KR20150108735A - The method and system for production of silicon and devicies - Google Patents

Abstract

In one embodiment of the present invention, catalytic gasification of silicon (or a compound containing Si containing silicon alloy) with a hydrogen source (such as hydrogen gas, atomic hydrogen, and protons) A mixture of hydrogen (and inert gas) is prepared. By simultaneously co-purifying all gases (silane and hydrogen, inert gas) in the gas mixture without separating the silane from the hydrogen, the mixture is co-purified and then fed without further dilution of the silane gas, Lt; / RTI > One aspect of the present invention is the need for an improved method, apparatus, and composition for a silane gas mixture for large scale, low cost fabrication of high purity silicon, as well as semiconductor integrated circuits, solar photovoltaic cells, LCD flat panels, lithium ion batteries, Including, but not limited to, the manufacture of turnkey applications. Thus, various embodiments of the present invention can significantly reduce cost and simplify the manufacturing process of silicon.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method and system for manufacturing silicon,

Related application

This application claims the benefit of 35 U.S.C. Claims of priority of U.S. Patent Application No. US13 / 751,090, filed on Jan. 27, 2013, entitled Method and System and Apparatus for the Production of Silicon under § 119 (e) The entirety of which is incorporated herein by reference.

Field of invention

The present invention relates to catalytic gasification of a silicon material comprising a silicon element, a silicon alloy and a compound containing Si by a hydrogen source such as hydrogen gas, ion (protons) and atomic hydrogen to form a silane mixture ≪ / RTI > The mixture is then co-purified to leave only silanes, hydrogen and inert gases for the production of devices containing high purity silicon and silicon.

Silanes, particularly monosilane (SiH ₄₎ gas is used more and more in the production of polysilicon, an integrated circuit (IC) electronic devices, liquid crystal display (LCD), and solar cells, such as. Since silane was first synthesized 150 years ago, a variety of techniques have been developed for making it, most of which involve complex processes and dangerous chemicals.

US 4407783 (Production of silane from silicon tetrafluoride; Oct. 4, 1983; Ulmer, Harry E. et al), US 3043664 (Mason, Robert W. Kelly, Donald H.) Teaches the preparation of silane SiH ₄ with silanes (e.g., SiCl ₄ and SiF ₄ ) and hydrides (such as LiH, NaH, or LiAlH ₄ ).

Also, US 4755201, US 5499506, US 6942844, US 6905576, US 6852301, and US 8105564 disclose a manufacturing process commercialized by Union Carbide in the 1980s. In this process, metallurgical grades of silicon (Met-Si), hydrogen and silicon tetrachloride (STC) are reacted with a copper catalyst at about 500 ° C and 30 atmospheres to form trichloride silane (TCS) Dichlorosilane (DCS) and STC, and the DCS is further redistributed as silane on the anion-exchange resin catalyst.

Ideally, the silane is prepared by hydrogenation of silicon. However, the direct reaction between silicon and hydrogen is thermodynamically unfavorable except at very high temperatures and very high pressures (up to 2000 ° C and 1000 atmospheres). Another challenge is that at high temperatures exceeding 300 캜, silane is re-decomposed into silicon micro-soot, which tends to extremely reduce the production yield. To date, no single successful experiment has been reported on this approach.

In addition, all other processes are focused on producing ultra high purity silane (99.9999%) by a tedious and energetic separation and purification process, but a mixture of silane and hydrogen and / or inert gas in the range of several ppm to 99% The final requirement for silane in practical commercial applications is being ignored. That is, the silane must be diluted with hydrogen or an inert gas (such as argon or helium) for use in a particular application.

In one embodiment of the present invention, the mixture of silane and hydrogen (optionally including an inert gas) comprises an Si-material comprising a silicon element, a silicon alloy and a compound containing Si, a hydrogen gas, an atomic hydrogen and / Is produced using catalytic gasification of a hydrogen source such as an ion (proton). When the catalyst is present, the reaction temperature can be greatly lowered and the reaction rate of the silane formation can be improved. The gas mixture (including silane and hydrogen, inert gas) can be co-purified simultaneously to remove phosphorus (P) and boron (B) compounds and other harmful impurities (without separating the silane from hydrogen or inert gas) . However, in order to produce nano silicon powders for lithium ion battery electrodes, removal of phosphorus (P) and boron (B) compounds is unnecessary and, optionally, phosphorus (P) and boron (B) . The co-purified mixture is then fed for downstream application. This can significantly reduce and simplify the manufacturing process of the silane and further downstream applications.

One aspect of the present invention addresses the need for an improved manufacturing method for large scale, low cost fabrication and for silane gas mixtures for field-ordered, turn-key turnkey applications. Such applications include, but are not limited to, the manufacture of high purity polysilicon, semiconductor devices such as integrated circuits, solar cells, LCD-flat panels, lithium ion battery electrode materials and other electronic devices. This can significantly reduce costs and simplify the manufacturing process of silicon and semiconductor devices.

One embodiment of the present invention provides a method for manufacturing silicon,

a) preparing a mixture of silane, hydrogen and an inert gas by catalytic gasification of a Si-material comprising a silicon element, a silicon alloy and a Si-containing material, a catalyst and a hydrogen source;

b) quenching the gas mixture immediately after the reaction to prevent decomposition of the silane;

c) co-refining silane, hydrogen and an inert gas;

d) preparing silicon using the purified silane mixture;

e) recycling the hydrogen and inert gas from step d) and returning to step a); And

f) recovering and recirculating the catalyst, and returning to step a).

Another embodiment provides a hydrogen source selected from hydrogen gas, atomic hydrogen, and ionic hydrogen. The catalyst is selected from the group consisting of the following materials.

a) noble metals, especially Pd, Pt, Rh, Re, Ru, and alloys thereof;

b) transition metals, especially Ni, Cu, Co Fe, and alloys thereof;

c) alkali metals, especially Na, K, Li, Ca and alloys thereof;

d) rare earth metals;

e) metal salts; Metal compounds such as oxides, and

f) metal hydrides.

Silicon alloys may be made of one or more of silicones and silicones and of alkali metals, alkaline earth metals, transition metals, rare earth metals, and low melting point metals, especially slabs, bulk, rods, granules, powders, fusions, suspensions in liquids, (Li, Na, K, Ns, Be, Mg, Ca, Sr, Ba, Al, Ga, In, Tl, K and Fe).

The gasification agent is selected from one or a combination of the following.

a) hydrogen (or D ₂₎ gas;

b) hydrogen ions in an acid or metal hydride or dissociation acid;

c) a hydrogen ion generated by an electrochemical cell; And

d) atomic hydrogen generated by plasma gasification.

Other embodiments include DC plasma, microwave; And provides atomic hydrogen including radio frequency (RF), hot wire, and glowing discharge.

Other embodiments provide rapid heat exchange with the cooling medium of the pre-fabricated silane mixture itself or quenching with rapid pressure drop of the prepared gas mixture.

Another embodiment of the present invention provides a system for the production of silanes,

Reaction chamber;

A hydrogen source for gasifying silicon and alloys such as atomic hydrogen by plasma and hydrogen ions by an electrochemical cell;

Means for supplying a hydrogen source and a silicon source to the reactor chamber;

(Silicon, alloys, and Si) in the chamber in the form of a solid, liquid slurry, slurry, paste, or vapor in any form of suspension, ingot, rod, stream of powder, A compound containing a compound of formula (I);

Means for administering a catalyst to the silicon and alloy;

Means for quenching the gas present in said reaction chamber;

Means for co-purifying said silane mixture after quenching said product gas mixture; And optionally

And means for recirculating the catalyst, hydrogen and inert gas recovered in the process at the end of the process.

Another embodiment provides a reaction chamber selected from a packed layer of a silicon powder, a graded layer, a fluidized bed, a moving bed, and a stirring bed and a ticking bed for fusing. The reaction chamber has the following conditions.

Temperature: -30 to 3000 占 폚, 200 to 3000 占 폚, 300 to 3000 占 폚, 500 to 3000 占 폚, 500 to 2000 占 폚, or 500 to 1500 占 폚; Pressure: 0.001 - 1000 Mpa; Input gas Hydrogen in inert gas: 1-99.99999%; Exhaust gas: 0.1 to 99% silane in hydrogen; And

Gas retention time: 0.001 to 1000 seconds.

Other exemplary embodiments of the invention will be apparent from the detailed description of the invention provided below. It is to be understood that the detailed description and specific embodiments disclosed by way of illustrative embodiments of the invention are for the purpose of description and are not intended to limit the scope of the invention.

Unless expressly stated otherwise, the method embodiments disclosed herein are not limited to any particular order or sequence. The described embodiments or portions of the elements may be performed or performed at the same time.

Figure 1 shows a process flow diagram of one embodiment of the present invention for the production of high purity polysilicon starting from low purity metallurgical silicon.
Figure 2 shows a process flow diagram of one embodiment of the present invention for the preparation of premixed silanes for in situ distributed turnkey applications starting from high purity silicon.
3 shows a multi-stage fluidized bed-hybrid chemical gasification reactor.
Figure 4 shows another multi-stage mobile bed chemical gasification reactor.
Figure 5a shows a schematic diagram of a high temperature and high pressure gasification reactor.
Figure 5b shows a distinct orange silane flame from a catalytic gasification reactor using hydrogen.
Figure 6 shows a reactor that combines the generation of RF plasma atomic hydrogen and silicon vaporization into a single unit.
Figure 7 shows a scanning electron micrograph of a silicon single crystal surface etched by Pd catalyst particles after heating in hydrogen at 900 占 폚 for 30 minutes.
Figure 8 shows an enlarged micrograph of the same etched silicon single crystal surface of Figure 7 showing the wedged channels produced by the movement of the catalyst particles.

Justice

The following are definitions of materials, methods, and equipment employed in embodiments of the present invention.

Metals: The following symbols are recorded on the periodic table:

Lithium, lithium, sodium, potassium, rubidium, cesium and frium, beryllium, magnesium, calcium and strontium, ), Barium (Ba), and radium (Ra);

Transition metals: Scandium (Sc), niobium (Nb), technetium (Tc), hafnium (Hf), mercury (Hg), actinium (Ac), ruthenium (Rf) (Cd), chromium (Cr), cobalt (Co), cobalt (Co), boron (Bh), hydrosium (Hs), metimine ), Tungsten (W), tantalum (W), tantalum (Ta), tantalum (Ta) Uranium (U), vanadium (V), zinc (Zn), and zirconium (Zr);

Noble metals: Ag, rhenium, Os, iridium, gold, palladium, platinum, rhodium and ruthenium;

(Al), gallium (Ga), indium (In), thallium (Tl), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Po) and tellurium (Te);

Rare earth metals: lanthanide series Y, lanthanum, cerium, praseodymium Pr, neodymium, prommium, samarium, europium, gadolinium, , Tb, Dy, Ho, Er, Tm, Yb, and Lu; (Th), Pro Actinium (Pa), Uranium (U), Np, Np, Pl, Am, Cm, (Cf), Einsteinium (Es), Fermium (Fm), Mendelium (Md), Novellum (No) and Lawrenium (Lr).

Si-material: one or a combination of silicon element, silicon alloy, and Si-compound:

Silicon Elements: metallurgical silicon, polysilicon, single crystal silicon. Various conventional engineering methods can be selected to produce silicon and silicon alloys in the form of ingots, bulk pieces, sheets, rods, granules, or powders.

Silicon alloy: Si-Mx, where M is at least one of the alkali and alkaline earth metals, transition metals, noble metals, rare earth metals and low melting point metals defined above, and in particular the following elements: Li, Be Ni, Cu, and Zn, where x is 0.01 wt% to 95 wt%. The alloy may be in the form of ingots, bulk pieces, sheets, rods, granules, powders, melts, and vapors.

A compound containing Si: Any material containing silicon such as oxides (SiO, SiO ₂ ), nitrides, carbides, hydrides, salts and ceramics is not a silicon element or a silicon alloy.

The Si-material may be in the form of a solid (in the form of ingot, rod, flow of powder), liquid melt, and vapor. This can be added as a mixture, suspension, slurry, or paste in a solution, molten salt matrix.

Hydrogen source: Also referred to herein as a source of hydrogen gasification, one or a combination of the following:

a hydrogen gas (isotope of hydrogen);

b) dissociating inorganic acids and organic acids such as HCl, HF, H ₂ SO ₄ , HNO ₃ , H ₃ PO ₄ , H ₂ CO ₃ , H ₄ SiO ₄ , acetic acid, or bases NH ₄ OH, and salts NH ₄ Cl, NH _{4 F, NH 4 NO 3,} (NH 4) 2 SO 4, (NH 4) 3 PO 4, (NH 4) 2 CO 4, (NH 4) 4 SiO hydrogen ions (protons) in the _4, and

c) metal hydrides (LiH, NaH, KH, NaAlH 4, NaLiH 4, NaAlH 4, NaAlH 4, NaAlH 4, NaAlH 4, etc.)

d) Hydrogen ions produced by an electrochemical cell employing an aqueous electrolyte, an organic electrolyte, a molten electrolyte, a polymer electrolyte, and a solid ceramic electrolyte.

e) Atomic hydrogen generated by a hydrogen plasma generated by microwave, RF, DC, glowing, and hot wires.

Catalysts and accelerators: one member selected from the following group or any combination thereof.

a) metals as defined above, in particular precious metals and transition metals;

b) Alkali metals and alkaline earth metals: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and francium (Fr) group 2 elements. Beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

c) Rare earth metals: Lanthanide series cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, tulium, ytterbium, lutetium; Actinide series Actinium, Thorium, Proton Actinium, Uranium, Nepidium, Plutonium, Amerium Crimium, Cerium, Calcium, Einsteinium, Fermium, Mendelium, Nobelium, Lorenzium.

d) Group III-VI metal

e) Alloy hydride, and

f) metal compounds such as oxides, organic salts and inorganic salts of the metal elements described in the above catalyst and promoter moieties.

Catalyst Preparation and Administration: If the catalyst can be widely dispersed on the Si-material, the Si-material is in direct contact with the hydrogen gasification source.

In one embodiment of the present invention, the catalyst may be added to the silicon when prepared metallurgically, similar to alloying, or may be added during the grinding process, or even from the solution when the catalyst can be homogeneously distributed Can be administered to the surface of the final granule. The dosage of the catalyst may range from 0.0001 wt% to 80 wt%, depending on the properties of the silicon and alloy materials. For example, in the case of a silicon ingot, a catalyst of 0.0001 wt% can be added to the surface, but in the case of fine silicon powder, it has a large specific surface area, so a catalyst of 20 wt% . Moreover, the catalyst can be recovered from the gasification reactor unit and returned to the catalyst input / feed production unit.

Catalytic reaction: As a chemical reaction promoted by the presence of a catalyst or an accelerator, the catalyst is not converted to the desired reaction product.

Si-Material Catalytic Gasification: The reaction between a Si-material and a hydrogen source in the presence of a catalyst under high temperature and high pressure, depending on the nature of the combination.

 However, the reaction product comprises a gaseous product containing at least one Si upon return to ambient conditions.

Silane: a silicon-hydrogen compound having the formula SixHy, wherein x is an integer comprising x = 1, 2, 3, 4, 5, -100; y = x, 2x, or 2x + 2. Monosilane (SiH ₄ ) is the most common form of silane. The silane may also be in the form of SixDyHz, where D is an isotope of hydrogen and x is an integer of 1, 2, 3, 4, 5, -100; (y + z) = x, 2x, or 2x + 2.

Silane co-purified (co-purification): high purity gas, or silane, hydrogen, and 95% pure or more of He, Ne, Ar, Kr, Xe, Rn, N _2, H _2, inert or non-reactive gas, such as D ₂ (1 ppm to 95% by weight of silane composition, the remainder being hydrogen and an inert gas), and the impurities are not more than 5.0%.

Inert gas such as He, Ar, N ₂ with purity of each component, and the total mixture (silane composition is 1 ppm to 95%, the remainder being Hydrogen and an inert gas) is 95% or more, and the other impurities are 5.0% or less.

Quenching: To quickly cool the reaction product to a temperature below 800 ° C within 10 seconds once the gas or gas mixture is discharged from the gasification chamber to prevent cracking of the silane.

Silane mixture Simultaneous-purification: Silane is not separated from hydrogen, inert gases such as He and Ar, but other impurities are removed to a level of less than 5.0% in the purified silane mixture.

Silicon Fabrication: Fabrication of silicon with a purity greater than 99.99% using a silane mixture; The shape of the silicon can be ingots, liquids, nano powders, granules, each produced by Siemens technique, vapor to liquid, or a centralized fluidized bed particulate polysilicon manufacturing system, respectively.

Silicon Device Fabrication: An apparatus comprising a si- element that can be fabricated using silanes, such as semiconductor devices such as integrated circuits, solar cells, LCD-flat panels, and other electronic devices.

Part A) Process method, reaction parameters and reactor

1 is a non-limiting example, in which the metallurgical silicon or silicon alloy to which the catalyst is applied from the unit 110 is hydrogen gas, a hydrogen ion produced by an electrochemical cell, or an atomic form by a plasma process at a high gasification temperature Hydrogen is vaporized through the gasification unit 120 to form a mixture of silane and hydrogen (or inert gas argon). This mixture can be rapidly cooled (quenched) from the reaction temperature to a temperature of 800 캜 or less by the heat exchanger 122 as soon as the mixture is discharged from the gasification unit, in order to prevent decomposition of the formed silane.

After quenching, the mixture can be purified in unit 130. The unit 130 does not separate hydrogen and argon from the silane and co-purifies them to remove other impurities. The purified silane mixture is used for downstream applications such as the production of polysilicon shown in unit 150 where the polysilicon production unit 150 is a unit of a centralized fluidized bed particulate polysilicon, vapor-liquid, or high purity polysilicon and / It is a Siemens reactor system that is converted into a hydrogen byproduct. The hydrogen and argon byproducts from the final polysilicon manufacturing unit 150 are recovered and recycled to the gasification unit as shown by the arrow 142. Hydrogen and argon may be added through unit 160 to compensate for process losses as shown by arrow 162. The catalyst is recovered from the bottom of the gasification unit and returned to the silicon or si containing compound containing a silicon alloy catalyst input unit (not shown).

Silanes are now widely used in the manufacture of semiconductor devices such as integrated circuits, solar cells, LCD-flat panels and other electronic devices. The ultra-high purity silane (99.9999%) in the bulk tank is transported to a re-bottling facility thousands of miles away for recharging within a small silander (less than 10 kg). The silane silane is transported to an application site such as a semiconductor manufacturing plant and diluted with hydrogen or argon as a silane gas mixture having a silane composition ranging from several ppm to about 99% for various chemical vapor deposition applications. This process is dangerous because it is expensive and the silane is a highly explosive gas. Therefore, field-ordered silane sources provide improvements in many industries.

Figure 2 shows an exemplary process flow diagram according to one embodiment of the present invention for the preparation of premixed silanes for on-site order dispense turnkey applications starting from high purity silicon and high purity hydrogen sources. As shown in FIG. 2, ultra high purity silicon is used as the starting material and is catalytically vaporized through the gasification unit 122 using hydrogen gas or atomic hydrogen produced by the plasma to produce silane and hydrogen (or inert Gaseous argon) mixture. The hydrogen plasma is preferably activated by radio frequency (RF) or microwave to prevent possible contamination such as caused by corrosion of the electrodes in the DC plasma.

The mixture is quenched by heat exchanger 123 to prevent decomposition of the silane as described above. After quenching, the mixture is refined in unit 132, and unit 132 removes impurities by simultaneous refining them without separating hydrogen and argon from the silane. The purified silane mixture is used for application of downstream CVD (142) devices, such as the IC shown in unit 152 and the manufacture of solar cells. Hydrogen and argon may be recycled back to the gasification unit and hydrogen and Ar may be added via unit 162 via 163 if desired. The composition in unit 142 may be further controlled by external silane or H ₂ through unit 162 depending on the specific silane concentration situation. There is no large-scale purification step other than filtration of the gas mixture in the whole process and, if necessary, an external dilution is added.

Gasification process and construction of reactor

Materials: Any Si-material can be used as a starting material. In one embodiment of the present invention for catalytic gasification to form a silane mixture for the production of polysilicon as shown in Figure 1, metallurgical silicon and silicon alloys are excellent starting materials. In the case of the field-ordered-distribution silane application as shown in FIG. 2, undoped single crystal or polycrystalline silicon can be used as the starting material.

Catalyst composition and input: The catalyst may be at least one element selected from the following group.

a) Precious metals, especially Pd, Pt, Rh, Re, etc.,

b) a transition metal, particularly Ni, Cu, Co, Fe, etc.,

c) alkali metals, especially Na, K, Li, Ca, etc.,

d) Rare earth metals

e) Group III-VI metal

f) metal alloys,

g) hydrides, and

h) Metal compounds: oxides, chlorides and organic salts and inorganic salts.

The catalyst may be added to the silicon when prepared metallurgically, similar to alloying, or it may be added during the grinding process, or even from the solution to the surface of the final granule if the catalyst can be homogeneously distributed . The dosage of the catalyst may range from 0.0001 wt% to 80 wt%, depending on the properties of the silicon and alloy materials. For example, in the case of a silicon ingot, a catalyst of 0.0001 wt% can be added to the surface, but in the case of fine silicon powder, it has a large specific surface area, so a catalyst of 20 wt% . Moreover, the catalyst can be recovered from the gasification reactor unit and returned to the catalyst input / raw material production unit.

Hydrogen gasification source: The gasification agent is selected from one or a combination of the following.

a) hydrogen gas (or an isotope of hydrogen);

b) hydrogen ions in the same dissociation acid as an acid or a metal hydride (LiH, NaAlH _4, etc.), or _{HCl, HF, H 2 SO 4} , H 3 PO 4, H 4 SiO 4, acid (proton) salts: NH ₄ Cl,

c) a hydrogen ion generated by an electrochemical cell; And

d) atomic hydrogen generated by plasma gasification.

Gasification Reactor Type: Depending on the type of silicon feedstock and the source of gaseous hydrogen, the reactor type may be selected from a packed bed of silicon or granules, a graded bed, a fluidized bed, a moving bed, or a combination thereof. The following table shows the reaction parameters of catalytic gasification of silicon.

Reaction conditions for the preparation of silanes using catalytic gasification Reaction parameter Lower limit maximum Temperature (℃) -30 3000 Pressure (Mpa) 0.1 - 1000 Retention time (sec) 0.001 1000 Catalyst feed (wt%) 0.0001 80 Ingress gas composition Hydrogen (%) in inert gas 1.0
99.9999 Exhaust gas composition Silane (%) in hydrogen 0.00001
99.9999

From a thermodynamic point of view, the higher the temperature and pressure, the more the conversion takes place. However, economic processes must be considered; Pressure and temperature should be optimized to achieve optimal results and manufacturability. High temperatures and high pressures also increase capital costs, and it is extremely important to prevent cracking of the silane. Thus, silicon and alloys can be in solid, liquid, or even gas phase over a certain temperature range.

Heating of the reactor can be carried out by internal heating such as induction heating, electric heating, or combustion heating. The heating unit can be installed inside or outside the reactor chamber. The reactants must be heated to achieve the reaction temperature. The heating unit is preferably selected from an electrical connection of the high particulate silicon layer and the power source. A voltage is applied to the layer of high purity particulate silicon. Due to the semiconductor properties of silicon, the high purity particulate silicon layer is heated and the temperature is raised. This method provides direct heating, high thermal efficiency, and high utilization efficiency. This can also help prevent contamination and ensure product purity. The heating unit may also include as many other conventional heating techniques as:

1) direct heating using resistive wires (silicon ingot, high purity SiC, high purity SiN, or high purity graphite and other materials);

2) indirect heating by microwave, plasma, laser or induction and other methods;

3) indirect heat radiation from the flame or rotary kiln over the entire length of the combustion tube that can provide heat;

4) If an outer jacket and an inner layer heat exchanger are used, the outer jacket heat exchanger can be used outside the jacket and thermal medium heating inductor converter; Heat transfer of the layer may be effected by heat induction, electrical induction, and electrode heating, etc.;

5) External heating methods, external heating methods such as reactants required in the reaction (for example, suspended gases and silicon particles themselves) are heated externally before being introduced into the reactor;

6) A reaction heat (coupling-reaction heating) which is formed by a chemical reaction such as chlorine (Cl ₂ ) or hydrogen chloride (HCl) is added to the system.

Catalytic gasification using hydrogen gas

As shown in Figure 3, the granules of the pre-dosed Si-material (compound containing si or Si containing silicon alloy or silicon alloy) can be introduced into the catalyst input mixer 001. After being well mixed, the silicon is introduced into the first reaction zone 203 at the top of the reactor chamber via the feed system 201. Since gasification is carried out under high temperature and high pressure in the presence of hydrogen, the silicon granules and powder feed system can be constructed with a series of interconnected chambers to gradually increase the pressure of the system.

The first reaction zone 203 is a packed bed and the material (silicon or alloy) is supported by a porous plate having side holes for moving the silicon to the adjacent lower reaction zone, The resulting gas mixture can pass through the packed bed in zone 203 to capture the dust formed from the reaction and preheat the silicon layer. The gas mixture is also preferably quenched below 800 ° C by heat exchanger 212 to dislodge dust in the downstream solid gas separator 208 and then prevent decomposition of the silane in the gas mixture.

To ensure a solid-gas reaction rate, the second reaction zone 205 of the reactor chamber, which is the middle portion, is constructed as a fluidized bed reaction zone.

In the third reaction zone 207, two (two or more) flow reaction segments can be formed by the gas mixture from the lower reaction zone. The configuration of the reaction zone can ensure maximum conversion and yield.

In one embodiment of the invention, the gaseous hydrogen source may be added in the reaction chamber at several locations. In particular, the hydrogen source may be added to the reaction zone 203 through the port 202 to cool the temperature of the silane to prevent decomposition and through the port 204 for equilibration of the gas flow rate, Can be stabilized.

The primary gaseous hydrogen source can be preheated and added through port 206 at the bottom of the reactor chamber, which reacts with silicon in reaction zone 207, and the resulting product mixture moves upward, Passes through zones 205 and 203 and finally falls through the reaction zone 208 towards the flow treatment.

On the other hand, some of the silicon particles descend sequentially through the reaction zones 203, 205, 207, and finally the residues are filled in 209 and collected by 211. The residues include catalyst components that are largely non-vaporized and are recovered by the catalyst recovery unit 213 and then returned to be mixed with the incoming silicon or alloy powder or subjected to a catalyst input process for the production of silicon and alloy raw materials Lt; / RTI >

4 shows a multi-stage mobile bed chemical gasification reactor, which is another embodiment of the present invention. This reaction chamber is divided into several segments by a conical gas distributor, and four moving bed reaction zones are connected in series. During the reaction, the silicon particles from 410 together with the recovered catalyst and the added catalyst move downward toward the mixer vessel 001 and then enter the reaction chamber.

The silicon particles sequentially pass through the reaction zones (004, 005, 006 and 007) and move downward, the particle size gradually decreases due to gasification, and finally the residues are charged into the catalyst recovery unit 480 Is recovered. The residues mainly contain the catalyst components and are recovered by 213 and then returned to be mixed with the incoming silicon or alloy powder or recycled to the catalyst input process for the production of silicon and alloy raw materials.

The gaseous hydrogen source may be introduced through ports 430, 450, and 470, respectively, and the gas mixture obtained is moved upwardly for each segment and then forced redistributed within the other upper layer. This prevents gas tunneling in the deep layer and ensures uniform and complete contact of the surface of the solid silicon particles with the gas during the reaction. The final gas mixture can be quickly cooled by the quench unit 440 to prevent cracking of the silane as it exits the reactor chamber.

High temperatures and high pressures are beneficial for gasification of silicon, but hydrogen can cause metal embrittlement at high temperatures, thus reducing mechanical strength. Therefore, internal heating can be employed, while the insulation liner on the inner surface of the reactor wall can be selected to maintain the reactor wall at a relatively low temperature to maintain a high gasification pressure.

Figure 5a shows a schematic view of the internal structure of one embodiment of the gasification reactor used in the present invention. The reactor chamber 570 is surrounded by a heating element 560. A power source for the heating unit is provided through a pressure-resistant connector 540. The temperature of the reactor is monitored through a thermocouple inserted through port 550. The reactor chamber and heating unit 560 are separated from the outer shell 510 of the reactor by an insulating layer 520. During gasification, the hydrogen source is introduced into the reactor via 500, and the formed gas mixture is discharged from 580 and rapidly cooled.

Catalytic gasification using protons produced by electrochemical generation cells

Hydrogenation of a compound by hydrogen ions (protons) is more reactive than hydrogen gas under the action of an electrode potential. Hydrogen ions (protons) can be generated using an electrochemical reaction chamber or a cell including an electrolyte, a positive electrode and a negative electrode, which is well known in the art. In one embodiment of the present invention, the following method of electrochemical construction can produce hydrogen ions that further improve silicon gasification to form silane.

Hydrogen Electrode: It is formed as a porous structure of its own high surface area such as transition metal Ti, Ni, Cu, Co, Fe, etc. such as noble metals Pd, Pt, Rh, Metal alloy. The electrodes must be uniformly distributed in contact with the incoming hydrogen gas and must be well wetted with the electrolyte.

Si-material electrodes (compounds containing silicon elements, si- alloys and si): silicon powder, granules, and packed layers of solid species or pastes or slurries with catalysis, fractionation layers, Can be selected. Further, since silicon and alloy are consumed during the course of the reaction, silicon containing the catalyst described in the above section is filled in the electrode chamber in the form of a flow of silicon granules, a sheet, a silicon rod and a silicon powder Or as a solid, paste or slurry of any suitable form.

Electrolytes and proton exchange membranes: The electrolyte can be a liquid, a high voltage electrolyte, in particular a nonaqueous proton, a molten salt, or a polymer gel electrolyte and a high temperature solid ceramic electrolyte capable of transporting protons during the gasification process.

Catalytic gasification by atomic hydrogen

Hydrogen plasma is used for etching the silicon surface for preferential etching of a specific surface for surface treatment before deposition, or for protection of the etching process from the etching process, some for the purpose of creating devices on silicon wafers come. It is well known that atomic hydrogen is advantageous for the hydrogenation reaction. However, atomic hydrogen can only be produced under certain conditions such as ultra-high temperature or electric arc or high frequency electromagnetic stimulation. To activate the formation of a hydrogen plasma, an inert gas such as argon and helium is typically added to the system to cause a hydrogen plasma. The atomic hydrogen form generally has a short lifetime and the concentration of atomic hydrogen and the contact time with the silicon surface are important factors in the hydrogen plasma chemical reaction. The silicon gasification reactor must combine atomic hydrogen evolution and be in immediate contact with silicon. As shown in the following table, the hydrogen plasma may be DC plasma, microwave; Radio frequency, hot wire, and glow discharge. Thus, the gasification reactor can be configured to use one or a combination of a packed bed, a graded bed, a fluid bed, and a moving bed of silicon powder to maximize gasification.

Figure 6 shows an RF plasma atomic hydrogen silicon gasification reactor. 610 is an induction coil, 640 is a reactor chamber made of a non-magnetic refractory material such as ceramic quartz, and hydrogen gas (optionally including Ar or He, which is a fluoride gas) is supplied by induction coil 610 Is introduced into the reactor chamber to form a plasma torch (630) under RF power. The silicon powder or granules 620 is circulated in the chamber by the torch until it is too small (by gasification) and can not be carried in the exhaust gas mixture stream. These electrodeless reactors are free from contamination of the erosion of the electrode material during operation. This is optimal for field-distribution turnkey silane applications. The following table also summarizes combinations of reactor types and plasma shapes that can be selected for specific applications. For example, in some embodiments, the method of manufacture of the present invention consists in producing a silane gas by exposing the silicon powder to a hydrogen plasma. The silicon body is manufactured to ultra-high purity for field application, and metallurgical grade silicon is used to minimize the cost of the final product for large scale applications.

Part B) Quenching of the silane mixture

Since the silane can decompose at relatively low temperatures, the silane mixture discharged from the high temperature reactor must be quenched as much as possible to prevent decomposition loss. The silane mixture discharged from the high temperature reactor can be rapidly quenched to a temperature of less than about 800 占 폚, less than 400 占 폚, less than 300 占 폚, less than 250 占 폚 to obtain a stable silane containing a gas mixture. This can be achieved by heat exchange with the refrigerant or by injection of a cold hydrogen stream. Alternatively, when the pressure of the reactor is high, the temperature of the gas can be drastically lowered by the rapid pressure drop of the exhaust gas.

Part C) Simultaneous purification of the silane mixture

Since dilute mixtures of silane and hydrogen and / or argon are used in industrial deposition such as chemical vapor deposition (CVD) for polysilicon, IC thin films, solar cells and LCDs, the subsequent deposition of silane from hydrogen to produce high purity silane Separation and purification are unnecessary and also waste of energy. Therefore, a silane mixture prepared by said co-purification without separating impurities from silane and hydrogen is preferred.

The boiling point of the silane in the process of the present invention, the gas involved and the major impurities Boiling point ℃ Molecular Weight SiH ₄ -112 < 32 H ₂ -259 2 Ar -185.85 40 PH ₃ -87.7 ° C, 34 H ₆ B ₂ -92 ° C

For all silane-related electronic applications, the most harmful impurities are boron (B) and phosphorus (P) compounds. However, in the case of battery-electrode-related electronic applications, boron (B) and phosphorus (P) compounds may even be added to improve conductivity. Since impurities from silicon provide a primary source of supply, the major impurities in question can be boron hydrides and phosphorus hydrides, which are formed during silicon hydrogen hydrogenation, as described in Table 2. Silane, hydrogen, and argon can be easily separated since they have a relatively low boiling point compared to H ₆ B ₂ and PH ₃ . In addition to conventional purification techniques such as distillation and concentration, the mixture can be co-purified by absorption and filtration using zeolites. Chemical absorbing and reacting agents, such as alkaline compounds (including corrosive agents, soda ash, CaO, MgO, metal oxides such as Al ₂ O ₃ , etc.) that selectively react with H ₆ B ₂ and PH ₃ also include H ₆ B ₂ and May be used alone or in combination with other purification and separation processes to remove PH ₃ . An additional purification step may be added to this process depending on the impurities generated within the scope of the invention.

The addition of an external silane or hydrogen can be easily carried out to adjust the composition of the silane to meet the particular application if necessary. Alternatively, the hydrogen concentration in the silane mixture can be reduced by compressing the silane / hydrogen mixture and passing it through a H ₂ separation membrane such as Pd. The hydrogen recovered in each step can be recycled to the hydrogen gasification unit.

Example

The following are several embodiments for the hydrogen gasification of silicon embodied in accordance with various embodiments of the present invention.

Example 1. Catalytic gasification of metallurgical silicon using hydrogen gas

2.0 wt% Cu, and 1 wt% Ni catalyst (using chloride) are applied on metal-silicon powders of 100-30 mesh through solution impregnation or coating. After drying, the silicon powders are each heated in a fluidized bed reactor, a graded bed and a packed bed reactor, respectively, in a flow of hydrogen of chemical purity of 900-1300 ° C. As shown in Fig. 5B, an orange flame was observed due to the combustion of the exhaust gas from the reactor, which indicates the formation of silane. Also, the weight of the silicon powder is significantly reduced after 10 hours of reaction. The exhaust gas from the reactor is also rapidly quenched to about 500 캜 or below, or 300 캜 or below, by passing the exhaust gas through a heat exchanger having a circulating coolant. On the other hand, the same amount of metallurgical silicon having no catalyst is heated under the same conditions, and mass loss of silicon is not detected.

Example 2. Catalytic hydrogen gasification on the surface of monocrystalline silicon

To obtain a microscopic understanding of silicon vaporization, a single crystal (100) wafer was selected and divided into two samples, Sample A and Sample B. A few drops of palladium acetate solution (including acetone) are sprayed onto the surface of Sample A. After drying, the wafer was crushed into small pieces and heated in hydrogen at various temperatures during a series of time intervals. In each case, a small piece of sample B is used as a control sample. After the reaction, each sample was examined for surface morphology under a scanning electron microscope (SEM).

Figure 7 shows a SEM micrograph of a sample A single crystal surface etched with Pd catalyst after heating in hydrogen at 900 占 폚 for 30 minutes. Pd forms catalyst particles as indicated by 711, 712, and 716 during the gasification reaction, which migrate on the single crystal surface while promoting the reaction between silicon and hydrogen at the catalyst and silicon interface, , 702, 703, 704, 705, 706). 8 is an enlarged photomicrograph of the etched monocrystalline surface of the same silicon. The channel start area 801, the bottom of the channel 802 formed early, and the channel wall 803 formed later are shown in the photograph.

Example 3: Gasification of silicon with atomic hydrogen produced by plasma using a commercial DC plasma torch, in which hydrogen is used to form hydrogen plasma, respectively, in a fluidized bed reactor, a fractionation bed and a packed bed reactor, ≪ / RTI > and a gold deposition on the downstream wall.

Example 4 Gasification of Silicon by Arsenic Hydrogen Generated by Plasma Generated with a Commercial ICP Plasma Torch Hydrogen is used to form a hydrogen plasma in the fluidized bed reactor, the grading layer and the packed bed reactor, respectively, and the formation of silane ≪ / RTI > and a gold deposition on the downstream wall.

Example 4: Electrochemical electrodes available from E-TEK, Inc (6 Mercer Road, Natick, MA 01760, USA) where the hydrogen source is; Elat / Std. With 20% Pt / C. Electrode, and the silicon electrode is a metal-silicon rod and Si-Ca, Si-Fe, SiAl, and Si-Mg alloys, and silane.

Example 5: Similar to Example 1, except that the gasification is effected using a silicon vapor which is evaporated using a tungsten heating graphite crucible. Silane formation is confirmed.

Example 6: Similar to Example 1, except that the gasification is carried out using a suspension of silicon particles in molten salt.

Example 7: Similar to Example 1, except that the gasification is using a silicon alloy melt containing hydrogen.

Example 8: Similar to Example 1, except that the gasification uses HCl that reacts with a small particle size powder of a silicon alloy.

Another embodiment of the present invention also includes a process method and system for making a silane using catalytic gasification of silicon and an alloy,

Reaction chamber; A packed bed, a fluidized bed, a sorted bed, a moving bed, and the like;

Hydrogen gas, atomic hydrogen by plasma and hydrogen ion by electrochemical cell; And dissociation of acid and hydrogen

Means for supplying a hydrogen source to the reactor chamber;

Means for administering a catalyst to the silicon and alloy;

Means for supplying silicon and alloy to the chamber in the form of a suspension in a silicon bulk, a silicon rod, a flow of silicon powder, a melt, a vapor, a liquid molten salt, or any other suitable form of solid, liquid or vapor silicon;

Means for quenching the gas present in said reactor chamber;

Means for co-purifying the silane mixture after quenching the product gas mixture; And optionally, means for recirculating the catalyst and hydrogen (inert gas) recovered in the process after the final application of the silane.

Exemplary processes for making silicon include,

a) a hydrogen source comprising hydrogen or a material capable of reacting with a silicon or si- material to form a silane, a catalyst capable of accelerating the reaction and / or lowering the temperature of the reaction, and optionally an inert gas ;

hydrogen and an inert gas by catalytic vaporization of a compound containing silicon or Si via said reaction of said hydrogen source with a compound containing silicon or Si in the presence of said catalyst at high temperature, Producing;

c) reducing the temperature of the gas mixture immediately after the gasification to a temperature of less than 800 ° C to prevent decomposition of the silane;

d) separating the silane and hydrogen and optionally an inert gas from the gas mixture to form a co-purified silane mixture having less than 5.0 percent of other impurities.

In the exemplary process,

e) decomposing the silane in the co-purified silane mixture and converting the co-purified silane mixture to a reacted gas mixture comprising hydrogen to produce a silicon or silicon device;

f) returning the reacted gas mixture comprising hydrogen as hydrogen source from step e) to step a);

g) recovering and recirculating the catalyst to return to the gasification step.

While embodiments of the present invention have been shown and described, these embodiments are not intended to illustrate and describe all possible forms of the present invention. Rather, the terms used in the specification are words of description and not of limitation, and it is understood that various changes may be made without departing from the spirit and scope of the present invention.

Claims (20)

As a process for producing silicon,
a) a hydrogen source comprising hydrogen or a material capable of reacting with a silicon or si- material to form a silane, a catalyst capable of accelerating the reaction and / or lowering the temperature of the reaction, and optionally an inert gas ;
hydrogen and an inert gas by catalytic vaporization of a compound containing silicon or Si via said reaction of said hydrogen source with a compound containing silicon or Si in the presence of said catalyst at high temperature, Producing;
c) reducing the temperature of the gas mixture immediately after the gasification to a temperature of less than 800 ° C to prevent decomposition of the silane;
d) separating the silane and hydrogen and optionally an inert gas from the gas mixture to form a co-purified silane mixture having less than 5.0 percent of other impurities. The method according to claim 1,
h) decomposing the silane in the co-purified silane mixture and converting the co-purified silane mixture to a reacted gas mixture comprising hydrogen to produce a silicon or silicon device;
i) returning a reacted gas mixture comprising hydrogen as a hydrogen source from step e) to step a);
j) recovering and recirculating the catalyst and returning to the gasification step. The method according to claim 1,
Wherein the catalyst comprises at least one of a metal, a metal alloy, a metal oxide, a metal salt, a metal hydride or a compound containing a metal; Wherein the metal is selected from the group consisting of a noble metal element, an alkali and an alkaline earth metal element, and an element consisting of a transition metal element, a rare earth metal element, and a low melting point metal element. The method according to claim 1,
Wherein the catalyst is a metal or metal alloy selected from the group consisting of a noble metal, an alkali metal, and a transition metal, a rare earth metal, and a low melting point metal. The method according to claim 1,
the si- material comprises at least one of a silicon element, a silicon alloy and a compound containing Si; Wherein the silicon alloy comprises at least one of a noble metal element, an alkali and an alkaline earth metal element, and a transition metal element, a rare earth metal element, and a low melting point metal element. The method according to claim 1,
The si- material comprising a silicon element, a silicon alloy and a compound containing Si may be in the form of an ingot, a slab, a bulk, a rod, a granule, a powder, a suspension in a liquid, ≪ / RTI > The method according to claim 1,
Wherein the hydrogen source is one or any combination of the following.
e) a hydrogen gas (H ₂ or D _2, HD);
f) hydrogen ions in acids, metal hydrides, or dissociated acids;
g) hydrogen ions generated by an electrochemical cell; And
h) (with or without an inert gas such as Ar) Plasma: DC plasma, microwave; Atomic hydrogen generated by radio frequency (RF), hot wire, and glow discharge, or the like, or combinations thereof. The method according to claim 1,
The quenching of the gas mixture is preferably carried out immediately after the reactor to prevent rapid heat exchange with the cooling medium of the previously prepared silane mixture itself or rapid decomposition of the silane into the pressure drop of the gas mixture produced, fair. The method according to claim 1,
Wherein said separation is carried out by distillation, absorption or filtration. The method according to claim 1,
Wherein the polysilicon manufacturing process is a liquid or Siemens reactor system from a centralized fluidized bed particulate polysilicon or vapor. The method according to claim 1,
Wherein the application is a large scale centralized or field dispensing application. 3. The method of claim 2,
Wherein the reactor type is a stirred layer and a ticking bed for a packed bed, a graded bed, a fluidized bed, a moving bed, or a frit of a silicon powder. The method according to claim 1,
The reaction conditions include,
Temperature: -30 to 3000 占 폚;
Pressure: 0.001-1000 MPa;
Input gas Hydrogen in inert gas: 1-99.99999%;
Exhaust gas: silane in hydrogen 0.5-99%;
And a residence time of the gas: 0.001 to 1000 seconds. The method according to claim 1,
Wherein the gasification catalyst is recovered and recycled to the feedstock. The method according to claim 1,
Wherein the hydrogen gas and the inert gas are recovered and recycled after the final application for feeding to the gasification process. The method according to claim 1,
Wherein the catalyst is capable of being incorporated onto a Si-containing compound comprising silicon and silicon alloy powder particle surfaces to be incorporated into the melt or solution. A reactor system for making a silane mixture,
a) a gasification chamber;
b) a silicon-material supply cylinder which is means for supplying silicon and alloy powder in a chamber in the form of silicon;
c) a hydrogen supply port for a hydrogen source to be fed into the gasification chamber;
d) a hydrogen source for vaporizing silicon and alloys such as atomic hydrogen by plasma and hydrogen ions by an electrochemical cell;
Means for supplying a hydrogen source and a silicon source to the reactor chamber;
e) quench unit
f) Internal heating unit
g) Simultaneous purification unit
Bulk, silicon rod, flow of silicon powder, melt, vapor, suspension in liquid molten salt, and any form of solid, liquid or vapor silicon;
Means for injecting said catalyst into silicon and alloy;
Means for quenching the gas present in the reaction chamber;
Means for co-purifying said silane mixture after quenching said product gas mixture; And optionally
Means for recirculating catalyst, hydrogen and inert gas recovered in said process at the end of said process. 17. The method of claim 16,
Wherein the reaction chamber is selected from a packed bed of silicon powder, a grading layer, a fluidized bed, a moving bed, and a stirring bed and a teaking layer for fusing. 17. The method of claim 16,
Wherein the gasification chamber is lined with a refractory material capable of withstanding the gasification temperature. 17. The method of claim 16,
Further comprising an internal heating unit surrounding the reaction chamber.

Images