JP3070216B2 - Surface microscope and microscopic method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus using an atomic force, a magnetic force and a tunnel current generated when a probe and a sample come close to each other, and relates to the surface morphology, physical properties, and magnetic properties of the sample. The present invention relates to an atomic force microscope, a magnetic force microscope, and similar devices suitable for obtaining information such as electrical properties and the like.

[0002]

2. Description of the Related Art Conventionally, a small force (repulsive force or attractive force) acting on a probe and a sample provided at a tip of a cantilever is kept constant, that is, a displacement (bending) of the cantilever is measured by an STM probe and is kept constant by servo. A method for observing the surface by scanning and controlling the sample while keeping the temperature as described in JP-A-62-1
No. 30302. Also, the method of detecting the gradient of the force applied to the probe by vibrating the probe is described in the journal.
Of Applied Physics Vol. 61 4723
Page 4729 (1987).

[0003]

In the above prior art, the surface structure is observed by controlling the position of the probe so as to keep the force acting on the probe constant. It can measure the leakage magnetic field and the leakage electric field in the sky. However, at what height from the surface are these leakage magnetism and leakage electric field values, or how the distribution of such leakage magnetism and leakage electric field is formed due to the structure of the sample surface? There was a disadvantage that it could not be predicted. That is, it was a very important task to simultaneously measure the surface structure and the leakage magnetic field or the leakage electric field distribution. Furthermore, it was possible to measure a small force in the height direction from the sample surface, but considering frictional force and magnetic force, it is desirable to measure a small force in the horizontal direction (in-plane direction), and this horizontal measurement is not possible. Met.

[0004]

In order to achieve the above object, in the present invention, at least means for vibrating a cantilever with a probe, means for measuring DC displacement of the cantilever, and means for measuring AC displacement of the cantilever. The solution was achieved by providing a means for measuring, and by simultaneously measuring the surface structure from the DC displacement and the leakage magnetism and leakage electric field distribution from the AC displacement. Further, by providing a means for rotating the cantilever in a rotational motion and shaking in the horizontal direction, or a means for detecting the amount of deflection of the light beam with a two-dimensional position sensor,
The second problem has been solved.

[0005]

The operation of the present invention will be described below. When the cantilever with the probe is vibrated with a small amplitude and the probe approaches the sample, the cantilever is bent by receiving a repulsive force or an attractive force, and the displacement of the probe is measured by a position detecting means using laser light or the like. The surface structure of the sample measures the DC displacement of the cantilever, and the Z of the sample or the probe is adjusted so that the force acting on the probe is constant, that is, the DC displacement is constant.
By controlling the position of the axis (the axis perpendicular to the sample), three-dimensional information is obtained from a change in the position of the sample or the position of the probe. At the same time, an AC displacement is selected from the output of the position detecting means, and the same component as the frequency being excited is extracted to measure the gradient of the force. This gradient can measure the leakage magnetism and the leakage electric field near the surface of the sample. Further, when measuring the leaked magnetic field or the leaked electric field above the sample, when the probe or the sample is scanned two-dimensionally in X and Y directions, the X, Y, and
The movement in the Z direction is stopped, the probe is moved from this surface to a desired height or a plurality of heights, and the gradient of the force acting on the probe at that time is measured. This makes it possible to measure the surface structure and the three-dimensional leakage magnetic distribution or leakage electric field distribution from the surface. When measuring the leakage magnetic distribution, a probe whose surface is covered with a magnetic material or a probe formed of a magnetic material is used. Also, when measuring the leakage electric field distribution,
At least the surface of the probe must be made of a conductive material. To detect atomic, magnetic or electrostatic forces,
Here, it can be realized by employing a non-contact, large-area displacement detection method, that is, an optical lever method, an optical interference method, a capacitance method, an optical critical angle method, or the like.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a view for explaining the configuration of a basic device of the present invention. As shown in the figure, the cantilever 1 having the probe 17 is supported by the piezoelectric element 15, and when the probe receives a force, the cantilever 1 bends and undergoes a vibration change. 1 has the function of detecting the displacement. Optical lever type detector is laser source 3,
It comprises a position sensor element 4 and a detection circuit 5. Only the low-frequency component 8 of the detection circuit output signal is input to the servo control circuit 9 and the Z-axis piezoelectric element of the XYZ-scanner 14 controls the low-frequency component of the displacement of the cantilever 1 to be constant. Thereby, the sample surface structure (AFM)
Image) can be observed. On the other hand, the lock-in amplifier 6 detects the same frequency component 7 of the detection circuit output signal and the piezoelectric element excitation signal, and measures the change in the gradient of the force with respect to the probe position in the XY directions on the sample surface. Thus, a leakage magnetic distribution, a leakage electric field distribution, and a potential distribution can be obtained and displayed on a display device (not shown). The detailed operation will be described below.

When the cantilever 1 with the probe 17 is vibrated with a small amplitude and the probe 17 approaches the sample 2, the cantilever 1 is bent by receiving a repulsive or attractive force, and the probe 17 is bent as described above.
Is measured by position detecting means using laser light (18: laser incident light, 19: reflected light from the back surface of the cantilever 1). The surface structure of the sample 2 measures the DC (low-frequency range where servo is possible) displacement of the cantilever 1 so that the force acting on the probe 17 is constant, that is, the DC displacement is constant. By controlling the position of the Z axis of the sample 2 (the axis perpendicular to the sample 2), three-dimensional information is obtained from a change in the position of the sample 2 or the position of the probe 17. At the same time, an alternating current (the same frequency component as the vibration frequency of the piezoelectric element 15) is selectively detected from the output of the position detection circuit 5 to measure the gradient of the force. This gradient can measure the leakage magnetism and the leakage electric field near the surface of the sample. At this time,
Excitation frequency cantilever 1 to detect force gradient
A method of detecting a change in the amplitude generated when the force acting on the probe 17 changes by slightly displacing the resonance point from the above, and the resonance frequency changes by applying the force acting on the probe 17, There is a method of detecting a force gradient from the change in the frequency. Quantitatively, the latter is more direct, and it is desirable to use the latter. Also, the response frequency of the servo system needs to be lower than the excitation frequency. That is, since the response frequency of the servo system is almost 5 kHz or less,
A vibration frequency of not less than Hz is required. When measuring the leakage magnetic distribution, a probe 17 whose surface is covered with a magnetic material or a probe 17 formed of a magnetic material is used. Also, when measuring the leakage electric field distribution, it is necessary that at least the probe surface is made of a conductive material. To detect atomic force, magnetic force and electrostatic force, use non-contact, large area displacement detection method other than optical lever method, that is, light interference method, capacitance method, optical critical angle method, etc. It can also be realized by

The system configuration of FIG. 1 shows that the conventional configurations of FIGS. 2 and 3 can be realized from one system configuration. FIG. 2 shows a configuration in a constant repulsion mode when observing a surface structure, and FIG. 3 shows a case in which a contour map of an arbitrary force gradient is obtained by a constant force gradient control. FIG.
Has a configuration in which the lock-in amplifier 6 for obtaining only the information on the force gradient shown in FIG. 1 is omitted. However, the probe may be vibrating. FIG. 3 shows a system for obtaining contours with a constant gradient of force. An AC displacement detection signal is input to a lock-in amplifier 6 and an output signal is input to a servo control system 9 to generate X
The Z-axis piezoelectric element of the YZ-scanner 14 is controlled, and the movement of the piezoelectric element is displayed on the display device 12 to obtain this contour map. This system configuration can also be easily changed from FIG.

FIGS. 2 and 3 are equivalent to the conventional system configuration. However, these disadvantages can clarify how the surface structure and the leakage magnetic field distribution and the leakage electric field distribution are combined in a complex manner. It was not. That is, each was only observed independently and could not be mixed and separated.

Therefore, the present invention can be further extended to a composite measurement of the surface structure and the three-dimensional leakage magnetic field distribution or the leakage electric field distribution. First, when measuring the leakage magnetism or the leakage electric field above the sample, it is necessary to obtain the surface position. That is, when the probe 17 or the sample 2 is two-dimensionally scanned in the X and Y directions in the constant repulsion mode, surface information is taken in.
At the same time, X, X,
The movement in the Y and Z directions is stopped, the probe 17 or the sample 17 is moved to a desired height or a plurality of heights from this surface, and the gradient of the force acting on the probe at that time is measured. This is repeated for each image, and the surface structure and 3
A dimensional leakage magnetic distribution or leakage electric field distribution can be measured. FIG. 4 shows the movement of the probe 17 at each pixel. FIG. 4 shows a state when the surface structure is captured in the constant repulsion mode. XYZ movement is held, and the sample 2 or the probe 17 is moved by adding an arbitrary distance thereto. At a distance and measure the force gradient there. After that, the distance between the sample probes is further reduced to the state described above, and the gradient of the force there is measured. In this figure, the force gradient at two points is measured on the sample, but it is desirable to measure many points if accurate data is to be obtained. The order of measurement is either within the scope of the present invention, either gradually approaching from a distance as shown in the figure, or moving away from a near point. In the figure, the probe is moved obliquely upward, but may be moved straight upward. FIG. 5 shows 3 using the above method.
4 shows a flowchart of a program applied to measure a two-dimensional leakage magnetic field distribution.

First, the probe 17 is moved to a scanning start position by a constant force servo. Thereafter, the probe 17 is moved to the position of the first measurement pixel, and the surface information (X ₁ , Y ₁ , Z ₁₁ ) is read. Then, the servo is held and the probe 17 is moved above the sample 2. At this time, the probe 17 is moved by adding ΔZ to the above Z ₁₁ and applying a voltage corresponding to the above to the Z piezo. The magnetic force gradient there is read. Further, a second value is input to ΔZ to read the magnetic force gradient at another position. When finished measuring the magnetic force gradient at a desired location, and inputs the original value Z ₁₁ to Z piezo. At the same time, when the constant force servo is performed, the probe 17 returns to the original surface of the sample 2, moves to the next pixel after a short waiting time, and repeats the above measurement. This is performed for the X axis, and when one line of data has been acquired, the Y axis is moved by one step, and data is acquired for the X axis. These movements are also performed for the Y axis, and all data are acquired. FIG. 6 shows a surface structure diagram (AFM image) corresponding to FIG.
3 shows a magnetic force gradient distribution. In this example, a sample was observed using the surface of a magneto-optical disk, and the surface structure and leakage magnetic distribution could be clearly understood.

FIG. 7 shows one specific example of the servo control circuit 9 for realizing FIG. In FIG. 7, a servo control circuit 9 converts a position error signal 20 into a PI (proportional integration or differentiation may be added) control circuit 30 and a hold circuit 3
1. The probe 17 or the sample 2 is controlled so that the position error signal 20 becomes zero through the power amplifier 32. Here, in particular, an adder circuit 27 is provided between the hold circuit 31 and the power amplifier 32 so that the V ₁ and V ₂ voltages can be sequentially applied during XYZ hold. FIG.
Shows a time chart of signals V ₃ to be added to the adder circuit 27 in FIG. 7. In the hold circuit 31, a sample hold circuit or an ADC (analog / digital converter)
DAC (digital, analog converter) is common to perform the by the coupling circuit, to which are input a signal V ₄ which controls the servo / hold, and measurement of the surface structure, and a measurement of the leakage magnetic field distribution to separate . That is, the former is a servo
The latter is performed during hold. When V ₄ is servo probe 17 to move between pixels in the XY scanning, by controlling the probe 17 or sample 2 in such a way that repulsive force constant, obtain surface structure information. The V ₄ that at the time of the hold had been made the V ₃ to zero V
_The probe 17 is gradually changed from ₁ to V _2, and the probe 17 is gradually approached from above the sample 2. The movement of the probe 17 is as shown in FIG. V ₁ and V ₂ at this time are set by potentiometers 21 and 22,
Generating an output voltage, such as V ₃ at switch 23, 24 and the delay circuit 25. Incidentally, V ₄ is the timing signal V ₅ 26 in synchronism with generated hold signal activates the switching circuits 23 and 24, to achieve these. Also,
Probe 17 during the period of T ₁ of the in the figure moves while servo control to the next measurement pixel. The above-described method is one specific example using an analog circuit, but the above sequence can be realized by computer control, and this is also within the scope of the present invention.

In addition, elemental analysis of the surface can be performed by inserting a spectroscopic analysis (STS) using a tunnel current, which is a conventional technique, between that shown in FIG. Measurement becomes possible. At this time,
The probe 17 has a magnetic material, and its surface needs to be covered with a conductive material. Further, by operating this example in a vacuum, the resonance characteristics are further improved without being affected by moisture, and high-precision measurement becomes possible. These are also within the scope of the present invention. In addition, the present invention can also be realized by using a displacement detection type cantilever that can detect the displacement of the probe without using an optical lever or the like. In particular, a piezoelectric element, a piezoresistive element, a strain gauge element, a semiconductor strain resistive element, and the like are formed on the surface of the cantilever by a semiconductor process. If these are used, higher performance can be realized.

FIG. 9 shows a state in which a coil 40 is wound around the magnetic probe 17,
This is a specific example of measuring a more accurate magnetic field distribution. The magnetic force at each magnetic pole is measured while changing the magnetic pole at the tip of the probe 17 to the S-pole and the N-pole by flowing a current in the coil 40 in both directions. Based on the obtained data, both data are subtracted to remove a small force other than the magnetic force, and the true magnetic force or the magnetic force gradient distribution is measured. 4 current or voltage sources
1 and 42, the switching switch 43 controls the coil 4
Switch the current to zero. The data may be measured by measuring a magnetic force or a magnetic force gradient for each pixel. As for the timing of data acquisition, when measuring the magnetic field distribution on the surface as shown in FIG. 1, the position of the probe 17 is held for each pixel and switched by an external control signal (preferably controlled by a computer) 44. After scanning the entire scanning area, the surface shape,
The magnetic information of each of the S pole and the N pole is obtained. FIG. 10 shows a specific example in which magnetic information is obtained when the magnetic field strength of the probe is changed by various currents. As in FIG. 9, the variable current source 45 is controlled by an external signal and the magnetic information in each case is obtained. Measure the distribution.
In this case, the magnetic distribution at various magnetic field strengths and the like can be measured at an arbitrary position. The method is as shown in FIG. At this time, instead of moving the probe position, measurement is performed by changing the magnetic field strength.

FIG. 11 shows an electrical configuration of a probe portion for realizing a method of measuring an electric field distribution or an electric field gradient distribution by coating a conductive material 47 on the probe 17. In this configuration, an arbitrary voltage is applied to the sample on the probe surface as in FIG. As the image, the electric field distribution and the gradient distribution of the electric field can be measured, and can be measured on the sample surface or at an arbitrary position on the sample. The method measures by changing the voltage instead of the magnetic field strength as described above.

FIG. 12 shows a method for simultaneously measuring magnetic information and electric field information when the probe is covered with a magnetic material 48 or only the surface with a magnetic material 48 and coated with a conductive material 47. In this case, the switch 43 is switched to the probe.
This can be performed by applying or not applying a potential from the power supply 49. When a potential is applied, the electrostatic force becomes stronger than the magnetic force, and the electric field intensity distribution or the electric field gradient distribution can be measured. Further, when the same potential is controlled by the external signal 44, the magnetic force is increased, and magnetic information can be measured. By measuring these operations on each pixel and the sample surface or an arbitrary position, it is possible to measure the surface or the three-dimensional spatial distribution on the surface.

FIG. 13 shows a specific example of measuring the magnetic distribution and the electric field distribution by vibrating the probe 17 in parallel with the surface of the sample 2. In this case, it is necessary to use a two-dimensional position sensor diode 50 for detecting the laser beam reflected light 19. A trajectory of the laser beam reflected light 19 such as 52 occurs corresponding to the trajectory 51 of the vibration of the probe 17. 5
Reference numeral 3 denotes a trajectory when a vertical force acts on the sample surface, which can be separately measured by the two-dimensional sensor 50. The vibration direction of the probe is a direction parallel to the end face of the base material 56 supporting the cantilever 1, and the X-axis scanning direction of the probe 17 is also desirably this direction. As a means for giving a vibration locus such as 51, it can be realized by rotating the base material by a piezo element. By repeating this motion and the motion of FIG. 1 or by synthesizing the motion, the gradient distribution of the magnetic force and electric force in the vertical and horizontal directions can be measured. Further, the vibration is stopped and the two-dimensional sensor 50 is stopped.
Magnetic force and electric force can also be measured only by the DC change of. Further, by including the probe control as shown in FIG. 8 in these measurements, a high-level magnetic and electric field distribution can be obtained. FIG. 14 shows a probe structure for obtaining magnetic information parallel to the surface. The magnetic material 54 is placed on the probe 56
Is deposited, and when the tip is set to a magnetization state such as 55, the magnetization state on the surface can be measured. At this time, the magnetization direction is desirably parallel to the trajectory 51 of the probe.

In this specific example, an example was shown in which the sample surface structure was observed and the magnetic force at an arbitrary height and the gradient of the electrostatic force were measured. By integrating these data from infinity based on these data, The true leakage magnetic field distribution and leakage electric field distribution can be obtained. Further, it is possible to determine the attenuation characteristics of the leakage magnetism and electric field from the sample surface. As described above, there are various data expressions based on the data shown in this specific example, but these do not depart from the present invention. In this embodiment, a fragmentary example is shown, but any combination of the above-described specific examples is within the scope of the present invention. Furthermore, these controls are very convenient using a computer.

[0020]

According to the present invention, it is possible to make a composite measurement of the sample surface structure and the leakage magnetic field and electric field distribution over the sample surface, which are impossible with the prior art. Becomes clear. In addition,
If the tunneling spectroscopy is combined, the surface composition and the relationship between them will become clear, which will be extremely effective in investigating the formation of fine magnetic distribution and the like. Further, in the conventional force gradient constant control technology, the leakage magnetic field and the electric field distribution from the sample surface were extremely unclear, but the present invention has enabled quantitative measurement.

[Brief description of the drawings]

FIG. 1 is a configuration diagram for applying the present invention to an optical lever type atomic force, a magnetic force, and an electrostatic force microscope to perform complex measurement of surface structure information and distribution of leakage magnetic field and leakage electric field on a surface.

FIG. 2 is a specific configuration diagram when FIG. 1 is operated in a constant repulsion mode.

FIG. 3 is a specific configuration diagram when FIG. 1 is operated in a constant force gradient mode.

FIG. 4 is a specific configuration diagram when the present invention is further extended to composite measurement of a surface structure and a three-dimensional leakage magnetic field distribution or a leakage electric field distribution.

FIG. 5 is a flowchart for three-dimensional magnetic field measurement.

FIG. 6 is a distribution diagram as a result of application to magneto-optics.

FIG. 7 is a block diagram of a servo control circuit 9 for realizing FIG. 4;

FIG. 8 is a time chart for explaining the operation of FIG. 7;

FIG. 9 is a configuration diagram for measuring a magnetic distribution by changing a magnetization direction of a probe.

FIG. 10 is a configuration diagram for measuring by changing the magnetism of a probe.

FIG. 11 is a configuration diagram for measuring an electrostatic force distribution by changing a charge of a probe.

FIG. 12 is a configuration diagram for simultaneously measuring an electrostatic force and a magnetic force distribution.

FIG. 13 is a configuration diagram for measuring a magnetic distribution and an electrostatic distribution parallel to a sample surface.

FIG. 14 is a configuration diagram of a probe structure for measuring a magnetic distribution parallel to the sample surface.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cantilever, 2 ... Sample, 3 ... Laser source, 4 ... Position sensor (PSD) (possible even with a two-part photodiode), 5 ... Displacement detection circuit, 6 ... Lock-in amplifier (Lock)
in Amp.), 7… Displacement detection signal of the same frequency as the excitation component,
8: displacement detection signal from DC component to low frequency component; 9: servo control circuit (servo control); 10, 10 ': Z-axis piezoelectric element drive signal; 11: force gradient signal; 12: display device; Scanning control circuit, 14: XYZ-scanner, 15: excitation (excitation) piezoelectric element, 16: excitation waveform generation circuit, 17: probe, 18: incident light for optical leverage (laser light), 19: from the back of the cantilever .., Position error (repulsion error) signals, 21, 22.
Potentiometer, 23, 24 switch, 25 delay circuit, 26 timing signal, 27 addition circuit, 30
PI control circuit, 31 hold circuit, 32 power amplifier, 40 coil, 41, 42, 49 current, voltage source,
43: changeover switch, 44: external signal, 45, 46
... variable current, voltage source, 47 ... conductive material, 48 ... magnetic material probe, 50 ... two-dimensional position sensor, 51 ... probe trace
52, 53: light beam locus, 54: probe material, 56: magnetic material, 55: direction of magnetization.

Continuation of the front page (72) Inventor Hajime Koyanagi 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (72) Inventor Tsuyoshi Hasegawa 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (56) References JP-A-3-68880 (JP, A) Martin, H .; K. Wick ramaginghe, "Magnetic imaging by" force microscopy "with 1000A resolution", Appl. Phys. Lett. , 50 (20), pp. 1455-1457, 18 May 1987. (58) Field surveyed (Int. Cl. ⁷ , DB name) G01B 21/00-21/32

Claims (18)

(57) [Claims] 1. A surface microscope that obtains surface information while keeping a small force acting on the probe at a constant level, or obtains surface information by a change in the small force. A means for vibrating at an amplitude or a means for vibrating a sample, a means for measuring a DC component of displacement of the cantilever (meaning from a DC component to a low frequency component) to detect repulsive and attractive forces, and a displacement of the cantilever A means for measuring the AC component (the same frequency component as the excitation frequency) to detect a change amount (gradient) of the minute force. 2. A surface microscope according to claim 1, further comprising means for detecting an amount of change in a small force at any X, Y position where an atomic force, a magnetic force, or an electrostatic force is to be measured. 3. The method according to claim 1, wherein the means for detecting the amount of change in the minute force is an optical lever system, an optical interference system,
A surface microscope using any one of a capacitance method and a photocritical angle method. 4. The surface microscope according to claim 1, wherein the tip of the probe is formed of a magnetic material. 5. The surface microscope according to claim 1, wherein the tip of the probe is covered with a conductor. 6. The sample surface shape according to claim 1, wherein a surface shape of the sample is measured using a DC component of the displacement of the cantilever, and a gradient of a force at an arbitrary height from the surface is measured based on the measured DC component. Surface microscope characterized by measuring from changes in the surface. 7. The surface microscope according to claim 1, wherein a displacement detecting element is provided on the surface of the cantilever. 8. The method according to claim 1, further comprising a function of three-dimensionally holding the probe at each measurement point, and moving the probe away from the sample by one or more points during the hold. A surface force microscope for measuring a leakage magnetic field distribution, an electric field distribution, and a potential distribution on a sample surface based on a small force acting on the probe or a gradient thereof obtained by measuring the AC component when the AC component is measured. 9. A surface microscope and a similar apparatus having display means for displaying a two-dimensional distribution of a leakage magnetic field distribution, an electric field distribution, or a potential distribution on a sample surface measured in claim 8. 10. A surface microscope having means for displaying a three-dimensional distribution of a leakage magnetic field distribution, an electric field distribution, and a potential distribution on a sample surface measured in claim 8. 11. The method according to claim 8, wherein a leakage magnetic field distribution in a height direction from the sample is obtained based on three-dimensional distribution data of a leakage magnetic field distribution, an electric field distribution, and a potential distribution on the surface of the sample.
A surface microscope having display means for displaying an electric field distribution and a potential distribution. 12. The method according to claim 1, wherein
A surface microscope wherein the probe and the sample are placed in a vacuum. 13. The method according to claim 1 , wherein
A surface microscope having a tunneling spectroscopy function using a tunnel current and a composition analysis function of a sample surface. 14. A surface microscope according to claim 1, further comprising means for switching between electrostatic force and magnetic force. 15. The method according to claim 1, further comprising means for changing a magnetization direction of the probe to measure an atomic force, a magnetic force, and an electrostatic force of a component perpendicular to the surface and a component horizontal to the surface. Surface microscope. 16. A repulsive force and attractive force are detected by measuring a direct current component (meaning from a direct current component to a low frequency component) of displacement of the cantilever while vibrating a probe attached to the cantilever with a small amplitude. In a surface microscopic method for measuring the AC component (the same frequency component as the excitation frequency) of the displacement of the cantilever and detecting the amount of change (gradient) of the minute force to obtain surface information of the sample, the repulsive force is constant. In the state, while capturing surface information of the sample, the movement of the probe or the sample is substantially stopped for each pixel, and the probe or the sample is moved to a desired height or a plurality of heights from the surface of the sample. A surface microscopy method characterized by measuring a gradient of a force acting on the probe at that time, repeating the measurement for each image, and measuring a surface structure and a gradient distribution of a force from the surface. 17. The surface microscopy method according to claim 16, wherein a stray magnetic field distribution is measured as the gradient distribution of the force from the surface. 18. The surface microscopy method according to claim 16, wherein a leakage electric field distribution is measured as a gradient distribution of the force from the surface.