DE1107651B - Process for purifying phosphorus or arsenic - Google Patents

Description

Process for the purification of phosphorus or arsenic The invention relates focus on the production of very pure phosphorus or arsenic that are ready for use in the manufacture of electronic and semiconductor materials such as phosphides and arsenides of indium, gallium, boron, aluminum, zinc and mixtures of these metals, are suitable.

According to the invention, arsenic and phosphorus are produced in a form which is relatively free of impurities and which is more uniform in their electrical properties is than that purified by previously known methods Elements. This also applies to their chemical compounds.

The invention relates to a method for purifying phosphorus and Arsenic, whereby the element is volatilized and it is in vapor form at a temperature subjected to the range from 850 to 1000 ° C and then cools the gaseous mixture, to condense the cleaned element. 'It's in the making of elemental Phosphorus and arsenic have been found to be the chemical elements that go along with these elements will contaminate the product. Examples of such impurities are z. B. the halogens, such as fluorine, chlorine, etc., and also sulfur compounds. Certain Forms of phosphorus, such as the so-called white phosphorus, found under water or oil are stored, can also absorb impurities from it.

Attempts have been made to the elemental phosphorus and the elemental Arsenic by distillation, e.g. B. at the boiling point to clean, but the usual Distillation processes have been found to offer little improvement in this regard the purity of the element.

It has now been found that elemental forms of phosphorus and Arsenic, including the various allotropic forms thereof, in their purity by thermal treatment of the element in gaseous form in a specific area increased temperature can be greatly improved. To such a cleaning to run, the phosphorus or arsenic is fed directly into a heated pipe made of an inert material such as quartz, while all foreign gases other than the steam to be treated are excluded. The one you want High degree of purity of these elements is also achieved by taking them when they are are volatilized, treated with hydrogen, helium and argon.

It has been found that a temperature in the range of 850.degree to 1000 ° C is necessary for cleaning, a preferred range between 900 and 950 ° C. The time during which the gaseous phosphorus or the gaseous arsenic is subjected to this high temperature is not critical and as appropriate, from 1 minute or less to 1 hour or more can be varied. Likewise, pressure is not a critical variable, so Vacuum, atmospheric pressure and overpressure can be used. It should however, no reactive gases other than the vapor of the element to be treated be present in the treatment zone.

If you want to purify phosphorus or arsenic in the presence of hydrogen, Helium or argon, the phosphorus or arsenic can be converted directly into a heated line made of an inert material such as quartz is, while at the same time hydrogen, argon or helium gas or mixtures of which are introduced in any proportions and the mixture of the gaseous Phosphorus or arsenic and the hydrogen, argon and / or helium gas is subjected to said high temperatures.

Preferably, the treatment with the gas, such as. B. Argon, im essentially carried out in the absence of any other gases. Responsive Gases such as oxygen must be carefully removed from the reaction vessel, even in small traces locked out will. The time during which the phosphorus is in contact with the hydrogen, Argon or helium is also not critical and can, as appropriate can be varied from 1 minute or less to 1 hour or more. The pressure is also not a critical variable, so that vacuum, atmospheric pressure and overpressure can be used if desired.

The amount of hydrogen, argon or helium used in the cleaning process is not critical. It has been found that the method according to the invention is applicable both when using very small proportions, ie 0.01 mol of phosphorus or arsenic, as well as when using large excesses, e.g. B. 100 moles of hydrogen, argon or helium per mole of phosphorus or arsenic are all effective in carrying out the cleaning process according to the invention. The hydrogen used, the argon or helium used can be of the usual technical purity, or they can be purified by chemical means.

After the phosphorus or arsenic is subjected to the heat treatment has been or has been brought into contact with the treatment agent, e.g. B. by passing through of the gaseous element through a section of a line provided with a filler body, z. B. by passing through quartz beads or quartz wool in a quartz tube is at the said elevated temperature, the phosphorus or the arsenic is through usual funds collected. In the method described, when using a continuous line the collection zone from a cooler section of the tubular Reactor or a cooling condenser. If desired, receiving vessels, which can be completed for this purpose, so that the collection of the phosphorus or arsenic in a tailpipe is allowed, which with is provided with a gas outlet. The collecting tube is then closed to the phosphorus or to keep the arsenic free from contact with air or other contaminants, until one wishes to make further use of it.

In the manufacture of electronic or semiconductor components As has been found, phosphorus and arsenic compounds must have an unusually high level Order of magnitude of purity have to be uniform and effective in these areas to act. For example, in the production of indium phosphide, a sample of the purified phosphorus, which is stored in a closed tube, as described above, is collected, later connected to a gaseous reaction system. Of the Phosphorus is then heated in its tube to form it in another tubular To volatilize section in which elemental indium lies. The phosphorus reacts then with the indium and gives the desired indium phosphide. By such methods other semiconductor components such as gallium phosphide, aluminum phosphide, Boron phosphide and zinc phosphide. Mixed metal phosphides, such as Zinc germanium phosphide, Zn Ge PZ, are also easily purified from the present Form of elemental phosphorus produced by the process according to the invention is received. The corresponding arsenic compounds are prepared in a similar manner. The apparatus used in carrying out the method according to the invention can also be modified to use vertical tubes in which, for example Arsenic or phosphorus of any allotropic form kept in a storage vessel is, directly in a tubular section, which is on the said higher Temperature is maintained, volatilized and then condensed in a suitable vessel will. If one uses the treatment agents according to the invention, namely hydrogen, Helium and / or argon, the tubular section of the device, which absorbs the volatilized phosphorus or the volatilized arsenic, also with connected to the inlet pipes for the introduction of treatment agents. It is however, it has been found that the temperature range from 850 to 1000 ° C in this Relationship is critical and that the use of the lower temperature, e.g. B. 700 ° C, does not result in any cleaning. It has also been found that the mere sublimation of elemental phosphorus or arsenic in a vacuum, e.g. B. at 450 ° C, which is a common sublimation temperature for phosphorus, or 600 ° C for arsenic, not the purification accomplished by the practical execution of the invention is achieved.

The high purity of what is produced by the process according to the invention Phosphorus and the arsenic obtained according to the invention is by common chemical Methods difficult to analyze and there was a fair indication of purity only obtained by passing the purified phosphorus or the purified arsenic Reacting with indium for the production of indium phosphide or arsenide used and then determines the electronic properties of such an indium compound. For example yielded the indium phosphide, which is so produced by volatilizing phosphorus into a body of metallic indium (99.999% pure) using a temperature of 450 ° C to volatilize the phosphorus and a temperature of 1060 ° C for execution the reaction of the indium and phosphorus produced a crystalline form of indium phosphide. This product was a measurement of electrical properties subjected to the concentration of impurities, expressed as atoms of Impurities per cubic centimeter of indium phosphide.

Control experiments were also carried out in which chemically pure Arsenic and phosphorus samples, both red and white phosphorus, in indium arsenide or phosphide without the treatment according to the invention. These Samples were also subjected to an electrical test. However, it was found that they give products that are essentially inferior to those that are used of the thermally treated or treated with hydrogen, argon or helium phosphor and arsenic were obtained.

The invention is explained in more detail below with the aid of examples.

Example 1 This example illustrates the purification of phosphorus by heat treatment alone, in the substantial absence of gases other than the volatilized phosphorus. The purification of red phosphorus was made carried out by placing a quartz boat with phosphorus in a quartz tube of 25 mm in diameter and 600 mm in length. The quartz tube was with two independent Heating jackets and a third cooling section which was in the atmosphere. At the exit end of the tube there was a connection to a previously made one Final section for the collection of the purified phosphorus in a lockable Quartz tube made. The first stove, the one around the boat, which the red one Containing phosphorus, was arranged, was heated to a temperature of 450 ° C, while the central section of the reactor, which was filled with quartz spheres inserted into the quartz tube was kept at a temperature of 925 ° C. The third Section was essentially at atmospheric temperature. The gaseous one Phosphorus went at atmospheric pressure after the purification treatment was completed, into the condenser section where the phosphorus is on the walls of the quartz pickup tube condensed. The pressure in the reaction system was kept at 760 mmHg. After this the above procedure was carried out for a period of 2 hours, the receiving tube was closed for storage, pending the material for a subsequent one Processing was needed.

The electrical properties of the test sample of the above example showed that the phosphorus had a purity of more than 99.9999-1-% in contrast to the phosphorus feedstock which was only 99.99% pure.

Control experiments were also carried out in which chemically pure Phosphorus samples of both red and white phosphorus in indium phosphide (according to the manner described above) without the heat treatment according to the invention became. These samples were also used for electrical testing, but it was found that they gave products inferior to those who did using thermally treated phosphorus.

Example 2 This example illustrates the purification of arsenic by heat treatment alone, in the substantial absence of gases other than the volatilized arsenic.

A similar treatment as described above, but below The use of metallic arsenic has also been found to give a purified one Product.

As had an indication of the purification achieved with arsenic a sample of arsenic on ingestion and after conversion to In As a purity of 5.6,1016 carriers per cubic centimeter of InAs.

The same starting arsenic gave when it reached 900 ° C at atmospheric pressure was heated only with arsenic vapor, with no foreign gases being present InAs product of 4.82-1016 carriers per cubic centimeter of InAs.

Example 3 This example illustrates the purification of elemental Phosphorus by treatment with hydrogen at the specified elevated temperature.

The purification of red phosphorus was carried out by a quartz boat with phosphorus in a quartz tube with a diameter of 25 mm and 600 mm in length. The quartz tube came with two independent heating jackets as well as one third cooling section, which was in the atmosphere, provided. At the inlet end of the Rohrs was a compound for the introduction of gaseous hydrogen into the Tube provided, while at the outlet end a vacuum connection as well as one before manufactured end section for the collection of the purified phosphor in one closed quartz tube were provided. The first oven to round off the red one Phosphorus-containing boats placed around it was raised to a temperature of 450 ° C, while the middle reactor section, the one in the quartz tube arranged quartz spheres was filled, was kept at a temperature of 925 ° C. The third section was essentially at atmospheric temperature. A The flow of hydrogen was started at the rate of 100 cc / min. in the pipe introduced so that phosphorus is volatilized from the supply of 18.61 g of red phosphorus became. This gaseous mixture of hydrogen and phosphorus then became essentially fed into the reactor section in the absence of any other gases. The gaseous mixture went to that after the purification reaction was completed Condenser section where the phosphorus condensed on the walls of the quartz pickup tube, while the hydrogen was withdrawn from the system. The pressure in the reaction system was maintained at 760 mm Hg. After the above procedure for a period of time of 2 hours had been carried out, the receiving tube was terminated, one Subjected to vacuum, and the vacuum connection was closed to the purified Keep phosphorus in an evacuated tube for storage until it is available for a subsequent one Processing was needed.

For another test carried out as described above, the system was purged with elemental argon after 2 hours of reaction and then completed while it was under atmospheric pressure. Example 4 A similar one Test as described in Example 13, but using white Phosphorus was found to give a purified product as shown in the table of Example 6 below. Example 5 About the effects of temperature to investigate, the procedure of Example 3 was followed in three experiments, which were carried out at 900 ° C, 715 to 735 ° C and 1000 ° C. The treated phosphorus was then converted into indium phosphide in the manner described above, and the electrical properties were measured (see table of the example below 6).

The indium phosphide was also measured to determine the mobility of the product as an indication of the purity of the elemental phosphorus used in the manufacture of such an indium phosphide was received. example 6 This example shows the use of specially purified hydrogen.

The procedure of Example 3 was followed, except that the Hydrogen stream was passed over metallic titanium at 840 ° C, followed by one pass followed by a cold trap that contained activated charcoal that was based on temperature was held by liquid nitrogen.

The electrical properties (impurity concentration in atoms per cubic centimeter) measured on indium phosphide prepared from the various test samples of the above examples are shown below. Impurity concentration Example reagent conditions tration Atoms each Cubic centimeter 3 red P 925 ° C + H2 1.16- 101 6 4 red P untreated (no H2) 5.6 - 1017 4 white P untreated (no Hz) 5.5 1017 4 white P 905 1 C + H2 1.4 101 6 5 red P 900 ° C + H., 1.4 101s 5 red P 715 to 7351 C + H2 3.5 1017 5 red P 1000 = `C + H2 1.7 -1016 6 red P 900 ° C (purified 8.2 - 101s H,) The above values show that there is a major improvement, for example by a factor of as great as 70, in the phosphorus moiety from the hydrogen purification process of the invention. Example 7 This example illustrates the purification of elemental arsenic by treatment with hydrogen at the indicated elevated temperature.

The purification of black, crystalline arsenic was carried out by that you put a quartz boat with arsenic in a quartz tube about 25 mm in diameter and brought about 900 mm length. The quartz tube came with two independent heating jackets (to 610 or 1000 ° C) as well as a third condensing section, which was in a coat kept at a lower temperature (200 ° C) became. At the inlet end of the tube was a connection for the introduction of gaseous Hydrogen is provided in the tube while at the outlet end a vacuum connection as well as a previously made final section for the collection of the purified Arsenic were provided in a sealed quartz tube. The first coat or first furnace, which was arranged around the tube and the boat which contained the arsenic was heated to a temperature of 610-- C, while the middle reactor section, which was filled with quartz rings lying in the quartz tube, at a temperature was kept at 1000 ° C. The third section was at one temperature of about 200 C. A flow of hydrogen was made at the rate of 50 to 60 cc / min. introduced into the tube, removing arsenic from the supply of 25 g of arsenic was volatilized. The gaseous mixture of hydrogen and arsenic was then made in the substantial absence of any other gases into the reactor section guided. The gaseous mixture went after the purification was completed, to the condenser section where the arsenic condensed on the walls of the quartz pickup tube, while the hydrogen was withdrawn from the system. The pressure in the reaction system was maintained at 760 mm Hg. After the above procedure for a time of 3 hours had been carried out, the receiving tube was removed from the treatment tube switched off, subjected to a vacuum and then closed the vacuum connection, to get the purified arsenic in an evacuated tube for storage until it was needed for subsequent processing.

The high purity of that produced by the process according to the invention Arsenic is difficult to analyze by common chemical methods. It was therefore found that this was the only way to obtain a reasonable indication of purity was able to use the purified arsenic to react with indium to form indium arsenide and then the electronic properties of such an indium arsenide to determine. The indium arsenide was made by volatilizing the arsenic into a body made of metallic indium, with a temperature of about 575 ° C to the Arsenic to volatilize, and a temperature of 940 to 960 ° C was applied, to bring about the conversion of the indium and arsenic. This resulted in a crystalline one Form of indium arsenide. The product was a measurement of electrical properties subjected to the concentration of impurity, expressed as atoms of impurity per cubic centimeter of indium arsenide.

Control experiments were also carried out using samples of arsenic electronic grade converted to indium arsenide without any hydrotreatment became. These samples were also used for electrical testing. It was however, found that there were products that are greatly inferior to those which are produced with the arsenic purified by the method according to the invention became.

The electrical properties (impurity concentration in atoms per cubic centimeter of indium arsenide) for the various test samples of the above examples are given below: Pollution Reagent conditions concentration Atoms each Cubic centimeter Black arsenic 610 ° C, no 2.6-1016 hydrogen Black arsenic 10001 C and less than Hydrogen 1.0-1016 The above values show that there is a major improvement, e.g. By a factor of at least 3, in the purity of the arsenic from the hydrogen purification process according to the invention. Example 8 The following examples illustrate the purification of elemental phosphorus by volatilizing it with subsequent treatment with gaseous argon or helium at the indicated elevated temperature.

The purification of red phosphorus was carried out by a quartz boat of phosphorus in a quartz tube about 25 mm in diameter and brought about 600 mm length. The quartz tube came with two independent heating jackets as well a third cooling section which was in the atmosphere. At the inlet end of the pipe was a connection for the introduction of gaseous argon into the pipe provided while at the exit end a vacuum connection as well as one before manufactured end section for the collection of the purified phosphor in one closed quartz tube were provided. The first furnace was around the pipe and the boat containing the red phosphorus was heated to a temperature of 450 ° C, while the middle reactor section, the one in the quartz tube lying quartz spheres was filled, was kept at a temperature of 925 ° C. The third section was at a temperature of 100 to 200 ° C, with the cool end was essentially atmospheric temperature. A stream of argon was carried out at the speed of 50 to 60 cc / min. inserted into the tube, whereby Phosphorus has been volatilized from the supply of 18.61 g of red phosphorus. The gas mixture of argon and phosphorus was then in the substantial absence of any other gases passed into the reaction section. The gas mixture went off after the Cleaning had been completed in the condenser section where the phosphorus was attached the walls of the quartz pickup tube condensed while the argon left the system was withdrawn. The pressure in the reaction system was kept at 760 mmHg. After performing the above procedure for a period of 2 hours had been, the receiving tube was closed, subjected to a vacuum and the Vacuum connection completed to the purified phosphorus in an evacuated one Preserve tube for storage until needed for subsequent processing became. Example 9 A test similar to that described above, however using white phosphorus was also found to give a highly purified one Product.

Example 10 An experiment similar to that in Example 8 above is described, but with 50 to 60 ccm / min. Helium, used to treat red phosphorus, was found to be a purified product. However, a control experiment showed that if the phosphorus is distilled at 450 ° C without the helium or argon, the product has a much lower purity.

The electrical properties (impurity concentration in atoms per cubic centimeter) for the various test samples are given below: Pollution concentration Reagent conditions atoms per cubic centimeter by InP Red P 715 ° C, no argon or 3.5-1017 helium White P 215 ° C, no argon or 5.5-1017 helium Red P 925 ° C + argon 4.2-1015 Red P 925 ° C -I- helium 4.5-1015 The above values show that there is a major improvement, e.g. By a factor as high as 130, in the purity of phosphorus from the argon and helium purification process according to the invention. Example 11 This example illustrates the purification of elemental arsenic by its volatilization followed by treatment with gaseous arsenic or helium at the indicated elevated temperature.

The purification of black, crystalline arsenic was carried out by that a quartz boat containing arsenic is placed in a quartz tube about 25 mm in diameter and brought about 600 mm length. The quartz tube came with two independent heating jackets with 610 or 1000 ° C as well as a third condensing section, which was in a coat kept at a lower temperature (200 ° C) became. At the inlet end of the tube was a connection for the introduction of gaseous Argon is provided in the tube while at the outlet end a vacuum connection as well like a pre-made final section for the collection of the purified arsenic were provided in a sealed quartz tube. The first section of the pipe was heated by a jacket-like furnace around the boat containing the arsenic around and heated to a temperature of about 610 ° C while the middle reactor section, the one with quartz rings arranged in the quartz tube was filled, was kept at a temperature of 1000 ° C. The third section was at a temperature of about 200 ° C. A stream of argon was with the speed of 50 to 60 ccm / min. introduced into the pipe, creating arsenic was volatilized by the addition of 25 g of arsenic. The gaseous mixture of argon and arsenic then became essentially in the absence of any other gases led into the reactor section. The gaseous mixture went out after the cleaning had been completed, in the condenser section where the arsenic was on the walls of the Quartz pickup tube condensed while the argon was withdrawn from the system. The pressure in the reaction system was kept at 760 mmHg. After the above Procedure was carried out over a period of 3 hours, that was The pickup tube was closed, vacuumed, and the vacuum connection was made completed the purified arsenic in an evacuated tube for storage until it was needed for subsequent processing. That The purity of the product was greatly improved compared to the starting material.

Example 12 An experiment similar to that described in Example 11 above is described, but with 50 to 60 ccm / min. Helium in the treatment of arsenic, also found a purified product.

Claims (3)

CLAIMS: 1. A method for the purification of phosphorous or arsenic, characterized in that volatilizes the element in question and gaseous a temperature in the range of 850 to 1000 ° C, in particular 900 to 950 ° C, subjecting, then cooled, and the purified Element condenses. 2. Process according to Claim 1, characterized in that the element is volatilized and brings it into contact with gaseous hydrogen, argon and / or helium. 3. Procedure according to claim 1 or 2, characterized in that the treatment essentially takes place in the absence of other reactive gases.