JP2007147347A - Probe, cantilever beam, scanning probe microscope, and measuring method of scanning tunnel microscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe capable of suppressing disturbance of a band structure even when a measuring sample is brought close to a sharpened part so as to be stabilized in a contact mode of AFM, a cantilever beam, a scanning probe microscope, and a measuring method of a scanning tunnel microscope. <P>SOLUTION: A gold thin film 104 formed to cover the sharpened part 103 is furthermore covered with a tunnel insulating film 105 comprising a silicon oxide or the like. Even when the distance between the sharpened part 103 and the measuring sample 201 becomes extremely short in the contact mode of AFM, measurement can be performed without disturbing the band structure of the measuring sample 201, since an insulating object as much as a portion of the tunnel insulating film 105 is interposed between the gold thin film 104 covering the sharpened part 103 and the measuring sample 201. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a probe, a cantilever, a scanning probe microscope, and a measuring method of a scanning tunnel microscope.

An atomic force microscope (hereinafter also referred to as AFM) is known as an apparatus for measuring the surface shape of a sample to be measured. AFM is an interatomic force that is received by providing a sharp point at the tip of the probe so that the interatomic force received from the arrangement of atoms on the surface of the sample to be measured can be detected and bringing the sharp part close to the sample to be measured. This is a device that scans the surface of the sample to be measured while controlling the distance between the sharp portion and the sample to be measured using force as a control signal.

In particular, a method in which the sharp portion of the probe is measured close to the sample to be measured is called contact mode measurement, and the sharp portion and the sample to be measured are close enough to allow a tunnel current to flow.

A technique for knowing the surface shape of a sample to be measured based on a control signal obtained by using an AFM is known. For example, as disclosed in Patent Document 1, approximate positioning is performed by AFM, and the distance between the sharp portion and the sample to be measured is controlled so that the tunnel current value flowing between the sharp portion and the sample to be measured is constant. A technique for measuring the surface shape of a sample is known.

Further, for example, Patent Document 2 discloses a technique in which a potential is applied between a sharp portion and a sample to be measured, and the potential is swept to know a relationship between a tunnel current flowing between the sharp portion and the sample to be measured and the potential. 3
4 is known.

The electron distribution of the sample to be measured can be known from the relationship between the tunnel current and the potential obtained by the measurement. For example, from the potential at which the tunnel current begins to flow, between the sharp point and a specific position of the sample to be measured. You can know the work function difference. Here, when a metal having a known work function is used for the sharp portion, it is possible to know the work function at a specific position of the sample to be measured.

JP-A-62-130302 JP-A-3-210465 JP-A-3-277903 JP-A-4-361110

However, in the technique of Patent Document 1 described above, when an insulating particle adheres to the sample to be measured, the tunnel current does not flow through the insulating particle, so the sharp portion maintains the tunnel current. There is a risk of approaching the particle and colliding in some cases.

In addition, if the sharp part approaches the sample to be measured to such an extent that it can be controlled in the AFM contact mode, the tunnel current flowing from the sharp part to the sample to be measured becomes excessive, and the band structure of the sample to be measured is disturbed. There is a problem that it is difficult to know the band structure and work function of the sample.

In the techniques of Patent Documents 2, 3, and 4 described above, only a description that a tunnel current flows between the sample to be measured and the sharp portion is illustrated, and the structure of the probe is not disclosed at all. Therefore, even if the techniques of Patent Documents 2, 3, and 4 are used, it is difficult to perform measurement while suppressing disturbance of the band structure of the sample to be measured.

Therefore, in the present invention, a probe, a cantilever, and the like that can solve such a conventional problem and suppress the disturbance of the band structure even when the sample to be measured and the sharp part are close to each other so as to be stable in the contact mode of AFM. It aims at providing the measuring method of a scanning probe microscope and a scanning tunnel microscope.

<Configuration 1> In order to solve the above-described problem, the probe of the present invention is a distance control that controls the distance between the probe and the sample to be measured using an atomic force acting between the probe and the sample to be measured as a control signal. Part
A probe used in a measuring apparatus for measuring the relationship between a tunnel current generated by applying a voltage so as to sweep a voltage between the probe and the sample to be measured, and the applied voltage. The needle has a pointed portion made up of a conductive portion and an insulating portion disposed so as to wrap the conductive portion at an end close to the sample to be measured, and the conductive portion is covered with a conductor or a conductor. The tunneling current flowing between the conductive part and the sample to be measured is formed to be detected, and the insulating part is applied to the conductive part from the measuring device with respect to the voltage applied to the conductive part. It has a thickness at which current intensity that can be measured by a measuring device can be obtained, and has a thickness that can suppress the influence on the band structure of the sample to be measured. In addition, the atomic force is used as a control signal. A secondary issue occurs when feedback control is performed. The probe is formed using an insulating film that is resistant to wear due to stress, and the probe is formed with a conductive mechanism for guiding the voltage applied by the measuring device to the conductive portion of the sharp portion. It is characterized by that.

According to this configuration, the measurement device measures the strength of the tunnel current with respect to the voltage applied to the conductive portion from the measurement device between the conductive portion of the sharp portion and the sample to be measured. Since the insulating portion has a thickness that can be obtained and has a thickness that can suppress the influence on the band structure of the sample to be measured, the measurement accuracy is maintained and the band structure of the sample to be measured is given. A probe that can extract the band structure of the sample to be measured while suppressing the influence can be configured.

In addition, since the insulation part uses an insulating film that is resistant to wear due to secondary stress, the amount of probe wear due to measurement can be suppressed, and measurements with high reproducibility can be performed. A possible probe can be obtained.

<Configuration 2> In the probe of the present invention described above, the insulating film is made of silicon oxide, silicon nitride, hafnium oxide, or a thiol-based self-assembled film.

According to this configuration, it is possible to form the insulating film that has excellent wear resistance and can be easily formed, and a probe that can perform highly reproducible measurement can be obtained.

<Configuration 3> In the probe of the present invention described above, the conductor is made of gold, ruthenium, or platinum which is a noble metal whose surface state is stable in the atmosphere.

According to this configuration, since the surface state of gold, ruthenium or platinum is stable even in the atmosphere, it is difficult to form a parasitic product on the surface of the conductor, and therefore a probe capable of calculating the value of the work function more accurately is provided. Obtainable.

<Configuration 4> The above-described cantilever according to the present invention is a cantilever having elasticity so as to bend by the atomic force, and the fixed end of the cantilever supports the cantilever. The free end portion of the cantilever is fixed to the probe having the sharp portion, and the atomic force acting between the sharp portion and the sample to be measured is converted to the atomic force. A bend detection unit for detecting the amount of bend caused by the cantilever, and the cantilever is covered with a conductor or a conductor, and the support and the probe are electrically connected to each other. It is connected.

By using this configuration, the interatomic force acting between the sharp portion and the sample to be measured can be detected as the amount of bending of the cantilever caused by the interatomic force. The distance control unit that controls the distance between the probe having the sharp portion and the sample to be measured because the atomic force that is difficult to measure can be converted into a deflection amount that can be easily measured and extracted. The atomic force can be given as a control signal.

Therefore, feedback control for controlling the deflection amount is possible, and the distance between the sharp portion and the sample to be measured can be controlled. Furthermore, the distance between the sharp part and the sample to be measured can be measured simultaneously.

In addition, the cantilever is covered with a conductor or a conductor, and the support and the probe are electrically connected, so that a voltage is transmitted from the support to the probe. Since the probe has the conductive mechanism for transmitting a voltage to the sharp portion, the voltage can be transmitted to the sharp portion by applying a voltage to the support.

<Structure 5> Further, in the above-described cantilever according to the present invention, the deflection detecting unit is provided with a light reflecting unit located on the free end side and positioned on the back surface of the probe, and a light beam is provided to the light reflecting unit. It is an optical lever that extracts the amount of deformation of the cantilever by irradiating and detecting the projection position of the light beam reflected by the light reflecting portion.

According to this configuration, the light beam is applied to the light reflecting means provided on the free end portion side of the cantilever, and the projection position of the light beam reflected by the light reflecting unit is detected. By using the optical lever, a cantilever beam that extracts the distance between the sharp portion and the sample to be measured expressed as the deformation amount of the cantilever beam without affecting the operation of the cantilever beam is obtained. be able to.

<Configuration 6> The above-described scanning probe microscope of the present invention is a scanning probe microscope using the cantilever according to Configuration 4, wherein the interatomic force acting between the sharp portion and the sample to be measured It is possible to control the distance between the sharp part and the sample to be measured at each measurement point so that the distance is maintained at least during the measurement using force as a control signal, and along the surface direction of the sample to be measured. The sharp portion and the sample to be measured are relatively movable.

According to this configuration, the sharp portion of the probe fixed to the cantilever and the distance between the sharp portion and the sample to be measured using the atomic force acting between the sample to be measured as a control signal. During measurement, the controlled or fixed state is maintained, and in the case of non-measurement, the sharp portion and the sample to be measured are relatively movable along the surface direction of the sample to be measured. It is possible to obtain a local current-voltage characteristic measuring apparatus that measures current-voltage characteristics in a region to be measured.

<Configuration 7> The measurement method using the above-described scanning probe microscope of the present invention is configured as Configuration 4
And measuring the tunnel current flowing between the sharp portion and the sample to be measured at least a part of the measurement points, using the probe fixed to the cantilever It is characterized by extracting a local band structure.

According to this measuring method, in order to investigate the local state density or band gap of the sample to be measured, the potential between the sharp portion and the sample to be measured is swung, and the tunnel current corresponding to the potential is measured. The tunnel current has a side where the potential energy has the same potential energy as the side that transmits the tunnel current, and there is an empty level corresponding to the potential energy on the receiving side. It can flow a proportional amount. Therefore, by using this measurement method, the local state density or the band gap can be examined at one point or multiple points.

<Structure 8> Further, the measurement method using the scanning probe microscope of the present invention described above simultaneously measures the surface shape of the sample to be measured using a signal for controlling the distance between the sharp portion and the sample to be measured. It is characterized by doing.

According to this measuring method, the correlation between the shape of the sample to be measured and the band structure can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1A is a perspective view for explaining the structure of a cantilever having a probe according to the present invention, and FIG. 1B is an enlarged sectional view of the cantilever according to the present invention. Hereinafter, FIG. 1 (a) and FIG. 1 (b).
The structure of the probe, the cantilever and the support will be described with reference to FIG.

As shown in FIG. 1A, a cantilever 101 having a thickness of about 1 μm, a length of about 150 μm, and a width of about 20 μm made of silicon oxide has a support 102 made of a silicon single crystal having a thickness of about 500 μm. It is joined.

The probe 100 made of silicon single crystal is disposed on the other end side of the cantilever 101 whose one end is fixed to the support 102.

A sharpened portion 103 is formed at the other end of the probe 100 whose one end is fixed to the cantilever 101. The tip angle of the sharp portion 103 is about 10 °, and has a structure excellent in observation of a fine structure.

Further, the back surface of the region of the cantilever 101 where the probe 100 is fixed functions as the light reflecting portion 106. For example, the deflection of the cantilever beam 101 due to the atomic force is extracted with little influence on the operation of the cantilever beam 101 by irradiating the light reflection unit 106 with, for example, a laser beam and detecting the fluctuation of the reflected light. Can do.

In addition, as shown in FIG. 1B, the potential applied to the support 102 is passed through the cantilever 101 and the probe 100 to the probe 100, the cantilever 101, the support 102, and the sharpened portion 103. It is covered with a thin gold film 104 so as to be transmitted to the sharp portion 103. When the gold thin film 104 is used, the film thickness is preferably about 10 nm to 100 nm. If the film thickness is 10 nm or more, the electrical parasitic resistance value can be suppressed to a value that can be ignored for the measurement of the tunnel current. A film thickness of 100 nm or less is preferable because the influence on the bending operation of the cantilever 101 can be suppressed. In addition, as a formation method of a gold thin film, a sputtering method etc. can be used, for example.

As shown in FIG. 1B, the gold thin film 104 located at the sharp point 103 is covered with a tunnel insulating film 105 made of, for example, a silicon oxide film. The tunnel insulating film 105 is provided so as to suppress the bending of the band in the sample to be measured due to the potential applied to the support 102 being directly applied to the sample to be measured. The thickness of the tunnel insulating film 105 is selected so as to suppress the bending of the band structure of the sample to be measured and not to drop the tunnel current value to a value that is difficult to measure when the tunnel current is measured. A film thickness of about 2 nm can be selected.

By performing tunnel current / voltage measurement (hereinafter referred to as STM) using the probe 100 having the sharp point 103, the electrical influence on the band structure of the sample to be measured can be suppressed,
STM that faithfully reflects the band structure of the sample to be measured can be performed.

In this embodiment, a silicon oxide film is used as the tunnel insulating film 105, but this is due to stress generated secondary to AFM measurement in a contact mode, such as silicon nitride, hafnium oxide, or a thiol-based self-assembled film. The insulating film is not particularly limited as long as it is resistant to wear, and can be used instead of the silicon oxide film used for the tunnel insulating film 105.

In the present embodiment, the gold thin film 104 is used so that the potential can be transmitted from the support 102 to the sharp portion 103. However, in this embodiment, the surface state is stable in the atmosphere like gold instead of the gold thin film. A thin film such as ruthenium or platinum which is a noble metal may be used.

Further, the material forming the probe 100 is not limited to single crystal silicon, and for example, a material such as silicon nitride may be used.

(Embodiment 2)
FIG. 2 is a configuration diagram of the AFM / STM using the probe, the cantilever, and the support described in the first embodiment. Hereinafter, the configuration of the AFM / STM will be described with reference to FIG. The Z axis is taken in the normal direction with respect to the measurement surface of the sample to be measured.

The sample 201 to be measured is arranged on a stage 202 having conductivity that can move in the X, Y, and Z directions. The stage 202 is disposed on a piezo drive device 203 that can be independently displaced in the X, Y, and Z directions.

The Z-axis servo circuit 208 operates using a signal from the laser light source 206 and an optical system 207 having a detection element such as a quadrant photodiode as a control signal, so that the deflection amount of the cantilever 101 is kept constant. Control the height. This control method is known as the configuration and operation of the AFM measuring apparatus.

Based on a signal from the CPU 210, a voltage applied to the support 102 from the voltage source 204, for example, modulated in a triangular wave shape, passes through the cantilever 101 and the probe 100 and the sharp portion 103.
And is applied to the sample 201 to be measured. The current value when the voltage is applied is ammeter 2.
05 is detected and transmitted to the CPU 210 for storage and processing. The CPU 210 performs signal processing based on the voltage value and the current value, and causes the CRT 211 to display the signal processing result and the like.

The X, Y scanning circuit 209 is used to measure the above-mentioned measurement in the defined plane.
Based on the signal from U210, the measurement target 201 on the stage 202 is driven in the X and Y directions by driving the piezo driving device 203 in the X and Y directions.

By using the above-described configuration, it is possible to obtain the relationship between the applied voltage, the tunnel current, and the X and Y coordinates as an in-plane distribution.

(Embodiment 3)
A tunnel current measurement method at each measurement point will be described below using the configuration described in the second embodiment. Since the same measurement is performed many times within a defined plane, a measurement method for one point will be described. FIG. 4 is a flowchart for executing this measurement method. The Z axis is taken in the normal direction with respect to the measurement surface of the sample to be measured.

First, as step 1, signals from the laser light source 206 and the optical system 207 are sent to the Z-axis servo circuit 20.
The height of the stage 202 is controlled so that the amount of bending of the cantilever 101 is kept constant as a control signal. By this treatment, the distance between the sharp portion 103 and the sample 201 to be measured is kept constant within the defined plane.

Next, as step 2, the servo of the Z-axis servo circuit 208 is stopped and the height of the stage 202 is held at a constant value in order to avoid displacement due to electromagnetic force due to application of a voltage described later. By this treatment, the sharp portion 103 and the sample 201 to be measured are caused by the electromagnetic force due to the application of a voltage described later.
The change of the distance between can be suppressed. This step is not essential, and may be omitted depending on the measurement conditions and the like, and the subsequent steps can be performed with the servo applied.

Next, as step 3, a voltage modulated in a triangular wave shape, for example, is applied to the sharp portion 103, and a tunnel current flowing between the sharp portion 103 and the sample 201 to be measured is measured.

Here, the example which calculates | requires the minimum unoccupied molecular orbital of an organic light-emitting body is demonstrated as an example of the physical quantity obtained by measuring and processing a tunnel current.

FIGS. 3A and 3B show the case where a voltage is applied between the sharp portion 103 and the sample 201 to be measured using the sample 201 to be measured in which the organic light-emitting body 302 is coated on the conductive substrate 301. It is a band diagram. As shown in FIG. 3A, the organic light emitter 302 formed on the conductive substrate 301.
The band structure of the highest occupied molecular orbital (described as HOMO in FIG. 3) and the smallest unoccupied molecular orbital (
3 is described as LUMO).

When a voltage is applied to the sharp portion 103 so as to increase the potential energy of electrons, a tunnel current e flows from the gold thin film 104 covering the sharp portion 103 into the organic light emitter 302 through the tunnel insulating film 105 due to a tunnel phenomenon. It becomes like this. Since the tunnel current flows into a state having the same energy level, the voltage at which the tunnel current starts to flow can be treated as the potential energy of the minimum empty molecular orbital of the organic light emitter 302.

In the gold thin film 104, a level corresponding to energy lower than the Fermi level (shown as FL in the drawing) is filled with electrons, and no electron exists in a level corresponding to energy higher than the Fermi level. It has a typical metal electron distribution.

In FIG. 3A, in order to reduce the influence of the measurement on the sample 201 to be measured, the sharp portion 1 is used.
A band diagram in the case where a tunnel insulating film 105 is interposed so as to cover the gold thin film 104 of FIG. Since the tunnel insulating film 105 is formed so as to suppress the disorder of the molecular orbitals when the applied voltage is directly applied to the sample 201 to be measured, the molecular orbital information in the organic light emitter 302 is obtained with high accuracy. Is possible.

FIG. 3B shows a band diagram in the case of using the probe 100 in which the tunnel insulating film 105 is removed from the sharp portion 103. Since the gold thin film 104 formed on the surface portion of the sharpened portion 103 is in direct contact with the organic light emitter 302, the band structure of the organic light emitter 302 is distorted. Therefore, the tunnel current flowing between the organic light emitter 302 and the gold thin film 104 is not required,
Since a tunnel current tunneling through the triangular potential 303 formed in the organic light-emitting body 302 is observed, measurement of the minimum unoccupied molecular orbital becomes extremely difficult.

Next, as Step 4, after the measurement of the tunnel current is completed, the piezo drive device 203 is driven to lift the probe 100, and when there are next measurement points ("Measurement end for all measurement points?" In the case of NO), the probe 100 is moved to the next measurement point, and the operation of Step 1 is performed.
When all the measurement points are measured (when “YES at all measurement points?”), The measurement ends.

Here, since the signal of the surface shape of the sample 201 to be measured is carried in the signal for controlling the Z-axis servo circuit 208 so as to keep the distance between the sample 201 to be measured and the sharp portion 103 constant, the CPU 210. By processing the signal from the Z-axis servo circuit 208, an AFM signal can be obtained simultaneously with the STM signal.

  Next, effects of the above-described first to third embodiments will be described.

(1) Since the pointed portion 103 of the probe 100 is covered with the gold thin film 104 and further covered with the tunnel insulating film 105, the sample 201 to be measured is placed when the sample 201 to be measured and the pointed portion 103 are brought close to each other in the AFM contact mode. The measurement can be performed while suppressing the disturbance of the band structure.

(2) By using silicon oxide as the material of the tunnel insulating film 105, the wear amount of the probe due to the measurement can be suppressed, and measurement with high reproducibility can be performed. The same effect can be obtained by using silicon nitride, hafnium oxide, or a thiol self-assembled film instead of silicon oxide.

(3) Since the sharp portion 103 of the probe 100 is covered with a gold thin film 104, which is a noble metal whose surface state is stable in the atmosphere, the surface potential is stable, and the relationship between the tunnel current and the applied voltage is reproduced. We can investigate well. The same effect can be obtained by using a ruthenium or platinum thin film instead of the gold thin film 104.

(4) By fixing the probe 100 to the cantilever 101 having elasticity, the atomic force relating to the sharp portion 103 formed on the probe 100 can be converted into a measurable amount of deflection and extracted. . Therefore, feedback control that directly controls the atomic force determined by the distance between the sharp portion 103 and the sample 201 to be measured is possible, and the relationship between the applied voltage and the tunnel current can be investigated with high reproducibility. Further, by processing the feedback control signal that directly controls the atomic force, the surface shape of the sample 201 to be measured can be investigated at the same time.

(5) The back surface of the region where the probe 100 is fixed to the cantilever 101 is caused to function as the light reflecting unit 106, for example, by irradiating a laser beam and detecting the shake of the reflected light. The bending of the cantilever 101 due to the force can be extracted with little influence on the operation of the cantilever 101.

(6) The sample 201 to be measured is placed on the stage 202 that can be scanned in the X and Y directions, and is scanned in the X and Y directions using the probe 100 having the sharp portion 103 having the tunnel insulating film 105 on the surface. By driving the stage 202 and measuring the relationship between the applied voltage and the tunnel current,
The in-plane distribution can be measured while suppressing the disturbance of the band structure of the sample 201 to be measured.

(A) is a perspective view for demonstrating the structure of the cantilever provided with the probe which concerns on 1st Embodiment. (B) is sectional drawing of the cantilever according to the first embodiment. The block diagram of AFM / STM which concerns on 2nd Embodiment. (A) is a band diagram when a tunnel insulating layer is formed, and (b) is a band diagram when a tunnel insulating layer is not formed. The flowchart for performing the measuring method which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Probe, 101 ... Cantilever, 102 ... Support body, 103 ... Sharp part, 104 ... Gold thin film as a conductive part, 105 ... Tunnel insulating film as an insulating film, 106 ... Light reflecting part, 201
... Sample to be measured, 202 ... Stage, 203 ... Piezo drive, 204 ... Voltage source, 205 ...
Ammeter, 206 ... Laser light source, 207 ... Optical system, 208 ... Z-axis servo circuit, 209 ... X,
Y scanning circuit 210 ... CPU 211 ... CRT 301 ... conductive substrate 302 ... organic light emitter 303 ... triangular potential

Claims (8)

A distance control unit that controls the distance between the probe and the sample to be measured using an atomic force acting between the probe and the sample to be measured as a control signal, and between the probe and the sample to be measured, A probe used in a measuring device for measuring a relationship between a tunnel current generated by applying voltage so as to sweep and an applied voltage,
The probe has, at an end portion on the side close to the sample to be measured, a conductive portion and a sharp portion including an insulating portion arranged so as to wrap the conductive portion,
The conductive portion is a conductor, or a conductor is coated, and is formed so that the tunnel current flowing between the conductive portion and the sample to be measured is detected,
The insulating part has a thickness that allows the tunnel current to be measured by the measuring apparatus with respect to the voltage applied to the conductive part from the measuring apparatus, and has a band structure of the sample to be measured. Using an insulating film that has a thickness that can suppress the effect on the effect, and in addition, is resistant to wear due to secondary stresses when feedback control is performed using the interatomic force as a control signal. Formed,
The probe further comprises a conductive mechanism for guiding the voltage applied by the measuring device to the conductive portion of the sharp portion. 2. The probe according to claim 1, wherein the insulating film is made of silicon oxide, silicon nitride, hafnium oxide, or a thiol self-assembled film. The probe according to claim 1, wherein the conductor is made of gold, ruthenium, or platinum, which is a noble metal whose surface state is stable in the atmosphere. The cantilever used for the distance control unit according to claim 1 and having elasticity so as to bend by the atomic force, wherein a fixed end of the cantilever is fixed to a support that supports the cantilever. ,
The free end portion of the cantilever is formed by fixing the probe having the sharp portion, and the atomic force acting between the sharp portion and the sample to be measured is generated by the atomic force. A bend detection unit for detecting the bend amount of the cantilever is provided, the cantilever is covered with a conductor or a conductor, and the support and the probe are electrically connected. Cantilever characterized by that. The deflection detection unit is provided with a light reflection unit located on the free end side and located on the back surface of the probe,
5. An optical lever that extracts a deformation amount of the cantilever by irradiating the light reflecting portion with a light beam and detecting a projection position of the light beam reflected by the light reflecting portion. Cantilever as described in. 5. A scanning probe microscope using the cantilever according to claim 4, wherein a distance between the sharp portion and the sample to be measured with the atomic force acting between the sharp portion and the sample to be measured as a control signal. Can be controlled so that the distance is maintained at least during measurement at each measurement point, and the sharp portion and the sample to be measured are relatively movable along the surface direction of the sample to be measured. A scanning probe microscope characterized by the above. Using the probe fixed to the cantilever according to claim 4, measure a tunnel current flowing between the sharp portion and the sample to be measured at least a part of the measurement points,
A measurement method using a scanning probe microscope, wherein a local band structure of a sample to be measured is extracted. 8. The measuring method using a scanning probe microscope according to claim 7, wherein a surface shape of the sample to be measured is simultaneously measured using a signal for controlling a distance between the sharp portion and the sample to be measured.

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