GOST 26239.8-84

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  ГОСТ 26239.8-84

GOST 26239.8−84 semiconductor Silicon and raw products to get it. Method for the determination of DICHLOROSILANE, trichlorosilane and silicon tetrachloride (Change No. 1)

GOST 26239.8−84

Group B59

STATE STANDARD OF THE USSR

SILICON IS A SEMICONDUCTOR AND SOURCE PRODUCTS TO OBTAIN

Method for the determination of DICHLOROSILANE, trichlorosilane and silicon tetrachloride

Semiconductor silicon and raw materials for its production. Method of dichlorsilane, trichlorsilane and silicon tetrachloride determination

AXTU 1709

Date of introduction 1986−01−01

The decision of the State Committee USSR on standards on July 13, 1984 N 2491* validity installed before 01.01.86 01.01.91**
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* See the label «notes»;
** Expiration removed by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (I & C N 11, 1995). — Note the manufacturer’s database.

The Change N 1, approved and in effect as of 01.01.91 by the resolution of Gosstandart of the USSR from 26.06.90 N 1848

Change No. 1 made by the manufacturer of the database in the text ICS N 10, 1990


This standard specifies a chromatographic method for the determination of DICHLOROSILANE from 0.02 to 10%, of the trichlorosilane from 0.02 to 100% and silicon tetrachloride from 0.02 to 100%, silicon tetrachloride distillation cleared and mixtures of silicon tetrachloride with trichlorosilane.

The method is based on chromatographic separation of the components in an isothermal mode with the subsequent detection of the thermal conductivity and the calculation of the mass fraction of the designated component areas of the chromatographic peaks from the coefficients of relative sensitivity of the detector to the designated components.

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 26239.0−84.

2. APPARATUS, MATERIALS AND REAGENTS

Chromatograph lxm-8МД with the thermal conductivity detector, registering the device, the drying unit is gas carrier, the syringe system of input samples.

The chromatographic column of glass or metal with a length of 4 m, with a diameter of 2−4 mm.

Electronic integrator I-02.

Trap of glass (Fig.1) with potassium hydroxide, h. e. a., preformed.

The roughing pump EXT 461М.

Vacuum drying Cabinet at temperatures up to 200 °C

Glasses glass with a capacity of 200 cm.

Porcelain Cup with a diameter of 50 mm.

Funnel glass process with a diameter of 2−4 mm.

Analytical scale.

The stopwatch according to GOST 5072−79*.
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* On the territory of the Russian Federation the document is not valid. For additional information, please refer to the link. — Note the manufacturer’s database.

Chromatographic syringes with a scale of 0 to 10 µl.

Boxy glass according to GOST 25336−82 5−10 cm.

Fiberglass.

Tube of PTFE with a diameter of 5 mm.

Sampler glass with a capacity of 50−100 cm,with PTFE stopcock, (Fig.2).

Damn.1. Glass trap

Glass trap

1 — entrance of the carrier gas; 2 — lattice; 3 — outlet of the carrier gas

Damn.1

Damn.2. Sampler

Sampler

1 — Teflon valve; 2 — external cavity valve; 3 — glass capacity

Damn.2

Glass pipettes with a capacity of 10−20 cm.

Media solid silenzione: chromaton N-AW, spirogram-2, zitohrom 1 CDMTCS, factions grained 0,250−0,315 mm.

Stationary phase — polymethylsiloxanes rubber SE-30.

The purified trichlorosilane with a mass fraction of impurities not more than 0.01%.

Silicon tetrachloride purified with a mass fraction of impurities not more than 0.01%.

The technical rectified ethyl alcohol GOST 18300−87.

Acetone according to GOST 2603−79.

Ether diethyl H. h

Carrier gas — helium gas.

Liquid nitrogen according to GOST 9293−74.

Chloroform medical GOST 20015−74*.
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* On the territory of the Russian Federation the document is not valid. Standards 20015−88. — Note the manufacturer’s database.

Angidro.

The phosphorus pentoxide.

Zeolite Na5X.

(Changed edition, Rev. N 1).

3. PREPARATION FOR ASSAY

3.1. Preparation of the sorbent and filling chromatographic columns

Solid carrier — chromaton N-AW, spirogram-2 or zitohrom 1 CDMTCS — dried in an oven at 120−130 °C for 5−6 h. the Dried medium (~100 g) is weighed in a porcelain Cup with error not more than 0.01 g.

Stationary phase in an amount of 10% by weight of the solid support is weighed in a beaker with an accuracy of at least 0.01 g and dissolved in chloroform (10 cmper 1 g of the stationary phase).

Solid media poured in a porcelain Cup with a solution of stationary phase in chloroform and thoroughly mixed. Then the solvent evaporate under continuous stirring by heating at 50 °C in a sealed hot plate in a fume hood.

The chromatographic column before filling clean with a cotton swab on the wire and washed successively with acetone, ethanol and diethyl ether. At the end of the washing column, dried at 100−120 °C by blowing a carrier gas for 30 min.

One end clean the dried column closed with a pad of fiberglass and connect the vacuum hose of PVC with a line booster pumping. Through the other end produce the filling of the sorbent column through a funnel under continuous pumping, and lightweight vibration speakers. You should fill the column to a level 3−5 mm below the edge. On completion of filling the second end of the column is also close pad of fiberglass. The filling of glass columns checked visually. If there are voids they eliminate gentle shaking of the column. Metal column filled dosed by volume, amount of sorbent.

Set the completed column in thermostat chromatograph and conditionerit — blow dry the carrier gas for 5−6 h at 250 °C. Heating until 250 °C is performed at a speed of 10−15 °C/min.

Drying of the carrier gas in the gas supply line there are two columns: the first along the gas carrier is filled with angerona, the second a phosphorus pentoxide in the mixture with the zeolite Na5X (10% phosphorus pentoxide by weight of the zeolite). The conditioned column is connected to the detector.

3.2. Preparation of the calibration mixtures

Preparation of the calibration mixture is conducted by mixing the components in the probe.

A calibration mixture comprising trichlorosilane and silicon tetrachloride, and the mass fraction of trichlorosilane in the mixture is about 20%, silicon tetrachloride was about 80%.

The probe weighed on an analytical balance. Poured into the sampler 20 cmof pure silicon tetrachloride. Pumped a fore pump external cavity tap to remove excess silicon tetrachloride. Weigh the sampling probe of silicon tetrachloride on an analytical balance and from the difference of the masses determine the number entered in the probe of silicon tetrachloride () in grams. Introduced into the probe 5 cmof trichlorosilane and also the gravimetric method determine its quantity (number) in grams. Mass proportions of the components (a) percentage calculated by the formula

,

where  — the mass of the -th component in the mixture,

The calibration mixture was stored in the sampler, avoiding prolonged contact of the mixture with the atmosphere.

(Changed edition, Rev. N 1).

3.3. Determination of the coefficients of relative sensitivity

Determination of the coefficients of relative sensitivity is on the chromatogram of the calibration mixture.

Include chromatograph chromatograph output and the operating mode in accordance with the manual of the device.

An operating mode of the chromatograph:

Time device output mode — 2 hours After reaching mode before starting work, carry out training speakers by 7−10-fold dose of the calibration mixture with a volume of 2·10cm.

The dose is via syringe.

In column ready-to-use device with a syringe injected 1 µl of the calibration mixture and record the chromatogram.

The identification of peaks in chromatograms is carried out according to the order of the output components. In the adopted testing conditions, the first column buirette trichlorosilane, and then silicon tetrachloride.

Area of chromatographic peaks (s) of trichlorosilane and silicon tetrachloride in volts per second is determined using an electronic integrator.

The coefficient of relative sensitivity for trichlorosilane (a) silicon tetrachloride is calculated by the formula

,

where ,  — mass fraction of trichlorosilane and silicon tetrachloride in the calibration mixture, %;

,  — area of chromatographic peaks of trichlorosilane and silicon tetrachloride in the chromatogram of the calibration mixture, In/sec.

The procedure for removing the chromatogram of the calibration mixture, determining areas of chromatographic peaks and the calculation repeated three times. Then calculate the arithmetic mean of the results of the three definitions .

The allowable divergence between the extreme values is 3%. In the case of large discrepancies the definition of the coefficient of relative sensitivity should be restarted.

The coefficient of relative sensitivity for the DICHLOROSILANE to silicon tetrachloride is calculated by the formula

.

3.4. Preparation of the sample.

The sampler is evacuated to a residual pressure of 10tor (13 PA). Rolled back to the probe attached to the PTFE tube with a diameter of 5 mm. the Free end of the tube immersed in a container with the sample, and open the tap of the probe. The sample is drawn into the sampler. Close the valve and pumped external cavity tap probe roughing pump to remove excess sample. Selected sample is poured into box.

4. ANALYSIS

An operating mode of the chromatograph in the analysis should be identical to the regime established at registration of the chromatogram of the calibration mixture for the calculation of the coefficients of relative sensitivity. Mode options is given in section 3.3.

Before the analysis, conduct training column chromatograph by 7−10-fold injection of doses of a sample volume of 5 ál. Dosing is by syringe.

Dosing of samples for analyses is carried out using a syringe. The volume of injection syringe doses should be 5−10 µl.

The registration peaks of the chromatograms is carried out in the position of the attenuator that provides the maximum of the peak in the optimal scale interval potentiometer. Area of chromatographic peaks () of all components of the sample is determined using an electronic integrator.

Recording of chromatograms and determination of the values of all the components is repeated three times.

5. PROCESSING OF THE RESULTS

5.1. Identification of components in samples is performed in order of release and held relative to the volumes specified in table.1.

Table 1

5.2. The mass fraction of components in the sample () in percent is calculated by the formula

,

where is the coefficient of relative sensitivity for the -th component of silicon tetrachloride;

 — area of chromatographic peak of the -th component In the/C;

 — the number of components in the sample.

For the results analysis be the arithmetic mean of results of three parallel measurements.

5.3. The difference between the largest and smallest results of the three parallel measurements with a confidence probability of 0.95 does not exceed the allowable absolute values of the differences of the three results of parallel measurements specified in the table.2.

Table 2

5.4. The correctness of the analysis results on the synthetic control mixtures. For this purpose according to claim 3.2 prepare two mixtures of composition close to that given in table.3.

Table 3

Determine the coefficient of relative sensitivity for the trichlorosilane to silicon tetrachloride according to claim 3.3, using a mixture of 1. Then, in sect.4 carry out the analysis of mixture 2 and div.5 calculate the concentration of trichlorosilane and silicon tetrachloride using in the calculation of the coefficient of relative sensitivity obtained for mixture 1.

The analysis is considered correct if the absolute value of the difference between the results of determination of mass fractions of components in the mixture 2 with confidence probability of 0.95 does not exceed 0.1% for the trichlorosilane, and 0.7% silicon tetrachloride.