JP2012163551A - Holder for electric detection electronic spin resonance apparatus and electric detection electronic spin resonance apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly reliably evaluate the density and the origin of a defect in an insulation film or in a semiconductor film by surely securing an electrical contact for electric detection electronic spin resonance measurement and remarkably reducing noise caused by contact resistance or the like.SOLUTION: A sample holder for electric detection electronic spin resonance is provided which includes, in order to solve steam problems, a pair of electrodes disposed on a measurement sample, a pair of wires connected to a pair of tungsten needles in contact with the electrodes, a bolt for mounting the wires to the sample holder via a spring washer and a nut, a partition formed around the measurement sample, a setscrew inserted into the partition, and a leaf spring disposed between the partition and the measurement sample.

Description

  The present invention relates to an electric detection electron spin resonance apparatus and a sample holder used therefor.

  The electric detection electron spin resonance method is a technique that applies the principle of the electron spin resonance method that has existed conventionally. This is a method for evaluating the density and origin of atomic level defects present in a film or at an interface in a sample having an insulating film or semiconductor structure sandwiched between any two electrodes. Advantages of the conventional electron spin resonance method include: 1. Very high sensitivity Since only the region sandwiched between the electrodes is the object to be measured, any structure existing outside the electrode is not disturbed by the measurement.

  In the electron spin resonance method, a magnetic field is applied to a sample while being irradiated with a microwave having a fixed frequency. Here, the magnetic field strength is variable and is swept. When a magnetic field is applied to the sample, the orbit of a defect having an unpaired electron causes Zeeman splitting and splits into two orbitals of a ground state and an excited state. At this stage, unpaired electrons exist in the ground state orbitals. Here, the Zeeman splitting width is proportional to the magnetic field strength. When the magnetic field intensity is swept and the energy of the irradiated microwave becomes equal to the Zeeman splitting width, unpaired electrons existing in the ground state absorb the microwave energy and transition to the excited state. A conventional technique for measuring the amount of absorption of microwaves as a function of magnetic field intensity and evaluating the density and origin of defects is the electron spin resonance method.

  On the other hand, in the electric detection electron spin resonance method, the absorption amount of microwaves is not measured. When a voltage is applied between two arbitrary electrodes, a leak current flows in an insulating film or a semiconductor film sandwiched between them. In this state, a microwave with a fixed frequency and a magnetic field with a variable intensity are applied. When the energy of the Zeeman splitting width is different from the energy of the irradiated microwave, the unpaired electron of the defect exists in the ground state orbit, and the spin direction of the unpaired electron is a conduction electron flowing in the film. This is the same as the spin direction. That is, both electron spin directions are equal. In this case, here, the direction of these spins is defined as upward. Of the two orbits of defects, the ground state orbitals already contain upward unpaired electrons. Therefore, upward conduction electrons cannot enter the same ground state orbit by Pauli exclusion. Also, the excited state orbit can only enter downward, that is, spins in the opposite direction. Therefore, the conduction electrons cannot enter both the ground state and excited state orbitals. This effect prevents conduction electrons from moving through the defects in the film, resulting in a decrease in electrical conductivity.

  On the other hand, when the Zeeman splitting width becomes equal to the energy of the microwave, the unpaired electrons absorb the microwave and become a downward spin, and transition to an excited state orbit. That is, a vacant space is created in the ground state in which the upward spin can enter. Since conduction electrons are upward spins, they can enter this orbit and move between the electrodes via defects in the film. Thus, the electrical conductivity increases. As described above, when the magnetic field intensity is swept while irradiating the microwave with a certain wavelength, the electric conductivity, that is, the amount of leak current flowing through the sample increases under a certain magnetic field intensity. From the amount of change in the leakage current amount, it is possible to evaluate the defect density, and from the magnetic field intensity at which the leakage current amount changes, the origin of the defect can be evaluated.

The issue here is measurement of the amount of change in leakage current. In general, the amount of change in the leakage current is as small as 10 ⁻⁴ or less, so measurement is very difficult. In particular, when there is a defect in electrical contact between the sample and the wiring and contact resistance occurs, it becomes a very large noise source. That is, in order to reduce noise, it is necessary to ensure electrical contact between the sample and the wiring and reduce contact resistance.

  In addition, the electric detection electron spin resonance method can increase the signal intensity, that is, the amount of change in leakage current, by lowering the sample temperature, but the material around the sample is deformed during this cooling, It may be difficult to ensure electrical contact.

  Furthermore, when irradiating microwaves, it is necessary to place the sample inside the quartz tube and then insert it into the microwave resonator. To ensure the stability of the microwave and magnetic field strength, There is a limit to the size of the resonator. Therefore, there is a size limitation on the inner diameter of the quartz tube into which the sample is put, and it is difficult to put a sample of φ4 mm or more.

  Here, in Patent Document 1, a holding member having a recess and a sample are held on the surface thereof, and a plate body that is accommodated in the recess, and a cover that is covered with the recess while the plate body is accommodated therein. A sample holder for an electron spin resonance apparatus is disclosed.

JP-A-8-35919

  In the sample holder for the electron spin resonance apparatus of Patent Document 1, the problem of electrical contact between the sample and the wiring is not considered, and current noise derived from contact resistance or the like can be reduced as much as possible. The leakage current flowing through the sample cannot be detected with high sensitivity.

  In view of the above problems, the present invention makes it possible to reliably ensure electrical contact for electrically detected electron spin resonance measurement, greatly reducing noise derived from contact resistance, etc., in an insulating film or a semiconductor film. The purpose is to make a reliable evaluation of the density of defects.

  The present invention includes a plurality of means for solving the above-described problems. For example, a pair of electrodes disposed on a measurement sample and a pair of tungsten needles in contact with the electrodes are connected. A wiring, a bolt for attaching the wiring to the sample holder via a spring washer and a nut, a partition formed around the measurement sample, an agate screw inserted in the partition, the partition and the measurement sample A sample holder for electron detection electron spin resonance comprising a leaf spring disposed between the two is provided.

  By using the sample holder of the present invention, it is possible to reliably ensure electrical contact with respect to the electrical detection electron spin resonance measurement, greatly reducing noise derived from contact resistance and the like, in an insulating film or a semiconductor film. It is possible to make a highly reliable evaluation of the density of defects.

It is the schematic which shows embodiment of the electric detection electron spin resonance measuring apparatus which uses the sample holder concerning this invention. It is a figure which shows the structure of the sample holder of Example 1 in this invention. In addition, it is the figure which looked at the sample holder from the top. It is a figure which shows the structure of the sample holder of Example 1 in this invention. In addition, it is the figure which looked at the sample holder from the side. It is a figure explaining embodiment at the time of performing an electric detection electron spin resonance measurement using the sample holder of Example 1 in the present invention. It is a figure which shows the result of the electric detection electron spin resonance measurement using the sample holder of Example 1 in this invention. When the sample holder of Example 1 of the present invention is used and the sample temperature is set to 100 K, when the sample holder of FIG. 4B is used and the sample temperature is set to room temperature, FIG. When the sample temperature is 100K, the sample temperature is 100K, the sample holder of Example 1 of the present invention is used, the gold coat at the tip of the tungsten needle is removed, and the sample temperature is 100K FIG. 6 is a diagram describing signals obtained by the electric detection electron spin resonance measurement in the four cases. It is a figure which shows the structure of the sample holder in the case of connecting between the electrode on a sample, and wiring by wire bonding. In addition, it is the figure which looked at the sample holder from the top. It is a figure which shows the structure of the sample holder of Example 2 in this invention. In addition, it is the figure which looked at the sample holder from the top. It is a figure which shows the structure of the sample holder of Example 2 in this invention. In addition, it is the figure which looked at the sample holder from the side. It is a figure explaining embodiment at the time of performing an electric detection electron spin resonance measurement using the sample holder of Example 2 in the present invention.

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

  In this embodiment, an example of a sample holder in an electric detection electron spin resonance apparatus and an example of a method of performing electric detection electron spin resonance measurement using the sample holder will be described.

  FIG. 1 is a schematic view of an electric detection electron spin resonance apparatus. A DC magnetic field sweeping electromagnet 101, an AC magnetic field applying electromagnet 102, a microwave irradiation unit 103, a microwave resonator 104, and a sample tube 105 introduced into the microwave resonator 104. Further, a sample holder 106 and a measurement sample 107 are inserted into the sample tube 105.

  FIGS. 2A and 2B are examples of the sample holder 106 used in the electric detection electron spin resonance apparatus in the present embodiment.

  A measurement sample 107 is installed on the surface of the sample holder 106. A pair of electrodes 201 arranged apart from each other are formed on the measurement sample 107. A pair of wirings 202 is formed on the surface of the sample holder 106. The wiring 202 is for applying a voltage between the pair of electrodes 201 and measuring a current flowing between the pair of electrodes 201, and may be a general metal such as gold or aluminum. The pair of wires is attached to the sample holder 106 by a pair of bolts 203 via a pair of spring washers 204 and a pair of nuts 205. A spring washer 204 and a nut 205 are installed below the bolt 203. Further, a partition 206 is provided around the measurement sample 107, and the partition 206 has two holes, so that a screw 207 can be inserted. Two holes are provided in one place on two adjacent sides of the partition 206. Further, leaf springs 208 are attached to two locations between the side opposite to the side where the scissors screw 207 of the partition 206 is provided and the measurement sample 107. A tungsten needle 209 whose tip is coated with gold 210 is in contact with the electrode 201 formed on the measurement sample 107. A tungsten needle 209 whose tip is coated with gold 210 passes between the bolt 203 and the spring washer 204 and is connected to the wiring 202. Furthermore, the tip of the wiring 202 is connected to a cable 211 connected to a power source / ammeter and a measurement system. With this structure, it is possible to apply a voltage between the pair of electrodes 201 and measure the current through the pair of cables 211 and the pair of tungsten needles 209 whose tips are coated with gold 210.

Here, a method of contacting the electrode 201 with a tungsten needle 209 whose tip is coated with gold 210 will be described. The movement of the tungsten needle 209 whose tip is coated with gold 210 in the z direction can be adjusted by tightening or loosening the bolt 203. However, if the tungsten needle 209 whose tip is coated with gold 210 is pressed too much, the tip penetrates the electrode 201 and causes physical damage to the measurement sample 107. Therefore, the spring washer 204 has a mechanism that can always keep the force applied to the electrode 201 within a certain range. The indentation strength is 100 to 200 N / m ² . When the value is smaller than this value, the portion of the gold 210 at the tip of the tungsten needle 209 whose tip is coated with the gold 210 cannot penetrate the natural oxide film formed on the electrode 201. As a result, it is difficult to ensure stable electrical contact. On the other hand, when the value is larger than this value, the measurement sample 107 is physically damaged through the electrode 201. Therefore, the pressing force needs to be 100 to 200 N / m ² .

  The movement in the x direction and the y direction is performed using a screw 207 and a leaf spring 208. By tightening the scissors screw 207, the measurement sample can be moved and can be restrained from the opposite side by the leaf spring 208, so that the position of the measurement sample 107 can be kept stable.

  With the sample holder 106 described above, it is possible to ensure stable electrical conduction to the electrode 201. Here, both the electrodes 201 are formed on the measurement sample 107, but even if one of the electrodes 201 is below the measurement sample 107, it is possible to ensure electrical continuity, so that there is no particular problem. Further, the position of the electrode 201 on the measurement sample 107 is arbitrary.

  Moreover, since microwaves are absorbed by metal, it is necessary to avoid using metal as much as possible. Therefore, the sample holder 106, the bolt 203, the spring washer 204, the nut 205, the partition 206, and the scissors screw 207 need to be non-metallic. However, when an insulating resin material or the like is used, deformation or distortion occurs when the measurement sample 107 is cooled. Therefore, the position of the tip of the tungsten needle 209 whose tip is coated with gold 210 is determined. , It will be displaced from the electrode 201, and it will be an obstacle to ensuring electrical continuity. Therefore, it is necessary to use a ceramic material such as high-purity glass instead of a resin material. With regard to the leaf spring 208, since the ceramic material lacks elasticity, the effect as a spring cannot be expected. Therefore, the leaf spring 208 needs to use metal. However, if a thick metal piece having a thickness of 1 mm or more is used, microwave absorption is too large. Therefore, it is desirable to use a metal having a thickness of 0.5 ± 0.1 mm, such as copper or gold. If it is thicker than this, the microwave absorption is large, which hinders measurement. Conversely, if it is thin, it will not function as a spring.

  As for the tungsten needle 209 whose tip is coated with gold 210, tungsten is a metal, and a natural oxide film is formed on the surface thereof in the atmosphere. Since the natural oxide film also hinders stable electrical conduction, it is necessary to coat the tip with gold 210 on which no natural oxide film is formed. The thickness of the coating is desirably 0.1 mm or less.

  Furthermore, the distance from the tip of the bolt 203 to the upper part of the tungsten needle 209 whose lower end is coated with gold 210 needs to be 4 mm or less. If this is exceeded, the sample holder 106 cannot be inserted into the sample tube 105. As described above, by separating the moving mechanism in the z direction and the x and y directions, the whole can be accommodated within 4 mm.

  By using the sample holder structure of the present embodiment described above, it is possible to ensure stable electrical conduction even in a low temperature state, and it is possible to suppress the entire size to 4 mm or less.

  Subsequently, a procedure for conducting the electric detection electron spin resonance measurement using the sample holder 106 in the present embodiment will be specifically described.

FIG. 3 is a diagram showing an experimental procedure of an electric detection electron spin resonance experiment. A cable 211 extends from the wiring 202 on the sample holder 106 on which the measurement sample 107 is installed, and is connected to the power source / ammeter 301. Here, the measurement sample 107 will be described using the structure of electrode-silicon nitride film (film thickness is 3 nm, including defects inside) -electrode, but it should be understood that other structures will not hinder the present invention. Absent. Here, a DC magnetic field sweeping electromagnet 101 applies and sweeps a DC magnetic field of 327 mT to 330 mT to the sample 107. At the same time, an AC magnetic field having an amplitude of 0.5 mT and a frequency of 80 Hz is applied by the AC magnetic field electromagnet 102. Further, the measurement sample 107 is irradiated with a microwave having a fixed frequency of 9.6 MHz by using the microwave irradiation unit 103 in this state. A voltage of 1 V is applied from the power source / ammeter 301 between the two electrodes 201 on the measurement sample 107. Here, the measurement sample 107 has a mechanism in which vaporized liquid nitrogen is blown through the transfer tube 303 from the dewar 302 filled with liquid nitrogen. Thereby, the sample temperature is cooled to 100K. Here, although it cooled to 100K using liquid nitrogen, even if it cools to further low temperature using liquid helium as a refrigerant, there is no problem in the present invention. Then, when the change amount of the leakage current at that time is detected using the lock-in amplifier 304 and plotted against the intensity of the DC magnetic field being swept, a signal 305 shown in FIG. 3B is obtained. From this signal intensity and the value of the magnetic field intensity giving a peak, it is estimated that the density of defects is 10 ¹⁸ and the origin is a dangling bond of Si.
It should be noted that a similar signal can be obtained by changing the sweep range of the DC magnetic field, the amplitude, frequency, microwave frequency, and voltage applied to the measurement sample 107 of the AC magnetic field. There is no.

  Next, the effect of the sample holder 106 in this embodiment will be described with reference to FIG.

  A signal 305 shown in FIG. 4A is an electric detection electron spin resonance signal measured using the sample holder 106 in the present embodiment. On the other hand, the signal 401 is a result of measurement using a sample holder 402 shown in FIG. Here, in the sample holder 402, the electrode 201 and the wiring 202 are connected by an aluminum thin wire 403 by wire bonding. On the other hand, the signal 404 is a result of measurement using the sample holder 402 shown in FIG. 4B and cooling the measurement sample 107 to 100 K using liquid nitrogen. The signal 405 is a result of measurement using the sample holder 106 shown in FIG. 2 and cooling the measurement sample 107 to 100 K using liquid nitrogen. However, the measurement is performed by removing the gold 210 at the tip of the tungsten needle 209 whose tip is coated with the gold 210.

  Compared with the signal 305, it can be seen that the signal 401 has much larger noise and it is difficult to obtain highly reliable data. This is because the measurement sample is physically destroyed by the impact force during wire bonding and a large noise is generated. In the signal 404, no signal is obtained. This is because, in the process of cooling the measurement sample 107, due to the difference in contraction rate of the material, the wire-bonded aluminum wiring 403 is peeled off from the electrode 201, so that electrical continuity cannot be secured. Further, in the signal 405, a signal having a shape similar to that of the signal 305 is obtained, but the noise is very large and the signal intensity is greatly attenuated. This is because the formation of the natural oxide film due to the peeling off of the gold 210 hinders securing of stable electrical conduction.

  From the above measurement results, the effect of the sample holder 106 of this example was verified.

  In the present embodiment, in the electrical detection electron spin resonance apparatus that facilitates ensuring electrical contact when installing a measurement sample, and further confirms that electrical contact is secured during electrical detection electron spin resonance measurement. An example of a sample holder and a method of performing electric detection electron spin resonance measurement using the sample holder will be described.

  FIG. 1 is a schematic view of an electric detection electron spin resonance apparatus. Since the electric detection electron spin resonance apparatus shown in FIG. 1 has already been described in the first embodiment, the description thereof will be omitted.

  FIGS. 5A and 5B are examples of the sample holder 106 used in the electric detection electron spin resonance apparatus in the present embodiment. Among the sample holders 106 used in the electric detection electron spin resonance apparatus of FIGS. 5A and 5B, the configuration denoted by the same reference numerals shown in FIGS. 2A and 2B described above, Description of portions having the same function is omitted.

  A tungsten needle 509 whose tip is coated with gold 510 is in contact with the electrode 201 formed on the measurement sample 107. A tungsten needle 509 whose tip is coated with gold 510 passes between the bolt 203 and the spring washer 204 and is connected to the wiring 202. With this structure, it is possible to apply a voltage between a pair of electrodes 201 and measure a current through a pair of cables 211 and a pair of tungsten needles 509 whose tips are coated with gold 510. A strain detector 512 is attached on the tungsten needle 509.

  Here, for the strain detector 512, for example, a strain gauge using a copper-nickel alloy is used. In this embodiment, a strain gauge using a copper-nickel alloy is used for the strain detector 512, but the material used for the strain gauge is not limited to a copper-nickel alloy, for example, a nickel-chromium alloy or silicon. But it ’s okay. The strain detector 512 is not limited to a strain gauge, and a strain sensor of a system using an optical fiber or a system using a semiconductor element may be used.

  In the case of a strain gauge using a copper-nickel alloy, the electrical resistance changes due to the expansion and contraction of the copper-nickel alloy. The electrical resistance is not limited to the copper-nickel alloy, and for example, the electrical resistance changes due to expansion and contraction even in a nickel-chromium alloy or silicon. By measuring the change in electrical resistance, the strain of the strain gauge can be measured.

  In the system using an optical fiber, the optical path length of light propagating through the inside changes as the optical fiber expands and contracts. The strain of the strain gauge can be measured by measuring the change in the interference intensity due to the optical interference between the detection light and the reference light using the laser light.

  In the system using a semiconductor element, the electrical resistance changes due to expansion and contraction, similar to a strain gauge using a copper-nickel alloy. By measuring the change in electrical resistance, the strain of the strain gauge can be measured.

  A signal line 513 from the strain detector 512 is connected to the wiring 514. Furthermore, the tip of the wiring 514 is connected to a cable 515 connected to the strain measuring device 516. With this structure, the strain of the tungsten needle 509 can be measured.

  Here, a method for measuring the force to be pressed when the tungsten needle 509 whose tip is coated with the gold 510 is brought into contact with the electrode 201 will be described. By tightening the bolt 203, the tungsten needle 509 is moved in the z direction and brought into contact with the electrode 201, and then pressed against the electrode 201 by further tightening the bolt. At this time, the strain amount of the tungsten needle 509 can be measured by reading the signal from the strain detector 512 with the strain measuring device 516. The distortion of the tungsten needle 509 is caused by the deflection of the tungsten needle 509 when the tungsten needle 509 is pressed against the electrode 201. Since the force for pushing the tungsten needle 509 into the electrode 201 is proportional to the strain of the tungsten needle 509, the force for pushing the tungsten needle 509 into the electrode 201 can be measured.

In order to ensure electrical contact, the force for pushing the tungsten needle 509 into the electrode 201 needs to be 100 to 200 N / m ² as described in the first embodiment. By adjusting the movement of the tungsten needle 509 in the z direction while measuring the force for pushing the tungsten needle 509 into the electrode 201 by the above method, the force for pushing the tungsten needle 509 into the electrode 201 is within the range of 100 to 200 N / m ² . It is easy to adjust and secure electrical contact.

  Further, a method for simultaneously measuring the contact force between the tungsten needle 509 and the electrode 201 during the electrical detection electron spin resonance measurement using the sample holder 106 in this embodiment will be described with reference to FIG. In the electric detection electron spin resonance apparatus shown in FIG. 6, the description of the components having the same functions as those shown in FIG. .

  A cable 515 extends from the wiring 514 on the sample holder 106 on which the measurement sample 107 is installed, and is connected to the strain measuring device 516.

  The contact force between the tungsten needle 509 and the electrode 201 can be measured by measuring the strain of the tungsten needle 509 using the strain measuring device 516 during the electric detection electron spin resonance measurement.

  When the sample is cooled during the measurement of the electric detection electron spin resonance, the contact state between the tungsten needle 509 and the electrode 201 may change due to thermal expansion of the sample or a component of the sample holder. In particular, when the sample is rapidly cooled or when long-time integrated measurement is performed, the contact state between the tungsten needle 509 and the electrode 201 is likely to change during the measurement.

  When the contact state between the tungsten needle 509 and the electrode 201 changes, electrical contact is not ensured, and noise is increased in the electric detection electron spin resonance signal.

  In such a case, it is possible to confirm that the electrical contact is ensured by measuring the contact force of the electrode 201 of the tungsten needle 509 during the electrical detection electron spin resonance measurement by the above method of the present embodiment. In addition, when the contact state of the probe changes, it is possible to take measures such as redoing the measurement, and it is possible to prevent the noise of the electric detection electron spin resonance signal from increasing.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described.

DESCRIPTION OF SYMBOLS 101 ... DC magnetic field sweeping electromagnet 102 ... AC magnetic field application electromagnet 103 ... Microwave irradiation unit 104 ... Microwave resonance cavity 105 ... Sample tube 106 ... Sample holder 107 ... Sample 201 ... Electrode 202 ... Wiring 203 ... Bolt 204 ... Spring washer 205 ... Nut 206 ... Partition 207 ... Pin screw 208 ... Leaf spring 209 ... Tip Gold-coated tungsten needle 210 ... Gold 211 ... Cable 301 ... Power source / Ammeter 302 ... Dewar 303 ... Transfer tube 304 ... Lock-in amplifier 305 ... Electrically detected electron spin resonance spectrum 401 measured with sample holder 106 Electricity measured at room temperature with sample holder 402 Electron emission spin resonance spectrum 402... Sample holder 403 used when measuring the signal 401... Aluminum wiring 404... Electrically detected electron spin resonance spectrum 405 measured at 100 K using the sample holder 402. -Electrical detection electron spin resonance spectrum 509 measured with the sample holder 106 of the present invention with the tip gold 210 peeled off ... a tungsten needle 510 with the tip coated with gold and a strain gauge attached. 512 ... Strain detector 513 ... Strain detector signal line 514 ... Wiring 515 ... Cable 516 ... Strain measuring instrument

Claims (12)

A pair of electrodes arranged on the measurement sample;
A pair of wires connected to a pair of tungsten needles in contact with the electrodes;
A bolt for attaching the wiring to the sample holder via a spring washer and a nut;
A partition formed around the measurement sample;
芋 screws inserted into the partition,
A sample holder for electrical detection electron spin resonance comprising a leaf spring disposed between the partition and the measurement sample.   2. The sample holder for electrically detected electron spin resonance according to claim 1, wherein the bolt, the spring washer, the nut, the partition, and the screw are made of ceramics such as high-purity glass.   2. The sample holder for electrically detecting electron spin resonance according to claim 1, wherein the leaf spring is gold or copper having a thickness of 0.5 ± 0.1 mm.   The sample holder for electrically detecting electron spin resonance according to claim 1, wherein the tip of the tungsten needle is coated with gold having a thickness of 0.1 mm or less.   The sample holder for an electric detection electron spin resonance apparatus according to claim 1, wherein the sample holder is within φ4 mm. The sample holder for an electric detection electron spin resonance apparatus according to claim 1, wherein the tip of the tungsten needle can be brought into contact with the electrode with a force of 100 to 200 N / m ² .   2. The sample holder for an electric detection electron spin resonance apparatus according to claim 1, wherein the contact force when the tip of the tungsten needle is pressed against the electrode is adjusted by a bolt and a spring washer.   The screw is provided on each of two adjacent sides of the partition, and the leaf spring is disposed between the side of the partition facing the side where the screw is inserted and the measurement sample. The sample holder for an electron spin resonance apparatus according to claim 1.   9. The electric detection electron spin according to claim 8, wherein adjustment of the lateral position when the tip of the tungsten needle is pressed against the electrode is performed by moving the measurement sample with a screw and a leaf spring. Resonator holder. The holder for an electric detection electron spin resonance apparatus according to claim 1,
A microwave irradiation unit for applying a microwave to the measurement sample;
An electric detection electron spin resonance apparatus comprising: an AC magnetic field electromagnet that applies an AC magnetic field to the measurement sample.   8. The sample holder for an electric detection electron spin resonance apparatus according to claim 7, wherein a contact force of the tip of the tungsten needle with respect to the electrode is measured by a contact force measuring device attached to the tungsten needle. The sample holder for an electric detection electron spin resonance apparatus according to claim 11, wherein the contact force measuring device measures a force applied to a tip of the tungsten needle by measuring a strain of the tungsten needle.

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