JP2018040659A - Ac magnetic field generator and hall effect measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Hall effect measurement device capable of measuring physical properties of a semiconductor accurately even under high temperature.SOLUTION: A Hall effect measurement device 1000 causes a first rotor R1, a second rotor R2 and a slit plate 2 coupled to a shaft Sft to rotate together with the shaft Sft at a constant angular velocity to thereby generate an AC magnetic field in a region between the first rotor R1 and the second rotor R2. The Hall effect measurement device 1000 includes a photosensor 3 which detects the position of a slit of the slit plate 2 to determine rotation angles of the first rotor R1 and the second rotor R2. A reference signal synchronized with the AC magnetic field can thus be accurately generated. The Hall effect measurement device 1000 can use the reference signal to perform measurement with Hall effect.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a Hall effect measuring apparatus.

  In order to measure the physical properties of a semiconductor sample, the carrier density and carrier mobility of the semiconductor sample are often measured. In order to measure the carrier density and carrier mobility of such a semiconductor sample, a Hall effect measuring device is used. In the Hall effect measurement device, an AC magnetic field is generated, and the measurement accuracy is improved by measuring a Hall voltage generated in a sample arranged in the AC magnetic field by a lock-in amplifier. For example, by using the Hall effect measuring apparatus disclosed in Patent Document 1, the carrier density and carrier mobility of a semiconductor sample can be measured.

JP 2005-49116 A

  However, since the Hall effect measuring apparatus of Patent Document 1 is based on the premise that a Hall element is used, there is a problem that measurement at a high temperature cannot be performed.

  In recent years, there has been a demand for the development of an apparatus capable of accurately measuring physical properties of diamond semiconductors and the like that are expected to be used as power devices. Since such a diamond semiconductor is assumed to be used as a power device, it is necessary to accurately measure physical properties of the diamond semiconductor at a high temperature (for example, a temperature of 400 degrees Celsius or higher).

  The Hall element is a semiconductor and does not operate normally at a high temperature (for example, a temperature of 100 degrees Celsius or higher). For this reason, an apparatus using a Hall element, such as the Hall effect measuring apparatus of Patent Document 1, cannot accurately measure the physical properties of a diamond semiconductor at a high temperature (for example, a temperature of 400 degrees Celsius or higher).

  Therefore, in view of the above problems, the present invention can accurately measure the physical properties of a semiconductor at room temperature (for example, a temperature of 50 degrees Celsius or lower) and at a high temperature (for example, a temperature of 400 degrees Celsius or higher). It aims at realizing an effect measuring device and an alternating magnetic field generator.

  In order to solve the above problems, a first invention is an AC magnetic field generator including a shaft, a drive unit, a slit plate, an optical sensor, a first rotating body, and a second rotating body.

  The drive unit rotates the shaft with the central axis of the shaft as a rotation axis.

  The slit plate is connected to the shaft so that the central axis of the shaft is a rotation axis, and includes a slit for position detection.

  The optical sensor includes a light emitting unit that emits light and a light receiving unit that detects light emitted from the light emitting unit. In the optical sensor, the light emitted from the light emitting unit passes through the position detection slit and reaches the light receiving unit in a state where the slit plate is rotated by a predetermined angle about the central axis of the shaft as the rotation axis. A light emitting part and a light receiving part are arranged.

  The first rotating body is connected to the shaft such that the central axis of the shaft is the rotating axis, and each of the first rotating body is a magnetized N (N: natural number and even number) region. To the first rotating body Nth magnetization region.

  The second rotating body is connected to the shaft such that the central axis of the shaft becomes the rotating axis, and the second rotating body Nth is from the second rotating body first magnetization region, which is N magnetized regions. Includes magnetized region.

  In a plan view viewed from the axial direction of the rotation axis, the first (2k−1) -th magnetization region (k: natural number, 1 ≦ k ≦ N / 2) is the second rotation-unit (2k−1). ) It is arranged so that an overlapping region which is a region overlapping with the magnetized region is generated.

  The first rotating body (2k-1) magnetization region and the second rotating body (2k-1) magnetization region are the same as the first rotating body (2k-1) magnetization region in the axial direction of the rotation axis of the overlapping region. Magnetization is performed so that a magnetic field in a first direction, which is a direction substantially parallel to the rotation axis, is generated between the two-rotor body (2k-1) magnetization region.

  In a plan view viewed from the axial direction of the rotation axis, the first rotating body 2k magnetization region is arranged so as to generate an overlapping region that overlaps the second rotation body 2k magnetization region.

  The second rotator 2k magnetization region and the second rotator 2k magnetization region are between the second rotator 2k magnetization region and the second rotator 2k magnetization region in the axial direction of the rotation axis of the overlapping region, Each is magnetized so that a magnetic field in a second direction that is substantially parallel to the rotation axis and opposite to the first direction is generated.

  In this AC magnetic field generator, the first rotator, the second rotator, and the slit plate connected to the shaft rotate at a constant angular velocity together with the shaft. An alternating magnetic field can be generated in the region between. In this AC magnetic field generator, the rotation angle of the first and second rotating bodies can be determined by detecting the position of the slit of the slit plate with an optical sensor, and a reference signal synchronized with the AC magnetic field can be generated with high accuracy. can do. In this AC magnetic field generator, measurement using the Hall effect can be performed by using the reference signal generated as described above.

  Therefore, in this AC magnetic field generator, it is not necessary to use a Hall element to acquire a reference signal as in the prior art. Further, in this AC magnetic field generation apparatus, the slit plate and the optical sensor for acquiring the reference signal are the regions (regions between the first rotating body and the second rotating body) where the sample to be measured is arranged. , It can be arranged at a location away from the region where the alternating magnetic field is generated. As a result, in this AC magnetic field generator, even if the region where the sample to be measured is placed is at a high temperature (for example, a temperature of 400 degrees Celsius or higher), a highly accurate reference signal is obtained by the slit plate and the optical sensor. Can be obtained.

  And the physical property evaluation value (for example, carrier density) of a sample is acquirable by performing the measurement using a Hall effect using the highly accurate reference signal acquired by this alternating current magnetic field generator.

  Therefore, by using this AC magnetic field generator, it is possible to accurately measure the physical properties of semiconductors even at high temperatures (for example, temperatures of 400 degrees Celsius or higher).

  2nd invention is 1st invention, Comprising: The 1st rotary body 1st magnetization area | region and the 1st rotary body Nth magnetization area | region are arrange | positioned separately, respectively, 2nd rotary body 1st magnetization The second rotor N-th magnetized region is disposed away from the region.

  Thereby, in this alternating current magnetic field generator, since the non-magnetized region can be secured in the first rotator and the second rotator, the rotation of the first rotator and the second rotator can change the magnetic field. A large magnetic field (magnetic field) can be generated efficiently.

  3rd invention is 1st or 2nd invention, Comprising: A 1st rotary body is further provided with the 1st yoke, and a 2nd rotary body is further provided with the 2nd yoke.

  The first yoke and the second yoke respectively include a first rotor N magnetization region from the first rotor first magnetization region, and a second rotor N magnetization region from the second rotor first magnetization region. Are formed in such a shape as to increase the magnetic flux density of the magnetic field formed by.

  In this AC magnetic field generator, the magnetic flux density of the magnetic field in the region where the sample to be measured is held (the region between the first rotating body and the second rotating body) is increased by the first yoke and the second yoke. Can do.

  A fourth invention includes the AC magnetic field generation apparatus according to any one of the first to third inventions, a sample holding unit, a constant current supply unit, an optical sensor control unit, and a measurement unit.

  The sample holding unit is a sample holding unit arranged between the first rotating body and the second rotating body in the axial direction of the rotating shaft, and holds a sample to be measured.

  The constant current supply unit supplies a constant current to the sample.

  The optical sensor control unit controls the optical sensor and acquires a detection signal indicating that the light receiving unit of the optical sensor has detected light from the light emitting unit.

  The measurement unit is a measurement signal that is a signal indicating the AC Hall voltage of the sample placed in a region where a constant current is supplied to the sample by the constant current supply unit and an AC magnetic field is generated by the AC magnetic field generator. And the Hall voltage value generated in the sample is acquired based on the acquired measurement signal and the detection signal acquired by the optical sensor control unit.

  Thereby, the Hall effect measuring apparatus provided with the alternating magnetic field generator which is one of the first to third inventions can be realized.

  According to the present invention, a Hall effect measuring device and an alternating magnetic field capable of accurately measuring semiconductor physical properties at room temperature (for example, a temperature of 50 degrees Celsius or lower) and at a high temperature (for example, a temperature of 400 degrees Celsius or higher). A generator can be realized.

The schematic block diagram of the Hall effect measuring apparatus 1000 of 1st Embodiment. The schematic block diagram of 1st rotary body R1 and 2nd rotary body R2 of the Hall effect measuring apparatus 1000 of 1st Embodiment. The schematic block diagram of the slit board 2 of the Hall effect measuring apparatus 1000 of 1st Embodiment. The schematic block diagram of 1st rotary body R1 and sample SP of the Hall effect measuring apparatus 1000 of 1st Embodiment. The schematic block diagram of the measurement part 6 of the Hall effect measuring apparatus 1000 of 1st Embodiment. The figure which shows the signal waveform (an example) of detection signal Det, reference signal Sig_ref, and signal Sig_msr acquired in the Hall effect measuring apparatus 1000. The schematic block diagram of the Hall effect measuring apparatus 1000A of a 1st modification. The schematic block diagram of the Hall effect measuring apparatus 1000B of a 2nd modification.

[First Embodiment]
The first embodiment will be described below with reference to the drawings.

<1.1: Configuration of Hall Effect Effect Measuring Device>
FIG. 1 is a schematic configuration diagram of a Hall effect measuring apparatus 1000 according to the first embodiment.

  FIG. 2 is a schematic configuration diagram of the first rotating body R1 and the second rotating body R2 of the Hall effect measuring apparatus 1000 of the first embodiment.

  FIG. 3 is a schematic configuration diagram of the slit plate 2 of the Hall effect measuring apparatus 1000 according to the first embodiment.

  FIG. 4 is a schematic configuration diagram of the first rotating body R1 and the sample SP of the Hall effect measuring apparatus 1000 according to the first embodiment.

  FIG. 5 is a schematic configuration diagram of the measurement unit 6 of the Hall effect measurement apparatus 1000 according to the first embodiment.

  In FIG. 1 to FIG. 4, the x axis, the y axis, and the z axis are set as shown in the respective drawings.

  As shown in FIG. 1, the Hall effect measuring apparatus 1000 includes a substrate B0, substrates B1 and B2 disposed on the substrate B0, a drive unit 1, a shaft Sft, a first rotating body R1, 2 rotary body R2 and the slit board 2 are provided.

  The Hall effect measuring apparatus 1000 includes an optical sensor 3 including a light emitting unit 31 and a light receiving unit 32, an optical sensor control unit 4, a constant current supply unit 5, a measurement unit 6, and a physical property evaluation value acquisition unit 7. Prepare. The Hall effect measurement apparatus 1000 includes a control unit (not shown) that controls each functional unit.

  The Hall effect measuring apparatus 1000 includes a sample holder (holder) HLD that holds a sample SP to be measured.

  The drive unit 1 is connected to the shaft Sft, and rotates the shaft Sft according to a control signal from the control unit.

  The shaft Sft is rotationally driven by the drive unit 1. The shaft Sft is connected to the first rotating body R1, the second rotating body R2, and the slit plate 2. The shaft Sft rotates with the center of the shaft Sft as a rotation axis (rotation axis R_ax in FIG. 1).

  The shaft Sft may be constituted by a single shaft, or may be constituted by a connecting shaft obtained by connecting a plurality of shafts. Further, the shaft Sft may include at least one of the first rotating body R1, the second rotating body R2, and the slit plate 2 as a shaft constituting the connecting shaft.

  For example, as shown in FIG. 1, the driving unit 1 is installed on a substrate B1 fixed on the substrate B0.

  1 and 2, the first rotating body R1 includes a first rotating body substrate R1B, a first rotating body first magnet Mg11, a first rotating body second magnet Mg12, and a first rotating body substrate R1B. Rotating body third magnet Mg13 and first rotating body fourth magnet Mg14 are provided.

  The first rotating body substrate R1B has a disk shape, and a hole (opening) for connecting the shaft Sft is formed in the central portion. The first rotating body substrate R1B is connected to the shaft Sft in a state where the shaft Sft is passed through the hole in the center portion. A flange may be provided on the first rotating body substrate R1B and the shaft Sft, and the first rotating body substrate R1B and the shaft Sft may be connected by the flange.

  The first rotating body substrate R1B rotates with the shaft Sft about the central axis of the shaft Sft as a rotation axis. In addition, the first rotating body substrate R1B has a first rotating body first magnet Mg11, a first rotating body second magnet Mg12, and a first rotating body third on the surface facing the second rotating body. It has an area for installing the magnet Mg13 and the first rotating body fourth magnet Mg14.

  The first rotating body first magnet Mg11 is a plate-like magnet and is magnetized in the thickness direction. The first rotating body first magnet Mg11 is disposed on the surface of the first rotating body substrate R1B facing the second rotating body R2.

  The 2nd magnet Mg12 for 1st rotary bodies is a flat magnet, and is magnetized in the thickness direction. The first rotating body second magnet Mg12 is installed on a surface of the first rotating body substrate R1B facing the second rotating body R2.

  The third magnet for the first rotating body Mg13 is a flat magnet and is magnetized in the thickness direction. The first rotating body third magnet Mg13 is installed on the surface of the first rotating body substrate R1B facing the second rotating body R2.

  The 4th magnet Mg14 for 1st rotary bodies is a flat magnet, and is magnetized in the thickness direction. The 4th magnet Mg14 for 1st rotary bodies is installed on the surface facing 2nd rotary body R2 of board | substrate R1B for 1st rotary bodies.

  The first rotating body first magnet Mg11, the first rotating body second magnet Mg12, the first rotating body third magnet Mg13, and the first rotating body fourth magnet Mg14, as shown in FIG. The first rotating body substrates R1B are arranged in a line in the circumferential direction, and are arranged apart from each other so as to ensure a non-magnetized region (gap) between adjacent magnets. Yes.

  The first rotating body first magnet Mg11, the first rotating body second magnet Mg12, the first rotating body third magnet Mg13, and the first rotating body fourth magnet Mg14 have substantially the same shape (for example, The flat surface has a rectangular shape (for example, a square shape).

  The first rotating body first magnet Mg11, the first rotating body second magnet Mg12, the first rotating body third magnet Mg13, and the first rotating body fourth magnet Mg14 are as shown in FIG. In addition, the magnetic poles on the surface facing the second rotating body R2 are installed so as to be different from the magnetic poles of the adjacent magnets.

For example, in the case of FIG.
(1) The magnetic pole on the surface of the first rotating body first magnet Mg11 facing the second rotating body R2 is an N pole,
(2) The magnetic pole on the surface of the second magnet for the first rotating body Mg12 on the side facing the second rotating body R2 is the S pole,
(3) The magnetic pole on the surface of the first rotating body third magnet Mg13 facing the second rotating body R2 is an N pole,
(4) The magnetic pole on the surface of the first rotating body fourth magnet Mg14 facing the second rotating body R2 is the S pole.

  As shown in FIGS. 1 and 2, the second rotating body R2 includes a second rotating body substrate R2B, a second rotating body first magnet Mg21, a second rotating body second magnet Mg22, and a second rotating body substrate R2B. Rotating body third magnet Mg23 and second rotating body fourth magnet Mg24 are provided.

  The second rotating body substrate R2B has a disk shape, and a hole for connecting the shaft Sft is formed in the center portion. The second rotating body substrate R2B is connected to the shaft Sft in a state where the shaft Sft is passed through the hole in the center portion. A flange may be provided on the second rotating body substrate R2B and the shaft Sft, and the second rotating body substrate R2B and the shaft Sft may be connected by the flange.

  The second rotating body substrate R2B rotates together with the shaft Sft with the central axis of the shaft Sft as the rotation axis. Further, the second rotating body substrate R2B has a second rotating body first magnet Mg21, a second rotating body second magnet Mg22, and a second rotating body third on the surface facing the first rotating body. An area for installing the magnet Mg23 and the fourth magnet for the second rotating body Mg24 is provided.

  The first magnet for the second rotating body Mg21 is a flat magnet and is magnetized in the thickness direction. The first magnet for the second rotating body Mg21 is installed on the surface of the second rotating body substrate R2B that faces the first rotating body R1.

  The second magnet for the second rotating body Mg22 is a flat magnet and is magnetized in the thickness direction. The second rotating body second magnet Mg22 is disposed on the surface of the second rotating body substrate R2B facing the first rotating body R1.

  The 3rd magnet Mg23 for 2nd rotary bodies is a flat magnet, and is magnetized by the thickness direction. The second rotating body third magnet Mg23 is disposed on the surface of the second rotating body substrate R2B facing the first rotating body R1.

  The 4th magnet Mg24 for 2nd rotary bodies is a flat magnet, and is magnetized by the thickness direction. The 4th magnet Mg24 for 2nd rotary bodies is installed on the surface facing the 1st rotary body R1 of board | substrate R2B for 2nd rotary bodies.

  As shown in FIG. 2, the first magnet for the second rotating body Mg21, the second magnet for the second rotating body Mg22, the third magnet for the second rotating body Mg23, and the fourth magnet for the second rotating body Mg24, The second rotating body substrate R2B is arranged in a line in the circumferential direction, and is spaced apart so as to ensure a non-magnetized region (gap) between adjacent magnets. Yes.

  The second rotating body first magnet Mg21, the second rotating body second magnet Mg22, the second rotating body third magnet Mg23, and the second rotating body fourth magnet Mg24 have substantially the same shape (for example, The flat surface has a rectangular shape (for example, a square shape).

  The second rotating body first magnet Mg21, the second rotating body second magnet Mg22, the second rotating body third magnet Mg23, and the second rotating body fourth magnet Mg24 are as shown in FIG. In addition, the magnetic poles on the surface facing the first rotating body R1 are installed so as to be different from the magnetic poles of the adjacent magnets.

For example, in the case of FIG.
(1) The magnetic pole on the surface of the second rotating body first magnet Mg21 facing the first rotating body R1 is the S pole,
(2) The magnetic pole on the surface of the second rotor second magnet Mg22 facing the first rotor R1 is an N pole,
(3) The magnetic pole on the surface of the second rotating body third magnet Mg23 facing the first rotating body R1 is the S pole,
(4) The magnetic pole on the surface of the second rotating body fourth magnet Mg24 facing the first rotating body R1 is an N pole.

  Further, as shown in FIG. 1, the first rotating body R1 and the second rotating body R2 are arranged apart from each other between the rotation axis directions (x-axis directions) so that the sample holder HLD can be arranged. ing. In the case of FIG. 1, a magnet (for example, for the second rotating body) installed on the second rotating body R2 from the surface of the magnet (for example, the first magnet for first rotating body Mg11) installed on the first rotating body R1. The first rotating body R1 and the second rotating body R2 are arranged so that the distance in the rotation axis direction (x-axis direction) to the surface of the first magnet Mg21) is d1.

  Further, the first rotating body first magnet Mg11 and the second rotating body first magnet Mg21 are, as shown in FIG. 2, the first rotating body first magnet Mg11 in a plan view viewed from the x-axis direction. And the first magnet for the second rotating body Mg21 are arranged so as to substantially coincide with each other and overlap. By arranging in this way, it is possible to generate a magnetic field in which the direction of the magnetic field is the x-axis positive direction between the first magnet for the first rotating body Mg11 and the first magnet for the second rotating body Mg21.

  As shown in FIG. 2, the second magnet for the first rotating body Mg12 and the second magnet for the second rotating body Mg22 are the same as the second magnet for the first rotating body Mg12 and the second magnet for the first rotating body, as viewed in the x-axis direction. It arrange | positions so that 2nd magnet Mg22 for 2 rotary bodies may substantially correspond and overlap. By arranging in this way, it is possible to generate a magnetic field in which the direction of the magnetic field is the negative x-axis direction between the first rotating body second magnet Mg12 and the second rotating body second magnet Mg22.

  As shown in FIG. 2, the first rotating body third magnet Mg <b> 13 and the second rotating body third magnet Mg <b> 23 are the same as the first rotating body third magnet Mg <b> 13 and the first rotating body third magnet Mg <b> 13 in a plan view as seen from the x-axis direction. It arrange | positions so that the 3rd magnet Mg23 for 2 rotary bodies may substantially correspond and overlap. By arranging in this way, it is possible to generate a magnetic field in which the direction of the magnetic field is the x-axis positive direction between the first rotating body third magnet Mg13 and the second rotating body third magnet Mg23.

  As shown in FIG. 2, the first rotating body fourth magnet Mg <b> 14 and the second rotating body fourth magnet Mg <b> 24 are the same as the first rotating body fourth magnet Mg <b> 14 and the second rotating body fourth magnet Mg <b> 14 in a plan view as seen from the x-axis direction. It arrange | positions so that the 4th magnet Mg24 for 2 rotors may substantially correspond and overlap. By arranging in this way, it is possible to generate a magnetic field in which the direction of the magnetic field is the negative x-axis direction between the first rotating body fourth magnet Mg14 and the second rotating body fourth magnet Mg24.

  By configuring the first rotating body R1 and the second rotating body R2 as described above and rotating the shaft Sft, in the space where the sample SP is arranged, the direction of the magnetic field is changed according to the rotation of the shaft Sft. Change. That is, by configuring the first rotating body R1 and the second rotating body R2 as described above and rotating the shaft Sft, an alternating magnetic field can be generated in the space where the sample SP is disposed.

  As shown in FIGS. 1 and 3, the slit plate 2 has a disk shape, and a hole (opening) for connecting the shaft Sft is formed in the center portion. The slit plate 2 is connected to the shaft Sft in a state where the shaft Sft is passed through the hole in the center portion. A flange may be provided on the slit plate 2 and the shaft Sft, and the slit plate 2 and the shaft Sft may be connected by the flange.

  The slit plate 2 rotates together with the shaft Sft with the central axis of the shaft Sft as the rotation axis. The slit plate 2 is formed with one or a plurality of slits. When the slit plate 2 includes a plurality of slits, the plurality of slits are equally arranged side by side in the circumferential direction, for example.

  Hereinafter, for convenience of explanation, a case where two slits Slt1 and Slt2 are formed in the slit plate 2 will be described as an example.

  As shown in FIG. 3, the slit Slt1 and the slit Slt2 are formed at positions that are opposite to each other in the radial direction in a plan view viewed from the x-axis direction.

  The slit Slt1 is formed at a position where the distance between the center point of the slit Slt1 and the rotation axis R_ax (center position of the slit plate) is the distance d2, and forms a circular opening having a radius r1. Is formed.

  The slit Slt2 is formed at a position where the distance between the center point of the slit Slt2 and the rotation axis R_ax (center position of the slit plate) is a distance d2, and a circular opening having a radius r1 is formed. Has been.

  When the slit plate 2 rotates about the rotation axis R_ax, the slit Slt1 is irradiated from the light emitting unit 31 of the optical sensor 3 when the slit Slt1 passes between the light emitting unit 31 and the light receiving unit 32 of the optical sensor 3. It is formed on the slit plate 2 in such a shape that the emitted light reaches the light receiving part 32.

  When the slit plate 2 rotates around the rotation axis R_ax, the slit Slt2 is irradiated from the light emitting unit 31 of the optical sensor 3 when the slit Slt2 passes between the light emitting unit 31 and the light receiving unit 32 of the optical sensor 3. It is formed on the slit plate 2 in such a shape that the emitted light reaches the light receiving part 32.

  Note that the shapes (shapes of the openings) of the slits Slt1 and Slt2 are not limited to the above, and when the slit Slt2 is located between the light emitting unit 31 and the light receiving unit 32 of the photosensor 3, the light emitting unit of the photosensor 3 is used. Any other shape may be used as long as it is an opening formed so that the light emitted from 31 reaches the light receiving unit 32.

  The radius r1 of the slit Slt1 (or slit Slt2) is such that the slit Slt1 (or slit Slt2) passes between the light emitting part 31 and the light receiving part 32 of the optical sensor 3 when the slit plate 2 rotates about the rotation axis R_ax. The light emitted from the light emitting unit 31 of the optical sensor 3 may be a value that sufficiently reaches the light receiving unit 32.

  The optical sensor 3 includes a light emitting unit 31 and a light receiving unit 32, and is controlled by the optical sensor control unit 4. The optical sensor 3 is realized by, for example, a photocoupler. As shown in FIGS. 1 and 3, the optical sensor 3 has a U-shape when viewed from the z-axis direction. As shown in FIG. 3, the optical sensor 3 includes a base portion 3b and a first side wall portion 3a extending from both ends of the base portion 3b in a direction perpendicular to the base portion 3b (y-axis positive direction in FIG. 3). And a second side wall 3c.

  As shown in FIG. 3, the first side wall portion 3a and the second side wall portion 3c of the optical sensor 3 are arranged so as to secure a space where the slit plate 2 can be arranged in the axial direction (x-axis direction) of the rotation axis R_ax. Has been. As shown in FIG. 3, the optical sensor 3 is installed at a position that does not contact the slit plate 2 and can maintain a state in which the rotation of the slit plate 2 is not hindered.

  The light emission part 31 is installed inside the 1st side wall part 3a. The light emitting unit 31 emits light with a predetermined intensity based on a command from the optical sensor control unit 4.

  The light receiving part 32 is installed inside the second side wall part 3c. When the light emitted from the light emitting unit 31 reaches the light receiving unit 32, the light receiving unit 32 outputs a detection signal indicating that the light has been detected to the optical sensor control unit 4.

  In the light emitting unit 31 and the light receiving unit 32, when the slit Slt1 (or slit Slt2) is positioned between the first side wall 3a and the second side wall 3c, the light emitted from the light emitting unit 31 is applied to the light receiving unit 32. Arranged to reach. By arranging the light emitting unit 31 and the light receiving unit 32 in this way, when the slit Slt1 (or slit Slt2) is located between the first side wall 3a and the second side wall 3c, the light emitting unit 31 emits light. The light passes through the slit Slt1 (or the slit Slt2) and reaches the light receiving unit 32.

  For example, as shown in FIG. 1, the optical sensor 3 is installed on a substrate B2 fixed on the substrate B0.

  The optical sensor control unit 4 controls the optical sensor 3 based on a command (control signal) from a control unit (not shown). For example, when receiving a control signal instructing to emit light from the light emitting unit 31 of the optical sensor 3 from the control unit, the optical sensor control unit 4 emits light from the light emitting unit 31 of the optical sensor 3 according to the control signal. Irradiate.

  The optical sensor control unit 4 receives a detection signal (a signal indicating that the light receiving unit 32 has detected light) from the optical sensor 3. Then, the optical sensor control unit 4 generates a detection signal Det based on the received signal, and outputs the generated detection signal Det to the measurement unit 6.

  The constant current supply unit 5 is a constant current source that supplies a constant current to the sample SP. For example, as shown in FIG. 4, a power supply terminal (not shown) of the constant current supply unit 5 is electrically connected to the end point p1 of the sample SP via a wiring, and the constant current supply unit 5 A GND terminal (not shown) is electrically connected to the end point p2 of the sample SP via a wiring. Thereby, a constant current (constant current I1) can be supplied from the constant current supply unit 5 to the sample SP.

  As shown in FIG. 5, the measurement unit 6 includes a potential difference acquisition unit 61, a reference signal acquisition unit 62, a multiplication unit 63, and an LPF unit 64. The measurement unit 6 is realized by, for example, a lock-in amplifier.

  The potential difference acquisition unit 61 is a functional unit for measuring the Hall voltage generated in the sample SP. As shown in FIGS. 1 and 4, the first terminal of the potential difference acquisition unit 61 is electrically connected to the end point p3 of the sample through the wiring, and the second terminal of the potential difference acquisition unit 61 is connected through the wiring. , Electrically connected to the end point p4 of the sample. The potential difference acquisition unit 61 uses the signal Sig1 input from the end point p3 of the sample through the wiring and the signal Sig2 input from the end point p4 of the sample through the wiring to the end point p3-end point of the sample SP. The potential difference between p4 (potential difference corresponding to the Hall voltage) is acquired. Then, the potential difference acquisition unit 61 outputs a signal indicating the potential difference (potential difference corresponding to the Hall voltage) between the end points p3 and p4 of the acquired sample SP to the multiplication unit 63 as a signal Sig_msr.

  The reference signal acquisition unit 62 receives the detection signal Det output from the optical sensor control unit 4. The reference signal acquisition unit 62 acquires the reference signal Sig_ref based on the detection signal Det, and outputs the acquired reference signal Sig_ref to the multiplication unit 63.

  The multiplier 63 receives the signal Sig_msr output from the potential difference acquisition unit 61 and the reference signal Sig_ref output from the reference signal acquisition unit 62. The multiplication unit 63 performs a multiplication process on the signal Sig_msr and the reference signal Sig_ref to obtain a multiplication signal Sig3. Then, the multiplier 63 outputs the acquired multiplication signal Sig3 to the LPF unit 64.

  The LPF unit 64 receives the multiplication signal Sig3 output from the multiplication unit 63. The LPF unit 64 performs LPF (low-pass filter) processing on the multiplication signal Sig3, and outputs the signal after LPF processing to the physical property evaluation value acquisition unit 7 as a signal Sig_out.

  The physical property evaluation value acquisition unit 7 receives the signal Sig_out output from the measurement unit 6. The physical property evaluation value acquisition unit 7 acquires a predetermined physical property evaluation value based on the signal Sig_out.

<1.2: Operation of Hall Effect Effect Measuring Device>
The operation of the Hall effect measuring apparatus 1000 configured as described above will be described below with reference to the drawings.

  FIG. 6 is a diagram illustrating signal waveforms (an example) of the detection signal Det, the reference signal Sig_ref, and the signal Sig_msr acquired in the Hall effect measurement apparatus 1000. Further, FIG. 6 schematically shows the magnetic field direction Dir_B in the region where the sample holding unit HLD and the sample SP are arranged. Note that “N” in the magnetic field direction Dir_B is the magnetic field direction in the region where the sample holding unit HLD and the sample SP are arranged, and the magnetic field direction Dir_B is “S”. It shows that the direction of the magnetic field in the region where the sample holder HLD and the sample SP are arranged is the negative direction of the x-axis.

  First, the sample SP to be measured is mounted on the sample holder HLD. For convenience of explanation, the sample SP is assumed to be a square flat object (semiconductor).

  Further, as shown in FIG. 4, the two wires connected to the measurement unit 6 are connected to the end points p3 and p4 of the sample SP, respectively. Further, the wiring connected to the power supply terminal (not shown) of the constant current supply unit 5 is connected to the end point p1 of the sample SP, and the wiring connected to the GND terminal (not shown) of the constant current supply unit 5. Is connected to the end point p2 of the sample SP.

  By connecting in this way, the constant current I1 is allowed to flow from the constant current supply unit 5 toward the end point p2 from the end point p1 of the sample SP, and the voltage (Hall voltage) between the end points p3 and p4 of the sample SP is measured. Can be measured.

  After wiring as described above, the sample holder HLD is mounted in the rotation axis direction (x-axis direction) of the first rotating body R1 and the second rotating body R2, as shown in FIG. Arranged between.

  Next, the control unit (not shown) outputs a control signal for rotating the shaft Sft at a predetermined frequency f1 [Hz] to the drive unit 1.

  The drive unit 1 rotates the shaft at a predetermined frequency f1 [Hz] according to the control signal. The predetermined frequency is preferably a frequency of 2 Hz or more.

  Since the first rotating body R1, the second rotating body R2, and the slit plate 2 are connected to the shaft Sft, the first rotating body R1, the second rotating body R2, and the slit plate 2 rotate at the frequency f1 together with the shaft Sft without causing a rotational shift. That is, the first rotating body R1, the second rotating body R2, and the slit plate 2 rotate together with the shaft Sft while maintaining a constant angular velocity at an angular frequency ω (= 2πf1) corresponding to the frequency f1.

  For convenience of explanation, the rotation direction of the shaft Sft will be described below assuming that it is a clockwise direction when viewed from the positive x-axis direction of the rotation axis R_ax.

  In a state where the first rotating body R1, the second rotating body R2, and the slit plate 2 are rotated together with the shaft Sft while maintaining a constant angular velocity at the angular frequency ω (= 2πf1), the optical sensor control unit 4 Control is performed so that light is emitted from the light emitting unit 31 of the optical sensor 3. The light receiving unit 32 of the optical sensor 3 detects light from the light emitting unit 31 that has passed through the slit plate 2 through the slits Slt1 and Slt2, and outputs a detection signal indicating that the light has been detected to the optical sensor control unit 4. .

  The optical sensor control unit 4 receives a detection signal (a signal indicating that the light receiving unit 32 has detected light) from the optical sensor 3, and generates a detection signal Det based on the received signal.

  For example, the optical sensor control unit 4 generates a detection signal Det as shown in FIG. That is, based on the detection signal from the optical sensor 3, the optical sensor control unit 4 sets the timing at which the light receiving unit 32 of the optical sensor 3 detects the light that has passed through the center of the slit Slt1 or Slt2 of the slit plate 2 to the rising edge ( A detection signal Det that generates a low level (logical negative level) to a high level (logical positive level) is generated.

  Then, the optical sensor control unit 4 outputs the generated detection signal Det to the reference signal acquisition unit 62 of the measurement unit 6.

  The potential difference acquisition unit 61 of the measurement unit 6 acquires the potential difference (potential difference corresponding to the Hall voltage) between the end points p3 and p4 of the sample SP by detecting the potential difference between the input signals Sig1 and Sig2. Then, the potential difference acquisition unit 61 outputs a signal indicating the potential difference (potential difference corresponding to the Hall voltage) between the end point p3 and the end point p4 of the acquired sample SP to the multiplication unit 63 as a signal Sig_msr.

The signal Sig_msr acquired by the measurement unit 6 is as shown in FIG.
Sig_msr = Acos (ωt)
t: time ω: angular frequency ω (= 2πf1 = 2π / T)
Can be approximated. Therefore, hereinafter, for convenience of explanation, the signal Sig_msr acquired by the measurement unit 6 will be described as described above. Note that, when the harmonic component is included in the signal Sig_msr, the harmonic component is removed by the processing in the multiplication unit 63 and the processing in the LPF unit 64. Therefore, there is no problem even if the above approximation is performed.

  The reference signal acquisition unit 62 acquires the reference signal Sig_ref based on the detection signal Det output from the optical sensor control unit 4. Specifically, as shown in FIG. 6, the reference signal acquisition unit 62 sets the rising edge of the detection signal Det corresponding to the timing at which the light that has passed through the slit Slt1 is detected as phase 0, and the light that has passed through the slit Slt2. A cosine signal having the phase π as the rising edge of the detection signal Det corresponding to the detected timing and the amplitude of 1 is generated as the reference signal Sig_ref.

In FIG. 6, when time t0 = 0, the reference signal acquisition unit 62
Sig_ref = cos (ωt)
t: time ω: angular frequency ω (= 2πf1 = 2π / T)
A reference signal Sig_ref is generated.

  Then, the reference signal acquisition unit 62 outputs the generated reference signal Sig_ref to the multiplication unit 63.

The multiplication unit 63 performs a multiplication process on the signal Sig_msr and the reference signal Sig_ref to obtain a multiplication signal Sig3. That is, the multiplication unit 63 performs a multiplication process corresponding to the following mathematical formula, and obtains a multiplication signal Sig3.
Sig3 = Sig_msr × Sig_ref
= Acos (ωt) × cos (ωt)
= (A / 2) {cos (2ωt) + cos (0)}
The LPF unit 64 performs LPF (low-pass filter) processing on the multiplication signal Sig3. Specifically, the LPF unit 64 is realized by an LPF having a cutoff frequency that can sufficiently remove the component “(A / 2) cos (2ωt)” of Sig3. Then, the LPF unit 64 performs an LPF (low-pass filter) process on the multiplication signal Sig3, thereby removing unnecessary high-frequency components and extracting a DC component “(A / 2) cos (0)”. That is, the LPF unit 64
Sig_out = (A / 2) cos (0) = A / 2
As a result, the signal Sig_out is acquired. Then, the LPF unit 64 outputs the acquired signal Sig_out to the physical property evaluation value acquisition unit 7.

The physical property evaluation value acquisition unit 7 acquires a predetermined physical property evaluation value based on the signal Sig_out output from the measurement unit 6. For example, the physical property evaluation value acquisition unit 7 performs the following processing when measuring the carrier density n of the sample SP. That is, the current value of the current I1 supplied to the sample SP by the constant current supply unit 5 is I, and the magnetic flux density (between the magnet Mg11 and the magnet Mg21, between the magnet Mg12 and the magnet Mg22, When the magnetic flux density between the magnet Mg13 and the magnet Mg23 and between the magnet Mg14 and the magnet Mg24 is B, the physical property evaluation value acquisition unit 7
V _H = 2 × Sig_out = A
n = IB / (eV _H t)
V _H : Measurement voltage (Hall voltage)
e: Elementary charge t: By performing a calculation process corresponding to the thickness of the sample SP, the carrier density n of the sample SP can be measured.
When the magnetic field change includes a harmonic component, the physical property evaluation value acquisition unit 7
B = B ₁ cos (ωt) + B ₃ cos (3ωt) ++ B ₅ cos (5ωt)
+ ... + B _{2n + 1} cos ((2n + 1) ωt)
As described above, the carrier density n of the sample SP can be measured by performing a calculation process corresponding to the above formula.

Further, if the resistivity ρ of the sample SP is acquired (measured) by, for example, a method in which the electrode is set at four symmetrical positions in the sample plane and the resistance voltage is measured, the physical property evaluation value acquisition unit 7 performs the following calculation process. By performing the above, the carrier mobility μ of the sample SP can also be acquired.
μ = 1 / (enρ)
ρ: Resistivity e: Elementary charge n: Carrier density As described above, in the Hall effect measuring apparatus 1000, the first rotating body R1, the second rotating body R2, and the slit plate 2 connected to the shaft Sft include the shaft. By rotating both Sft at a constant angular velocity, an alternating magnetic field can be generated in the region where the sample SP is disposed. In the Hall effect measuring apparatus 1000, the positions of the slits Slt1 and Slt2 of the slit plate 2 are detected by the optical sensor 3, and the reference signal Sig_ref is generated based on the detected signal. For this reason, in the Hall effect measuring apparatus 1000, it is not necessary to use a Hall element in order to acquire a reference signal unlike the prior art. Further, in the Hall effect measuring apparatus 1000, the slit plate 2 and the optical sensor 3 for acquiring the reference signal Sig_ref can be arranged in a region that includes the sample SP and is separated from the region that generates the AC magnetic field. it can. As a result, in the Hall effect measuring apparatus 1000, even when the region including the sample SP is at a high temperature (for example, a temperature of 400 degrees Celsius or higher), the slit plate 2 and the optical sensor 3 are used to provide a highly accurate reference signal Sig_ref. Can be obtained.

  And in the Hall effect measuring apparatus 1000, the physical property evaluation value (for example, carrier density) of the sample SP can be acquired by performing the above calculation process by the measurement unit using the highly accurate reference signal Sig_ref.

  As described above, the Hall effect measuring apparatus 1000 can accurately measure the physical properties of a semiconductor even at a high temperature (for example, a temperature of 400 degrees Celsius or higher). Note that the Hall effect measurement apparatus 1000 can accurately measure the physical properties of a semiconductor even at room temperature (for example, a temperature of 50 degrees Celsius or less).

  The “AC magnetic field generator” is realized by the shaft Sft, the drive unit 1, the first rotating body R1, the second rotating body R2, the slit plate 2, and the optical sensor 3.

≪First modification≫
Next, a first modification of the first embodiment will be described.

  FIG. 7 is a schematic configuration diagram of a Hall effect measuring apparatus 1000A of the first modification.

  In addition, in this modification, about the part similar to the said embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  In the Hall effect measuring apparatus 1000A of this modification, as shown in FIG. 7, the first yoke Yk1 provided on the first rotating body R1 and the second yoke Yk2 provided on the second rotating body R2 are further provided. Prepare.

  For example, as shown in FIG. 7, the first yoke Yk1 is arranged between the first rotating body substrate R1B and the first rotating body magnets Mg11 to Mg14 in a cross-sectional view as viewed from the z-axis direction. Yes. For example, as shown in FIG. 7, the first yoke Yk1 has a disk-like shape having substantially the same radius as the first rotating body substrate R1B. By providing the first yoke Yk1 having such a shape on the first rotating body R1, the magnetic flux density of the magnetic field in the region where the sample SP is held can be increased. The first yoke Yk1 is fixed to the first rotor substrate R1B and rotates together with the shaft Sft.

  For example, as shown in FIG. 7, the second yoke Yk2 is disposed between the second rotating body substrate R2B and the second rotating body magnets Mg21 to Mg24 in a cross-sectional view viewed from the z-axis direction. Yes. For example, as shown in FIG. 7, the second yoke Yk2 has a disk-like shape having substantially the same radius as the second rotating body substrate R2B. By providing the second yoke Yk2 having such a shape on the second rotating body R2, the magnetic flux density of the magnetic field in the region where the sample SP is held can be increased. The second yoke Yk2 is fixed to the second rotor substrate R2B and rotates together with the shaft Sft.

  The Hall effect measuring apparatus 1000A configured as described above has the same effect as the Hall effect measuring apparatus 1000 of the first embodiment, and a region in which the sample SP is held by the first yoke Yk1 and the second yoke Yk2. The magnetic flux density of the magnetic field can be increased.

≪Second modification≫
Next, a second modification of the first embodiment will be described.

  FIG. 8 is a schematic configuration diagram of a Hall effect measuring apparatus 1000B of the second modification.

  In addition, in this modification, about the part similar to the said embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  In the Hall effect measuring apparatus 1000B of this modification, as shown in FIG. 8, the sample holder HLD is housed in the housing C1, and the housing C1 is supported by the base B3.

  That is, the sample holding unit HLD and the mechanism of the rotational drive system of the Hall effect measuring apparatus 1000B are structurally separated. For this reason, in the Hall effect measuring apparatus 1000B, vibration or the like when the shaft Sft is rotated by the driving unit 1 is not transmitted to the sample holding unit HLD. As a result, the Hall effect measuring apparatus 1000B can measure physical properties with higher accuracy.

  In addition, as shown in FIG. 8, you may make it equip the housing | casing C1 with the heating apparatus (heater (for example, ceramic heater)) HT. By doing in this way, sample SP can be heated with the said heating apparatus, and the physical property measurement of sample SP in a high temperature state can be performed.

[Other Embodiments]
In FIG. 1, FIG. 7, and FIG. 8, the letters “N” and “S” are shown to clearly indicate the magnetic poles of the magnet, but this is for convenience. The letters “N” and “S” in the drawing are given for the sake of convenience in order to clearly indicate the magnetization direction of the flat magnet magnetized in the thickness direction.
In the said embodiment, although 1st rotary body R1 was provided with the four magnets Mg11-Mg14 and 2nd rotary body R2 was provided with the four magnets Mg21-Mg24, it was limited to this. Absent. For example, the first rotating body R1 of the Hall effect measuring device includes N (N: a natural number of 2 or more) magnets (for example, N magnets arranged uniformly in the circumferential direction), and the second rotating body. R2 may include N magnets (N: a natural number of 2 or more) (for example, N magnets arranged uniformly in the circumferential direction). The first rotating body R1 and the second rotating body R2 are rotated by the N pairs of magnets of the first rotating body R1 and the second rotating body R2, thereby rotating the first rotating body R1 and the second rotation in the rotation axis direction. An alternating magnetic field may be generated between the body R2.

  Part or all of the processing of each functional block in the above embodiment may be realized by a program. A part or all of the processing of each functional block in the above embodiment is performed by a central processing unit (CPU) in the computer. In addition, a program for performing each processing is stored in a storage device such as a hard disk or a ROM, and is read out and executed in the ROM or the RAM.

  Each processing of the above embodiment may be realized by hardware, or may be realized by software (including a case where the processing is realized together with an OS (Operating System), middleware, or a predetermined library). Further, it may be realized by mixed processing of software and hardware. Needless to say, when the Hall effect measuring apparatus according to the above embodiment is realized by hardware, it is necessary to adjust the timing for performing each process. In the above embodiment, for convenience of explanation, details of timing adjustment of various signals generated in actual hardware design are omitted.

  Moreover, the execution order of the processing method in the said embodiment is not necessarily restricted to description of the said embodiment, The execution order can be changed in the range which does not deviate from the summary of invention.

  A computer program that causes a computer to execute the above-described method and a computer-readable recording medium that records the program are included in the scope of the present invention. Here, examples of the computer-readable recording medium include a flexible disk, hard disk, CD-ROM, MO, DVD, DVD-ROM, DVD-RAM, large-capacity DVD, next-generation DVD, and semiconductor memory. .

  The computer program is not limited to the one recorded on the recording medium, and may be transmitted via a telecommunication line, a wireless or wired communication line, a network represented by the Internet, or the like.

  The specific configuration of the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the invention.

  ADVANTAGE OF THE INVENTION According to this invention, the Hall effect measuring apparatus and alternating current magnetic field generator which can measure the physical property of a semiconductor accurately also at high temperature are realizable. For this reason, this invention is useful in the physical property measurement related industrial field | area, and can be implemented in the said field | area.

1000, 1000A, 1000B Hall effect measuring device Sft Shaft 1 Driving unit 2 Slit plate 3 Optical sensor 4 Optical sensor control unit 5 Constant current supply unit 6 Measuring unit 7 Physical property evaluation value acquisition unit SP Sample HLD Sample holding unit

Claims (4)

A shaft,
A drive unit that rotates the shaft with the central axis of the shaft as a rotation axis;
A slit plate that is connected to the shaft such that the central axis of the shaft is a rotation axis, and includes a slit for position detection;
A light sensor including a light emitting unit that emits light and a light receiving unit that detects light emitted from the light emitting unit, wherein the slit plate is rotated by a predetermined angle with the central axis of the shaft as a rotation axis And the light sensor in which the light emitting part and the light receiving part are arranged so that the light emitted by the light emitting part passes through the position detection slit and reaches the light receiving part,
The first rotating body is connected to the shaft so that the center axis of the shaft is a rotation axis, and the first rotation from the first rotating body first magnetizing region, which is each magnetized N (N: natural number and even number) region. A first rotating body including a body Nth magnetization region;
The shaft is connected to the shaft so that the central axis of the shaft is a rotation axis, and includes the second rotating body first magnetization region to the second rotating body Nth magnetization region, which are N regions each magnetized. A second rotating body;
With
In a plan view seen from the axial direction of the rotation axis, the first rotation body (2k−1) magnetization region (k: natural number, 1 ≦ k ≦ N / 2) is the second rotation body (2k−1). It is arranged so that an overlapping area that is an area overlapping with the magnetized area occurs,
The first rotating body second (2k-1) magnetization region and the second rotating body second (2k-1) magnetization region are the first rotating body second (2k-1) in the axial direction of the rotation axis of the overlapping region. ) Magnetized so that a magnetic field in a first direction, which is a direction substantially parallel to the rotation axis, is generated between the magnetized region and the second (2k-1) magnetized region of the second rotating body;
In the plan view seen from the axial direction of the rotating shaft, the first rotating body 2k magnetization region is arranged so as to generate an overlapping region that overlaps the second rotating body 2k magnetization region,
The second rotating body 2k magnetization region and the second rotating body 2k magnetization region are the second rotating body 2k magnetization region and the second rotating body 2k magnetization in the axial direction of the rotation axis of the overlapping region. Magnetized so as to generate a magnetic field in a second direction that is in a direction substantially parallel to the rotation axis and opposite to the first direction, between the regions,
AC magnetic field generator. The first rotator first magnetization region to the first rotator Nth magnetization region are arranged separately from each other,
The second rotator first magnetization region to the second rotator Nth magnetization region are arranged separately from each other,
The AC magnetic field generator according to claim 1. The first rotating body further includes a first yoke,
The second rotating body further includes a second yoke,
The first yoke and the second yoke respectively include a first rotor N magnetization region from the first rotor first magnetization region and a second rotor N magnetization region from the second rotor first magnetization region. Formed with a shape that increases the magnetic flux density of the magnetic field formed by
The AC magnetic field generator according to claim 1 or 2. An AC magnetic field generator according to any one of claims 1 to 3,
A sample holder disposed between the first rotating body and the second rotating body in the axial direction of the rotating shaft, the sample holding section holding a sample to be measured;
A constant current supply unit for supplying a constant current to the sample;
An optical sensor control unit that controls the optical sensor and acquires a detection signal indicating that the light receiving unit of the optical sensor has detected light from the light emitting unit;
A measurement signal which is a signal indicating an AC Hall voltage of the sample arranged in a region where a constant current is supplied to the sample by the constant current supply unit and an AC magnetic field is generated by the AC magnetic field generator. A measurement unit that acquires a Hall voltage value generated in the sample based on the acquired measurement signal and the detection signal acquired by the optical sensor control unit,
Hall effect measuring device.

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