WO2023226629A1

WO2023226629A1 - Deoxidizing and purifying method for mo source

Info

Publication number: WO2023226629A1
Application number: PCT/CN2023/089015
Authority: WO
Inventors: 邢怀勇; 朱熠; 郭锦源; 崔安民; 李芳芳; 常华; 陈化冰
Original assignee: 江苏南大光电材料股份有限公司
Priority date: 2022-05-23
Filing date: 2023-04-18
Publication date: 2023-11-30
Also published as: CN114773372A

Abstract

The present invention relates to the technical field of semiconductor materials, and provides a deoxidizing and purifying method for an MO source. The method comprises the following steps: selecting a hydroboron as a reducing agent; and deoxidizing an MO source by using the reducing agent. The deoxidizing and purifying method for an MO source has the advantages of good purifying effects, reduced possibility of side reactions, and simple process procedure, and no new impurity being introduced.

Description

MO source oxygen removal and purification method

This application claims priority to the Chinese patent application submitted to the China Patent Office on May 23, 2022, with the application number 2022105644724 and the invention name "MO Source Oxygen Removal Purification Method". The entire content of the application is incorporated herein by reference. .

Technical field

The present invention relates to the technical field of semiconductor materials, and in particular to a method for oxygen removal and purification of MO sources.

Background technique

High-purity MO sources are high-purity metal organic compounds. Common ones include trimethylgallium, trimethylindium, trimethylaluminum, triethylgallium, triethylaluminum, triethylindium, dimethylzinc, diethyl Basic zinc, trimethyl antimony, etc., with a purity of ≥99.9999%, are the supporting source materials for the modern compound semiconductor industry. It is an important raw material for the growth of optoelectronic materials in metal organic vapor deposition technology (MOCVD) and chemical beam epitaxy (CBE). Mainly used in LED industry, new generation solar cells. In addition, it is also used for the growth of epitaxial wafers of Group III nitride semiconductor materials mainly AlGaN, GaN, and AlN. It is the core raw material for growing epitaxial wafers of third-generation semiconductors such as AlGaN, GaN, and AlN, and is also used for phase change memory and radio frequency integration. One of the core raw materials for circuit chips and so on.

The quality of the MO source seriously affects the quality of its downstream compound semiconductors. When the MO source contains oxygen components as impurities to produce compound semiconductor materials, oxygen atoms will be combined in the semiconductor thin layer. As a result, the electrical and optical characteristics are extremely deteriorated, and the performance and life of the thin-layer components are reduced. Therefore, in order to produce high-quality, high-performance, and long-life compound semiconductors, low-oxygen MO sources are urgently needed as raw materials for the production of compound semiconductors.

In current technology, the complex compound method is usually used to remove the oxygen impurity content in the MO source. However, this method has complex process operations, requires high temperatures during decomposition, and may introduce new impurities; in addition, Japanese patent Kokai No. .67230/1990 (JP-A-2-67230) proposed a method for purifying MO sources containing oxygen-containing components, in which hydride metal compounds such as sodium hydride, lithium aluminum hydride, etc. are used as oxygen scavenging reagents, but hydride metal The compounds themselves have a high tendency to decompose water, and their handling needs to be strictly controlled to maintain or control the activity of the reagents; Japanese Patent Publication No. 112991/1991 (JP-A-3-112991) proposes a method for purifying alkanes containing oxygen-containing components. Aluminum-based methods, in which the oxygen-containing component is treated with aluminum halides such as aluminum bromide, aluminum iodide, etc., but aluminum halides themselves also have a high tendency to decompose moisture, and their treatment also needs to be strictly controlled to maintain or control the reagents activity, and halogens may increase the risk of corrosion in stainless steel reactors; Japanese patent JP31338893(43) proposes a method using alkali metal halides, It reacts with oxygen-containing components to form a complex, and then achieves the oxygen removal effect through distillation. However, other solvents are also required to process the mixture during the operation process, so the process operation is more complicated; domestic patent CN1749260B proposed a method A method of adding sodium to reflux and remove oxygen. This method will cause part of the MO source to react with metallic sodium at high temperatures, resulting in the loss of the MO source.

Contents of the invention

The object of the present invention is to provide a method for oxygen removal and purification of MO sources, which has the advantages of simplifying steps and not introducing new impurities during the oxygen removal process.

In order to achieve the above object, embodiments of the present invention provide a method for deoxidizing and purifying MO sources, which is characterized by including the following steps: selecting borohydride as a reducing agent; and using the reducing agent to deoxidize the MO source.

In one or more embodiments of the present invention, the borohydride is at least one of sodium borohydride and potassium borohydride.

In one or more embodiments of the present invention, the mass ratio of the reducing agent to the MO source is 1:1-100.

In one or more embodiments of the present invention, selecting borohydride as the reducing agent further includes: pretreating the reducing agent to remove water and oxygen in the reducing agent.

In one or more embodiments of the present invention, pretreatment of the reducing agent specifically includes: placing the reducing agent in a container, placing the container in an oven to dry, and during the drying process, the container is evacuated Process, and then add inert protective gas to the container.

In one or more embodiments of the present invention, deoxygenating the MO source using a reducing agent is carried out through a first distillation system. The first distillation system includes a first stirring device, a reflux condensation device and a heating device. The processing specifically includes: removing the reducing agent and MO from the first distillation system under stirring conditions to remove oxygen in the MO source; and performing rectification to obtain the purified MO source.

In one or more embodiments of the present invention, the stirring rate of the first stirring device is 20-200r/min, the heating temperature of the heating device is 50-150°C, and the heating time is 2-10h; during the distillation process, The weight ratio of the front fraction, the middle fraction and the kettle residue is 1-3:2-8:1-3.

In one or more embodiments of the present invention, the deoxygenation treatment of the MO source using a reducing agent is carried out through a second distillation system. The second distillation system includes a rectification column, a packing column and a condenser. The deoxygenation treatment is specifically The method is as follows: adding the reducing agent as a packing into the packed column, and passing the MO source through the second distillation system for distillation treatment.

In one or more embodiments of the present invention, in the distillation treatment step, the weight ratio of the front fraction, the middle fraction, and the kettle residue is 1 to 3: 2 to 8: 1 to 3.

In one or more embodiments of the present invention, the MO source oxygen removal and purification method further includes: detecting the oxygen content of the MO source after the oxygen removal treatment.

Compared with the prior art, according to the MO source oxygen removal and purification method according to the embodiment of the present invention, borohydride, which is weakly reducing and does not react with the MO source, is selected as the reducing agent, and the reducing agent is used to react with the oxygen-containing components in the MO source. The oxygen-containing impurities in the MO source are removed by the reaction, so the MO source oxygen removal and purification method of the present invention has the advantages of simple process flow and no introduction of new impurities.

Description of the drawings

Figure 1 is a schematic flow diagram of a MO source oxygen removal and purification method according to an embodiment of the present invention;

Figure 2 is a schematic flow diagram of an MO source oxygen removal and purification method according to other embodiments of the present invention;

Figure 3 is a schematic diagram of a device for pretreating a reducing agent according to an embodiment of the present invention.

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

As shown in Figure 1, the MO source oxygen removal and purification method according to the preferred embodiment of the present invention includes the following steps:

S1. Select borohydride as the reducing agent.

In step S1, the borohydride may be at least one of sodium borohydride and potassium borohydride. Boron hydride, which has weak reducing properties and does not react with the MO source, is selected as the reducing agent, so that the reducing agent can remove oxygen-containing impurities in the MO source without reacting with the MO source.

The mass ratio of reducing agent to MO source is 1:1~100. That is, using 100 parts by mass of the reducing agent can remove 1 to 100 parts by mass of oxygen-containing impurities in the MO source. The specific mass ratio can be adjusted according to the amount of oxygen-containing impurities in the MO source. And 1 part by mass can represent 1g, 5g, 1kg, etc. You can select the mass corresponding to 1 part by mass according to your needs.

Because among the borohydrides purchased directly on the market, such as sodium borohydride and potassium borohydride, for example, when a certain borohydride is tested with a moisture meter, its water content ranges from 300 to 1200 ppm, and the weak reducing agent selected is a solid reagent. , a trace amount of air will be included in the solid and solid space structure; due to the above reasons, the reducing agent purchased directly on the market cannot be used directly to deoxygenate the high-purity MO source.

Therefore, selecting borohydride as a reducing agent also includes pretreating the reducing agent to remove water and oxygen in the reducing agent.

The above-mentioned pretreatment can specifically include: placing the reducing agent in a container, placing the container in an oven to dry, performing a vacuum treatment on the container during the drying process, and then filling the container with inert protective gas.

The above containers can be stainless steel cylinders. The inert protective gas may be at least one of nitrogen and argon. During the above process, the temperature of the oven can be set to 100~150℃, and the drying time can be 2~20h.

During the drying process, the container is evacuated, and then inert protective gas is replenished into the container. This operation can be repeated many times, which can achieve better water and oxygen removal.

In a specific embodiment, as shown in Figure 3, the selected reducing agent is placed into a stainless steel cylinder with a volume of 4L (a filter is provided in the cylinder to prevent the reducing agent from being extracted), and is heated, dried, and replaced with nitrogen in an oven. , ensure that water and oxygen in the reducing agent are completely removed; the drying temperature is set to 150°C, and the drying time is 10 hours; under the conditions of oven heating and drying, a vacuum pump is used to dry the steel at the same time. After the bottle pumping pressure reaches 0kpa, maintain it for 30 minutes and then add nitrogen through the pipeline to normal pressure. Repeat 5 times, heat, dry, and replace with nitrogen.

S2. Use a reducing agent to deoxidize the MO source.

There are many ways to use a reducing agent to deoxidize the MO source.

In a specific embodiment, using a reducing agent to deoxygenate the MO source can be performed through the first distillation system. Wherein, the first distillation system may include a first stirring device, a reflux condensation device and a heating device.

The oxygen removal treatment may specifically include: heating the reducing agent and the MO source in the first distillation system, removing the oxygen in the MO source under stirring conditions; and then performing rectification to obtain the purified MO source. In this embodiment, the first distillation system may further include a reaction vessel such as a reaction kettle or a flask. Reducing agent and MO source can be added to the reaction vessel.

The stirring speed of the first stirring device can be 20 to 200 r/min, the heating temperature of the heating device can be 50 to 150°C, and the heating time can be 2 to 10 hours. This process allows the reducing agent to fully react with the MO source.

During the distillation process, the weight ratio of the front fraction, the middle fraction and the kettle residue is 1 to 3:2 to 8:1 to 3. Among them, the middle fraction can be considered as the purified MO source.

In another specific embodiment, using a reducing agent to deoxygenate the MO source can be performed through a second distillation system. Wherein, the second distillation system includes a distillation column, a packed column and a condenser.

The oxygen removal treatment can specifically include: adding a reducing agent as a filler into the packed column, and passing the MO source through the packed column containing the reducing agent to perform oxygen removal treatment. In the distillation treatment step, the weight ratio of the front fraction, the middle fraction, and the kettle residue is 1 to 3:2 to 8:1 to 3. Among them, the middle fraction can be considered as the purified MO source.

As shown in Figure 2, the MO source oxygen removal and purification method of the present invention also includes:

S3. Use a nuclear magnetic resonance spectrometer to detect the oxygen content of the MO source after oxygen removal.

In S3, the MO source after the oxygen removal treatment can be detected using a nuclear magnetic resonance spectrometer, thereby detecting the oxygen content of the MO source after the oxygen removal treatment. For example, it can be stipulated that when the test result is that the oxygen content is less than 5 ppm, it is a qualified product.

The MO source oxygen removal and purification method of the present invention will be described in detail below with reference to specific examples.

Example 1

Step 1. Selection and treatment of reducing agent

Select commercially available sodium borohydride as the reducing agent, weigh 100g of sodium borohydride, and place it in an oven for heating and drying. The drying temperature is 100°C and the drying time is 10 hours. At the same time, use a vacuum pump to pump the pressure of the cylinder to 0kpa and maintain it for 30 minutes. Then add nitrogen through the pipeline to normal pressure, repeat 5 times.

Step 2: Reducing agent to deoxidize MO source

Add the treated 100g sodium borohydride and 1000g trimethylaluminum into a 2L flask equipped with a stirrer and a reflux condenser, and use a heating device to gradually heat the mixture to 80°C with a stirring speed of 200r/min. Reflux for 2 hours, then heat to the boiling point of the product while keeping the stirring speed constant, and take the mixture according to the ratio of front fraction, middle fraction, and bottom fraction of 3:4:3.

Step 3. Detection of oxygen content of purified MO source

The collected middle fractions were detected using a nuclear magnetic resonance spectrometer, and the analysis results of the middle fractions are listed in Table 1.

Table 1

Example 2

Step 1. Selection and treatment of reducing agent

Select sodium borohydride as the reducing agent, and bake 100g of sodium borohydride in an oven at 110°C for 15 hours to remove the moisture. At the same time, use a vacuum pump to pump the pressure of the cylinder to 0kpa, maintain it for 30 minutes, and then add nitrogen through the pipeline to normal. Press, repeat 5 times;

Step 2: Reducing agent to deoxidize MO source

Add the treated 100g of sodium borohydride and 2000g of trimethylaluminum into a 5L flask equipped with a stirrer and a reflux condenser, and gradually heat the mixture to 100°C and reflux for 5 hours at a stirring speed of 100r/min. , then heat to the boiling point of the product while keeping the stirring speed constant, and take it out according to the ratio of front fraction, middle fraction, and stillage residue of 2:6:2;

Step 3. Detection of oxygen content of purified MO source

The collected middle fractions were detected using a nuclear magnetic resonance spectrometer, and the analysis results of the middle fractions are listed in Table 2.

Table 2

Example 3

Step 1. Selection and treatment of reducing agent

Select potassium borohydride as the reducing agent, and bake 50g of potassium borohydride in an oven at 100°C for 10 hours to remove the moisture and air in it. At the same time, use a vacuum pump to pump the pressure of the cylinder to 0kpa, maintain it for 30 minutes, and then add nitrogen through the pipeline. to normal pressure, repeat 5 times;

Step 2: Reducing agent to deoxidize MO source

Add the treated 50g sodium borohydride and 4000g trimethylgallium into a 10L flask equipped with a stirrer and a reflux condenser, and gradually heat the mixture to 50°C and reflux for 5 hours at a stirring speed of 20r/min. , and then heated to 60°C while the stirring speed remains unchanged, and the proportion of front fraction, middle fraction, and stillage residue is 1:8:1;

Step 3. Detection of oxygen content of purified MO source

The collected middle fractions were detected using a nuclear magnetic resonance spectrometer, and the analysis results of the middle fractions are listed in Table 3.

table 3

Example 4

Step 1. Selection and treatment of reducing agent

Select sodium borohydride as the reducing agent, and bake 100g of sodium borohydride in an oven at 110°C for 15 hours to remove the moisture. At the same time, use a vacuum pump to pump the pressure of the cylinder to 0kpa, maintain it for 30 minutes, and then add nitrogen through the pipeline to normal. Press, repeat 5 times

Step 2: Reducing agent to deoxidize MO source

Add 100g of treated sodium borohydride as filler to the packed column, and then add 1000g of trimethylgallium to the 2L flask of the rectification equipment assembled from the packed column, distillation column and condenser, and heat to 60 ℃, carry out rectification, and collect according to the ratio of front fraction, middle fraction and stillage residue to 3:6:1;

Step 3. Detection of oxygen content of purified MO source

The collected middle fractions were detected using a nuclear magnetic resonance spectrometer, and the analysis results of the middle fractions are listed in Table 4.

Table 4

Example 5

Step 1. Selection and treatment of reducing agent

Select potassium borohydride as the reducing agent, bake 50g of potassium borohydride in an oven at 100°C for 10 hours to remove the moisture; at the same time, use a vacuum pump to pump the pressure of the cylinder to 0kpa, maintain it for 30 minutes, and then add nitrogen through the pipeline to normal. Press, repeat 5 times;

Step 2: Reducing agent to deoxidize MO source

Add 50g of treated potassium borohydride as a filler to the packed column, and then add 3000g of trimethylgallium to the 5L flask of the rectification equipment assembled from the packed column, distillation column and condenser, and heat until the product boiling point, carry out rectification, and collect according to the ratio of front distillate, middle distillate and stillage residue of 2:6:2;

Step 3. Detection of oxygen content of purified MO source

The collected middle fractions were detected using a nuclear magnetic resonance spectrometer, and the analysis results of the middle fractions are listed in Table 5.

table 5

Comparative example 1

Step 1. Selection and treatment of reducing agent

Select commercially available sodium borohydride as the reducing agent and weigh 100g of sodium borohydride;

Step 2: Reducing agent to deoxidize MO source

Add 100g sodium borohydride and 1000g trimethylaluminum directly into a 2L flask equipped with a stirrer and a reflux condenser, and gradually heat the mixture to 80°C and reflux for 6 hours at a stirring speed of 60r/min. Heat to the boiling point of the product while keeping the stirring speed constant, and collect according to the ratio of front fraction, middle fraction, and stillage residue of 2:6:2;

Step 3. Detection of oxygen content of purified MO source

Table 6

Comparative example 2

Step 1. Selection and treatment of reducing agent

Select aluminum powder (100 mesh diameter) as the reducing agent, activate 50g of aluminum powder, and remove impurities and oxide films on its surface;

Step 2: Reducing agent to deoxidize MO source

Add 50g of activated aluminum powder and 4000g of trimethylaluminum into a 10L flask equipped with a stirrer and a reflux condenser, and gradually heat the mixture to 100°C and reflux for 4 hours at a stirring speed of 60r/min. Then, heat to the boiling point of the product while keeping the stirring speed constant, and take it out according to the ratio of front fraction, middle fraction, and stillage residue of 2:6:2;

Step 3. Detection of oxygen content of purified MO source

The collected middle fractions were detected using a nuclear magnetic resonance spectrometer, and the analysis results of the middle fractions are listed in Table 9.

Table 7

Comparative example 3

Step 1. Selection and treatment of reducing agent

Select oxalic acid as the reducing agent, bake 50g of oxalic acid in an oven at 100°C for 3 hours to remove the moisture; at the same time, use a vacuum pump to pump the pressure of the cylinder to 0kpa, maintain it for 30 minutes, then add nitrogen through the pipeline to normal pressure, repeat 5 Second-rate;

Step 2: Reducing agent to deoxidize MO source

The treated 10g of oxalic acid was placed in a 100ml flask, and then 10g of trimethylaluminum was added, and a violent reaction occurred between the two.

Comparative example 4

Step 1. Selection and treatment of reducing agent

Select 50g ferrous sulfate as the reducing agent, bake the ferrous sulfate in an oven at 100°C for 3 hours to remove the moisture; at the same time, use a vacuum pump to pump the pressure of the cylinder to 0kpa, maintain it for 30 minutes, and then add nitrogen through the pipeline to normal. Press, repeat 5 times;

Step 2: Reducing agent to deoxidize MO source

Place the treated 10g of ferrous sulfate into a 100ml flask, then add 10g of trimethylaluminum, and the two react violently.

Comparative example 5

Step 1. Selection and treatment of reducing agent

Select activated carbon as the reducing agent, bake 50g of activated carbon in an oven at 100°C for 10 hours to remove the moisture; at the same time, use a vacuum pump to pump the pressure of the cylinder to 0kpa, maintain it for 30 minutes, then add nitrogen through the pipeline to normal pressure, repeat 5 Second-rate

Step 2: Reducing agent to deoxidize MO source

Add 50g of the treated activated carbon and 4000g of trimethylgallium into a 10L flask equipped with a stirrer and a reflux condenser, and gradually heat the mixture to 50°C and reflux for 5 hours at a stirring speed of 200r/min. Heat to 60°C while the stirring speed remains unchanged, and collect according to the ratio of front fraction, middle fraction, and stillage residue of 2:6:2;

Step 3. Detection of oxygen content of purified MO source

The collected middle fractions were detected using a nuclear magnetic resonance spectrometer, and the analysis results of the middle fractions are listed in Table 8.

Table 8

It can be known from the data in Tables 1 to 5 that after selecting borohydride as the reducing agent in Examples 1 to 5, the amount of oxygen-containing components in the MO source is greatly reduced, thereby obtaining a higher purity MO source.

From the data in Table 1 and Table 6, it can be known that directly selecting commercially available sodium borohydride as the reducing agent will not only fail to reduce the oxygen content of the MO source, but may even increase the oxygen content of the MO source.

From the data in Comparative Examples 2-5 and Tables 7 and 8, it can be known that most reducing agents not only fail to reduce the oxygen content of the MO source, but may even increase the oxygen content of the MO source, and some reducing agents will Reacts with MO source, resulting in waste of MO source.

In other embodiments, the selection of the reducing agent in the MO source oxygen removal and purification method of the present invention can be adjusted according to actual needs and the specific type of MO source.

In other embodiments, the content and proportion of each component in the MO source oxygen removal and purification method of the present invention, as well as the processing conditions (such as temperature, stirring rate and other parameters) can be determined according to actual needs and the specific type of MO source. Make adjustments.

The MO source oxygen removal and purification method of the present invention can obtain a stable low-oxygen high-purity MO source, and by adjusting the ratio of the reducing agent to the MO source, the organic purity of the purified MO source can reach 99.9999%, and the oxygen content is <5 ppm.

In summary, the MO source oxygen removal and purification method of the present invention has the advantages of good purification effect, reduced possibility of side reactions, simple process flow, and no introduction of new impurities.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and illustration. These descriptions are not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical applications, thereby enabling others skilled in the art to make and utilize various exemplary embodiments of the invention and various different applications. Choice and change. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

A method for oxygen removal and purification of MO source, which is characterized by including the following steps:

Select borohydride as the reducing agent;

Use a reducing agent to deoxidize the MO source.
The MO source oxygen removal and purification method of claim 1, wherein the borohydride is at least one of sodium borohydride and potassium borohydride.
The MO source oxygen removal and purification method according to claim 1, characterized in that the mass ratio of the reducing agent to the MO source is 1:1 to 100.
The MO source oxygen removal and purification method as claimed in claim 1, characterized in that selecting borohydride as the reducing agent further includes:

The reducing agent is pretreated to remove water and oxygen from the reducing agent.
The MO source oxygen removal and purification method as claimed in claim 4, characterized in that the pretreatment of the reducing agent is specifically:

The reducing agent is placed in a container, and the container is placed in an oven to dry. During the drying process, the container is evacuated, and then inert protective gas is added to the container.
The MO source deoxygenation purification method according to claim 1, characterized in that using a reducing agent to deoxygenate the MO source is carried out through a first distillation system, and the first distillation system includes a first stirring device, a reflux condensation device and a heating device. Device, the specific deoxidation treatment is:

The reducing agent and MO source are heated in the first distillation system, and the oxygen in the MO source is removed under stirring conditions;

Distillation is then performed to obtain the purified MO source.
The MO source oxygen removal and purification method according to claim 6, characterized in that the stirring rate of the first stirring device is 20-200r/min, the heating temperature of the heating device is 50-150°C, and the heating time is 2-10h; During the distillation process, the weight ratio of the front fraction, the middle fraction and the kettle residue is 1 to 3:2 to 8:1 to 3.
The MO source deoxygenation purification method as claimed in claim 1, characterized in that the deoxygenation treatment of the MO source using a reducing agent is carried out through a second distillation system, and the second distillation system includes a rectification column, a packing column and a condenser, The specific steps of deoxidation treatment are:

The reducing agent is added into the packed column as a packing, and the MO source is rectified through the second distillation system.
The MO source deoxygenation purification method according to claim 8, characterized in that, in the distillation treatment step, the weight ratio of the front fraction, the middle fraction, and the still residue is 1 to 3:2 to 8:1 to 3.
The MO source oxygen removal and purification method as claimed in claim 1, characterized in that the MO source oxygen removal and purification method further includes:

The oxygen content of the MO source after oxygen removal treatment was detected using a nuclear magnetic resonance spectrometer.