This standard applies to the determination of carrier Hall mobility in extrinsic semiconductor single crystal samples. To obtain the Hall mobility, the resistivity and the Hall coefficient must be measured, so this standard also applies to the measurement of these parameters separately. This method has only been measured in a limited range and in the laboratory on germanium, silicon and gallium arsenide, but the method can also be applied to other semiconductor single crystal materials. The measurement technique described is at least applicable to samples with a room temperature resistivity of up to 104Ωcm. GB/T 4326-1984 Measurement method of Hall mobility and Hall coefficient of extrinsic semiconductor single crystals GB/T4326-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Measurement method of Hall mobility and Hall coefficient of extrinsic semiconductor single crystals
Extrinsic semiconductor single crystalsmeasurement of Hall mobitity and Hall coefficient UDC 621.315
592:621
.317.3
G134326*-84
This standard applies to the determination of carrier Hall mobility in extrinsic semiconductor single crystal samples. To obtain the Hall mobility, it is necessary to measure the resistivity and the Hall coefficient, so this standard also applies to the measurement of these parameters separately. This method is limited to laboratory measurements on germanium, silicon and gallium arsenide, but the method can also be applied to other semiconductor single crystal materials. The measurement technique described is at least applicable to samples with a room temperature resistivity of up to 10*cm. 1 Terminology
1.1 Resistivity
1.1.1 Resistivity is the ratio of the potential gradient parallel to the current flow in the material to the current density. Resistivity should be measured under zero magnetic flux. 1.1.2 Resistivity is a quantity directly measured in a material. In a non-isotropic material with a single type of current carrier, the relationship between resistivity and basic material parameters is as follows:
p=(neμ)
W: p--electric constant, .cm;
n--carrier concentration, cm-3;
e--carrier charge value, C;
-carrier mobility, cm2/V·s
It must be pointed out that for intrinsic semiconductors and some P-type semiconductors such as P-Ge (there are two types of holes), formula (1) is obviously not applicable, and the following relationship must be used:
(neμ)
where in, and u, represent the quantity of the first type of current carrier. (2)
1.2 Hall coefficient
1.2.1 When a perpendicular electric field and magnetic field are applied to an isotropic solid at the same time, the current is deflected in the perpendicular direction, and a transverse electric field is established on both sides of the sample, which is called the Hall electric field (see Figure 1). National Bureau of Standards 1984-04-12 Issued
1985-03-01 Implementation
GB 4326--84
E, (N)
E, (P type)
Figure 1 Hall effect symbol regulations
1.2.2 The Hall coefficient is the ratio of the Hall electric field to the product of the current density and the magnetic flux density. Rh =- Ey / Jx. Bz
Where: RH is the Hall coefficient, cm/C;
Ey is the transverse electric field, V/cm;
Jx is the current density, A·cm~2;
Bz is the magnetic flux density, Gs.
1 (P-type)
1.2.3 For N-type non-intrinsic semiconductors that are mainly electron-conducting, the Hall coefficient is negative; while for P-type non-intrinsic semiconductors that are mainly hole-conducting, the Hall coefficient is positive. 1.2.4 The Hall coefficient is a quantity that can be directly measured in a material. In non-intrinsic semiconductors with a single type of carrier, the relationship between the Hall coefficient and the basic parameters of the material is as follows:
RH =r/n·g
Formula: RH—Hall coefficient, cm3/C
-Hall factor;
-carrier concentration, cm\3
-carrier charge, C.
(4)
1.2.5 The Hall factor r is a proportional factor that depends on the band structure, scattering mechanism, sample temperature, magnetic flux density and sample crystal orientation. Its value is usually close to 1. In specific cases, in order to accurately determine the carrier concentration from the measured Hall coefficient, detailed data on the r value are required, but in many cases, this data is unknown and can only be estimated. When making comparative measurements, the measurer should take a consistent r value. In the absence of other data, it can usually be taken as 1.1.3. Hall mobility
1.3.1 Hall mobility is the ratio of the absolute value of the Hall coefficient to the resistivity. μH=IRHI/p
Where: μH-Hall mobility, cm2.V-}.s-1, IR|——absolute value of Hall coefficient, cm~3.C; p
-resistivity, 2.cm.
GB4326—84
1.3.2 Hall mobility has practical physical meaning only in the case of: a carrier system. In such a system, there is the following relationship between Hall mobility μ and conductivity mobility: μH=ru
Where: μ conductivity mobility, cm2.V1·s\1. (6)
Only when the value of ~ is known, the accurate value of carrier mobility can be obtained based on the measured values ​​of Hall coefficient and resistivity. 1.4 Units
In order to coordinate the quantities of different units used in customary use, the magnetic flux density must be expressed in V·s·cm-2, that is: 1V·s·cm2=108Gs
2 Preparation and requirements of samples
2.1 Sampling
The sample is cut from a single crystal ingot and processed into the required shape as required. It should be noted that the sample must be a complete single crystal. 2.2 Grinding
Generally, the cut sample should be ground with M28-M20 aluminum oxide or silicon carbide abrasive slurry. For samples with good enough cutting flatness, grinding is not required. The surface of the sample should have a uniform matte finish, then be cleaned with detergent or ultrasonically cleaned with organic solvents, and then rinsed in pure water.
2.3 Specimen shape
Specimen shape can be processed into the required shape by mechanical processing such as ultrasonic cutting, grinding cutting or sawing, etc. - parallelepiped, bridge or disc shape.
2.3.1 The diagram of parallelepiped specimen is shown in Figure 2 (a). The total length of the specimen should be between 1.0 and 1.5 cm, and the aspect ratio should be greater than 5 and at least not less than 4.
(a) No contact
(b) Eight contact
(c) Eight contact
Figure 2 Typical parallelepiped specimen
2.3.2 The diagram of bridge specimen is shown in Figure 3, any of the contact patterns shown in the figure. 212
GB 4326-84
Figure 3 Typical bridge-type test specimen
2.3.2.1 Eight contact test specimens—The following requirements are made for the geometric dimensions of the test specimens, see Figure 3 (a) and (c): Ls ≥ 4W
Ws≥3a
b1, b2≥Ws
1.0cmsLs1.5cm
b1 =bi± 0.005cm
d =d ±0.005cm
dz =dz ± 0.005cm
÷Ls±0.005cm
b, +di =
2.3.2.2 Six contact test specimens
Ls ± 0.005cm
The following requirements are made for the sample geometry, see Figure 3 (b) and (d): Ws≥3a
b1 b2≥2Ws
1.0cmLs≤1.5cm
b =bi ±0.005cm
b2=62 ±0.005cm
d, = di ±0.005cm
2.3.3 Thin sheet sample
-Can be of any shape, but the symmetrical shape of Figure 4 is recommended. If the electrodes are prepared in the same plane, the shape shown in Figure 4 (b) must be used. The sample must be completely free of holes. The size range is: Lp≥1.5cm
Where Lp is the circumference of the sample. This sample shape is not recommended when measuring anisotropic materials. 213
2.4 Etching
(a) [
GB 4326—84
(b)
(c) Square
Figure 4 Typical symmetrical thin slice specimen
The formed specimen needs to be etched after cleaning. 2.4.1 For germanium: The recommended etching solution is a mixture of 1 part hydrogen peroxide, 1 part hydrofluoric acid and 4 parts pure water, and the etching is carried out at 25±5℃ for 3 to 5 minutes.
2.4.2 For silicon: The recommended etching solution is potassium hydroxide solution, and the etching is carried out at 90℃ for 3 to 5 minutes. 2.4.3 For arsenic oxide: The recommended etching solution is a mixture of 5 parts sodium hydroxide and 1 part hydrogen peroxide, and the etching is carried out at boiling point for 3 to 5 minutes.
2.4.4 The recommended resistivity of pure water at 25°C should be greater than 10 2M2. The recommended concentration of hydrogen peroxide is 30%; the concentration of potassium hydroxide is 82%; the concentration of sodium hydroxide is 95%; the concentration of hydrofluoric acid is 40%; and the concentration of nitric acid is 65%. 2.5 Preparation of electrodes
The sample after etching must be rinsed and cleaned, and then the electrode is prepared by the following method. 2.5.1 For germanium: Use zinc fluoride flux to apply tin-indium or steel solder. 2.5.2 For silicon: Etch with etchant CP-4A only in the contact area for no more than 15 seconds. Or etch with a mixture of etchant: HNO,: HF = 10:1 for no more than 1 minute, wash with water, wash with concentrated hydrofluoric acid, and then wash with deionized water. Apply metal contacts by plating, sputtering or evaporation technology. For P-type silicon, use gold or aluminum, for N-type silicon, use nickel, etc. If necessary, a low-power Tesla coil can be used to prepare better ohmic contacts through contact discharge. 2.5.3 For monumentalization, etch with a mixture of etchant H2O2: HF: HO = 1:1:4 for no more than 10 seconds, and wash with clean water. Coat the steel and bake at 500℃ for a few seconds in a nitrogen-hydrogen mixed atmosphere. Or use electroplating, sputtering and evaporation techniques to coat metals such as gold and the contacts of the horn, discharge a low-power Tesla coil, and then coat the steel. It can also be coated with tin-doped indium solder (for N-type gallium arsenide) and zinc-doped tin solder (for P-type gallium arsenide) using an ultrasonic coating.
2.5.4 For half-hexahedral specimens, the electrodes should completely cover the two ends of the specimen in contact with the current. The width of other potential electrodes should be less than 0.02cm. Regardless of the shape, the electrode configuration should be as accurate as possible. 2.5.5 For thin-sheet specimens, keep the contact size as small as possible. Usually the electrode should be placed on the edge of the specimen, and its linear dimension should not be greater than 0.01Lp: If the electrode must be placed on a plane, it should be as small as possible and as close to the edge as possible. The repair factor for limited size is given by Vanderbilt.
3 Equipment
3.1 Equipment for wafer preparation
3.1.1 It is recommended to use an internal circle slicer and a high-precision external circle slicer. 214
GB 4326-84
3.1.2 Grinding equipment suitable for preparing flat metallographic specimens and auxiliary tools. 3.2 Corrosion equipment
Chemical laboratories and corresponding instruments and equipment for the use of acids (including hydrofluoric acid) and solvents. 3.3 Equipment for shaping specimens
Including high-precision external cylindrical slicers, ultrasonic machining machines and corrosion cutting equipment. The dies used should keep the specimen size tolerance within the range of: 1?.
3.4 ​​Geometric dimension measurement equipment for specimens
3.4.1 Thickness measurement Measuring instruments recommended are dry ruler, outer diameter ruler and graduated electric thickness gauge. The thickness measurement accuracy of the sample is required to be ±1%.
3.4.2 Width and length measuring instruments. It is recommended to use a microscope with a scale and graduated mechanical stage. The width and length of the sample are required to be measured with an accuracy of ±1%.
3.5 Equipment for preparing electrode contacts
Ordinary or ultrasonic soldering iron, suitable for electroplating, sputtering or evaporation equipment for gold, aluminum, nickel, etc., low-power Tesla wire, etc. 3.6 Orientation equipment
For equipment that requires specific In the case of face-cut specimens, an X-ray orientation device or an optical orientation device should be used. 3.7 Magnets
A calibrated magnet that provides a uniform magnetic flux density of 1% over the area of ​​the specimen placed therein. The direction of the magnetic flux must be reversible. The accuracy of the magnetic flux density is required to reach ±1%. This magnet can be an electromagnet or a permanent magnet. The electromagnet can be an electromagnet with a magnetic shoe or a spiral tube without a magnetic shoe. When using an electromagnet, appropriate equipment should be available to ensure that the stability of the magnetic flux density during measurement is within ±1%.
3.8 Electronic Equipment
3.8.1 A current source capable of maintaining a constant current through the specimen of ±0.5% during measurement. This may be an electronically regulated power supply or a series connection of batteries with a resistance equal to 10 times the total resistance of the specimen (including contact resistance). The magnitude of the current is required to be less than the current required to establish a 1Vc electric field at the specimen.
3.8.2 A standard resistor with the same resistance as the specimen, the value of which must be known to 0.1%. 3.8.3 For voltage measurement, it is recommended to use a digital voltmeter with high accuracy and high input impedance. The voltage measurement accuracy shall be better than 0.5%, and the input impedance of the instrument shall be at least 103 times the total resistance of the specimen being tested. Potentiometers, tube voltmeters, and electrometers that meet this requirement may also be used.
3.8.4 A conversion device suitable for current reversal, corresponding to the change in voltage reading and for sequentially connecting different potential wires to the measuring voltage device.
3.8.5 A transistor tracer to determine the contact properties of the extended electrodes. 3.9 Environmental Control Device
3.9.1 The sample holder should be placed in the center of the magnetic field. For measurements that need to be made at low temperatures, the sample holder can be placed in a Dewar flask, or the sample can be directly mounted on the cold head of a cryogenic refrigerator. Cryogenic containers should preferably be made of glass, metal or foamed polystyrene. Metal Dewar flasks must be made of non-magnetic materials. Due to the presence of such materials, the change in the magnetic flux density value at the sample position is no more than ±1%. 3.9.2 During the measurement process, temperature detectors and sample temperature control equipment, including copper-constantan thermocouples, platinum resistance thermometers or other components. When obtaining the concentration and temperature relationship in the range of liquid nitrogen temperature to room temperature, the temperature measurement accuracy should be better than ±0.5K. For the measurement of lower temperature, the temperature measurement accuracy is required to reach ±0.05K. During the measurement, the temperature stability should reach the value of the temperature measurement accuracy.
3.9.3 The sample is placed in an opaque container and the surrounding of the sample is kept insulated. When making low-flow measurements, the sample holder must be able to block both light and room temperature radiation. When making measurements different from room temperature, the sample holder must consider the mechanical stress on the sample due to slight expansion. For the case where the sample is not directly immersed in the coolant, in order to allow heat exchange between the sample and the insulated container to cool the sample, an inert gas with a pressure greater than 100 Torr, preferably hydrogen, can be passed into the container. 3.10 Positioning device
GB4326-84
In order to make the sample plane strictly perpendicular to the magnetic avoidance direction, mechanical positioning or electric positioning should be considered. It is determined by the method of scientific positioning. A. Measurement procedure
4.1 Installation of samples
Put the sample with prepared electrodes on the sample holder and connect the wires. It should be noted that the sample surface should be strictly perpendicular to the magnetic flux direction. 4.2 Resistivity measurement
Measure under zero magnetic field and constant temperature conditions. When using an electromagnet with a magnetic shoe, the residual magnetic flux density must be small enough not to affect the resistivity measurement at all.
4.2.1 Parallelliptic bridge-shaped sample Press the sample according to Figure 5 and measure the temperature of the sample. Set the contact selector to 1, 2 and 4, measure the voltage drop (+I), (+［) and V(+I), check the stability of the current, change the current direction and repeatedly measure V(1), V, (～［) and V(－1), check the stability of the current, and the voltage deviation between the two measurements should not exceed 0.5%. Measurement Measure the sample temperature and check the temperature stability. If the temperature difference between the two times is outside the allowable range, the above process should be repeated after the temperature stabilizes. (u) Eight contact samples
Figure 5 Circuit for measuring bridge-type and parallelepiped samples (b) ※ Dig contact sample
C—constant current source, R—standard resistor, CR—current reversing switch; D—potential difference galvanometer system (or digital voltmeter), PR—potential reversing switch, S—potential selection switch
4.2.2 Thin sheet sample Connect the sample according to Figure 6. First measure the potential drop V, (+1) across the standard resistor with the potential selector, and then connect the contact selector to positions 1, 2, 3 and 4, measure V (+I), V (+I), V (+I) and V, (+), check the current stability, current reversal, repeat The above process. Check the current stability as before. Repeat the temperature measurement to check whether the temperature is stable. If the temperature difference between the two times is outside the allowable range, the above process should be repeated after the temperature is stabilized. 216
4.3 Hall measurement
GB4326-84
Figure 6 Circuit for measuring thin sample
Screen
C-constant current source, R-standard electric attachment; CR-current switch; D-potential difference meter galvanometer system (or digital voltmeter); S-contact selection switch, PS-potential selection switch
If an electromagnet with residual magnetism is used to provide the magnetic flux, follow the appropriate procedure below. If a permanent magnet with known magnetic flux density is used, or an electromagnet with a marked current and magnetic flux density relationship and no residual magnetism is used, the measurement of magnetic flux density can be omitted. 4.3.1 Half-hexahedron or bridge-shaped sample Connect the sample according to Figure 5. Measure the temperature of the sample. The flux is switched on and adjusted to the required stop flux density value, and the flux density is measured. In the case of forward current, the selector is switched to position 1 [V, (+1, +B)}, position 3 [V (+I, +B)] and (for six-contact specimens) position 5 [V, (+I, +B)}, and the potential drop is measured. In order to check the stability of the current, the voltage drop is repeated when switching to position 1. If the second measured V deviates from the first by more than 0.5%, check the equipment and make necessary changes, repeating the procedure until the specified stability. Reverse the direction of the current and repeat the measurements of V, (-1, +B), V (-1, +B) and (for six-contact specimens) V, (-I, +B). To verify the stability of the flux, repeat the measurement of the flux density. If the second flux density deviates from the first by more than 1%, make necessary improvements and repeat the procedure until the specified stability. Then change the direction of the flux by 180 and adjust it to the same flux density (sand 1%), measure the flux density and repeat the potential measurements of (-1, -B), V, (-I, -B), and (for six-contact specimens) V, (-I, -B). Check the stability of the current as before, reverse the current and repeat the measurements of (+I, -B), V (+I, -B) and (for six-contact specimens) V (+I, B). Check the stability of the current and flux density as before. Check the temperature stability as before. If the temperature difference between the two times is outside the allowable range, repeat the above process after the temperature is stabilized.
All potential difference signs and values ​​must be confirmed and recorded. 4.3.2 Thin-sheet specimen Connect the specimen according to Figure 6, measure the specimen temperature, turn on the magnetic flux and adjust it to the required positive magnetic flux density value, and measure the magnetic flux density. Under the forward current, first measure V, (+I, +B), and then measure the potential drop V, (+I, +B) and V (+I, +B) across the specimen when the contact selector is turned on position 5 and position 6. Change the current direction and re-measure Vs (1, +B), Vs (-I, +B) and V. (-I, +B). Change the magnetic flux direction and adjust it to the original magnetic flux density value, and repeat the measurement of V, (-I, B), (-l, -B), V. (-I, -B). Change the current direction and repeat the measurement of V. (+I, B), V (+I, -B), V. (+I, -B). During the measurement, check the stability of the current at any time, requiring the change to be less than ±0.5%, and the stability of the magnetic flux density, requiring the change to be less than ±1%. Check the repeatability of the temperature as before. If the difference between the two measured temperatures is outside the allowable range, repeat the above process after the temperature is stabilized. 217
5 Result calculation
5.1 Parallel hexahedron or bridge-shaped specimen
GB 4326—84
5.1.1 Calculation of resistivity. The resistivity pa (Q cm) between a pair of conductivity electrodes is given by the following formula: PA:
rV2(+DV2(-D
-RWs-ts/d.
LV(+)+V(-)-
The resistivity pB (Q cm) between another pair of conductivity electrodes is given by the following formula: PB:
VA(+1)V(-1)-
2L5(+)+(-1)
The average resistivity is given by the following formula:
.R.Wst, /d2
(pA+pB)
（8）
Where: length unit is centimeter; resistance unit is ohm; potential unit is arbitrary but must be consistent. If 0A and Pε are not equal within ±10%, it means that the sample has non-uniformity that does not meet the requirements. In principle, such a sample should be discarded and replaced with a sample with uniformity that meets the requirements.
5.1.2 Hall coefficient
The Hall coefficient (RH) (cm2/C) is calculated according to formula (10). V:(+I, +B)V3(-I, +B)
RH = 2.50 ×107 . [
V(+I, +B)+V,(-1, +B)
V(-1, -B)
V(-I,-B)
V3(+I, -B)
V(+I, - B)-
.R.-t./B
Where: the length unit is centimeter, the resistance unit is ohm; the voltage unit is arbitrary but must be consistent, and the unit of B is Gauss. For N-type materials, R is negative, and for P-type materials, R is positive. The sample can measure two Hall coefficient values ​​and take the half average. RH=
(Ru+Ru)
If R, and R are not equal within 10%, it means that the sample has non-uniformity that does not meet the requirements. In principle, such a sample should be discarded and replaced with a sample that meets the uniformity requirements. 5.1.3 The Hall mobility is calculated using formula (5). 5.2 Thin slice sample
5.2.1 Resistivity calculation. The obtained data can be used to calculate two resistivity values ​​p (Q·cm) and p (Q·cm). PA = 1 1331- f t.[V(+D+(+D)+)+V(-D)Vs(+)
pB = 1.1331.f.ts. [
V:(+D +V(+1)
Vs(+1)
.R. ...
V,(-1)+Va(-1)) -Rs
+........
Vs(--)
Where: length unit is centimeter; resistance unit is ohm; voltage unit is arbitrary but must be consistent. f is the related function of Q4 or Q:. QA=
V2(+D)V(-1)-
-V(+)+(-)
-Va(+)V4(-)-
V,(+I)Vs(-I)-
[V+VC/[WG+VR]
The factor f is shown as a function of Q in Figure 7. If Q is less than 1, its reciprocal is taken. (14)
If , and P are not equal within ±10%, it means that the sample has non-uniformity that does not meet the requirements. In principle, such a sample should be discarded and replaced by a sample with uniformity that meets the requirements. The average resistivity is given by the following formula:
5.2.2 Hall coefficient
GB 4326—84
(PA+PB)
Function relationship diagram of factor versus Q
The Hall coefficient (RHc, RH) (cm\/C) is calculated according to formulas (16) and (17). Rtl= 2.50×10 [V(+I +B)
Vs(+I, +B)
Vs(-I, +B)
Vs(-I,+B)
Vs(+I, -B)] -Re -ts/B
V(+I,-B)
Ve(+I,+B)
R.=2.50x107.
L v(+1, +B)
Ve(+I, -B)-
.Rsts/B
V(+I,-B)J
Vs(-l, +B)
V(-I, +B)
V,(-I, -B)
Vs(-I,-B)
Ve(-l, -B)
V(-I,-B)bZxz.net
·（16）
（17）
Where: length unit is cm; resistance unit is ohm; voltage unit is arbitrary but must be consistent; B unit is Gauss. If RH and R are not equal within ±10%, it means that the sample has non-uniformity that does not meet the requirements. In principle, such a sample should be discarded and replaced with a sample with uniformity that meets the requirements. 5.2.3 Hall mobility is calculated using formula (5). 6 Precautions
6.1 High contact resistance can lead to false results, so the ohmic contact characteristics of the electrode are crucial to the measurement. Before measurement, the sample electrode should be checked for ohmic characteristics using a VI characteristic tester. For all possible combinations of contacts, take two at a time and make a full ohmic property check on both polarities. When observed on a general transistor plotter, a linear VI characteristic is obtained over an order of magnitude including the actual current used, with no obvious bend. 6.2 Photoconductivity and photovoltaic effects can seriously affect the measured resistivity, especially for materials close to intrinsic. Therefore, the test sample should be placed in a light shield.
6.3 During the measurement process, it is necessary to ensure that Ohm's law holds and the material resistivity does not change with the electric field. Usually an electric field of less than 1V/cm is selected. 219
GB 432684
Due to the effect of the electric field in the sample, a small number of current carriers may be injected. For high-life and high-resistance materials, this injection conduction reduces the resistivity within the distance along the bridge. When a very low voltage is applied, repeated measurements can determine whether there is carrier injection. In the absence of injection, no resistivity change will be found. When measuring, choose as low a voltage as possible. 6.4 Since the temperature coefficient of resistivity of flat conductors is large, the sample temperature should be known during measurement. The load current used during measurement should be small to avoid the current heating the sample. When the current is applied to the sample, the change in resistivity reading can be used to determine whether the measuring current is appropriate.
6.5 High-frequency currents near the measuring device are likely to cause induced pseudo currents, so the measuring device should be placed behind a good off-frequency electromagnetic shield.
6.6 When measuring off-resistance samples, surface leakage is a serious problem. When the surface conditions of the sample being tested change, the measurement results will also change. At the same time, leakage and shunt in other parts of the circuit, including the test voltage meter, should be prevented. The connecting cable should be as short as possible, otherwise! Large capacitance values ​​will prolong the test time of high-resistance samples. 6.7 Uneven impurity concentration or uneven magnetic flux density in the sample will cause inaccurate measurements, which may even cause extreme errors. 6.8 The Hall electrodes of parallelepiped and bridge-shaped samples must be kept away from the current contact end to avoid short-circuit effects. The sample geometry given in the figure will ensure that the reduction in Hall voltage caused by the short-circuit effect is less than 1%. 6.9 For anisotropic materials such as N-type silicon and N-type germanium, the Hall measurement is affected by the direction of the current and magnetic field relative to the crystal axis. 6.10 When measuring the Hall voltage, the current and magnetic field commutation measurement can eliminate other side effects except the Ettinghausen effect. The error caused by the Eindhoven effect is small and can be ignored, especially when the specimen is in good thermal contact with its surroundings. 6.11 Any false electromotive force that may be generated in the measuring circuit, such as thermoelectric potential, shall be carefully checked and eliminated. 7 Report
7.1 The report suitable for arbitration test shall include the following: Identification of the test specimen.
b. Test temperature.
c. Shape and corresponding dimensions of the test specimen.
d. The size of the standard resistor for each measurement, the voltage drop across the standard resistor, the size and polarity, the conductivity voltage, the Hall voltage and the magnetic flux density.
e. Calculation of average resistivity, average Hall coefficient (including sign) and Hall mobility.
f. Identification of the instruments used to measure current, voltage, magnetic flux density and specimen geometry. 7.2 For comparative tests of the same specimen in different systems, the tests shall be carried out under the same test conditions, including temperature, magnetic flux density and specimen current. The so-called same means that the differences between them can only be within the allowable range. 8 Precision
The expected precision of this standard is ±7%, which is applicable to materials such as germanium and gallium silicide with resistivity between 0.01 and 102 cm.
Additional Notes:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by the Beijing Nonferrous Metals Research Institute. The main drafter of this standard was Feng Yi.
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