GOST 25948-83

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  ГОСТ 25948-83

GOST 25948−83 (ST SEV 3910−82) gallium Arsenide and gallium phosphide single crystal. Measurement of electrical resistivity and Hall coefficient (Change No. 1)

GOST 25948−83
(ST CMEA 3910−82)

Group B09
STATE STANDARD OF THE USSR

GALLIUM ARSENIDE AND GALLIUM PHOSPHIDE SINGLE CRYSTAL

Measurement of electrical resistivity and Hall coefficient

Monocrystal gallium arsenide and gallium phosphide. Measurement of specific electric resistance and Hall-coefficient

AXTU 1772

Valid from 01.01.85
to 01.01.90*
________________________________
* Expiration removed
Protocol N 4−93 inter-state Council
for standardization, Metrology and certification
(IUS N 4, 1994). — Note the manufacturer’s database.

DEVELOPED by the Ministry of nonferrous metallurgy of the USSR

PERFORMERS

A. V. Elyutin, N. N. Soloviev, N. And. Suchkov, V. M. Mikhailov

INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

Member Of The Board Of A. P. Snurnikov

APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on standards of 28 October 1983, N 5178

The Change N 1, approved and introduced with effect from 01.01.90 by the resolution of Gosstandart of the USSR from 22.03.89 N 606

Change No. 1 made by the manufacturer of the database in the text IUS N 6, 1989


This standard specifies a method of measuring resistivity, Hall coefficient and determine the type of conductivity, concentration and hall mobility of main charge carriers for semiconducting materials with electrical resistivity between 10to 10Ohm·cm monocrystalline gallium arsenide and gallium phosphide.

The standard fully complies ST SEV 3910−82.

(Changed edition, Rev. N 1).

1. THE ESSENCE OF THE METHOD

1.1. Determination of electrical resistivity based on the measurement of longitudinal electric field and current density caused by this field.

1.2. The definition of the Hall coefficient is based on measurement of transverse electric field occurring in the semiconductor placed in a magnetic field of induction at course through it of a current density in the direction perpendicular to the magnetic field.

1.3. Type conductivity semiconductor material is determined by the sign of the Hall EMF in accordance with the devil.1.

(Changed edition, Rev. N 1).

Damn.1*

_______________
* Drawing 1. (Changed edition, Rev. N 1).

1.4. The concentration and mobility of major charge carriers is determined by calculation on the basis of data on the measurement of electrical resistivity and Hall coefficient.

2. EQUIPMENT

2.1. Block diagram of the setup for measuring resistivity and Hall coefficient are presented for the devil.2.

1 — the measured sample; 2 — magnet; 3 — a constant current source; 4 — the measuring device; 5 — switching device

Damn.2

2.1.1. The measuring unit must be certified. Basic relative error of installation in the control samples with electrical resistivity Ohm·cm should not exceed the measurement of resistivity is ±5% and of the Hall coefficient ±8%; in the control samples with electrical resistivity Ohm·cm should not exceed, respectively, ±12% and ±15%.

2.1.2. Carrying out measurements and processing of results with the use of automation in the algorithms described in the present standard, specifically the use of units such as the «Hall-100», «Hall 200», subject to the requirements of paragraph 2.1.1.

2.1.1, 2.1.2. (Added, Rev. N 1).

2.2. Requirements for the structural elements of the scheme depending on the measured material parameters are given in table.1−2.

2.2.1. The magnet provides the creation of magnetic fields of variable polarity, must meet the requirements of table.1.

Table 1

Note. Measurement of the Hall coefficient in gallium arsenide -type conductivity with the concentration of main charge carriers of more than 1·10cmperformed with the value of at least 0.7 Tesla.

2.2.2. A constant current source, ensuring the creation in the measurement circuit an electric current of variable polarity, must meet the requirements of table.2. The recording error of electric current shall not exceed 1% when measuring material with a specific electric resistance Ω·cm and 3% in the measurement of semi-insulating material with a specific electric resistance in Ohm·cm.

Table 2

2.2.1, 2.2.2. (Changed edition, Rev. N 1).

2.2.3. A device for measuring electrical voltage must meet the requirements of table.2.

The error of measurement of electrical voltage shall not exceed 1% for control of a material with a specific electric resistance Ω·cm and 2.5% — in the control of semi-insulating material with a specific electric resistance in Ohm·cm.

2.2.4. The switching device must provide under the control of the same sample conduct measurement operations using a single measuring device. The value of electrical insulation resistance of the switching device contacts shall not be less than the input electrical resistance measuring device.

2.2.3, 2.2.4. (Changed edition, Rev. N 1).

2.3. Auxiliary means

2.3.1. The sample holder must ensure:

perpendicular to the sample plane in the direction of the magnetic field with the deviation from perpendicularity of ±3°;

the possibility of measuring the darkening of the sample;

according to the dielectric properties of structural materials resistance measuring device.

2.3.2 Micrometer or other tool to measure the sample thickness with an accuracy of not more than 1·10cm and with an uncertainty of less than 3·10cm to measure the thickness of 0.06 cm

2.3.3. (Deleted, Rev. N 1).

2.3.4. Device for measuring absolute values of magnetic induction with an accuracy of not more than 2%.

2.3.5. Thermometer with a measuring error of not more than 0.5 K.

3. SAMPLING METHODS

3.1. The measurements were carried out on samples in the form of plane-parallel plates in the form of a square (Fig.3) or of arbitrary shape, either on samples of cruciform shape (Fig.4).

Damn.3

Damn.4

(Changed edition, Rev. N 1).

3.1.1. Allowed to carry out measurements on samples in the form of a parallelepiped that meet the requirements of the cruciform samples (table.3).

(Added, Rev. N 1).

3.2. Measurements of semi-insulating material with a specific electric resistance >10Ω·cm is performed on samples cross shape (or parallelepiped).

3.3. Requirements for the characteristics of the samples are given in table.3.

Table 3

For plates of arbitrary shape, the transverse dimension of the sample should be not less than 0.7, see

3.2, 3.3. (Changed edition, Rev. N 1).

4. THE PREPARATION OF THE MEASUREMENTS

4.1. On the sample cross shape applied to six electrical contacts.

4.2. The sample in the form of a plane-parallel plate is applied to four electrical contact, positioned on the front surface or the periphery of the plate.

(Changed edition, Rev. N 1).

4.3. Electrical contacts must have:

linear volt-ampere characteristics (measurement results should not depend on the specific measurement modes);

small transfer resistance (recommended methods of assessment are set depending on kinds of semiconductor single crystal materials).

4.4. Before measurements of electrophysical parameters measured geometric dimensions of the sample.

4.4.1. The thickness of the sample in the form of a plane-parallel plate is measured at three points: one in the center and two on the periphery of the plate. If the transverse linear size of the sample exceeds 5 cm, the thickness of the sample is measured at 5 points: one in the center and four at the periphery of the sample. As a result of the thickness measurement should be the arithmetic mean of the obtained values.

4.4.2. Geometrical dimensions of samples cruciform shape measure two times at opposite ends of the sample. The measurement result should be the arithmetic mean of the obtained values.

4.4, 4.4.1, 4.4.2. (Added, Rev. N 1).

5. MEASUREMENTS

5.1. The measurements were carried out at a fixed temperature. Permissible deviation of the temperature during the measurement is not more than 0.5 K.

5.2. Measurements on samples in the form of plane-parallel plates.

5.2.1. The sample set in the holder, and is passed through electric current using the adjacent perimeter of the sample pair of contacts. Record the current value and the potential difference occurring at the second pair of contacts in the following order:

, ;

, ;

, ;

, .

(Changed edition, Rev. N 1).

5.2.2. Enter the magnetic field, the fixed values of current , magnetic induction and the potential difference in the following order:

, ;

, ;

, ;

,

Digital indexes correspond to the contacts of the sample (Fig.3). Currents measurements within the same paragraph (5.2.1 or 5.2.2) should be the same; the values of currents when measuring at different points may vary within the requirements table.2.

5.3. Measurements on samples of cruciform shape

5.3.1. The sample set in the holder, and is passed through electric current. Record the values of electric current in two directions , and the potential difference :

;

;

;

.

5.3.2. Introduce a magnetic field, fixed values of magnetic induction, electric current in two directions , and the potential difference :

, ;

, ;

, ;

, .

Digital indexes correspond to the contacts of the sample (Fig.4).

6. PROCESSING OF THE RESULTS

6.1. Processing of results of measurements on the sample in the form of a plane-parallel plate

6.1.1. The values of the voltages , , , and coefficients , calculated by the formulas:

; (1)

; (2)

; (3)

. (4)

When calculating the stress values , and coefficients , consider the algebraic signs of the quantities obtained in the measurements.

In determining the ratios and divide a large amount less to get the result more 1.

; (5)

. (6)

When determining the values and take into account the algebraic signs of the quantities obtained in the measurements.

(Changed edition, Rev. N 1).

6.1.2. Define the adjustment factors and in accordance with the mandatory application.

6.1.3. The average values of voltages and calculated by the formula:

; (7)

. (8)

6.1.4. Electrical resistivity , Ohm·cm, is calculated by the formula

, (9)

where the value of electric current at which measurements were conducted according to claim 5.2.1, And;

 — the thickness of the measured sample, cm;

 — the average value of voltage while measuring specific electrical resistance, V.

6.1.5. The Hall coefficient , cm/CR, is calculated by the formula

, (10)

where the value of magnetic field induction, T;

the value of electric current at which measurements were conducted according to claim 5.2.2, And;

 — the average value of the EMF Hall V.

6.1.6. The concentration of major charge carriers , cm, is calculated by the formula

, (11)

where is the charge of the electron; CL;

 — hall factor, assumed equal to 1.

(Changed edition, Rev. N 1).

6.1.7. Hall mobility of main charge carriers , cm, is calculated by the formula

. (12)

6.2. Processing of results of measurements on the sample cross shape

6.2.1. The values of stresses , , are calculated by the formulas:

; (13)

; (14)

. (15)

When determining the values , ,  — take into account the algebraic signs of the quantities obtained in the measurements.

(Changed edition, Rev. N 1).

6.2.2. The average values , , calculated by the formulas:

; (16)

; (17)

. (18)

6.2.3. Electrical resistivity , Ohm·cm and a Hall coefficient , cm/CR, calculated by the formulas:

; (19)

, (20)

where ,  — the value of electric current calculated by the formulas (17) and (18), And;

the cross — sectional area of sample, cm: ,

where  — thickness of sample, cm;

 — width of sample, cm;

,  — stress values, computed according to the formulas (13), (16);

the value of magnetic field induction in the gap of the magnet, T;

 — the distance between the contacts 1 and 2, 3, and 4 cm (black

vol. 4).

6.2.4. The concentration and mobility of major charge carriers is calculated according to the formulas (11) and (12).

6.2.5. The values of electrical resistivity and the concentration of the main charge carriers in semi-materials (Ohm·cm) can be reduced to a temperature of formula

; (21)

; (22)

, (23)

where is the Boltzmann’s constant; eV K;

 — temperature measurement, K;

 — the activation energy of deep impurity center, polyzoniida defining material properties, eV.

For GaAs -type conductivity eV.

For GaPe

V.

6.2.6. The results of the measurements to represent a number with three significant digits indicating the order of magnitude. The results of measurements and calculations are rounded in accordance with the rule: if the first (right to left) from the cast numbers more or is equal 5, the last digit is increased by 1; if less than 5, the remaining numbers do not change.

6.2.7. Interval, which is the minimum value of the total error of measurement of the electrical resistivity with confidence probability is ±5% for samples with electrical resistivity Ohm·cm; ±12% for the samples with electrical resistivity Ohm·cm.

6.2.8. Interval, which is the minimum value of the total error of measurement of the concentration of the basic carriers of a charge with confidence probability is ±8% for samples with electrical resistivity Ohm·cm; ±15% for samples with electrical resistivity Ohm·cm.

6.2.9. Interval, which is the minimum value of the total error of measurement of the mobility of main charge carriers with confidence probability is ±8% for samples with electrical resistivity Ohm·cm; ±10% for samples with electrical resistivity Ohm·cm.

6.2.10. The presence in a controlled sample of impurities, inhomogeneity of the distribution of electrophysical parameters increases the total measurement error, which is set in the metrological certification of the method as applied to specific products.

6.2.5−6.2.10. (Added, Rev. N 1).

6.3−6.9. (Deleted, Rev. N 1).