WO2018007136A1

WO2018007136A1 - Ion microscopy device

Info

Publication number: WO2018007136A1
Application number: PCT/EP2017/064872
Authority: WO
Inventors: Nico Klingner; René HELLER; Gregor Hlawacek; Stefan Facsko; Johannes VON BORANY; Richard Arthur WILHELM
Original assignee: Helmholtz-Zentrum Dresden - Rossendorf E. V.
Priority date: 2016-07-06
Filing date: 2017-06-19
Publication date: 2018-01-11
Also published as: DE102016112328B3

Abstract

The invention relates to an ion microscopy device having an ion source for generating an ion beam, a detector, a voltage source and a photon pulse generator, wherein the ion microscopy device is designed to irradiate an object with the ion beam with the generation of interaction particles, wherein the ion source has a gas ionization chamber, a pointed electrode arranged in the latter and a counter-electrode, the detector is used to capture the interaction particles, the voltage source is used to apply an electrical voltage between the electrode and the counter-electrode, and the photon pulse generator is used to generate photon pulses directed into the ionization chamber in such a manner that an ion pulse can be generated by means of a photon pulse, wherein the ion microscopy device is designed to capture the period of time between a photon pulse and the capture of the interaction particles generated by the ion pulse generated by means of this photon pulse by means of the detector.

Description

lonenmikroskopievorrichtung

The invention relates to an ion microscopy device, i. a microscope based on scanning an object to be examined with an ion beam and detecting the interaction of the ion beam with the object.

In ion microscopes, an examination subject to be examined by irradiating the object with an ion beam and detecting the by the

Interaction of the ion beam with the object imaged by the same outgoing particle. The ion beam used to scan the examination subject is also referred to as the primary ion beam, the ions of the

Primary ion beams are also referred to as primary ions. For imaging, e.g. the primary ions emitted by the object are used, e.g. the primary ions passed through the object and / or those of the object

backscattered primary ions. For imaging, the secondary particles generated by interaction of the primary ion beam with the object, e.g.

Secondary electrons, secondary ions and photons can be used. The

Imaging can e.g. by detecting the properties and the number of emanating from the object under investigation primary and secondary particles.

In ionic microscopes, a gas field ion source (GFIS) can be used to generate the primary ions

Ion microscopes may e.g. Helium ions, neon ions, hydrogen ions and / or nitrogen ions can be used as primary ions. Imaging takes place

by default by detecting the secondary electrons, e.g. by determining the yield of secondary electrons by means of a secondary electron detector and from this an image of the sample surface is generated. In addition to normal imaging, elemental analysis may also be of interest in order to obtain information about the (local) material composition of the examination subject, e.g. Statements about the chemical composition of the examination object.

In this regard, for example, in the article "Nanometer scale elemental analysis in the helium ion microscope using time of flight spectroscopy" (N. Klingner et al. Ultramicroscopy, 162, 2016, p. 91 ff.) Describes the implementation of elemental analysis in a helium ion microscope by means of time-of-flight spectrometry, in which a pulsed ion beam is used to realize the time-of-flight spectrometry. Accordingly, the flight times of the scattered primary particles and sputtered secondary particles generated by a primary ion beam become the same

Covering the distance to a detector need, recorded and based thereon present at each impact point of the primary ion beam

Material composition determined. The pulsed ion beam is generated by providing a continuous ion beam by means of a GFIS and passing this ion beam through an aperture (here a Faraday cup serves as an aperture) by means of an electrostatic deflection unit of the ion microscope by momentarily applying the electric deflection voltage applied to the deflection unit is lowered. The pulsing of the primary ion beam by means of the deflection unit of the ion microscope, however, is associated with large ion pulse durations (of a minimum of about 17 nanoseconds). Since the time resolution of the time of flight spectrometry is dominated by the pulse duration of the ion pulses, large ion pulse durations are accompanied by a correspondingly low (relative) time and mass resolution. In addition, the pulsing of the primary ion beam by means of the deflection unit is accompanied by a moving, not exactly axially along the optical axis extending primary ion beam, resulting in a deterioration of the spatial resolution with pulsed ion beam.

DE 11 2011 104 535 T5 describes an emission gun for emitting charged particles, in particular for an ion microscope, wherein the

Emission gun has a tip, an extraction electrode and an ion collector in a vacuum chamber, and wherein the emission gun has a cleaning light irradiation device for irradiating the tip with ultraviolet or infrared light for the purpose of cleaning the tip.

In the article "Nanosecond electron microscopes" (O. Bostanjoglo et al.

Ultramicroscopy, 81, 2000, p. 141 ff.), The observation of samples

described by electron microscopy, the samples during the

Observation be irradiated with laser pulses. The invention provides an ion microscopy apparatus by means of which imaging and analysis of an object to be examined is possible with high accuracy, for example with high spatial, temporal and / or mass resolution. According to the invention, an ion microscopy apparatus (hereinafter also referred to as an ion microscope) is provided which is suitable for imaging a

An object of investigation can be designed and by means of which an analysis (for example an element analysis) of the examination subject is also made possible. The ion microscope has an ion source for generating an ion beam. The ion source comprises an ionization chamber, a gas supply device for supplying a gas into the ionization chamber, a tip-shaped electrode (also referred to as tip electrode or emitter tip) arranged in the ionization chamber, and a counterelectrode, so that the ion source contains all components of a conventional gas field ion. Source and therefore hereinafter also referred to as gas field ion source (GFIS). Gas field ion sources are also referred to as gas field ionization ion sources or gas field ion sources. As a gas, e.g. Helium, neon, argon, xenon, hydrogen or nitrogen be provided or a gas mixture with one or more of the aforementioned gases as an ingredient. However, other gases are possible, e.g. Noble gases.

The ionization chamber forms a gas receiving volume for receiving the gas supplied by the gas supply device, which gas is ionized upon operation of the ion microscope in the ionization chamber. The counter-electrode is arranged at a distance from the tip-shaped electrode, so that when an electrical voltage is applied between the electrode and the electrode

Counterelectrode resulting electric field (at least partially) the

Ionisationskammer interspersed or runs in the ionization chamber, so that the gas ions are accelerated to form a Primärionenstrahls of the electric field. The counterelectrode can be arranged, for example, in the ionization chamber. The ionization chamber can have an outlet opening through which the primary ion beam can emerge from the ionization chamber. The counter electrode can, for example, on the wall of the ionization chamber (eg annular) to the outlet opening to be arranged running around, for example, as a border of the outlet opening.

The ion microscope has a voltage source which is used for applying an electrical voltage, in particular a direct electrical voltage (for example in the form of a high voltage), between the electrode and the

Counter electrode is formed to generate an electric field. By means of the voltage source, the positive voltage pole is formed on the tip-shaped electrode and the negative voltage pole on the counter electrode, so that the tip-shaped electrode is at a higher electrical potential than the counter electrode. The electric field passes through the ionization chamber and thus also the gas absorbed therein. The ion microscope may be designed to drive the voltage source such that the means of

Voltage source between the electrode and the counter electrode applied voltage (in particular the amount of voltage) is adjustable.

The ion microscope may e.g. be designed such that it operates in a continuous beam mode, the ion source as a conventional gas field ion source. In the continuous beam mode, the voltage source is driven by the ion microscope such that the electric field caused by the electrical voltage between the electrode and the counter electrode for ionizing (at least part) of the in the ionization chamber

absorbed gas to form a continuous (i.e.

uninterrupted) primary ion beam. In the continuous-beam mode, the amount of voltage applied between the electrode and the counter electrode is therefore large enough to cause ionization of the gas to form a gas

to cause continuous primary ion beam.

In the continuous beam mode, the voltage source is thus controlled in such a way that the electric field produced between the electrode and the counterelectrode for ionizing (at least a part of) the in the ionization chamber

absorbed gas sufficient and the thus generated gas ions to form a continuous Primärionenstrahls of the electrode in the direction To be accelerated toward the counter electrode. In the continuous-beam mode, the voltage source is driven in such a way that the magnitude of the voltage applied between the electrode and the counterelectrode is at least so great that the gas received in the ionization chamber is (at least partially) ionized. It can be provided that in the continuous beam mode, the voltage applied between the electrode and the counterelectrode is constant in time and the primary ion beam is formed with a temporally constant ion current.

The ion microscope is (for example by means of an ion-optical beam guiding device) designed such that the ion beam can be directed to an object area so that an object to be examined in the object area irradiated with the ion beam and scanned, with backscattered particles of the ion beam and / or sputtered (ie from the examination object

detached) particles of the examination subject are generated as interaction particles. In the present case, the term interaction particles is understood to mean particles which, due to the interaction of the primary ion beam with the examination subject, are emitted starting from the examination subject, with the exception of secondary electrons and photons.

Interactive particles in the form of backscattered particles of the ion beam may e.g. be scattered ions and / or neutralized ions (i.e., atoms) of the primary ion beam at the object to be examined. Interactive particles in the form of sputtered particles of the object under examination may e.g. Be ions and / or atoms of the examination object. The ion microscope has a detector which is arranged and designed in such a way that at least part of the interaction particles can be detected by it (also referred to as interaction particle detector). Of the

Interaction particle detector may e.g. be designed to detect electrically neutral and / or electrically charged interaction particles,

in particular for detecting atoms, molecules, molecular fragments and / or ions, for example for detecting ions of the primary ion beam, neutralized ions (ie atoms) of the primary ion beam, atoms, molecules or molecular fragments and / or ions of the examination subject. The interaction particle detector may be, for example, a single particle detector. The interaction particle detector may, for example, a micro-channel plate (English "micro-channel plate"), a

Semiconductor detector or a secondary electron multiplier or a microchannel plate, a semiconductor detector or a

Have secondary electron multiplier as a detector element.

The interaction particle detector can be arranged and designed in such a way that it can detect interaction particles which can be detected from the object region (or the object under examination) in the direction of the latter

Primary ion beam facing side of the object area (or the

Object to be examined). The detector can thus be designed and arranged for detecting interaction particles in a backscatter geometry. It can e.g. that the interaction particle detector is arranged on the side of the object region (or of the examination object) facing the primary ion beam or the ion source, that is to say that is arranged at a backscatter angle relative to the primary ion beam.

The ion microscope may include, in addition to the interaction particle detector, a secondary electron detector arranged and

is formed so that at least a part of the secondary electrons generated by means of the primary ion beam can be detected by it. The ion microscope may be formed in a known manner for imaging the examination subject by means of the detected secondary electrons, the ion microscope comprising e.g. can be operated in continuous-beam mode.

The ion microscope also has a device for generating

Photon pulses on (hereinafter also referred to as photon pulse generator). The photon pulse generator is designed and arranged such that it can be used to generate photon pulses (ie pulses of photons) which are directed to a position (also referred to below as a photon pulse target position) in the ionization chamber. The photon pulse generator is thus designed and arranged such that the photon pulses generated by it are directed to the photon pulse target position and hit the photon pulse target position, wherein the Photon pulse target position in the ionization chamber is located. The ion microscope may be formed (eg by means of a focusing optics) such that the photon pulses are focused onto the photon pulse target position, in this case the

Photon pulse target position also referred to as photon pulse focus position.

The photon pulse target position is located in the ionization chamber on the tip-shaped electrode or in the vicinity of the tip-shaped electrode such that the target photon pulse position overlaps the field-elevation region that exists between the electrode and the electrode when an electric field is applied

Counter electrode results. The ion microscope may e.g. be formed so that the distance between the tip-shaped electrode and the photon pulse target position is not greater than 1 micron. The ion microscope may e.g. be formed such that the photon pulse target position on the tip-shaped

Electrode (e.g., on the tip of the tip-shaped electrode), so that the

Photon pulses are directed to the tip-shaped electrode and on the

tip-shaped electrode (e.g., on its tip). However, the ion microscope may also be formed such that the target photon pulse position does not lie on the tip-shaped electrode, so that the photon pulses are not directed to the electrode and do not hit the tip-shaped electrode but to a position away from the tip. It can e.g. be provided that the tip-shaped electrode has an axis in the form of a longitudinal axis or

Symmetry axis and the photon pulses are directed to a photon pulse target position on this axis, the distance of the target position from the tip of the electrode e.g. at most 1 micrometer.

The photon pulse generator may e.g. for generating laser pulses as

Accordingly, the photon pulse generator may be e.g. be a pulsed laser. The photon pulses may e.g. Photons one

Have or consist of wavelength in the range of 10 nm to 3 mm. The photon pulses can, for example, photons of a wavelength from 10 nm to 380 nm (ultraviolet radiation or UV radiation), a wavelength of 380 nm to 780 nm (visible light), a wavelength of 780 nm to 1 mm (infrared radiation or IR radiation ) or a wavelength of 30 μιτι to 3 mm (terahertz radiation or THz radiation) or consist thereof. Terahertz radiation can, for example, support low heating of the tip electrode and short pulse times. The photon pulses are also referred to as optical pulses, but with this designation no limitation of the wavelength of the photons of the photon pulses to visible light is implied. The photon pulse generator is arranged such that the photon pulses generated by it in the

Ionization chamber are irradiated. The photon pulse generator may be located inside or outside the ionization chamber. It can e.g. be provided that the photon pulse generator outside the ionization chamber

is arranged and the ionization chamber has a window or a recess as an optical input, wherein the photon pulses are irradiated through the optical input into the ionization chamber.

By means of the photon pulse generator photon pulses in the

Be entered ionization chamber, whereby a pulsed energy input can take place in a gas contained therein. By means of the pulsed introduction of energy, a temporal structuring of the ion beam generated by the ion source can take place, e.g. by the ionization of the gas is supported by means of the photon pulses. The time-structured ion beam thus generated can subsequently be used for further analysis of the examination subject. Since photon pulses can be generated easily with very short pulse durations and thus one

enable high-resolution temporal structuring of the ion beam, this also allows an analysis of the examination subject with a high temporal resolution. Since the temporal structuring of the ion beam by means of

Photon pulses does not require a deviation of the ion beam from the optical axis of the ion microscope or its ion optics and no movement of the ion beam, thereby also an analysis with high spatial resolution allows.

With regard to the spectrometry of scattered or sputtered particles, it is thus possible, for example on a size scale of a few to a few hundred nanometers, to achieve previously unattainable time resolutions and thus energy and mass resolutions. With lasers pulse widths in the range of femtoseconds to picoseconds are technically easy to achieve. If, for example, it is possible to generate an ion pulse with a pulse width of 10 ps, a relative velocity of 100 ns can be achieved Time resolution of 1: 10000 can be achieved. Alternatively, with the same relative time resolution, shorter flight times result in shorter flight times and thus shorter ones

Air routes possible. When using same detectors at the end of the

Flight distance are covered with the same area of the detectors larger solid angles. As a result of the enlargement of the solid angle, more particles can be detected per amount of primary ions, which improves the statistical uncertainty of the measurement. Alternatively, with the same number of spectrometry particles, fewer primary ions can be applied to the examination object or the sample, resulting in less radiation damage. This allows e.g. the

Investigating smaller objects before a critical amount of radiation damage has occurred.

The ion microscope is designed in such a way that in a mode (also referred to as pulse beam mode) the voltage source and the photon pulse generator are controlled in such a way that an electrical voltage (eg time constant) between the electrode and the counterelectrode of the GFIS is created and at the same time by means of the photon pulse generator

Photon pulses are generated and registered in the ionization chamber. The ionization chamber of the GFIS and thus also a gas absorbed therein are penetrated by the voltage generated by the electric field. By means of the photon pulses, energy is introduced into the ionization chamber penetrated by the electric field or the gas received therein. The

Voltage source is driven to output a voltage (in particular a DC electrical voltage, for example in the form of a high voltage electrical), so that the gas by means of the electrical voltage

excited electric field is excited, wherein the photon pulse generator for generating photon pulses is formed (for example, by being designed to generate photon pulses of corresponding intensity and / or wavelength) that means of the photon pulses, the excited by the electric field gas at least partially ionized is so that in pulse-beam mode by means of a photon pulse (eg by means of each photon pulse), an ion pulse is generated and thus from the ion source, a pulsed ion beam can be generated. In the pulse beam mode is thus by means of the voltage source, an electrical

Voltage is applied between the electrode and the counter electrode of the GFIS and photon pulses are simultaneously generated by the photon pulse generator and introduced into the ionization chamber, wherein an ionization of the gas caused by the combined effect of the voltage caused by the electrical voltage

electric field and the photon pulses, so that a pulsed ion beam is generated in the pulse beam mode. In continuous wave mode, however, by means of the voltage source, an electrical voltage between the electrode and the

The counter electrode of the GFIS applied, wherein the amount of voltage applied in the continuous-beam mode voltage is greater than the amount of the pulse-beam mode

voltage applied, so that in the continuous beam mode of the photon pulse generator no photon pulses are generated and an ionization of the gas is effected solely by means of the electric field caused by the electrical voltage. The in the continuous-beam mode and in the pulse-beam mode of the

Voltage source provided DC voltages can e.g. be several kilovolts, the voltage in the pulse-beam mode is smaller than in the continuous-beam mode.

According to one embodiment, the ion microscope is designed in such a way that in the pulse beam mode the voltage source is driven by it in such a way that the electric field caused by the electrical voltage between the electrode and the counterelectrode is not sufficient to ionize the electric field

Ionisationskammer recorded gas to form a continuous Primärionenstrahls sufficient. It can therefore be provided that in the pulse-beam mode, the voltage is adjusted such that the amount of voltage applied between the electrode and the counterelectrode is not large enough to cause ionization of the gas to form a continuous primary ion beam. The ion microscope may in particular be designed in such a way that in the pulse-beam mode the voltage source is driven by it in such a way that the voltage caused by the electrical voltage between the electrode and the counter electrode

caused electric field alone is not sufficient to ionize the gas. The The ion microscope can thus be designed in such a way that in the pulse-beam mode the voltage source is driven such that the electric field caused by the electrical voltage between the electrode and the counterelectrode alone is insufficient to ionize the gas, and that ionization of the gas only by the entry of a photon pulse takes place (so that an ionization of the gas takes place only by the combined effect of the electrical voltage caused by the electric field and the photon pulses). Accordingly, the photon pulse generator, in particular for generating photon pulses directed to a position in the ionization chamber, can be designed in such a way that at least a part of that of the electric field

gas is ionized by means of the photon pulses, so that an ion pulse is generated by means of a photon pulse (for example by means of each photon pulse) and thus a pulsed ion beam can be generated by the ion source. According to this variant, therefore, the amount of voltage applied by means of the voltage source between the electrode and the counterelectrode is too small to be in the

Ionization chamber gas to be ionized alone by means of the voltage caused by the electric field. The criterion that this is due to the electrical voltage between the electrode and the counter electrode

caused electric field is not sufficient to ionize the gas can, for. to be considered fulfilled when alone by the electric field

for example, is less than 100 ions per second (the ionization rate indicating the number of ions produced per time). In contrast, in the continuous-beam mode, the voltage applied by the voltage source is so large that the ionization rate caused solely by the electric field is substantially higher than the threshold value, eg greater than 10 ⁷ ions per second. More generally, it can be provided, for example, that the electrical voltages present in the pulse-beam mode and in the continuous-beam mode are such that the ratio of the ionization rate, which is produced in the continuous-beam mode solely by the electric field, to the ionization rate that is present in the pulse-beam mode. Mode is caused solely by the electric field is greater than a predetermined threshold, the threshold may be eg 10 ³ . In pulse-beam mode, the amount of voltage applied between the electrode and the counter electrode by the voltage source is less than in the continuous-beam mode. It may be provided that in the pulse-beam mode, the electric field alone is insufficient for ionizing the gas received in the ionization chamber of the ion source, wherein the residual excitation required for the ionization of the gas is introduced into the gas by means of the photon pulses, so that gas ions are generated by means of each photon pulse which ones are

subsequently accelerated in the direction of the counterelectrode, generating an ion pulse in the electric field, so that a pulsed primary ion beam can be generated by the ion microscope in pulse-beam mode.

By generating the ion pulses by means of the photon pulses, the ion pulses can be formed with very short ion pulse durations, because

Photon pulses can be generated easily with very short pulse durations and the pulse duration of the ion pulse generated by means of a photon pulse essentially corresponds to the duration of the causing photon pulse. Thus, very short ion pulses can be generated over time by means of the photon pulses. Since the generation of the ion pulses by means of the photon pulses does not require a deflection of the primary ion beam from the optical axis of the ion microscope or the ion optics, an exact positioning of the ion beam on the examination object can be carried out with a small incident surface. By ionization by optical pulses or photon pulses thus very short pulses of ions can be generated in time, which can be focused with the microscope on a small impact surface (eg with a diameter of a few nanometers), so that the ions temporally and spatially focused in the to be examined object can be introduced.

The interaction of the ion pulses with the examination object can be investigated by means of different methods. In any case, temporally short ion pulses with a small-area and exactly positioned impact point on the examination object enable a study with high temporal and / or spatial resolution. To operate the gas field ion source is between the top or

tip-shaped electrode and the counter electrode of the GFIS applied an electrical voltage such that the tip is at a more positive or higher electrical potential than the counter electrode.

In the continuous-beam mode, the magnitude of the voltage is set so high, as in the conventional operation of a GFIS, that the high field gradients resulting from the field elevation at the tip end of the electrode bring about ionization of the gas present there. So if a gas in this as well

Due to the high field gradient, electrons of the gas atoms pass into the tip due to the high field gradient, resulting in positively charged gas ions, which in turn are accelerated in the electric field towards the counterelectrode. With smaller voltages and correspondingly smaller electric field gradients, fewer and fewer gas atoms are ionized at the tip, so that practically no gas ionization occurs below a corresponding threshold value of the voltage due to the associated electric field. In this case, an ionization of the gas atoms by the irradiation of a photon pulse in the ionization chamber, in particular in the field of field elevation in the vicinity of the tip, take place. The ionization by means of the photon pulses can be effected by different processes.

According to a first ionization process, a pulse of coherent photons (eg, laser pulses) of high intensity injected into the gas infiltrated and thus biased by the electric field results in an additional local increase in the electric field gradient by the electric field associated with the coherent photons electromagnetic wave. The short-term increased potential difference leads to an increased transition of electrons of the gas atoms into the tip electrode and thus to an increased ionization rate. Tunnel ionization by laser pulses can occur, for example, from power densities of 10 ¹² to 10 ¹⁵ W / cm ² , depending on the wavelength. By the already existing

Potential difference in the presence of an electric field - as in the present case Pulsed beam mode - in a GFIS tunnel ionization can already take place at lower power densities. For effectively increasing the ionization rate, the photon pulse is preferably applied to a position very close to the tip or on the surface of the tip of the tip-shaped electrode, so that the field strength of the electric wave with the increased field gradient (of the electric field generated by the electric voltage caused) overlaps near the top.

According to a second ionization process, the entry of a photon pulse by absorption of photons by shell electrons of the gas atoms in a GFIS can lead to ionization. By absorbing the electrons are raised to higher energy potentials, whereby the binding to the associated gas atom or to be overcome for the ionization potential barrier is lowered. Due to the potential difference and field elevation near the means of

electrical tension toughened tip is lowered by the

Binding energy of the electrons also increases the transition rate of the electrons. Already excited electrons in higher shells can also absorb further photons, this process being known as multiphoton absorption. The ionization in a GFIS by absorption of photons is therefore also possible by optical pulses with low intensity. The lifetime of the excited states is in the range of femto- to attoseconds for most states, so that the temporal intensity profile of the resulting ion pulse is dominated by the duration of the optical pulse. In order for the thus optically excited atoms at the tip of the electrode to be ionized, the distance of the optical excitation pulse must not exceed the range of excited atoms. Due to the short lifetime, the excited atoms would otherwise fall back into stable states before they can reach the area of field elevation.

The ionization of a particular element in the ion source can also be done by resonant absorption of photons. For resonant absorption, the energy of the photons used must correspond to the potential difference of the electrons between two energy states. Accordingly, the

For example, to operate the GFIS with a given gas be formed, wherein by means of the Gaszuführvorrichtung a predetermined gas in the ionization chamber of the GFIS is supplied, and wherein the photon pulse generator for generating photon pulses is designed such that the energy of a photon of the photon pulses of the energy difference of two

Energy states of the electrons of the gas corresponds.

The ion microscopy device may comprise a blanking device (also referred to as "blanking unit") which is arranged in the beam path of the ion beam and is designed to hide the ion beam from the object region (for example electrostatically) first state (also referred to as blanking state), the ion beam is masked out of the object area, and that the ion beam is transmitted to the object area in a second state (also referred to as a pass state), the ion microscope is for driving the Ausblendvorrichtung so formed that of the ion microscope the

Blanking device can be set either in the blanking state or in the on-state.

The fade-out device may e.g. a deflection unit, which is designed to deflect the ion beam, and a diaphragm. The deflection unit may e.g. be designed to deflect the primary ion beam by means of electric and / or magnetic fields. The deflection unit and the diaphragm can be arranged and configured in such a way that the ion beam can be selectively directed either to a passage opening of the diaphragm or to a shielding section of the diaphragm by means of the deflection unit so that the ion beam can pass through the ion beam when the ion beam is positioned on the passage opening and Thus, not hidden (pass-state), and that when positioning the

Ion beam is blocked on the shielding of the ion beam and thus hidden (blanking state). The deflection unit may e.g. a

be electrostatic deflection unit and may, for example, a capacitor (also referred to as deflection capacitor) have or be a deflection capacitor. The masking device or its deflection unit can be, for example, a masking device or deflection unit already present in conventional ion microscopes. According to one embodiment, the ion microscope is designed for synchronized (temporally coordinated) driving of the photon pulse generator and the masking device. By activating the photon pulse generator synchronized with the masking device, the temporal structuring of the ion beam generated by means of the photon pulses can be varied by means of the blanking device, which enables, for example, sharper pulse profiles and / or shorter pulse durations. The ion microscope may, for example, be designed in such a way that from it the

Blanking device is switched in each case only in a predetermined time window after generating a photon pulse in the forward state and otherwise switched to the blanking state. The ion microscope may e.g. be formed such that from him in each case after a predetermined first period of time after the generation of each photon pulse, the

Blanking device is switched to the on state and after a predetermined second period of time after the generation of each photon pulse, the blanking device is switched back to the blanking state (wherein the second time period is greater than the first time period).

According to one embodiment, the ion microscope is synchronized to

Controlling the photon pulse generator and the Ausblendvorrichtung formed such that the pulses of ions generated by the photon pulses by means of the blanking device (for example, when passing through the blanking device) are partially hidden, so that a part of each ion pulse by means of

Blanking is hidden and the remaining part of the ion pulse is not hidden (but is transmitted to the object area or the examination object). Because of the known airspeed of the primary ions (which is due to the mass and charge state of the ions as well as through the

Acceleration voltage of the primary ions is given) and the known microscope geometry or the known distance between the ion source and Blanking the time window is known, within which an ion pulse passes through the blanking device, the blanking device can be controlled such that from it a part of each ion pulse is hidden. As a result, for example, the pulse duration of the ion pulses can be further reduced. In the ion source different elements are ionized and / or different

Generating charge states, filtering by elements and / or charge states can be performed by partially masking out each ion pulse. Different states of charge or types of ions can thus by the

Combination of the photon pulse-induced ion pulse generation with the time-correlated activation of the masking device are filtered. As an alternative or in addition to the masking unit, the ion microscope for selecting specific elements and / or charge states may comprise a Wien filter or an omega filter which is arranged in the beam path of the ion beam. The interaction of pulsed pulsed-beam mode

Primary ion beam with the examination object can be detected by different methods and used for material analysis and / or imaging. According to various embodiments, the ion microscope for analyzing the examination subject is formed by means of time-of-flight spectrometry, e.g. by means of backscatter time-of-flight spectrometry (English as ToF-BS for "time of flight

backscattering spectrometry "), secondary ion

Time-of-flight mass spectrometry (ToF SIMS) and / or secondary neutral particle time-of-flight mass spectrometry (referred to as "time of flight neutral neutral mass spectrometry" ToF-SNMS). By means of time-of-flight spectrometry, e.g. with known mass of the detected particles whose kinetic energy and known kinetic energy of the detected particles whose mass are determined, which in turn (possibly incorporating the known detection geometry) conclusions on the

Composition of the examination object are possible.

The ion microscope is for detecting the time interval or interval between a photon pulse and the detection of the interaction particles, which are generated by the ion pulse generated by means of this photon pulse, formed by the detector (this period of time is also referred to below as the measuring period). The ion microscope is thus for detecting between a photon pulse and detecting the generated thereby

Interaction particles formed by the detector lying period of time. The beginning of this period (also referred to as start time) is so by the

Given a photon pulse, e.g. by the time of generation of the photon pulse by the photon pulse generator. The end of this period (also referred to as stop time) is given by the detection of the respective interaction particle by the detector, e.g. by the time of the impact of the

Interacting particle on the detector. It can e.g. be provided that the ion microscope for detecting the start time and the stop time and the

Determining the measuring period is formed as a difference between the detected stop time and the detected start time. According to a further embodiment, the ion microscope is designed in such a way that it determines the time of flight or duration of flight which the interaction particles travel to cover the distance between the object area (or

Examination object) and the detector, based on the detected measurement period can be determined. The measuring time span includes the time of flight of the primary ions from the ion source to the object area or object to be examined (hereinafter also referred to as primary-ion time of flight) and the time of flight of the

Interaction particles from the object area or the object to be examined to the interaction particle detector (also referred to as interaction particle flight time), wherein the measurement period beyond, for example, may still include a time portion attributable to the transmitter (hereinafter referred to as the electronic time component). The primary ion time of flight is known because of the known kinetic energy of the primary ions and the known flight distance from the ion source to the object region, and the electronic time fraction is usually negligibly small and / or otherwise determined. Therefore, the interaction particle flight time can be determined, for example, by subtracting from the measurement time period the primary ion time of flight and possibly the electronic time portion. Thus, the ion microscope can detect the time of flight be formed, which require the interaction particles of the object area or object to be examined to the detector.

Based on the flight time, e.g. for backscattered particles of the primary ion beam - since their mass is known - whose kinetic energy is determined, resulting in the inclusion of the known detection geometry or scattering geometry

(Backscatter angle, solid angle covered by the detector, distance between detector and object)

Test object as known for Rutherford backscatter spectrometry.

According to a further embodiment, the ion microscope for carrying out secondary ion mass spectrometry (SIMS) can be formed by means of time-of-flight spectrometry. For this purpose, the ions released from the examination object by means of sputtering must first be brought to a substantially uniform kinetic energy.

Accordingly, the ion microscope can be used e.g. an electrode (also referred to as a secondary ion accelerating electrode) and for applying a

Voltage (also referred to as secondary ion acceleration voltage) between the object region and the secondary ion acceleration electrode to be formed such that the from the

Examined object liberated secondary ions towards the

Secondary ion accelerating electrode are accelerated towards. The

Secondary ion acceleration voltage is a DC voltage (of e.g.

several 100 volts, e.g. +/- 500 volts) whose negative or positive pole is e.g. abuts the secondary ion accelerating electrode. Accordingly, by means of the secondary ion accelerating electrode, all secondary ions can be applied to one of the

Secondary ion acceleration voltage corresponding kinetic energy are brought, so now in a known manner by measuring the time of flight of the secondary ions whose mass can be determined. The secondary ion accelerating electrode may be e.g. between the object area and the

Interaction particle detector be arranged so that the secondary ions be accelerated by the secondary ion acceleration voltage from the object area toward the interaction particle detector.

According to a further embodiment, the ion microscope is designed in such a way that photon pulses directed at it on the object area can be generated, the photon pulses being e.g. can be focused on a position in the object area. For this purpose, the ion microscope may e.g. a photon pulse generator configured to generate photon pulses directed to a position in the object area. This photon pulse generator may e.g. be identical to the photon pulse generator, by means of which the photon pulses directed into the ionization chamber are generated, or may be a separate further photon pulse generator.

By means of the photon pulses directed at the object area, e.g. electrically neutral interaction particles which are generated by the impact of the primary ion beam on the examination object, are ionized, therefore, the photon pulses directed to the object area are also referred to as Nachionisations- photon pulses. For a better distinction also be directed into the ionization chamber photon pulses, which are used to ionize the in

Ionisationskammer recorded gases serve, also referred to as primary ionization photon pulses. The post ionization photon pulses may be e.g.

Be laser pulses. By post-ionization, e.g. the yield of for the

Secondary ion mass spectrometry available sputtered

Particles are increased and a secondary neutral particle mass spectrometry are enabled. The ion microscope may e.g. be formed such that in the presence of an examination object in the object area the

Nachionisations photon pulses impinge on the examination subject or run past the examination subject. The ion microscope may in particular be designed such that the post-ionization photon pulses are each directed to the position on which the ion beam impinges in the object region or on the examination object. According to one embodiment, the ion microscope for generating photon pulses directed onto the object area is designed such that in each case a post-ionization photon pulse and an ion pulse overlap in time in the photon pulse

Impact incident object or in each case a Nachionisations- photon pulse at a predetermined time interval after each ion pulse in the object area hits.

Since by means of the post-ionization photon pulses a time-limited and time-matched to the ion pulses energy input for Nachionisation is possible Nachionisations photon pulses enable effective ionization of neutral interaction particles with low energy input, whereby a high ionization yield is possible with little damage to the object to be examined. As a result of the ion pulse, which is very short in time, it is possible to ionize primary particles scattered with a post-ionization photon pulse and / or sputtered secondary particles during or shortly after a primary ion pulse hits the surface of the examination subject. The post ionization photon pulse may e.g. directly on the point of impact of the primary ion beam on the

Object of examination or shortly above this point of impact. The ionization of electrically neutral sputtered particles allows the

Secondary particle mass spectrometry on nanometer scale, which is not possible with this lateral resolution. Compared to secondary ion mass spectrometry, secondary neutral particle mass spectrometry can provide quantitatively more accurate values for the composition of the object under investigation.

The ion microscope may be formed by means of the secondary ion accelerating electrode for accelerating electroless secondary particles dissolved out of the examination subject, thereby enabling secondary ion mass spectrometry and secondary neutral particle mass spectrometry. To increase the quality of analysis can be provided, the electrically charged secondary particles of the electrically neutral

Separate secondary particles and only use the electrically charged secondary particles for analysis. For this purpose, the ion microscope may comprise a filter device which is designed for the spatial separation of interaction particles with different electrical charges by means of an electric and / or magnetic field. By way of example, the filter device may be designed so that sputtered secondary ions of the examination object from sputtered atoms of the examination object can be separated from it (at a secondary ion acceleration voltage applied between the object area and the secondary ion acceleration electrode). The spatial separation of the (electrically charged)

Secondary ions from the (electrically neutral) secondary atoms can e.g. take place by means of an electric and / or a magnetic field, wherein the

Filter device for generating such a field may be formed and thus may be formed as an electromagnetic filter device. The

Filter device can be designed in particular for the spatial separation of the secondary ions of the secondary atoms such that exclusively the

Secondary ions impinge on the interaction detector. The filter device may e.g. to be a reflectron.

In order to select charged secondary particles and reduce the background, the ions can thus be separated from neutral particles by an electric or magnetic field. In order to influence the ion microscope as little as possible, however, an electrostatic deflection is more suitable, wherein a reflectron in addition to the selection can compensate for energy differences of the charged particles, whereby a higher mass resolution is possible. Thus, a pulsed ion beam can be generated by means of the ion microscope and a time-resolved measurement of the properties of

Interaction particles, which upon impact of the ion beam on the

Object to be generated, done. From these properties, then, e.g. Statements about the chemical composition of the

Be obtained from the examination object. So can on the basis of

Interaction particle flight times are closed, for example, on the energy and / or mass of the interaction particles. By analyzing the energy and / or the mass of the interaction particles can be, for example, the chemical and analyze the elementary composition of the examination subject. On the basis of the high spatial resolution enabled, for example, an analysis in the nanometer range is possible. Such analysis is of great importance in many areas, for example in materials science, biophysics, microbiology, geology and chemistry.

By the pulses of the primary ion beam, in particular the time or the time window is defined, in which primary ions impinge on the examination object. By being able to generate the ion pulses with short pulse durations, it is possible to measure the interaction particle flight times with a high time resolution, so that a high-resolution time-of-flight spectrometry is made possible.

The invention will now be described by way of example with reference to the attached figure, in which:

1 shows an ion microscopy device according to one embodiment.

FIG. 1 schematically shows an ion microscopy device or a

Ion microscope 1 according to one embodiment. The ion microscope 1 has an ion source 3 for generating a primary ion beam 5. The ion source 3 has an ionization chamber 7 and a gas supply device 9 for supplying a gas 11 into the ionization chamber 7 (in FIG. 1, the supplied gas is illustrated by the arrow 11). As an example, helium is provided as the gas in the present case, but other gas such as e.g. Neon, another noble gas, hydrogen, nitrogen or a gas mixture may be provided as a gas 11. The ion source 3 also has a tip-shaped electrode 13 and a

Counter electrode 15, which are arranged in the ionization chamber 7. The

Ionization chamber 7 has an outlet opening 17 through which the ion beam 5 can emerge from the ionization chamber 7. The counter electrode 15 is arranged as an example at the outlet opening 17. The ion beam 5 can run in a vacuum chamber, wherein FIG. 1 omits a representation of a housing or a vacuum chamber of the ion microscope 1 for the sake of clarity. The ion microscope 1 is designed such that the ion beam 5 is arranged on an object region 19 and an object region 19 arranged in it

Object to be examined 21 can be directed so that the primary ion beam 5 hits the object area 1 9 and the examination object 21 arranged there. For this purpose, the ion microscope has e.g. a particle or

Ion optics with two ion-optical elements 23, 25 and an aperture 27 on. The particle optics and the ion optical elements 23, 25 are shown only schematically for illustrative purposes, the ion optical elements 23, 25 may e.g. be electrostatic elements. By means of the particle optics, the primary ion beam 5 can be guided over the object region 19 or the examination object 21 and focused thereon. The ion microscope 1 further has a masking device 29 arranged in the beam path of the primary ion beam 5, with a deflection unit 31 and a diaphragm 33.

At the impact position 35 of the primary ion beam 5 on the examination object 21, interaction particles in the form of backscattered particles of the object 21 are produced due to the interaction of the ion beam 5 with the object 21

Primary ion beam 5 (also referred to as backscattered primary particles) and in the form of sputtered particles of the examination object 21 (also sputtered

Secondary particles designated), which move from the examination object 21 in the direction of the primary ion beam 5 facing side of the object area 19 and the examination object 21 out. In FIG. 1, the

Movement direction of the backscattered primary particles and the sputtered

Secondary particles schematically illustrated by the arrows 37. The

Backscattered primary particles may e.g. Ions and / or neutralized ions (i.e., atoms) of the ionic steel 5. The sputtered secondary particles may e.g. Be ions and / or atoms of the material of the examination object 21. In addition to the interaction particles, 35 secondary electrons are generated at the impact position.

The ion microscope 1 has a detector 39, which is used to detect the

Interaction particles is formed. The interaction particle detector 39 is on the side facing the primary ion beam 5 and the ion source 3 side of the Object area 19 arranged. The detector 39 is thus arranged relative to the primary ion beam 5 and the object 21 at a backscatter angle or in a backscatter geometry. The interaction particle detector 39 is designed for detecting the interaction particles, in particular for detecting atoms and ions. As an example, the interaction particle detector 39 is a single-particle detector, for example with a micro-channel plate (English "micro-channel plate") as a sensitive element.

The ion microscope 1 also has a further detector 41 which is connected to the

Detecting secondary electrons is formed.

The ion microscope 1 has a voltage source 43, which is designed to apply an electrical voltage between the electrode 13 and the counter electrode 15. From the voltage source 43, a DC voltage in the form of a high voltage is provided, whose positive pole is connected to the tip-shaped electrode 13 and whose negative pole is connected to the counter electrode 15. The voltage source 43 is a controllable or adjustable

Voltage source, wherein the amount of voltage provided by the voltage source 43 is variably adjustable. Upon application of an electrical voltage between the electrode 13 and the counter electrode 15, an electric field is formed between them, which passes through the ionization chamber 7 and thus also the gas 11 received therein.

The ion microscope 1 is so for driving the voltage source 43

configured such that the amount of the voltage applied by means of the voltage source 43 between the electrode 13 and the counter electrode is adjustable. For this purpose, the ion microscope 1 has as an example a control device or control unit 45 which is connected to the voltage source 43 and to

Driving the voltage source 43 is formed such that the amount of voltage provided by the voltage source 43 is variably set to a predetermined value by the control unit 45. The ion microscope 1 also has a photon pulse generator 47, which is designed and arranged such that photon pulses 49 can be generated by it, which are directed to a position in the ionization chamber 7. As an example, the photon pulse generator 47 is a pulsed laser so that the photon pulses 49 are laser pulses. The ionization chamber 7 has an optical input

Viewing window 51, through which the photon pulses 49 in the

Ionization chamber 7 are irradiated. The photon pulses 49 are focused on the tip of the tip-shaped electrode 13 by means of a focusing lens 53 in such a way that the focus region of the photon pulses 49 overlaps the tip of the electrode 13.

The control unit 45 is connected to the masking device 29 (e.g., each by means of a uni- or bidirectional data / communication link)

Interaction particle detector 39, the secondary electron detector 41, the voltage source 43 and the photon pulse generator 47 is connected (in Figure 1, the connection between the control unit 45 and the secondary electron detector 41 is not shown). The control unit 45 is for driving the

Blanking device 29, the voltage source 43 and the photon pulse generator 47 is formed. The control unit 45 may also be e.g. to read out the

Interaction particle detector 39 and the secondary electron detector 41 may be formed.

The ion microscope 1 is designed such that it can be operated in a continuous-beam mode and in a pulse-beam mode.

In the continuous jet mode, the ion source 3 is operated like a conventional gas field ion source. In the continuous-beam mode, the photon pulse generator 47 and the voltage source 43 are controlled by the control unit 45 such that no photon pulses are generated by the photon pulse generator 47, and that from the voltage source 43, an electrical voltage between the electrode 13 and the counter electrode 15 is created. By doing

Continuous beam mode, the voltage source 43 is driven such that the amount of voltage applied between the electrode 13 and the counter electrode 15 for ionizing (at least part of) the gas 11 received in the ionizing chamber 7 is sufficient, even without photon pulses by means of the photon pulse generator 47 in the ionization chamber 7 and the therein

recorded gas 11 are registered, wherein the thus generated gas ions (forming not shown) to accelerate from the electrode 13 in the direction of the counter electrode 15 to form a continuous or uninterrupted primary ion beam. In the continuous-beam mode, the voltage source 43 is thus controlled in such a way that the electric field produced by the electrical voltage between the electrode 13 and the counterelectrode 15 alone is sufficient for ionizing the gas 11 to form a continuous ion beam.

In the pulse-beam mode, the voltage source 43 and the photon pulse generator 47 are controlled by the control unit 45 such that of the

Voltage source 43 to form an electric field, a voltage (with a non-zero amount) between the electrode 13 and the

Counter electrode 15 is applied, and that at the same time photon pulses 49 are generated by the photon pulse generator 47 and are introduced into the gas 11 penetrated by the electric field. In contrast to the continuous-beam mode, however, in the pulse-beam mode, the voltage source 43 is controlled by the control unit 45 in such a way that the voltage caused by the voltage between the

Electrode 13 and the counter electrode 15 caused electric field alone is not sufficient to ionize the gas 11 to form a continuous ion beam. In the pulse-beam mode, the amount of voltage applied between the electrode 13 and the counter electrode 15 is smaller than in the continuous-beam mode. In the pulse-beam mode, the voltage can be adjusted such that no ionization of the gas 11 takes place by the electric field caused by the voltage alone. In the pulse beam mode, an ionization of the gas 11 takes place by introducing photon pulses 49 into the excited and excited by the electric field gas 11 to form ion pulses 5. In the pulse-beam mode thus takes place an ionization of the gas 11 by the combination of the excitation of the gas 11 by the voltage applied between the electrode 13 and the counter electrode 15 electrical voltage with the simultaneous excitation of the gas 11 by the entry of photon pulses 49. In this case, an ion pulse of each photon pulse 49 is the fifth generated so that in the pulse beam mode of the ion source 3, a pulsed ion beam 5 is generated, wherein the pulse duration of the ion pulses 5 substantially corresponds to the pulse duration of the photon pulses 49 (in Figure 1, each photon pulse through a dash of the pulsed photon beam 49 and each ion pulse through illustrates a dash of the pulsed ion beam 5, wherein the

Illustrating the stroke length corresponds in each case to the pulse duration).

As an example, by means of the photon pulse generator 47 temporally short

Photon pulses are generated with a duration of less than 1 ns. The result is a temporally very short ion pulse with a comparable pulse duration, which can be laterally focused by the ion optics to a focal point of a few nanometers and can be scanned over the surface of the examination object 21. The time of flight of the primary ions from the ion source 7 to the surface of the

Object to be examined 21 is due to the high energy sharpness of the

Ion microscope and the low beam expansion substantially constant.

Both in continuous-wave mode and in pulse-beam mode, the

Ion microscope 1 in a known manner for imaging by means of

Secondary electron detector 41 may be formed, e.g. by measuring the yield of secondary electrons to obtain an image of the surface of the

To receive the examination object. Moreover, the ion microscope 1 for analyzing the examination subject 1 is formed by the interaction particle detector 39 in the pulse beam mode. In the pulse beam mode, an ion pulse 5 can be generated by a photon pulse 49 introduced into the ionization chamber 7, and interaction particles in the form of backscattered primary particles and / or sputtered secondary particles are generated by the impingement of this ion pulse 5 on the examination object 21. The ion microscope 1 may be e.g. be designed such that in

Pulsed beam mode of each introduced into the ionization chamber 7

Photon pulse 49, an ion pulse 5 is generated. Some of the interaction particles strike and are detected by the interaction particle detector 39. The control unit 45 is connected to the photon pulse generator 47 and the interaction particle detector 39. The ion microscope 1 is formed by means of the control unit 45 for detecting the period of time (also referred to as measurement period) passing between the detector 39 between a photon pulse 49 and the detection of the interaction particles generated by the ion pulse 5 generated by this photon pulse , The ion microscope 1 is thus designed to detect the period of time lying between a photon pulse 49 and the detection of the interaction particles generated thereby by the interaction particle detector 39 as a measurement time span.

As an example, the ion microscope is formed by means of the control unit 45 for detecting the time span between the generation of a photon pulse 49 and the impact of the interaction particles generated thereby on the detector 39. The control unit 45 is connected both to the photon pulse generator 47 and to the interaction particle detector 39 and is designed such that both the time (of generation) of a photon pulse by the photon pulse generator 47 and the times of the photon pulse generator 47 Impact of the interaction particles generated thereby can be detected on the detector 39, so that by means of the control unit 45 and the intermediate measuring period can be detected.

The ion microscope 1 is also designed in such a way that it can determine the time of flight, which determines the interaction particles for covering the distance between the object region, based on the detected measuring period (between a photon pulse and the detection of the interaction particles generated thereby by the detector 39) 19 (or the examination object 21) and the interaction particle detector 39 need. As an example, that is

Ion microscope 1 for determining the interaction particle flight time formed by the known time of flight of the primary ions from the ion source 3 to the object to be examined 21 and possibly on the

Evaluation is deducted declining time portion. By detecting the interaction particle flight times of the ion microscope 1, the By means of the ion microscope 1, a time-of-flight spectrometry, for example a backscatter time-of-flight spectrometry, can be carried out.

By means of the masking device 29, the primary ion beam 5 and thus e.g. a portion of each ion pulse are faded out of the object area 19, whereby e.g. the time duration of the ion pulses 5 impinging on the object region 19 can be shortened and / or the ion pulses can be filtered according to different elements and / or charge states. The masking device 29 has the deflection unit 31 and the diaphragm 33. The deflection unit 31 is for deflecting the primary ion beam 5 by means of a

formed electric field. As an example, the deflection unit 31 is a

Capacitor in which an electrical field can be generated by applying an electrical voltage, by means of which the primary ion beam 5 can be deflected. The diaphragm 33 has an aperture and a shielding portion. The diaphragm 33 is arranged such that the primary ion beam 5 through the

Aperture passes and hits the object area 19 when no electrical voltage is applied to the capacitor 31. The masking device 29 or its capacitor 31 can by means of

Control unit 45 are controlled such that the Ausblendvorrichtung 29 is selectively placed in an on state or in a blanking state. In the on-state, no voltage is applied to the capacitor 31, so that the primary ion beam 5 is not deflected by the capacitor 31 and strikes the object region 19 or the examination object 21. In the blanking state, a voltage is applied to the capacitor 31 in such a way that the primary ion beam 5 is directed onto the shielding section of the diaphragm and therefore away from the diaphragm

Shielding blocked and hidden from the object area 19. The ion microscope 1 is designed such that the photon pulse generator 47 is synchronized by means of the control unit 45 to the masking device 29

can be controlled. The ion microscope 1 is by means of the control unit 45 in particular for the synchronized driving of the photon pulse generator 47 and the Ausblendvornchtung 29 formed such that the generated by means of the photon pulses 49 ion pulses 5 by means of the Ausblendvorrichtung 29 partially

be hidden, so that a part of each ion pulse 5 by means of

Blanking device 29 is hidden.

The masking device 29 can be controlled in particular by means of the control unit 45 such that a part of each ion pulse 5 is masked out of the object region 19 by the masking unit 29 and the remaining part of the ion pulse is not masked out, but is transmitted to the object region 19. Thus, the ion pulses have a longer pulse duration before reaching the blanking device 29 than after passing through the blanking device 29, so that the pulse duration of the ion pulses arriving in the object region can be shortened by means of the blanking device 29 (in FIG. 1, where each ion pulse is represented by a dash of the pulsed ion beam 5 illustrated by the

Stroke length after passing through the blanking device 29 is smaller than before

Passing through the blanking device 29).

The ion microscope 1 further optionally has a second photon pulse generator 55 in the form of a pulsed laser 55, which is arranged and configured in such a way that photon pulses 57 directed at the object region 19 can be generated in the form of laser pulses 57, by means of which they are electrically neutral

Interaction particles can be ionized. The one of the on the

Object area 19 directed photon pulse generator 55 generated photon pulses 57 are also referred to as Nachionisations- photon pulses 57. The

Post ionization photon pulses 57 are directed to the respective impact position 35 of the primary ion steel 5.

The control unit 45 is also connected to the second photon pulse generator 55

connected and designed to drive the same. The control unit 45 may be designed, for example, for the synchronized activation of the first photon pulse generator 47 and of the second photon pulse generator 55 such that in each case a post-ionization photon pulse 57 and an ion pulse 5 impinge on the object region 19 in overlapping temporal or one after-ionization photon pulse 57 in a predetermined time interval after each ion pulse 5 impinges in the object region 19.

The ion microscope 1 optionally has a secondary ion accelerating electrode 59 (e.g., in the form of a metal wire mesh) disposed between the object region 19 and the interaction particle detector 39. The ion microscope 1 can be used to apply an electrical voltage (also known as

Secondary ion accelerating voltage) between the object region 19 and the secondary ion accelerating electrode 59 may be formed such that the object region 19 is at a higher electric potential than the electrode 59 and thus the electrically positively charged secondary ions from the object region 19 to the electrode 59 and thus also towards the

Interaction particle detector 39 are accelerated towards. By means of the secondary ion acceleration electrode 59, the interaction particles present in the form of secondary ions can be brought to a speed corresponding to the secondary ion acceleration voltage, whereby a secondary ion time-of-flight mass spectrometry can be carried out by means of the ion microscope 1. In combination with the after-ionization photon pulses 57, a secondary neutral particle time-of-flight mass spectrometry can also be carried out by means of the ion microscope 1.

Scattered primary particles and sputtered secondary particles can after

Covering the flight path from the interaction particle detector 39 (which may be an individual particle detector, for example). By the time between the primary ion generating photon pulse (e.g., triggering thereof) and registration of the particles by the detector 39, one can infer the mass of the particles. However, in order to enable a clear determination, either the mass or the energy of the particle must be known. In backscatter spectrometry, the mass is known while for secondary ion spectrometry the sputtered secondary ions using the

Secondary ion acceleration voltage to a largely constant or the same energy to be accelerated. The ion microscope 1 can also have a filter device (not shown) which is used for the spatial separation of the secondary ions accelerated by means of the secondary ion acceleration electrode 59

Secondary atoms is formed. Since the secondary ions are electrically charged, whereas the secondary atoms are electrically neutral, such a spatial separation of the secondary ions and the secondary atoms can take place by means of an electric and / or magnetic field, wherein the filter device can be configured such that it is in an active state such field is generated and no field is generated in a passive state.

The filter device may e.g. be formed such that when the active state of the filter device only the (electrically charged) secondary ions are passed to the interaction particle detector 39, but not the (electrically neutral) secondary atoms. For such a configuration, the

Interaction particle detector 39 e.g. (differently than shown in Figure 1) arranged and / or shielded by a shielding device that the interaction particle detector 39 is not accessible from the object area 19 via a rectilinear route, but exclusively over a curved route, the filter device for guiding the charged secondary ions along the curved route is formed. The

Filter device may be, for example, a reflectron.

List of reference numbers used

I ion microscope / ion microscopy device

3 ion source

5 ion beam / ion pulse

7 ionization chamber

9 gas supply device

I i gas

13 tip-shaped electrode

15 counterelectrode

17 outlet opening

19 object area

21 examination object

23, 25 ion-optical element

27 aperture diaphragm

29 Blanking device

31 Deflection unit of the blanking device

33 Aperture stop aperture

35 Impact position of the primary ion beam on the object under examination 37 Movement of backscattered primary particles and sputtered particles

offspring

39 Interaction particle detector

41 secondary electron detector

43 voltage source

45 control unit / controller

47 first photon pulse generator / pulsed laser

49 photon pulse / laser pulse

51 optical input / viewing window

53 focusing lens

55 second photon pulse generator / pulsed laser

57 post ionization photon pulses / post ionization laser pulses

59 secondary ion accelerating electrode

Claims

claims

1 . An ion microscopy device comprising:

an ion source (3) for generating an ion beam (5), the ion source comprising an ionization chamber (7), a gas supply device (9) for supplying a gas (11) into the ionization chamber, a tip - shaped electrode (13) disposed in the ionization chamber, and Counter electrode (15), and wherein the ion microscopy apparatus for directing the ion beam (5) on a

Object region (19) is formed so that an object (21) arranged in the object region can be irradiated with the ion beam, whereby backscattered particles of the ion beam and / or sputtered particles of the object can be generated as interaction particles (37),

a detector (39) for detecting the interaction particles,

a voltage source (43) for applying an electric voltage between the electrode (13) and the counter electrode (15), and

a photon pulse generator (47) for generating photon pulses (49) directed to a position in the ionization chamber (7),

characterized in that

the ion microscopy device in a mode for driving the

Voltage source (43) and the photon pulse generator (47) is designed such that by means of the voltage source (43) generating an ionization chamber (7) and a gas absorbed therein an electric field between the electric field electrode (13) and the Counter electrode (15) can be applied, and that by means of the photon pulse generator (47) photon pulses (49) can be generated and introduced into the penetrated by the electric field ionization chamber (7), so that in the ionization chamber (7) recorded gas (11) can be excited by the electric field and by means of each photon pulse (49) at least a portion of the excited gas is ionizable, so by means of a

Photon pulse an ion pulse can be generated and thus from the ion source a pulsed ion beam (5) can be generated,

wherein the ion microscopy device is for detecting the time span between a photon pulse (49) and the detection of the interaction particles (37) generated by the ion pulse (5) generated by means of this photon pulse, is formed by the detector (39).

2. An ion microscopy device according to claim 1, wherein the photon pulse generator (47) is designed to generate laser pulses as photon pulses (49).

3. An ion microscopy device according to claim 1 or 2, wherein the

is formed in the mode for driving the voltage source (43) such that the electrical field caused by the electrical voltage between the electrode (13) and the counter electrode (15) is not sufficient for ionizing the gas (11) to form a continuous ion beam ,

4. An ion microscopy device according to any one of claims 1 to 3, wherein the ion microscopy device for determining the time of flight, which the

Interaction particle (37) for covering the distance between the

Object area (19) and the detector (39) need to be formed based on the detected period of time.

5. An ion microscopy device according to one of claims 1 to 4, further comprising a masking device (29) which is arranged in the beam path of the ion beam (5) and designed to hide the ion beam from the object region (19), wherein the ion microscopy device for synchronized

Controlling the photon pulse generator (47) and the Ausblendvorrichtung (29) is formed.

6. An ion microscopy device according to claim 5, wherein the

Lonenmikroskopievorrichtung for synchronized driving of the photon pulse generator (47) and the Ausblendvorrichtung (29) is designed such that the generated by the photon pulses (49) ion pulses (5) by means of

Blanking device (29) are partially ausblendbar.

7. An ion microscopy device according to any one of claims 1 to 6, wherein the Ion microscopy device for generating on the object area (19) directed photon pulses (57) is formed.

8. An ion microscopy device according to claim 7, wherein the

Ion microscopy apparatus for generating on the object region (19) directed photon pulses (57) is formed such that in each case one

Photon pulse (57) and an ion pulse (5) overlap temporally overlapping in the object area (19) or each a photon pulse (57) at a predetermined time interval after each ion pulse (5) in the object area (19) impinges.

9. An ion microscopy device according to any one of claims 1 to 8, further comprising an accelerating electrode (59), wherein the

An ion microscopy device for applying an acceleration voltage between the object region (19) and the acceleration electrode (59) is formed such that the object region (19) is at a higher electric potential than the acceleration electrode (59).

10. An ion microscopy device according to claim 1, further comprising a filter device for spatially separating

Interaction particles with different electrical charges by means of an electric and / or magnetic field is formed.