surface of the receptor layer 315. In some embodiments, the first conductive layer 320 and / or the second conductive layer 325 can be or include a metallic transparent conductive material, a conductive carbon film, and / or other conductive materials compatible with chemical vapor deposition, physical vapor deposition, epitaxy, or other techniques for depositing conductive materials with controlled purity and thickness on the order of tens of nanometers to hundreds of nanometers. To this end, the first conductive layer 320 can be characterized by a substantially uniform thickness (e.g., limited by and within the tolerances of the manufacturing method) below a threshold at which the conductive material interferes with incident particles (e.g., as determined by simulating the interaction volume between the secondary electrons / BSEs and the detector unit 310). The first conductive layer 320 can be disposed on the receptor layer as a patterned film or patterned layer (e.g., in the shape of a grid or other geometric configuration) for distributing the electrostatic field on the surface. In this case, the first surface will not be covered by material of the first conductive layer 320 in the mesh portion of the grid, which may improve detection of some incoming particles.

[0057] The example charged particle sensor 300 includes a first contact 355, a second contact 360, a bias circuit 365, and a current measurement circuit 370. The first contact 355 is electrically coupled to the first conductive layer 320. The second contact 360 is electrically coupled to the second conductive layer 325. In this manner, the example charged particle sensor 300 can be configured to apply a bias voltage across the receptor layer 315. For example, the bias circuit 365 can be configured to apply a bias voltage having a magnitude of about 0.1 V to about 5 kV (including subranges, fractions, and interpolated values ​​thereof) across the receptor layer 315. In some embodiments, the magnitude of the bias voltage can be about 0.2V, about 0.3V, about 0.4V, about 0.5V, about 0.6V, about 0.7V, about 0.8V, about 0.9V, about 1.0V, about 1.0V, about 2.0V, about 3.0V, about 4.0V, about 5.0V, about 6.0V, about 7.0V, about 8.0V, about 9.0V, about 10.0V, about 20V, about 30V, about 40V, about The bias voltage may be about 50 V, about 60 V, about 70 V, about 80 V, about 90 V, about 100 V, about 200 V, about 300 V, about 400 V, about 500 V, about 600 V, about 700 V, about 800 V, about 900 V, about 1.0 kV, about 1.5 kV, about 2.0 kV, about 2.5 kV, about 3.0 kV, about 3.5 kV, about 4.0 kV, about 4.5 kV, or about 5.0 kV, including fractions and interpolated values ​​thereof. A larger magnitude bias voltage increases the likelihood that the charged particle sensor will interfere with the operation of the charged particle microscope (e.g., by forming a partial discharge or by deflecting and / or deforming the primary electron beam 240). Conversely, a smaller magnitude bias voltage may impair the performance of the charged particle sensor of the present disclosure (e.g., by favoring electron-hole recombination).

[0058] Without being limited to a particular physical mechanism or phenomenon, the charged particle sensor of the present disclosure may be configured to respond to high energy particles 375 (e.g., Figure 2AThe secondary electrons 244 of the first conductive layer 320 are incident on the acceptor layer 315 (for example, by the orientation of the first conductive layer 320 toward the sample stage 120) to generate an electrical signal. The penetration of the high-energy particles 375 into the acceptor layer can generate electron-hole pairs, which can be separated and driven to the corresponding conductive layer by the force of the bias voltage. The current measurement circuit 370 can be configured to integrate the current drawn from the acceptor layer 315 and / or returned to ground or relative to ground over a period of time (for example, coordinated with the scanning pattern of the SEM as part of imaging or for a defined exposure time for point mode analysis). The magnitude of the bias voltage can be based at least in part on the thickness of the acceptor layer 315 as a method of improving the efficiency of the detector (for example, by reducing the probability of electron-hole recombination in the acceptor layer 315). In this way, the bias voltage can be proportional to the thickness, from about 0.01V to about 100V per μm of thickness, including its sub-ranges, fractions, and interpolated values. In some embodiments, the bias voltage can be about 0.01 V per μm, about 0.1 V per μm, about 0.5 V per μm, about 1.0 V per μm, about 2.0 V per μm, about 3.0 V per μm, about 4.0 V per μm, about 5.0 V per μm, about 6.0 V per μm, about 7.0 V per μm, about 8.0 V per μm, about 9.0 V per μm, about 10.0 V per μm, about 20.0 V per μm, about 30.0 V per μm, about 40.0 V per μm, about 50.0 V per μm, about 60.0 V per μm, about 70.0 V per μm, about 80.0 V per μm, about 90.0 V per μm, or about 100.0 V per μm, including interpolated values ​​and fractions thereof.

[0059] The acceptor layer 315 can be or include a semiconductor material characterized by a band gap equal to or greater than about 2.0 eV. In some embodiments, the semiconductor material can be characterized by a band gap of about 2.0 eV to about 6.5 eV, including subranges, fractions, and interpolated values ​​thereof. To this end, the band gap can be about 2.5 eV, about 3.0 eV, about 3.5 eV, about 4.0 eV, about 4.5 eV, about 5.0 eV, about 5.5 eV, about 6.0 eV, or about 6.5 eV, including fractions and interpolated values ​​thereof.

[0060] The material for the acceptor layer 315 can be selected based on the criteria of band gap, radiation hardness and / or manufacturability. To this end, the semiconductor material of the acceptor layer 315 can be or include sp 3 Hybridized carbon (e.g., diamond, diamond-like carbon, etc.). 3 Hybridized carbon may be characterized by an impurity concentration equal to or less than about 5 ppb and may also be referred to as "electronic grade." 3Hybridized carbon can be synthesized as a conformal coating on various substrates by synthesis from dissociated carbon source gases (e.g., chemical vapor deposition) to form single crystal diamond, polycrystalline diamond, diamond-like carbon, etc. In this manner, the acceptor layer 315 can be characterized by at least one material region having a band gap of about 5.5 eV.

[0061] In some embodiments, the semiconductor material includes one or more materials selected from the group consisting of silicon carbide (2.3 eV to 3.3 eV), single crystal diamond (5.5 eV), polycrystalline diamond (5.5 eV), gallium nitride (3.4 eV), gallium phosphide (2.26 eV), cadmium sulfide (2.42 eV), aluminum phosphide (2.45 eV), zinc selenide (2.7 eV), zinc sulfide (3.6 eV), or aluminum nitride (6.2 eV). The values ​​provided describe the intrinsic band gap of the corresponding material, which can be modified to be higher or lower than the value by doping during synthesis. The band gap can be an intrinsic property of the material, but can also be modified by doping with P-type or N-type dopants (e.g., doping silicon narrow gap materials).

[0062] The example charged particle sensor 300 may be configured to be coupled to Figure 1 In an example charged particle microscope 100 (eg, as a wide bandgap detector 130). Figure 3 The electronic and material aspects of the charged particle sensor of the present disclosure are described in detail below.

[0063] Figure 4 Two image sequences from two scintillator detectors are shown, illustrating saturation and recovery of the scintillator after application of an ion beam to a sample, according to some embodiments. The top image sequence is produced from an ETD detector view of the surface of the sample. The bottom image sequence is produced from a secondary electron detector view of the surface of the sample. Secondary particle detectors are similar to ETDs in that scintillator elements coupled to photomultiplier tubes are used to detect ions and / or secondary electrons (e.g., secondary ions) generated by the interaction of ions in the beam with atoms of the sample. As Figure 4 As shown, the secondary particle detector is configured to detect secondary electrons from the sample.

[0064] Since both the ETD and the secondary particle detector use scintillators, the generation of a high flux of detectable particles (e.g., secondary electrons detected by the ETD or secondary particle detector) can saturate the scintillator. For each sequence, the leftmost image shows the activation of the ion beam (e.g., Figure 1The sample surface imaged using the corresponding detector before the FIB 115 of the sequence is activated. The second image in each sequence shows the image produced using the corresponding detector after the ion beam has been activated. Time t=0s represents the time when the ion beam is deactivated. As shown in the second image, both the ETD and the secondary particle detector are fully saturated, and no identifiable features of the sample surface seen in the first image are produced in each sequence.

[0065] The third and fourth images in each sequence are acquired a few seconds after the second image. For the ETD detector, the third image is produced at t=2s and the fourth image is produced at t=5s, while for the secondary particle detector, the third image is produced at t=4s and the fourth image is produced at t=8s. After two seconds, the ETD detector is still saturated. A rectangular region of the sample is vaguely identifiable, but other features cannot be resolved. After five seconds, the saturation has relaxed slightly, but the image is still noticeably blurred, with excess signal being detectable across the entire sample. Similarly, after four and eight seconds, the secondary particle detector also remains saturated, but the saturation is relaxed. After eight seconds, the image produced by the secondary particle detector is close to the image produced before saturation from operation of the ion beam. Saturation of the scintillator element can last for ten seconds or more, depending on the material used for the scintillator element. As Figure 4 As shown, saturation generally must be fully relaxed before a usable image can be produced from a conventional scintillator detector.

[0066] Figure 5A is an image from a scintillator detector (eg, ETD) generated when an ion beam is first applied to a sample, then stopped and an electron beam is applied to the sample, according to some embodiments. Figure 5B is with Figure 5A The images are generated simultaneously from wide bandgap detectors (e.g. Figure 1 An image of a wide bandgap detector 130).

[0067] Because images from ETD detectors and wide bandgap detectors for SEM systems are generated via a raster of an electron beam across a sample (e.g., scanning the beam in a grid pattern), each row of pixels in the image can be generated as the electron beam moves across the sample. The scanning speed of the electron beam can be adjusted; a typical fast scan time for a row can be about 100μs, and slower scan times can be used. The resulting full raster of the sample may take from a few milliseconds (30ms to 50ms) to a few seconds (1s to 2s) to produce. Therefore, as the raster moves from the top to the bottom of the image, an image is produced over increasing time. For the first part of the image generation, an ion beam (e.g., PFIB) is turned on and directed to a portion of the sample. After a period of time, the ion beam is deactivated. For Figure 5A and Figure 5B, the electron beam remains activated for the entire image generation. In some examples, the electron beam and the ion beam can be alternately activated and deactivated.

[0068] When the ion beam is active, the ETD detector is saturated by the flux of secondary electrons emitted from the sample. Figure 5A As shown, when the ion beam is deactivated, the ETD is fully saturated. As the grating advances (downward in the image), time passes and the ETD scintillator begins to relax. Details of the sample surface (including fiducial marks) become more recognizable, but saturation artifacts remain throughout the image.

[0069] On the contrary, Figure 5B As shown, the wide bandgap detector does not exhibit saturation and a usable signal for generating an image can be effectively obtained immediately after deactivation of the ion beam and activation of the electron beam. By "effectively immediately", a usable signal can be obtained within the response time of the detector to the activation of the electron beam and can correspond to the per-pixel dwell time of the raster scan speed, which can be about 1 μs. The wide bandgap detector is also sensitive to secondary electrons generated when the ion beam is in an activated state, thereby revealing features of the sample surface during ion beam operation (but with some distortion), which cannot be detected by conventional ETD. If not saturated, ETD and other detectors using scintillators can also reveal features of the sample surface during ion beam operation. Because the raster scan time to produce an entire row of images can be about 100 μs, a usable signal for producing an undistorted row of image pixels can be obtained by the wide bandgap detector within about 100 μs after the ion beam is deactivated. Since effectively no delay between operations with an ion beam (e.g., milling) and imaging with an electron beam is necessary before a usable image can be obtained, alternating switching between ion and electron beams can be performed with delays limited only by the control electronics (e.g., on the order of milliseconds.) Thus, milling operations can be verified and guided by SEM imaging at a significantly higher rate, thereby increasing the throughput of milling (or other ion beam) operations.

[0070] Figure 6 is a schematic diagram of a wide bandgap detector 630 in a dual beam charged particle microscope system 600 positioned near a sample 625 according to some embodiments. The dual beam charged particle microscope system 600 may be Figure 1 An example of a dual beam charged particle microscope 100 includes an electron beam column 605 and a FIB 615 that can generate an electron beam and an ion beam, respectively. In addition to the wide bandgap detector 630, the dual beam charged particle microscope system 600 can also include an ETD 635.

[0071] like Figure 6As shown, the ETD 635 can be positioned within the vacuum chamber of the dual beam charged particle microscope system 600, at a first distance 645 from the sample 625. For example, the end of the ETD 635 with the collection grid can be placed about 10 cm from the sample (e.g., the first distance 645 is about 10 cm). The scintillator of the ETD 635 can have a high accelerating potential (e.g., 10 kV), thereby causing a deflection or change in the electron beam when the end of the ETD 635 is positioned close to the sample and / or the beam axis during operation of the system in SEM, TEM, or STEM mode.

[0072] The wide bandgap detector 630 can be positioned within the vacuum chamber of the dual beam charged particle microscope system 600 at a second distance 640 from the sample 625. Because the receptor material (e.g., Figure 3 The bias voltage of the receptor layer 315 of the electron beam may be lower, so the wide bandgap detector 630 can be positioned closer to the sample than the ETD 635. In addition, the wide bandgap detector 630 can be operated without a collection grid (or without a voltage applied to the collection grid). For example, the end of the wide bandgap detector 630 can be positioned as close to 7 mm from the sample during operation without significantly affecting the electron beam and maintaining image quality. In some embodiments, the second distance 640 may be between about 7 mm and 10 cm. Depending on the characteristics of the sample (e.g., material, surface profile, etc.), secondary electrons emitted during operation of the electron beam may be preferentially emitted within an angular distribution relative to the beam axis. For example, improved detection of secondary electrons can be achieved using a detector positioned at an angle of 45° to the beam axis, or using a detector positioned at an angle greater than 45° to the beam axis, including, for example, 50°, 60°, 75°, or about 90° to the beam axis (and / or fractions and interpolated values ​​of these angular positions)). The ability to position the wide bandgap detector 630 at a second distance 640 that is significantly closer than a conventional ETD 635 may allow the wide bandgap detector 630 to be positioned at an angle to improve detection of secondary electrons.

[0073] In some embodiments, the dual-beam charged particle microscope system 600 can be operated without the ETD 635 and only with the wide bandgap detector 630. For example, the wide bandgap detector 630 can replace the ETD or other scintillator detector in the charged particle microscope system. Replacing the ETD can free up space within the limited volume of the vacuum chamber of the dual-beam charged particle microscope system 600, thereby allowing improved positioning of the wide bandgap detector 630 or providing space for additional wide bandgap detectors. For example, in some embodiments, the dual-beam charged particle microscope system 600 may include two or more wide bandgap detectors positioned at different locations within the vacuum chamber to simultaneously obtain secondary electron signals according to two different orientations relative to the sample 625.

[0074] Figure 7 is a schematic diagram of a wide bandgap detector 730 in a dual beam charged particle microscope 700 positioned at the end of an ion beam column according to some embodiments. The dual beam charged particle microscope 700 may be Figure 1 An example of a dual-beam charged particle microscope 100 includes an electron beam column 705 and a FIB 715 that can generate an electron beam and an ion beam, respectively.

[0075] exist Figure 7 In the illustrated embodiment, the wide bandgap detector 730 may be arranged annularly and positioned at the end of the beam column of the FIB 715. The annular arrangement may include a hole in the middle of the annular arrangement to allow the ion beam to pass through during operation. The detector unit may be shaped to accommodate the hole. For example, the hole may extend through the detector unit and perforate the first conductive layer (e.g., first conductive layer 320), the receptor layer (e.g., receptor layer 315), and the second conductive layer (e.g., second conductive layer 325) so that the detector unit can be positioned around the beam axis (e.g., beam axis B), wherein the first conductive layer is oriented to face the sample 725. In some embodiments, the wide bandgap detector 730 may include more than one detector unit (e.g., a segment including a separate receptor layer and a conductor layer) arranged as a sector or concentric detector unit in an annular configuration. The positioning of the wide bandgap detector 730 at the end of the ion beam column of the FIB 715 may be advantageous during electron beam operation due to the position of the end of the ion beam column relative to the sample and / or by allowing additional wide bandgap detectors to be placed in the position of the ion beam column. The wide bandgap detector 730 can detect secondary electrons 744 emitted from the sample 725 during operation of the electron beam. Additionally, positioning the wide bandgap detector 730 at the end of the ion beam column can allow for improved detection of energetic particles, including secondary electrons, during operation of the ion beam.

[0076] Figure 8 is a flow chart of an example process 800 for operating a charged particle microscope system having a charged particle sensor according to some embodiments. The charged particle microscope system can be an example of other charged particle microscope systems described herein, including Figure 1 A dual beam charged particle microscope system 100. The charged particle sensor may be an example of a wide bandgap detector as described herein, including Figure 1A wide bandgap detector 130. The charged particle microscope system may include a computer system configured to perform the operations of process 800. For example, the computer system may be configured to adjust parameters of the electron beam (e.g., accelerating potential, beam focusing parameters, beam current, beam deflection, etc.), parameters of the ion beam (e.g., accelerating potential, beam focusing parameters, ion species selection, beam current, etc.), scanning / imaging parameters for SEM and / or STEM modes (e.g., scan time, dwell time, etc.), activation / deactivation of both the electron beam and the ion beam (or additional beams present in a multi-beam system, such as a laser beam), detector settings (e.g., bias voltage, collector grid voltage, etc.), and other suitable parameters for operation of such a microscopy system.

[0077] At block 802, a charged particle microscope system may cause emission of an electron beam. The electron beam may be emitted from an electron source and may be generated using an electron beam column (e.g., Figure 1 The electron beam may be focused / shaped by one or more electromagnetic components in an electron beam column 105 of a charged particle microscope system. The electron beam may be directed to a sample chamber (e.g., Figure 1 The electron beam is directed onto a sample in a vacuum chamber 110. When the electron beam interacts with atoms of the sample, the electron beam may generate a first flux of detectable particles. The detectable particles may include secondary electrons, BSEs, photons, ions, etc.

[0078] At block 804, the charged particle microscope system may cause emission of an ion beam. The ion beam may be emitted from an ion source (e.g., Figure 1 The ion beam may be directed to a sample positioned in a sample chamber of a charged particle microscope system. When the ion beam interacts with atoms of the sample, the ion beam may generate a second flux of detectable particles. The detectable particles may include ions, secondary electrons, photons, etc.

[0079] At block 806, the charged particle microscope system can stop the ion beam. The ion beam can be operated, for example, to remove a portion of a sample. Once the portion of the sample has been removed, the emission of the ion beam can be stopped.

[0080] At box 808, the charged particle microscope system may detect a signal at a charged particle sensor in the sample chamber. The charged particle sensor may include a detector unit having a semiconductor layer characterized by a band gap equal to or greater than about 2.0 eV. The signal may be generated by a first flux of detectable particles associated with the electron beam. For example, the first flux of detectable particles may be secondary electrons of a first flux generated by the electron beam based on an interaction between the electron beam and the sample in the sample chamber. In some embodiments, the signal can be used to generate an image of the surface of the sample. In some embodiments, the first flux of detectable particles may be backscattered electrons of the first flux generated from the sample in the sample chamber by scattering of the electron beam.

[0081] In some examples, the charged particle sensor can be configured to detect a signal generated by detectable particles generated by the ion beam. For example, the electron beam can be deactivated and the ion beam can be activated to perform imaging, wherein the charged particle sensor is configured to detect secondary electrons generated by the interaction of the ion beam with the sample.

[0082] In some embodiments, operation of a charged particle microscope system may include directing an electron beam onto a sample while simultaneously directing an ion beam onto the sample. Figure 5A and Figure 5B As shown, when the ion beam is activated, the electron beam can be directed onto the sample to perform imaging of the sample. In some embodiments, directing the electron beam onto the sample can occur after the ion beam has been deactivated. For example, the electron beam can be deactivated (or directed away from the sample) during operation of the ion beam. After deactivating the ion beam, the electron beam can be activated and directed onto the sample.

[0083] In some embodiments, detecting a signal at the charged particle sensor may occur after desaturation of the charged particle sensor. Desaturation of the charged particle sensor may occur within about 100 μs after stopping emission of the ion beam. The charged particle sensor may be saturated with detectable particles of the second flux. For example, the detectable particles of the second flux may include secondary electrons generated by the interaction of the ion beam with atoms of the sample. In this way, a usable signal may be detected at the charged particle sensor within about 100 μs after stopping emission of the ion beam. In some embodiments, causing emission of the electron beam may occur within about 100 μs after stopping emission of the ion beam.

[0084] In some embodiments, detecting a signal at a charged particle sensor may omit the use of a conductive collector mesh coupled to the charged particle sensor. In some embodiments, the conductive collector mesh may not be present at all in the charged particle sensor. In other embodiments, the conductive collector mesh may be coupled to the charged particle sensor, but may not have an applied voltage when detecting a signal.

[0085] Despite the above Figure 8 The description of process 800 is with reference to a charged particle microscope system using an ion beam, but systems incorporating a laser beam or other suitable particle beam as an alternative or supplement to the ion beam are contemplated. For example, in embodiments where the charged particle microscope system uses a laser beam for milling, ablation, surface preparation, etc., the laser beam may be substituted for the ion beam in process 800.

[0086] In the foregoing description, various embodiments have been described. For the purpose of explanation, specific configurations and details have been set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to those skilled in the art that these embodiments can be put into practice without these specific details. In addition, in order not to obscure the described embodiments, well-known features may have been omitted or simplified. Although the example embodiments described herein focus on electron microscopy systems, and specifically focus on dual-beam SEM systems, these are meant to be non-restrictive exemplary embodiments. The embodiments disclosed herein are not limited to such materials, but are intended to address charged particle beam systems, for which a wide range of particle arrays can be applied to imaging, microscopic analysis and / or processing of materials on an atomic scale. Such particles may include, but are not limited to, electrons, ions or photons in TEM systems, SEM systems, STEM systems, ion beam systems and / or particle accelerator systems.

[0087] Some embodiments of the present disclosure include a system having one or more data processors and / or logic circuits. In some embodiments, the system includes a non-transitory computer-readable storage medium containing instructions, which, when executed on one or more data processors, causes the one or more data processors to perform part or all of one or more methods disclosed herein and / or part or all of one or more processes and workflows. Some embodiments of the present disclosure include a computer program product tangibly embodied in a non-transitory machine-readable storage medium, the computer program product including instructions configured to cause one or more data processors to perform part or all of one or more methods disclosed herein and / or one or more processes (including, for example, Figure 8 part or all of process 800).

[0088] The terms and expressions employed herein are used as terms of description rather than limitation, and when such terms and expressions are used, it is not intended to exclude any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the claims. Therefore, it should be understood that while the present disclosure includes specific embodiments and optional features, modifications and changes to the concepts disclosed herein may be made by those skilled in the art, and such modifications and changes are deemed to be within the scope of the appended claims.

[0089] When a term is used without explicit definition, it is understood that unless the term has a special and / or particular meaning in the field of charged particle microscopy systems or other related fields, the term refers to the ordinary meaning of the word. The term "about" or "substantially" is used to indicate a deviation from a stated property or numerical value, wherein the deviation has little or no effect on the corresponding function, property or attribute of the described structure. In the illustrated example where one dimensional parameter is described as "substantially equal to" another dimensional parameter, the term "substantially" is intended to reflect that the two dimensions being compared may be unequal within permissible limits (such as manufacturing tolerances). Similarly, where a geometric parameter (such as alignment or angular orientation) is described as "approximately" perpendicular, "substantially" perpendicular, or "substantially" parallel, the term "about" or "substantially" is intended to reflect that the alignment or angular orientation may differ from the precisely stated condition (e.g., not precisely perpendicular) within permissible limits. For dimensional values ​​(such as diameter, length, width, etc.), the term "about" may be understood to describe a deviation of up to ±10% from the stated value. For example, a dimension of "about 10 mm" may describe a dimension of 9 mm to 11 mm. In the present disclosure, a "sub-range" refers to a range between two stated ranges and / or including values ​​in one of the two stated ranges.

[0090] This description provides exemplary embodiments and is not intended to limit the scope, applicability or configuration of the present disclosure. Instead, the subsequent description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing various embodiments. It should be understood that various changes may be made to the function and arrangement of the elements without departing from the spirit and scope set forth in the appended claims.

[0091] Specific details are given in the description to provide a thorough understanding of the embodiments. However, it should be understood that the embodiments may be practiced without these specific details. For example, specific system components, systems, processes, and other elements of the present disclosure may be shown in schematic form or omitted from the illustrations to avoid obscuring the embodiments due to unnecessary details. In other cases, well-known circuits, processes, components, structures, and / or technologies may be shown without unnecessary details.

Claims

1. A charged particle microscope system, comprising: Vacuum chamber; a sample stage, the sample stage being disposed in the vacuum chamber and configured to receive a sample to be tested in the vacuum chamber; a first beam source operable to direct a first particle beam into the vacuum chamber toward the sample stage; a second beam source operable to direct a second particle beam into the vacuum chamber toward the sample stage; a first charged particle sensor disposed at a first position in the vacuum chamber and comprising a detector cell having a semiconductor layer spanned at a first level of electrical bias and characterized by a bandgap equal to or greater than about 2.0 eV, and oriented to detect secondary electrons generated based on an interaction between the first particle beam or the second particle beam and a sample disposed on the sample stage; and A second charged particle sensor is disposed at a second position in the vacuum chamber and includes a scintillator detector electrically biased at a second level greater than the first level, the second charged particle sensor being configured to be saturated from electrons generated based on an interaction between the second particle beam and the sample disposed on the sample stage.

2. The charged particle microscope system of claim 1, wherein the first level is approximately 1 kV.

3. The charged particle microscope system of claim 1, wherein the second level is approximately 10 kV.

4. A charged particle microscope system according to claim 1, wherein the first position is closer to the sample stage than the second position.

5. The charged particle microscope system of claim 1, wherein the distance between the first position and the sample stage is about 7 mm to about 10 cm.

6. The charged particle microscope system of claim 1, wherein the distance between the second position and the sample stage is about 10 cm.

7. A charged particle microscope system according to claim 1, wherein the semiconductor layer comprises one or more materials selected from the group consisting of silicon carbide, single crystal diamond, polycrystalline diamond, gallium nitride, gallium phosphide, cadmium sulfide, aluminum phosphide, zinc selenide, zinc sulfide and aluminum nitride.

8. The charged particle microscope system of claim 1, wherein the first particle beam is an electron beam.

9. The charged particle microscope system of claim 1, wherein the second particle beam is an ion beam, or wherein the second particle beam is a laser beam.

10. The charged particle microscope system of claim 9, wherein the ion beam is configured for milling or polishing.

11. A charged particle sensor, comprising: a housing configured to be incorporated into a charged particle microscope system; and A detector unit mechanically coupled to the housing, the detector unit comprising a semiconductor layer characterized by a band gap equal to or greater than about 2.0 eV, wherein the housing is configured to be mechanically coupled to the charged particle microscope system such that when the housing is mechanically coupled to the charged particle microscope system, the charged particle sensor is disposed in a chamber of the charged particle microscope system and is oriented to detect secondary electrons from the sample.

12. The charged particle sensor of claim 11, wherein the housing is configured to mechanically couple with an end of an ion beam column, and wherein the housing and the detector unit form an annular configuration at the end of the ion beam column.

13. The charged particle sensor of claim 11, wherein the housing is configured to mechanically couple with the charged particle microscope system at a position where the angle between the axis of the electron beam and a line from the sample to the detector unit is approximately 45°.

14. The charged particle sensor of claim 11, wherein the detector cell is electrically biased across the semiconductor layer at a voltage of about 0.01 V to about 10 kV.

15. A method of operating a charged particle microscope system, the method comprising: causing emission of an electron beam to be directed onto a sample positioned in a sample chamber, the electron beam generating a first flux of detectable particles; causing emission of an ion beam to be directed onto the sample in the sample chamber, the ion beam generating a second flux of detectable particles greater than the first flux; stopping said emission of said ion beam; as well as A signal is detected at a charged particle sensor in the sample chamber, the charged particle sensor comprising a detector cell having a semiconductor layer characterized by a band gap equal to or greater than about 2.0 eV, and the signal is generated by detectable particles of the first flux associated with the electron beam.

16. The method of claim 15, wherein detecting the signal at the charged particle sensor occurs after desaturation of the charged particle sensor, the desaturation occurring within about 100 μs after ceasing the emission of the ion beam.

17. The method of claim 15, wherein detecting the signal at the charged particle sensor omits the use of a conductive collector mesh coupled to the charged particle sensor.

18. The method of claim 15, wherein causing the emission of the electron beam occurs within about 100 μs after ceasing the emission of the ion beam.

19. The method of claim 15, wherein detecting the signal at the charged particle sensor comprises detecting secondary electrons generated based on an interaction between the electron beam or the ion beam and a sample in the sample chamber.

20. The method of claim 15, wherein detecting the signal at the charged particle sensor comprises detecting backscattered electrons generated from the sample in the sample chamber by scattering of the electron beam.

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