JP2005265435A - Method for evaluating physical properties of minute region and scanning probe microscope used therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for evaluating the physical properties of the minute region on the surface of a solid and a scanning probe microscope used therein to evaluate even a substance of high resistivity such as an oxide or the like without restricting an evaluation object to a good conductor. <P>SOLUTION: The scanning probe microscope is used to bring a probe having conductivity into contact with the surface of a sample, to apply bias voltage across the sample and the probe, to irradiate the contact position with the tip of the probe on the surface of the sample or the vicinity thereof with light, to detect the current flowing across the sample and the probe and to use the result of this detection to evaluate the physical properties of the minute region. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for evaluating physical properties of a minute region on a solid surface and a scanning probe microscope used therefor.

  There are various methods for evaluating the physical properties of a minute region on the surface of a solid depending on the purpose. For example, as a method for examining the dopant distribution of a semiconductor sample, there is secondary ion mass spectrometry (Patent Document 1 and Patent Document 2). In this method, when primary ions are accelerated and collide with a sample, the types of constituent elements released from the sample as secondary ions are evaluated by mass spectrometry. According to this evaluation method, the dopant distribution in the sample depth direction can be examined with high sensitivity.

  However, since this method is an analysis method in which primary ions collide with a sample and the elements constituting the sample are ionized and blown away, it has not been possible to perform non-destructive evaluation. That is, although this method can analyze the composition of a sample, it has been difficult to make a detailed evaluation of the sample state such as physical properties and characteristics of the sample. Further, from the viewpoint of analysis and evaluation of a micro area, the area when the area of analysis and evaluation is narrowed down is about 15 μm × 15 μm, and the resolution is about 500 nm, and analysis and evaluation of a micro area below that is difficult. There was a problem that there was.

  In recent years, various scanning probe microscopes such as a scanning tunneling microscope have come to be used in particular as means for examining physical properties of a micro area of a sample and evaluating characteristics. For example, a method for obtaining a physical property amount from a tunnel current generated by bringing a probe close to a sample (Patent Document 3), or a probe of a scanning tunneling microscope is brought close to a sample such as a semiconductor, and a tunnel is formed between the probe and the sample. A method of obtaining physical properties such as dopant distribution and carrier density of a sample by flowing a current, inducing a plasmon mode in the sample by this current, and detecting near-field light induced by the plasmon mode (Patent Document 4) In addition, by irradiating the sample with infrared light having energy smaller than the band gap of the sample to excite surface plasmons and measuring the near-field light induced by this, the dopant distribution and carrier density of the sample are measured. A method for obtaining a physical property amount (Patent Document 5) has been proposed.

  In addition, a spin polarization microscope has been proposed as a method for performing evaluation in a fine region such as a magnetic recording medium (Patent Document 6). In this method, spin-polarized electrons are generated by irradiating the probe with circularly polarized light, and the electrons are injected into the sample by the tunnel effect, and the tunnel current is detected and evaluated.

However, in these methods, for example, in the case of a scanning tunneling microscope, a tunnel current needs to flow between the probe and the sample, and thus there is a restriction that the sample must be conductive. . For non-conducting substances, measurement is often performed by coating a thin conductive film on the surface, but this method obtains information on surface irregularities. It did not evaluate the physical properties or surface properties of the material.
JP 2001-59826 A JP 2001-141676 A JP-A-7-72159 JP 2000-12636 A JP 2000-260832 A JP-A-62-139240

  As described above, of the conventional methods for evaluating the physical properties of the micro area on the sample surface, secondary ion mass spectrometry is difficult to evaluate the physical characteristics of the micro area, and a scanning probe such as a scanning tunneling microscope is used. The method of evaluating physical properties using a microscope has a restriction that the sample is limited to those having conductivity.

  The present invention pays attention to the above-mentioned problems in the prior art for evaluating physical properties in a micro area on the surface of a sample, and provides a new micro area physical property evaluation method that solves these problems, and a scanning probe microscope used therefor Is to provide.

  The inventors focused on the fact that the photoconductivity and the resulting photocurrent behavior when the sample is irradiated with light reflect the physical properties of the sample. As a result of repeated studies with the aim of detecting the photocurrent and detecting the photocurrent and using it to evaluate the physical properties in a microscopic region, the present invention has been achieved.

  The method for evaluating physical properties of a micro region according to the present invention is a method for evaluating physical properties of a micro region using a scanning probe microscope, wherein a conductive probe is brought into contact with the surface of the sample, and the sample is placed between the sample and the probe. It is characterized in that a bias voltage is applied to irradiate light at or near the position where the tip of the probe contacts on the surface of the sample to detect the current flowing between the sample and the probe. .

  In the present invention, a current flowing in a minute region is detected by applying a voltage in a state where light is irradiated on the sample surface to cause photoconductivity. In such photoconductivity, electrons in the impurity level are excited as photocarriers in the conduction band by light irradiation, or electrons are excited from the valence band to the impurity level to generate holes in the valence band. This is thought to be caused by a mechanism such as Here, the impurity level is generated due to various causes such as a lattice irregularity in addition to the presence of impurities in the matrix.

  In a substance such as a semiconductor, electron or hole photocarriers excited by light irradiation are excited to an energy band to become free electrons and often exhibit relatively large photoconductivity. In contrast, in the case of oxide materials, photocarriers are not expected to be excited in the same way as in the case of semiconductors, but the conductivity changes due to light irradiation even in such materials. It was found that the photocurrent can be detected and the physical properties of the material can be evaluated by measuring the photocurrent.

  Excitation of photocarriers by light irradiation depends on the energy of the irradiated light. For this reason, if the relationship between the wavelength of light to be irradiated and the excitation of photocarriers is clarified by measurement, detailed physical properties of the sample can be evaluated.

  The scanning probe microscope of the present invention includes a conductive probe, contact means for bringing the tip of the probe into contact with the surface of the sample, and the tip of the probe while making contact with the surface of the sample. A moving means for relatively moving the positional relationship between the tip of the probe and the sample; a light irradiating means for irradiating light at or near the position where the tip of the probe contacts the surface of the sample; and the sample and the probe A voltage applying means for applying a bias voltage between the needle and a current detecting means for detecting a current flowing between the sample and the probe are provided.

  According to the present invention, even when the conductivity of a sample to be measured is small, carriers can be generated by irradiating light to increase conductivity, and photocurrent can be detected. For this reason, it is possible to perform physical property evaluation by the method of the present invention even for a material having high resistivity, which has conventionally been difficult to perform physical property evaluation with a scanning probe microscope.

  In the method for evaluating physical properties of a minute region of the present invention, a flowing current is detected by bringing a probe into contact with a sample, irradiating the probe with light, and applying a bias voltage. In this respect, the present invention is different from an evaluation method using a normal scanning tunneling microscope in which the probe and the sample are kept in non-contact and the tunnel current flowing between the probe and the sample is controlled to be constant. Thus, the present invention makes it possible to evaluate the physical properties of a micro area of a sample by a photocurrent that cannot be obtained by a normal scanning tunneling microscope.

  According to the present invention, it has become possible to evaluate the physical properties of a micro region of a sample that could not be evaluated by a conventional method. In addition, even when the conductivity of the sample is small, the physical properties of a minute region can be evaluated by providing conductivity by light irradiation.

  Next, the present invention will be described in more detail and specifically by showing embodiments of the present invention with reference to the drawings.

  FIG. 1 is a diagram schematically showing an embodiment of the configuration of photocurrent measurement of the present invention. In FIG. 1, a conductive probe 1 is kept in contact with a sample 2 by position control. This position control is performed precisely by detecting the position of the probe 1 by a detection system and feeding back the detection result to the scanner 3, whereby the distance between the probe 1 and the sample 2 is zero. Keeps the state. A bias voltage from the voltage control unit 4 is applied between the probe 1 and the sample 2. On the other hand, the light from the light source 5 is condensed by the condensing unit 6, and the irradiation light 9 irradiates the surface of the sample 2. The sample 2 receives this light irradiation, the conductivity increases due to the photoconductive effect, and the amount of current flowing increases due to the application of the bias voltage. This increase in current amount also appears as a change in voltage-current characteristics. The contact state between the probe 1 and the sample 2 can be confirmed using a device such as a nanoscope.

  In this manner, the probe 1 is brought into contact with the surface of the sample 2, the sample 2 is irradiated with the irradiation light 9 to excite carriers such as conduction electrons and holes in the sample 2, and the probe is controlled by the voltage control unit 4. By applying a voltage between 1 and sample 2 to generate a photocurrent, and measuring and evaluating this photocurrent, the physical properties of sample 2 are evaluated.

  In the irradiation using the condensing unit 6 for the irradiation light 9 shown in FIG. 1, the light is irradiated from the back surface of the probe 1, thereby condensing the probe 1 at or near the position where the probe 1 contacts the sample 2. I am letting. In this case, the light is not blocked by the back surface of the probe 1 and its support mechanism, and a sufficient amount of light is condensed and irradiated at the position where the probe 1 on the surface of the sample 2 contacts. To. In order to obtain such a configuration, a configuration of a metal microscope, a configuration of a cylindrical lamp house described in JP-A-5-71949, or the like can be used.

  Further, as shown in FIG. 2, the light emitted from the light source 5 is condensed using the condensing unit 6 and the optical path is changed using the illustrated mirror 10 or a prism, whereby the sample 2 is viewed from an oblique direction. You may make it irradiate to the position where the probe 1 of the surface of this contacts, or its vicinity. Further, using an optical fiber, the irradiation light 9 may be guided to the vicinity of the position where the probe 1 on the surface of the sample 2 contacts, and irradiated. Furthermore, when irradiation from the back surface of the sample 2 is possible and effective, light irradiation from the back surface can also be used. In FIG. 2, the same reference numerals are used for the same reference numerals as those in FIG.

  As the probe 1, for example, a silicon nitride (silicon nitride) or a carbon nanotube can be used as a commonly available probe. In this case, the probe material is sufficiently conductive. In the case where it does not have the property, for example, a metal coating such as gold, silver, copper, etc., imparted with conductivity can be used. For example, it is possible to preferably use a silicon nitride that is provided with metal conductivity by metal coating.

  When the probe 1 has metal conductivity and the sample 2 has conductivity as a semiconductor, the probe 1 and the sample 2 come into contact with each other to form a Schottky junction. An electric field is applied to the bonding surface, and the sample 2 is excited by electrons or holes as carriers by light irradiation to generate a photocurrent. By measuring this current, the probe 1 of the sample 2 is in contact with the microscopic surface. The physical properties characteristic of the area can be evaluated. At this time, detailed information on the physical properties of the sample 2 can be obtained by changing the wavelength of the irradiated light and the amount of incident light to examine the dependence of the photocurrent on the light wavelength and light intensity.

  In addition, the voltage-current characteristic between the probe 1 and the sample 2 is measured without light irradiation, that is, the dark current characteristic is measured, and this is compared with the above-described photocurrent characteristic. More powerful data can be obtained about physical properties such as dopant distribution and current barrier height.

  The data measured in this way is converted into digital data via the current measuring unit 7 in FIG. 1 and input to the personal computer 8. In the personal computer 8, the current-voltage characteristic and its distribution can be calculated by the built-in software, and the result can be displayed on the display unit 9. Moreover, the current-voltage characteristic when not irradiating light can be measured, and the difference from this can be obtained. By performing this measurement while changing the position of the probe 1, the plane distribution can be obtained with the resolution of the scanning probe microscope.

  In such photocurrent measurement and analysis, the bias voltage is fixed and the wavelength and light quantity of the irradiated light are changed to measure the light wavelength dependence and light quantity dependence of the photocurrent characteristics. By measuring the temperature dependence of the photocurrent characteristics by changing the temperature at a constant temperature, the physical properties and their distribution in the micro region of the sample 2 can be evaluated in more detail and displayed.

  When a material such as many oxides is used as the sample 2, the resistivity of the sample 2 at room temperature is high, so that the probe 1 is brought into contact with the sample 2 and a bias voltage is applied to irradiate light. In some cases, the value of the flowing current is small, making it difficult to measure the photocurrent. In such a case, it was found that a photocurrent that can be easily measured can be obtained by increasing the temperature of the sample 2 to reduce the resistivity and then performing light irradiation. As a means for promoting the photocurrent as described above, a method of changing the temperature of the sample 2 locally or as a whole of the sample 2 can be supplementarily used. As a specific means for changing the temperature of the sample 2, for example, a method using a high-temperature sample stage can be selected. Examples of the high-temperature sample stage that can be used for such purposes include those manufactured by Seiko Instruments Inc.

  FIG. 3 is a diagram showing the relationship between the control current and the oscillation output of a laser diode (manufactured by Neoarc) that emits light having a wavelength of 407 nm as an example of a laser diode that can be used as the light source 5. When this laser diode is used, it can be seen that the oscillation output can be adjusted by the control current when the control current is set to 45 mA or more.

  As the light source 5, various lamps such as a mercury lamp can be used taking advantage of the characteristics of the wavelength distribution of each lamp.

  In the physical property evaluation of the microscopic area of the present invention, when the sample 2 is irradiated with light and the photocurrent is measured, as described above, the sample 2 is heated and given a temperature change. At the time of measurement, a change in at least one of a magnetic field, an electric field, and a sound field can be applied to the sample 2. More information on the physical properties of the sample 2 can be obtained from the change in the detection current caused by adding any of these.

  Next, the main points of the apparatus configuration including the relative position control between the probe 1 and the sample 2 and the contact state control between them in the apparatus used for evaluating the physical properties of the micro area according to the present invention will be described.

  FIG. 4 is a block diagram of an embodiment of such an apparatus configuration. This block diagram includes a block A for measuring and evaluating photocurrent characteristics in a fine region, and a block B for controlling the relative position between the probe 1 and the sample 2 and controlling the contact state between the probe 1 and the sample 2. Can be divided.

  The block A constitutes a photocurrent measuring unit. In the photocurrent measurement unit of block A, as already described with reference to FIG. 1, a bias voltage is applied between the probe 1 and the sample 2 that are kept in contact with each other, and the light from the light source 5 is collected by the condensing unit 6. The photocurrent signal flowing between the probe 1 and the sample 2 is detected by the current detection preamplifier 11 and amplified by the current amplifier 12 by irradiating the surface of the sample 2 with the light collected by Then, the current data processing unit 13 performs data processing. 4 correspond to reference numerals 7 to 8 in FIG. The result of data processing in the current data processing unit 13 is displayed on the current characteristic display unit 14.

  On the other hand, the block B precisely controls the relative positional relationship between the probe 1 and the sample 2 and the contact state between the probe 1 and the sample 2 necessary for measuring the photocurrent characteristics of the fine region in the block A. It is. Its configuration and function are the same as those of a scanning probe microscope such as a normal scanning tunneling microscope. In block B, the control unit 17 controls the coarse movement mechanism 20 for largely moving the relative position of the piezo element 18 and the probe 1 and the sample 2, and moves the probe 1 relative to the sample 2. The scanning is performed and the contact state between the probe 1 and the sample 2 is maintained. The piezoelectric element 18 that is an actuator for controlling the relative position between the probe 1 and the sample 2 can also be provided on the probe side for position control.

  The position of the probe 1 in contact with the sample 2 is detected by a probe displacement detection unit 15 using a capacitance type or optical lever system, and the detection result is processed by a displacement data processing unit 16. The control signal is input to the control unit 17 and a control signal based on the input is input to the piezo element 18 constituting the scanner to perform precise control. This control result reflects the surface shape of the sample 2 and is displayed on the surface shape display unit 19.

  An optical lever method can be used for detecting the displacement of the probe 1. When using the optical lever system, it is necessary to prevent the position control by the optical lever from being disturbed by the light source 5, and it is necessary to prevent the photocurrent of the sample 2 from being affected by the light used in the optical lever system. is there. For this reason, it is preferable to select and use light having a wavelength that does not cause a photoconductive effect on the sample 2 to be measured as light for the lever. In addition, the photodetector used for the optical lever is protected by an optical filter that passes only light in the vicinity of the wavelength range of light used in the optical lever method, and only the light in the vicinity of the wavelength range of light used in the optical lever method is detected. It is preferable to do.

  In FIG. 5, an example of the spectral sensitivity of the photodetector used for the optical lever is shown by a dotted line. This photodetector can be protected by an optical filter so that, for example, as shown by a solid line in FIG. 5, the sensitivity is provided only in the vicinity of the wavelength range of light used in the optical lever system. By doing so, the influence of the light of the light source 5 can be eliminated, and the function of the light lever can be prevented from being disturbed by the light of the light source 5.

  Next, examples of the present invention will be described. These examples show specific examples of the present invention and do not limit the scope of the present invention. The scope of the present invention is determined based on the claims.

  Using the configuration of photocurrent measurement shown in FIG. 1, the photocurrent characteristics of a fine region were measured for a sample 2 of a silicon wafer having a size of 25 mm × 25 mm × 1 mm and doped with boron. By using the function of the scanning probe microscope apparatus (SPA-300HV, manufactured by Seiko Instruments Inc.), the position control between the probe 1 and the sample 2 shown in the block B of FIG. 4 described above was performed. . As the light source 5, a laser diode (manufactured by Neoarc) that emits light having a wavelength of 407 nm was used. In addition, a metal microscope (manufactured by Olympus) attached to the used scanning probe microscope was used as the condensing unit 6. The measured current data was processed (digital processing) using software attached to the scanning probe microscope apparatus.

  This apparatus employs an optical lever method for detecting the position of the probe 1. The scanner 3 on which the sample stage is placed uses a piezo element, and can be controlled with ± 200 V / 18 bits in the xy direction and ± 200 V / 21 bits in the z direction. The resolution is 0.3 nm in the xy direction and 0.01 nm in the z direction, and the bias voltage between the probe 1 and the sample 2 can be varied within a range of ± 10V. For the probe 1, a silicon nitride material coated with gold as a metal conductive coating was used.

  With the above-described configuration, the probe 1 and the sample 2 were brought into contact with each other to form a Schottky junction between a metal and a silicon wafer, and voltage-current characteristic data of a minute region described below was measured.

  Prior to the acquisition of voltage-current characteristic data, the function of the scanning electron microscope is used, and the computer software attached to the apparatus is used for data processing, and the shape image, current image, and friction image of the silicon wafer sample 2 are used. I tried to observe. As a result, regarding the shape image, since the silicon wafer was very flat and ± 0.01 nm, the signal due to the shape of the surface was below the ambient noise level. In the current image, a pattern due to the regular arrangement of atoms was observed. Further, the friction image on the silicon wafer surface was below the ambient noise level as in the case of the shape image.

  Subsequently, the current-voltage characteristics of the silicon wafer when no light was irradiated were obtained. The measurement range was a range of 100 nm square in the xy direction, and the relationship of current to this bias voltage was determined while moving the position every 10 nm. For data processing of the measurement results, software attached to the scanning probe microscope was used, and voltage-current characteristics were obtained with the horizontal axis representing voltage and the vertical axis representing current for each position.

  The results are shown in FIG. The voltage-current characteristics in FIG. 6 indicate that a Schottky junction is obtained. In FIG. 6, the voltage-current characteristics are substantially well aligned, and the breakdown voltage on the negative voltage side is also well aligned.

  Next, the same measurement was performed on the same measurement point in a state where light was irradiated using the laser diode of the light source 5. The result is shown in FIG. According to the measurement result of FIG. 7, the voltage-current characteristic curve 7b having a lower breakdown voltage is obtained in addition to the voltage-current characteristic curve 7a having almost the same breakdown voltage and almost the same breakdown voltage. Has appeared. This is because carriers are excited in a specific part of the silicon wafer by light irradiation, and the breakdown voltage of this part is lowered.

  The measurement position of the silicon wafer sample 2 of Example 1 was changed, and the voltage-current characteristics of the fine region were obtained in the same procedure as in Example 1 for another 100 nm square range. First, the voltage-current characteristic in the state which does not irradiate light was calculated | required. The result is shown in FIG. In FIG. 8, focusing on the negative voltage side of the voltage-current characteristic, that is, the reverse bias side, in addition to the curve group 8a in which the voltage-current characteristic is substantially uniform and the breakdown voltage is substantially uniform, the voltage-current characteristic having a lower breakdown voltage. It can be seen that the curve 8b exists. This corresponds to the impurity portion of the silicon wafer, which is considered to change the Schottky junction characteristics, and in particular to lower the breakdown voltage.

  Next, the same measurement was performed on the same measurement point in a state where light was irradiated using the laser diode of the light source 5. The result is shown in FIG. In FIG. 9, the curve of the voltage-current characteristic converges to almost one curve group, and the breakdown voltages thereof are almost uniform. This is because the carrier is supplied not only to the impurity part of the silicon wafer but also to other parts as a result of the carrier being supplied to the sample 2 by light irradiation, and as a result, the breakdown voltage is almost uniform. Show.

  Thus, it can be seen that a difference in physical properties of the sample 2 that is not found when light is not irradiated is detected as a clear voltage-current characteristic difference by irradiating light and measuring the photocurrent. .

With respect to β-alumina sample 2 having dimensions of 25 mm × 25 mm × 1 mm, the photocurrent characteristics in a fine region were measured. The measurement conditions were the same as in Example 1 except that the temperature of Sample 2 was increased to 400 ° C. using a high-temperature test stand. Here, the temperature of Sample 2 was set to 400 ° C. in the change in the electrical conductivity of glass and related materials shown in FIG. 10 (according to “Glass Science Fundamentals and Applications” written by Sakuhana Sakuo) The electrical conductivity σ of alumina was about 10 ⁻¹ Ω ⁻¹ · cm ⁻¹ at 400 ° C., and therefore the resistivity was about 10 Ω · cm (10 ⁻¹ Ω · m), so that the current could be measured easily. Is.

  The measurement results are shown in FIG. In FIG. 11, only the voltage-current curve at one measurement point shows a low breakdown voltage under a reverse bias. Of these measurement points, it is considered that only this measurement point has a significant increase in carriers due to light irradiation, resulting in a decrease in breakdown voltage. Thus, it was found that among the measurement points of the sample 2, the position of the measurement point was different from the other positions in the material properties.

  According to the present invention, if a method of measuring the photocurrent of a micro area by irradiating a sample with light is used, it has become possible to evaluate the physical properties of the micro area which could not be clarified by a conventional method. In addition, even when the sample is not a good conductor at room temperature, for example, glass and other materials, by measuring the photocurrent in a minute region by irradiating light in a state where the temperature of the sample is increased and the conductivity is increased, The physical properties can be evaluated relatively easily. Therefore, the new physical property evaluation means of the present invention is expected to be widely used in many industrial fields including the material field.

It is the figure which showed typically one Embodiment of the structure of the photocurrent measurement by this invention. It is the figure which showed typically one Embodiment in the case of irradiating light from a diagonal direction with respect to a sample in the photocurrent measurement by this invention. In this invention, it is the figure which showed an example of the relationship between the control current and oscillation output of the laser diode used as a light source. It is the block diagram which showed the principal part about one Embodiment of the structure including control of the relative position of the probe and a sample in the apparatus used for the physical property evaluation of the micro area | region in this invention. It is the figure which showed the example of the sensitivity curve at the time of protecting the photodetector used for an optical lever with an optical filter. In Example 1, it is the figure which showed the result of having calculated | required the relationship of the electric current with respect to the bias voltage of each point, moving a position for every 10 nm when not irradiating light to a silicon wafer. It is the figure which showed the result of having calculated | required the relationship of the electric current with respect to the bias voltage of each point, moving a position every 10 nm in the state which irradiated the silicon wafer in Example 1. FIG. In Example 2, it is the figure which showed the result of having calculated | required the relationship of the electric current with respect to the bias voltage of each point, moving a position for every 10 nm when not irradiating light to a silicon wafer. In Example 2, it is the figure which showed the result of having calculated | required the relationship of the electric current with respect to the bias voltage of each point, moving a position every 10 nm in the state which irradiated the light to the silicon wafer. It is the figure which showed the temperature change of the electrical conductivity of glass and related material. In Example 3, it is the figure which showed the result of having measured the photocurrent characteristic of the micro area | region in the state which raised the temperature to 400 degreeC using the high temperature test stand for the sample of (beta) -alumina.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Probe, 2 ... Sample, 3 ... Scanner, 4 ... Voltage control part, 5 ... Light source, 6 ... Condensing part, 7 ... Current measurement part, 8 ... Personal computer, 9 ... Display part, 11 ... Before current detection Amplifying section, 12 ... Current amplifying section, 13 ... Current data processing section, 14 ... Current characteristic display section, 17 ... Control section, 18 ... Piezo element, 19 ... Surface shape display section, 20 ... Coarse motion mechanism

Claims (13)

  A method for evaluating the physical properties of a micro region using a scanning probe microscope, wherein a conductive probe is brought into contact with the surface of a sample, a bias voltage is applied between the sample and the probe, and Physical properties of a micro region characterized by comprising each operation of irradiating light at or near the position where the tip of the probe contacts on the surface and detecting a current flowing between the sample and the probe Evaluation methods.   The physical property evaluation method for a micro region according to claim 1, further comprising an operation of changing at least one of a wavelength and an intensity of the light.   3. The method for evaluating physical properties of a micro region according to claim 1, wherein a laser beam is used as the light.   The physical property evaluation method for a micro region according to any one of claims 1 to 3, further comprising an operation for giving a temperature change to the sample.   5. The physical property evaluation method for a micro region according to claim 1, further comprising an operation of applying at least one of a magnetic field, an electric field, and a sound field to the sample.   6. The method according to claim 1, further comprising an operation of detecting a current flowing between the sample and the probe when the sample surface is not irradiated with light and comparing the detected current. For evaluating the physical properties of micro-regions by detecting the current of the current. A conductive probe;
A contact means for bringing the tip of the probe into contact with the surface of the sample;
Moving means for relatively moving the positional relationship between the tip of the probe and the sample while bringing the tip of the probe into contact with the surface of the sample;
A light irradiating means for irradiating light at or near the position where the tip of the probe contacts the surface of the sample;
Voltage applying means for applying a bias voltage between the sample and the probe;
Current detection means for detecting current flowing between the sample and the probe;
A scanning probe microscope comprising:   8. The scanning probe microscope according to claim 7, wherein the light irradiating means includes a changing means for changing at least one of a wavelength and an intensity of light irradiated on the sample.   9. The scanning probe microscope according to claim 7, wherein the irradiating means uses a laser as a light source.   The probe is coupled to a cantilever that detects displacement by an optical lever system, and a photodetector that detects the displacement of the probe by the optical lever system transmits light from the optical lever and emits light from the light irradiation means. The scanning probe microscope according to claim 7, wherein the scanning probe microscope is protected by a filter that blocks light.   The scanning probe microscope according to any one of claims 7 to 10, further comprising temperature changing means for giving a temperature change to the sample.   The scanning probe microscope according to claim 7, further comprising an application unit configured to apply at least one of a magnetic field, an electric field, and a sound field to the sample. The surface shape display means for obtaining and displaying the surface shape of the sample from the amount of displacement of the probe when the relative position between the probe and the sample is moved by the moving means. The scanning probe microscope according to any one of 7 to 12.

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