A silane pretreatment method and system for silicon isotope abundance testing

Abstract

This invention belongs to the field of isotope chemical analysis technology and discloses a silane pretreatment method and system for silicon isotope abundance testing, comprising the following steps: Step 1, the front end of the silane injection system is connected to a silane cylinder, and the rear end is connected to an absorption bottle containing an alkaline solution, the rear end of which is connected to a silane tail gas tank; Step 2, the silane injection system is purged with inert gas to fill it with an inert gas atmosphere; Step 3, the silane injection system is evacuated using a vacuum pump; Step 4, silane is introduced into the absorption bottle under negative pressure, and after absorption, the absorbent is collected and the silicon isotope abundance is tested using a silicon isotope abundance testing instrument. This method avoids silane leakage and spontaneous combustion during abundance analysis, and the solution form reduces its flammability, effectively ensuring the safety of experimental personnel.

Description

Technical Field

[0001] This invention relates to the field of isotope chemical analysis technology, and in particular to a silane pretreatment method and system for silicon isotope abundance testing. Background Technology

[0002] Silicon isotope materials are mainly used in semiconductor and chip manufacturing, quantum technology, and bioimaging. For example, silicon-28 isotope is one of the key materials in quantum computing and semiconductors. Its zero-spin characteristic and extremely low impurity content can reduce the influence of electronic noise and low thermal noise, reduce the decoherence effect of qubits, and help improve the stability and lifespan of quantum technology devices. Some studies are exploring the use of silicon-29 as an imaging agent for hyperpolarized magnetic resonance imaging (HMI) to obtain stronger signals and clearer images. Silanes are an important application form of silicon isotopes, and downstream customers have stringent requirements for product abundance. Therefore, achieving accurate determination of silicon isotope abundance in SiH4 is of great significance.

[0003] SiH4 is a colorless gas at room temperature and pressure. It is chemically reactive and can spontaneously combust in air, producing silicon dioxide and water. In current technology, SiH4 gas is usually directly introduced into the analytical instrument for isotope abundance analysis, which has problems such as large sample consumption, easy equipment contamination, and the sample gas being prone to ignition. Summary of the Invention

[0004] To address the problem of silane abundance testing, this invention discloses a silane pretreatment method and system for silicon isotope abundance testing. In this invention, the silane gas is the gas to be tested, which is introduced into an absorption bottle through a silane injection system, causing the silane to dissolve in the solution and transforming it into a liquid sample for testing.

[0005] The technical solution adopted to achieve the purpose of this invention is: A silane pretreatment method for silicon isotope abundance testing includes the following steps: Step 1: Connect the front end of the silane injection system to the silane cylinder and the rear end to the absorption bottle, which contains an alkaline solution. Connect the rear end of the absorption bottle to the silane tail gas tank. Step 2: Purge the silane injection system with inert gas to fill the silane injection system with an inert gas atmosphere; Step 3: Evacuate the silane injection system using a vacuum pump; Step 4: Silane is introduced into the absorption bottle under negative pressure. After absorption, the absorption liquid is taken and the silicon isotope abundance is tested using a silicon isotope abundance testing instrument.

[0006] In the above technical solution, the alkaline solution in step 1 is ammonia water, sodium hydroxide, potassium hydroxide or lithium hydroxide with a mass fraction of 5-50%.

[0007] In the above technical solution, in step 1, the air inlet pipe in the absorption bottle is inserted below the surface of the absorption liquid, and the air outlet pipe is above the surface of the absorption liquid.

[0008] In the above technical solution, the purging pressure in step 2 is 0.05~0.2MPa.

[0009] In the above technical solution, the vacuum level in step 3 reaches below -0.08 MPa.

[0010] In the above technical solution, the amount of silane introduced in step 4 is 0.05~0.5g.

[0011] In the above technical solution, the silicon isotope abundance testing instrument in step 4 is a high-resolution inductively coupled plasma mass spectrometer.

[0012] A silane pretreatment system for silicon isotope abundance testing includes a silane cylinder, an absorption bottle, a silane tail gas tank, a vacuum pump, and an inert gas cylinder, wherein: The pipeline between the silane cylinder and the absorption bottle is sequentially equipped with a pressure reducing valve, a first needle valve, and a second needle valve. A first branch pipe and a second branch pipe are connected between the first and second needle valves. A third needle valve is installed on the first branch pipe. The end of the first branch pipe is connected to the vacuum pump via a vacuum line and to an inert gas cylinder via an inert gas purging line. A one-way valve is installed on the pipeline between the inert gas cylinder and the third needle valve. A fourth needle valve is installed on the pipeline between the vacuum pump and the third needle valve. A pressure gauge is connected to the end of the second branch pipe, and a fifth needle valve is installed on the second branch pipe. A sixth needle valve is provided on the pipeline between the absorption bottle and the silane tail gas tank.

[0013] In the above technical solution, the pressure gauge has a range of -0.1MPa to 1MPa.

[0014] A processing method based on the silane pretreatment system includes the following steps: Step 1: Connect each of the silane pretreatment systems and fill the absorption bottle with the absorption liquid.

[0015] Step 2: Open the valve of the inert gas cylinder, and open the first needle valve, third needle valve, fifth needle valve, second needle valve, and sixth needle valve to purge the silane pretreatment system with nitrogen.

[0016] Step 3: Close the second needle valve, the sixth needle valve, and the valve of the inert gas cylinder. Then open the pressure reducing valve and the fourth needle valve, and turn on the vacuum pump to evacuate the system.

[0017] Step 4: Close the pressure reducing valve, the fourth needle valve, the vacuum pump, and the third needle valve. Open the valve of the silane cylinder, open the pressure reducing valve to control the outlet pressure, and wait for the silane gas to fill the pipeline from the first needle valve to the second needle valve. Then close the first needle valve and open the sixth needle valve and the second needle valve to allow the silane gas to enter the absorbent liquid.

[0018] Step 5: Close the second needle valve and open the first needle valve to allow silane gas to refill the pipeline from the first needle valve to the second needle valve. Then close the first needle valve, open the sixth needle valve, and slowly open the second needle valve to allow silane gas to re-enter the absorbent liquid.

[0019] Step 6: Repeat step 5, passing silane gas through the absorbent 4-5 times until the absorbent becomes cloudy, yielding silane- 28 Si absorbent, silane-... was analyzed using a silicon isotope abundance analyzer. 28 The silicon isotope abundance was determined using the Si absorber.

[0020] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a silane pretreatment method for silicon isotope abundance testing. This method converts silane into a more stable form, allows for precise control of the injection volume, reduces silane gas consumption, and avoids corrosion of the instrument flow path by silane gas. This method prevents silane leakage and spontaneous combustion during abundance analysis; the solution form reduces its flammability, effectively ensuring the safety of laboratory personnel. Attached Figure Description

[0021] Figure 1 The diagram shown is a schematic representation of the silane pretreatment system of the present invention.

[0022] In the diagram: 1-Silane cylinder, 2-Absorption bottle, 3-Silane tail gas tank, 4-Vacuum pump, 5-Inert gas cylinder, 6-Pressure reducing valve, 7-First branch pipe, 8-Second branch pipe, 9-One-way valve; A - First needle valve, B - Second needle valve, C - Third needle valve, D - Fourth needle valve, E - Fifth needle valve, F - Sixth needle valve. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0024] Example 1 like Figure 1 As shown, a silane pretreatment system for silicon isotope abundance testing includes a silane cylinder 1, an absorption bottle 2, a silane tail gas tank 3, a vacuum pump 4, and an inert gas cylinder 5, wherein: A pressure reducing valve 6, a first needle valve A, and a second needle valve B are sequentially installed on the pipeline between the silane cylinder 1 and the absorption bottle 2. A first branch pipe 7 and a second branch pipe 8 are connected on the pipeline between the first needle valve A and the second needle valve B. A third needle valve C is installed on the first branch pipe 7. The end of the first branch pipe 7 is connected to the vacuum pump 4 through a vacuum pipeline and to the inert gas cylinder 5 through an inert gas purging pipeline. A one-way valve 9 is installed on the pipeline between the inert gas cylinder 5 and the third needle valve C. A fourth needle valve D is installed on the pipeline between the vacuum pump 4 and the third needle valve C. A pressure gauge is connected to the end of the second branch pipe 8, and a fifth needle valve E is installed on the second branch pipe 8. A sixth needle valve F is provided on the pipeline between the absorption bottle 2 and the silane tail gas tank 3.

[0025] Example 2 This embodiment uses silane- 28 Si is the sample to be absorbed, and 25% ammonia solution is used as the absorption liquid. The pretreatment steps are as follows: (1) Connect the silane pretreatment system and fill the absorption bottle 2 with 100g of ammonia water with a mass fraction of 25%.

[0026] (2) Open the valve of the inert gas cylinder 5, and open the first needle valve A, the third needle valve C, the fifth needle valve E, the second needle valve B, and the sixth needle valve F to purge the silane pretreatment system with nitrogen and maintain the purging pressure at 0.1 MPa.

[0027] (3) Close the second needle valve B, the sixth needle valve F, and the cylinder valve of the inert gas cylinder 5. Then open the pressure reducing valve 6 and the fourth needle valve D, and turn on the vacuum pump 4 to reduce the pressure gauge reading to -0.09MPa.

[0028] (4) Close pressure reducing valve 6, fourth needle valve D, vacuum pump 4, and third needle valve C. Open the valve of silane cylinder 1, open pressure reducing valve 6 and control the outlet pressure at 0.1MPa. After waiting for 10s, close the first needle valve A. Silane gas fills the pipeline from the first needle valve A to the second needle valve B. Open the sixth needle valve F and the second needle valve B to allow silane gas to enter the absorbent.

[0029] (5) Then, close the second needle valve B and open the first needle valve A, so that the silane gas refills the pipeline from the first needle valve A to the second needle valve B. Then close the first needle valve A, open the sixth needle valve F, and slowly open the second needle valve B, so that the silane gas re-enters the absorbent liquid.

[0030] (6) Repeat step (5) so that the silane gas is passed into the absorption liquid 4-5 times. The solution in the absorption bottle becomes cloudy, and silane is obtained. 28 Si absorbent solution. The final weight gain of the absorbent solution was 0.08g.

[0031] The pretreatment steps of this invention were used to test silane-Si with an abundance of 99.99%. 28 The sample was tested using a high-resolution inductively coupled plasma mass spectrometer. 28 The Si abundance was 99.987%.

[0032] Example 3 This embodiment uses silane- 28 Si is the sample to be absorbed, and a 25% lithium hydroxide solution is used as the absorption liquid. The pretreatment steps are as follows: (1) Connect the silane pretreatment system and fill the absorption bottle 2 with 150g of 25% lithium hydroxide solution.

[0033] (2) Open the valve of the inert gas cylinder 5, and open the first needle valve A, the third needle valve C, the fifth needle valve E, the second needle valve B, and the sixth needle valve F to purge the silane pretreatment system with nitrogen and maintain the purging pressure at 0.1 MPa.

[0034] (3) Close the second needle valve B, the sixth needle valve F, and the cylinder valve of the inert gas cylinder 5. Then open the pressure reducing valve 6 and the fourth needle valve D, and turn on the vacuum pump 4 to reduce the pressure gauge reading to -0.09MPa.

[0035] (4) Close pressure reducing valve 6, fourth needle valve D, vacuum pump 4, and third needle valve C. Open the valve of silane cylinder 1, open pressure reducing valve 6 and control the outlet pressure at 0.1MPa. After waiting for 10s, close the first needle valve A. Silane gas fills the pipeline from the first needle valve A to the second needle valve B. Open the sixth needle valve F and the second needle valve B to allow silane gas to enter the absorbent.

[0036] (5) Then, close the second needle valve B and open the first needle valve A, so that the silane gas refills the pipeline from the first needle valve A to the second needle valve B. Then close the first needle valve A, open the sixth needle valve F, and slowly open the second needle valve B, so that the silane gas re-enters the absorbent liquid.

[0037] (6) Repeat step (5) so that the silane gas is passed into the absorption liquid 4-5 times. The solution in the absorption bottle becomes cloudy, and silane is obtained. 28 Si absorbent solution. The final weight gain of the absorbent solution was 0.12g.

[0038] The pretreatment steps of this invention were used to test silane-Si with an abundance of 99.99%. 28 The sample was tested using a high-resolution inductively coupled plasma mass spectrometer. 28 The Si abundance was 99.991%.

[0039] Example 4 This embodiment uses silane- 28Si is the sample to be absorbed, and a 25% sodium hydroxide solution is used as the absorption liquid. The pretreatment steps are as follows: (1) Connect the silane pretreatment system and fill absorption bottle 2 with 120g of sodium hydroxide with a mass fraction of 25%.

[0040] (2) Open the valve of the inert gas cylinder 5, and open the first needle valve A, the third needle valve C, the fifth needle valve E, the second needle valve B, and the sixth needle valve F to purge the silane pretreatment system with nitrogen and maintain the purging pressure at 0.1 MPa.

[0041] (3) Close the second needle valve B, the sixth needle valve F, and the cylinder valve of the inert gas cylinder 5. Then open the pressure reducing valve 6 and the fourth needle valve D, and turn on the vacuum pump 4 to reduce the pressure gauge reading to -0.09MPa.

[0042] (4) Close pressure reducing valve 6, fourth needle valve D, vacuum pump 4, and third needle valve C. Open the valve of silane cylinder 1, open pressure reducing valve 6 and control the outlet pressure at 0.1MPa. After waiting for 10s, close the first needle valve A. Silane gas fills the pipeline from the first needle valve A to the second needle valve B. Open the sixth needle valve F and the second needle valve B to allow silane gas to enter the absorbent.

[0043] (5) Then, close the second needle valve B and open the first needle valve A, so that the silane gas refills the pipeline from the first needle valve A to the second needle valve B. Then close the first needle valve A, open the sixth needle valve F, and slowly open the second needle valve B, so that the silane gas re-enters the absorbent liquid.

[0044] (6) Repeat step (5) so that the silane gas is passed into the absorption liquid 4-5 times. The solution in the absorption bottle becomes cloudy, and silane is obtained. 28 Si absorbent solution. The final weight gain of the absorbent solution was 0.16g.

[0045] The pretreatment steps of this invention were used to test silane-Si with an abundance of 99.99%. 28 The sample was tested using a high-resolution inductively coupled plasma mass spectrometer. 28 The Si abundance was 99.985%.

[0046] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A silane pretreatment method for silicon isotope abundance testing, characterized in that, Includes the following steps: Step 1: Connect the front end of the silane injection system to the silane cylinder and the rear end to the absorption bottle, which contains an alkaline solution. Connect the rear end of the absorption bottle to the silane tail gas tank. Step 2: Purge the silane injection system with inert gas to fill the silane injection system with an inert gas atmosphere; Step 3: Evacuate the silane injection system using a vacuum pump; Step 4: Silane is introduced into the absorption bottle under negative pressure. After absorption, the absorption liquid is taken and the silicon isotope abundance is tested using a silicon isotope abundance testing instrument.

2. The silane pretreatment method as described in claim 1, characterized in that, The alkaline solution in step 1 is ammonia, sodium hydroxide, potassium hydroxide, or lithium hydroxide with a mass fraction of 5-50%.

3. The silane pretreatment method as described in claim 1, characterized in that, In step 1, the air inlet pipe in the absorption bottle is inserted below the surface of the absorption liquid, and the air outlet pipe is above the surface of the absorption liquid.

4. The silane pretreatment method as described in claim 1, characterized in that, The purging pressure in step 2 is 0.05~0.2MPa.

5. The silane pretreatment method as described in claim 1, characterized in that, In step 3, the vacuum level reaches below -0.08 MPa.

6. The silane pretreatment method as described in claim 1, characterized in that, In step 4, the amount of silane introduced is 0.05~0.5g.

7. The silane pretreatment method as described in claim 1, characterized in that, In step 4, the instrument used to test the abundance of silicon isotopes is a high-resolution inductively coupled plasma mass spectrometer.

8. A silane pretreatment system for silicon isotope abundance testing, characterized in that, This includes silane cylinders, absorption bottles, silane tail gas tanks, vacuum pumps, and inert gas cylinders, among which: The pipeline between the silane cylinder and the absorption bottle is sequentially equipped with a pressure reducing valve, a first needle valve, and a second needle valve. A first branch pipe and a second branch pipe are connected between the first and second needle valves. A third needle valve is installed on the first branch pipe. The end of the first branch pipe is connected to the vacuum pump via a vacuum line and to an inert gas cylinder via an inert gas purging line. A one-way valve is installed on the pipeline between the inert gas cylinder and the third needle valve. A fourth needle valve is installed on the pipeline between the vacuum pump and the third needle valve. A pressure gauge is connected to the end of the second branch pipe, and a fifth needle valve is installed on the second branch pipe. A sixth needle valve is provided on the pipeline between the absorption bottle and the silane tail gas tank.

9. The silane pretreatment system as described in claim 8, characterized in that, The pressure gauge has a range of -0.1 MPa to 1 MPa.

10. A processing method based on the silane pretreatment system as described in claim 8, characterized in that, Includes the following steps: Step 1: Connect each of the silane pretreatment systems and fill the absorption bottle with absorption liquid; Step 2: Open the valve of the inert gas cylinder, and open the first needle valve, third needle valve, fifth needle valve, second needle valve, and sixth needle valve to purge the silane pretreatment system with nitrogen. Step 3: Close the second needle valve, the sixth needle valve, and the valve of the inert gas cylinder. Then open the pressure reducing valve and the fourth needle valve, and turn on the vacuum pump to evacuate the vacuum. Step 4: Close the pressure reducing valve, the fourth needle valve, the vacuum pump, and the third needle valve; open the silane cylinder valve, open the pressure reducing valve to control the outlet pressure, wait for the silane gas to fill the pipeline from the first needle valve to the second needle valve, close the first needle valve, and open the sixth needle valve and the second needle valve to allow the silane gas to enter the absorption liquid. Step 5: Close the second needle valve and open the first needle valve to allow silane gas to refill the pipeline from the first needle valve to the second needle valve. Then close the first needle valve, open the sixth needle valve, and slowly open the second needle valve to allow silane gas to re-enter the absorbent liquid. Step 6: Repeat step 5, passing silane gas through the absorbent 4-5 times until the absorbent becomes cloudy, yielding silane- 28 Si absorbent, silane-... was analyzed using a silicon isotope abundance analyzer. 28 The silicon isotope abundance was determined using the Si absorber.

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