HIGH-PURITY PARTICULATED SILICON MATERIAL AND METHOD FOR PRODUCTION

Abstract

A product according to the invention and a method according to the invention for producing a high-purity particulate silicon material are disclosed. The high-purity particulate silicon material has a relatively small size, a low surface area, and a relatively smooth, rounded shape, making it attractive as a high-purity, high-performance starting material for the production of silicon crystals and silicon wafers made from the silicon crystals. This invention also relates to methods for producing the high-purity particulate silicon material.

Description

FIELD OF THE INVENTIONThis invention relates to a high purity particulate silicon material having a relatively small size, a low surface area and a relatively smooth, rounded shape which makes it attractive as a high purity, high performance feedstock for use in the production of silicon crystals and wafers. The invention also relates to methods for producing the high purity particulate silicon material.BACKGROUND OF THE INVENTIONThis invention relates to the production of silicon particles used for the production of silicon crystals, particularly for the inexpensive production of silicon crystals in large quantities.Silicon crystals and wafers made from silicon crystals are an important starting material for the manufacture of integrated circuits, power devices (MOSFETs, IGBTs), microelectronic devices and solar cells. The silicon crystals are machined, sliced and polished to produce crystalline silicon wafers (wafers) used in the integrated circuit manufacturing processes, power devices, and solar cells. The silicon crystals must be almost free of crystal defects and must contain very few metallic impurities such as nickel, iron, copper, chromium and carbon (ranging from parts per million (ppm) to parts per billion (ppt)). Contaminants, particularly metallic contaminants, are problematic in the manufacture of integrated circuits because they adversely affect their electrical performance. Metallic impurities such as chromium, cobalt, iron, nickel and copper reduce the efficiency of solar cells. Impurities can be incorporated into the particulate silicon material at any time during the manufacturing process, and measures must be taken to avoid impurities and to remove impurities.Polycrystalline silicon is a starting material for the production of monocrystalline or multicrystalline silicon blocks which are required for the production of silicon wafers. High quality polycrystalline silicon (also called polysilicon) is required for the production of wafers for efficient solar cells for photovoltaic panels and high power silicon wafers for semiconductor devices. Moreover, a high purity silicon particle feedstock provides a higher yield in the crystallization processes, e.g., by allowing larger ingot production, which lowers production costs and ultimately the per-wafer cost.The production of silicon crystals and wafers is a costly process, and the users of silicon wafers are constantly exerting pressure, reducing the production costs and improving the quality of the wafers. Key elements of wafer performance include metallic contaminants and surface defects. Metallic impurities such as iron may impair the electrical properties of the crystalline silicon wafer, while metallic impurities such as nickel may lead to surface defects-defects that may lead to failure of semiconductor devices. Manufacturers of silicon crystals and silicon wafers must continually work to reduce the cost and improve the performance of these products by reducing the impurities in crystal growth and wafer manufacture while reducing the manufacturing cost. Metallic impurities in the silicon wafers originate from the silicon metal used as a starting material for the production of silicon crystals. Semiconductor device manufacturers are constantly administering pressure to reduce metal contaminants in silicon wafers because the metal contaminants degrade semiconductor device performance - future generations of advanced devices therefore require silicon particles with ever-lesser metal contaminants.Silicon crystal and silicon wafer manufacturers have standardized the specifications for the production of high purity silicon particles to maximize the continuity of the silicon crystal growth process. The silicon particles must meet the requirements of purity, size and packaging. Methods for producing silicon crystals with high purity silicon particles at low production costs include the production of crystals with diameters of 300-450 mm, the production of crystals with a large mass (>350 kg) and the use of methods for replenishing the contents of a container, generally a crucible, with silicon particles while the crucible still contains molten material, the so-called replenishment (re-charging).There are several processes for producing high purity polycrystalline silicon, including fluidized bed reduction and the Siemens process. The polycrystalline silicon produced by the Siemens process is so pure that it is suitable both for integrated circuits and for solar cells. The Siemens method is a chemical vapor deposition (CVD) method in which a process vessel is equipped with a series of parallel, long (meters) and thin (mm diameter or cross section) silicon filaments serving as a substrate, two or more of the silicon filaments being connected at the tip to a silicon bridge, so that they form an approximately U-shape (U-rod). The process vessel is sealed, flushed with inert gas, and then a mixture of hydrogen and a chlorosilane gas (typically trichlorosilane (HSiCl 3) or silicon tetrachloride (SiCl 4) is introduced into the process vessel. 'chlorosilane' may refer to any type of silane characterized by one or more chlorine atoms bonded to silicon, and includes, among others, monochlorosilane (H 3 SiCl), dichlorosilane (H 2 SiCl 2), trichlorosilane (HSiCl 3), Silicon tetrachloride (SiCl 4) and various chlorinated disilanes such as hexachlorodisilane ((SiCl 3)2) and pentachlorodisilane (HCl 5 Si 2). Since the impurities in a silicon crystal must be extremely low, the chlorosilane gas generally has a concentration of metallic impurities in the ppb ppt range. Subsequently, electrical current is applied to the filaments to heat them to a target temperature in the range of 800-1200°C, a temperature high enough to decompose the chlorosilane gas stream, resulting in the deposition of silicon on the filaments and the increase in diameter of the coated filaments. After a sufficient time, the process is terminated and the coated threads, now referred to as "rods", are removed. The weight of each silicon rod is typically between 100 and 250 kg and the diameter is typically between 100 and 200 mm.Due to the very low content of impurities in the chlorosilane gas as a starting material, the produced silicon has a content of metallic impurities equal to or lower than that of the chlorosilane gas. The polysilicon produced by this process is often referred to as the ultra cleanest man-made material of the world. The total concentration of the iron, nickel, and copper impurities in this silicon rod material, referred to as bulk impurities, must be 40 pptw, 30 pptw, 20 pptw, or 10 pptw or less, measured in parts by weight per billion (pptw). The concentration of carbon impurities is less than 10 ppbw (parts per billion weight).The validation of the content of donor and acceptor impurities (e.g. phosphorus, arsenic, boron and aluminum) and of metallic impurities in silicon rods is carried out by known methods, including the method defined in SEMI MF1723, to which reference is made here. The validation of the content of metal impurities is carried out by taking out the freezing region (the solidified impurities melted and coated by the induction coil from one end of the surface of the crystalline material to the other during the float zone process) of the crystal by the method of SEMI MF1723, dissolving with HF / HNO 3 and preparing a suitable sample for examination by ICP-MS methods. Due to the very low impurities, the ICP-MS tests must operate with a minimum detection limit for the element concentration of metal impurities of <10 ppta or <1 ppta. The validation of the bulk carbon in silicon can be determined by secondary ion mass spectrometry or by Fourier transform infrared spectroscopy using the methods described in M. Porrini et al., Solid State Phenomena Vols. 108-109 (2005), pp. 591-596, which is hereby fully incorporated by reference.The high purity polycrystalline silicon produced by the Siemens method can then be used for producing high purity monocrystalline silicon by various methods, for example the Czochralski method (CZ method). Most of the silicon particles used in the CZ method are produced by the Siemens method. In the CZ method, silicon particles commonly referred to as polysilicon (a polycrystalline form of silicon) are melted in a quartz crucible in a furnace. Then, a small silicon crystal in the form of a small diameter cylinder called a seed crystal is immersed in the molten silicon crucible and then slowly drawn into a long cylindrical vertical chamber maintained in an inert environment. The crucible rotates continuously about a vertical axis while the seed crystal is simultaneously rotated in the opposite direction and the seed crystal is slowly moved (pulled) out of the crucible. The molten silicon in the crucible solidifies on the pulled-out seed crystal and forms a single crystal ingot whose diameter is much larger than that of the seed crystal. During this process, the ingot is pulled from the melt at a controlled rate to form an ingot having the desired diameter and the volume of molten silicon is consumed. Because of the high purity of such crystals, most semiconductor chips for electric equipment and solar panels are made of monocrystalline silicon produced by the Czochralski method.As mentioned above, there is a constant tendency for manufacturers to produce larger, high purity monocrystalline silicon crystals at low cost. The cost reduction methods include steps for maximizing the efficiency of the apparatus and the process time. In order to achieve a maximum level of efficiency and purity, the polysilicon feedstock used in the CZ process must be in the form of small particles. The ideal shape of these particles is spherical and small to minimize the clearances between the particles charged into the crucible. Larger and / or irregularly shaped chips or lumps of silicon feedstock require a longer melting time due to their size and the larger spaces between the particles in the crucible, so that after the feedstock has been completely melted, a volume of molten silicon remains which is smaller than the volume occupied by the particles. If this filling volume of the molten silicon is not maximized, the efficiency of the crystal growth process is lowered. To melt the silicon in an appropriate time, small particles are used to ensure close packing of the particles in the crucible. The quartz crucible, which receives the polycrystalline material in a CZ reactor, is exposed to extreme temperatures upon melting of the silicon and cooling of the reactor after pulling the ingot. One method to extend the lifetime of the crucible, allow pulling of a longer crystal, and shorten the process time between pulling ingots, thereby improving the efficiency and cost efficiency of the crystal growth process, is to replenish the crucible with polycrystalline silicon material particles while the crucible still contains a residual volume of molten material, which is referred to as refilling (recharging).There are two methods of replenishing (recharging) intermittently (batch), in which after taking a crystal from a CZ furnace (a furnace used in the Czochralski method), a quartz container filled with silicon particles is introduced into the cylindrical vertical chamber of the CZ furnace above the crucible and then the bottom is opened to allow the silicon particles to fall into the crucible, and continuously, the silicon particles are supplied to the crucible throughout crystal growth. Typical requirements for silicon particles used in replenishing crucibles for the production of high performance silicon crystals and silicon wafers include minimum and maximum limits on silicon particle size, minimum metal impurities, and high purity packages. The silicon particles used in the replenishment are sorted such that the particles have a typical size range of about > / =3 mm to < / =75 mm. The target areas may be between 5 mm and 50 mm or 20 mm and 70 mm. The particles are packaged in ultra-pure polymer bags in clean room environments with at least ISO 5 particle control (e.g. the packaging can also be done with ISO 4 particle control). It is highly desirable that the silicon particles have low surface and bulk impurities, as this is required to keep the crystals produced low in impurities. For example, the total concentration of metal impurities (sum of surface and bulk impurities) such as iron, nickel, copper and chromium should be in the range of 1-50 pptw and carbon below 100 ppbw.The polycrystalline silicon rods produced by CVD are not in a state suitable for the production of single-crystal silicon crystals. The polycrystalline silicon rods must be broken into small pieces. When a silicon rod is removed from the Siemens CVD process, it is in its ultra cleanest state. A major challenge for silicon particle manufacturers is the conversion of the silicon rods into small particles, a process referred to as comminution (commi nution). The most common comminution methods include jaw breakers, roller breakers and the manual breaking of the rods with hammers by humans. The silicon rods can be comminuted to a considerable extent to contaminate the surfaces of the silicon particles.In order to produce high purity silicon particles, the technology for comminution of silicon rods into particles must be capable of delivering particles with minimal additional contamination of the surface of the particles. Originally, the comminution was carried out in a clean room in which the staff with hammers broken the silicon rods into large pieces and disintegrated the large pieces into smaller pieces by further peening. The pieces were then sorted manually on a bench into the desired particle size range. The particles were then manually filtered into bags which generally had a weight of 5 kg + / - 50 g of particles per bag. FIG. 1 shows this process flow.The process flow shown in FIG. 1 is known in the art. It is labor intensive, slow, involves undesirable impurities and, because of the manual nature of the process, results in undesirable variations in particle size and impurities as well as product waste. An improvement of the method shown in FIG. 1 is shown in FIG. 2. Mechanical comminution of large silicon rods with jaw or roll breakers has been developed to better control comminution and obtain particles in the desired size range. The particles were sorted by sieving to achieve a higher consistency of the particle size range. Chemical cleaning with acid, e.g., mixtures of H 2 O 2+ HCl or H 2 O 2+ HF or HNO 3+ HF, are used to remove surface contaminants added during the comminution process.A new method of comminution is high voltage pulse crushing (HVPC). In this method, a silicon rod is wholly or partly immersed in a vessel filled with deionized water. Two or more metal electrodes are placed over the rod, and a high voltage generated across the electrodes generates an electric arc discharge. This discharge generates a high pressure shock wave in the container, which breaks the silicon rod into pieces. The high voltage pulse grinder may be calibrated to produce a particular size range of particles. In addition, the silicon pieces / particles can be crushed in the high voltage pulse crusher either with or without a silicon rod. In addition, silicon in both polycrystalline and monocrystalline form can be comminuted by HVPC. Commercial applications of HVPC to silicon are limited to the production of silicon for solar cell applications. Heretofore, HVPC has not gained acceptance in the production of silicon semiconductors because the HVPC method tends to contaminate crushed silicon particles with high concentrations of metal contaminants. These contaminants originate from the electrodes of the HVPC system. The contaminants make it difficult to clean the silicon particles to such an extent that they can be used for the production of silicon crystals and silicon wafers.Variations of these comminution techniques are practiced today to produce commercial bulks of high purity silicon particles. However, both manual and machine comminution result in undesirable variations in particle size and shape, particle surface area, contaminants and operating costs, each of which is inconvenient to meet the future need for silicon crystal growth for more cost effective high purity silicon particles of higher consistency.As mentioned above, high voltage pulse comminution has proved very successful for silicon rod or crystal comminution in the silicon solar industry, while the HVPC method has not been successful in the silicon semiconductor industry because of the contamination caused by the HVPC process. Therefore, the use of HVPC to produce semiconductor-grade particles has not been successful. However, the Applicant has unexpectedly discovered a novel process for the successful production of silicon particles which comprises high voltage pulse comminution and meets the high purity requirements of the semiconductor industry.When the silicon particles are formed, they are transported, typically via conveyor belts made of or coated with plastic / polymers, and to a sorting system that sorts the particles into a target size range by separating the particles that are too small and too large to correspond to the target size range. The sorting is generally done by conveying the silicon particles over screens of different opening sizes to separate out a range of particles corresponding to minimum and maximum particle sizes. The separated pieces are often inspected using a machine that passes the silicon pieces past a camera (e.g., CANTY Tiltizer, JM Canty, Inc., Buffalo, NY), images the particles, and then determines the particle size metrics such as distributions by linear dimensions (minimum length, maximum length), volume, and aspect ratio.The conveyor belts rub off the moving silicon particles, creating very small silicon particles (often referred to as "fines") and silicon dust. These small particles and dust do not produce silicon particles of the required size and are therefore waste, which makes the process more expensive. Moreover, since these fine silica particles and dusts are derived from the surface of the crushed silica particles, they often have a high degree of fouling. The fines and dust rub the plastic belts and produce carbon particles. The fine silicon particles, the dust and the carbon particles are deposited continuously on the conveyor belts and are transferred to the subsequent silicon particles moving on the conveyor belt, thereby further contaminating the silicon particles. This contamination of the silicon particles has metallic surface contaminants of up to 1000 ppbw and carbon contaminants of up to 300 ppbw. In order to keep these sources of contamination in hand, the manufacturing process must be interrupted regularly in order to clean and / or replace the conveyor belts, which increases the costs for the production of silicon particles.Another strategy for reducing surface contamination is to dissolve the impurities and / or the surface of the silicon using acid chemistry to reduce the level of impurities on the surface to the range of 1-100 ppta. Since both metallic and nonmetallic contaminants have adverse effects on the quality of the product in the production of high purity silicon, it is also advantageous to attempt to remove contaminants as they occur (i.e., during comminution). The usual method for cleaning the silicon pieces is cleaning with acidic chemical mixtures of HF / H 2 O 2 / HCl / HNO 3, such as HF / HNO 3 and / or HF / H 2 O 2 and / or H 2 O 2 / HCl, in order to dissolve the upper surface of the silicon and the impurities as well as fine silicon parts and dust. Carbon contaminants that cannot be dissolved by the silicon etchants can be rinsed from the silicon particles. After cleaning with acidic chemical mixtures, the silicon particles are rinsed with high purity deionized water, dried and packaged. The various comminution methods described above (peening, jaw crushing, high voltage pulse comminution) require a special cleaning strategy to free the silicon surface from metal and carbon contaminants to a level of 1-100 ppta.The impurities accumulated on the surface of the silicon particles are a major problem in the use of silicon in the CZ crystal growth method, and the manufacturers of silicon seek new and better ways to minimize surface contamination. Another strategy is to control the handling of the silicon by automation, i.e. no human being contacts the silicon after it has been loaded into the comminution process. Another strategy is to optimize the comminution process to minimize the surface area of the particles by controlling their size and shape with the aim of producing a particle with an aspect ratio of as much as possible one.Accordingly, there remains an urgent need for high purity silicon which meets the ever increasing demands of the semiconductor industry, as well as for new and improved processes for producing high purity silicon particulate materials.These limitations have provided an issue for the invention of an improved technology for the production of high purity silicon particles and have resulted in higher purity silicon particles.SUMMARY OF THE INVENTIONAn object of the present invention is to provide high purity silicon particles with very low impurities.Another object of the present invention is to provide a method for producing high purity silicon particles which enables low cost production of silicon crystals with very low levels of impurities.In one aspect, the present invention provides a crushing method capable of producing small particles having a low surface area and a rounded shape, and a cleaning method providing highly pure particulate silicon material. The inventors have discovered a method of grinding that consists in placing silicon in a clean room of at least ISO 7, typically a high purity (ppta) silicon rod, typically a high purity polycrystalline silicon rod, typically a high purity polycrystalline silicon rod produced by the Siemens process, in a process vessel filled with water, typically high purity deionized (DI) water, placing the process vessel in a high voltage pulse grinding system (HVPC), and grinding the rod into small silicon particles. The process vessel is mechanically emptied and rinsed with deionized water, the particles are mechanically conveyed onto a vibrating screen belt, and the pieces are sorted and separated on the vibrating screen belt in the presence of a shower of high purity deionized water. By showering / flushing the silicon particles with water, the dust is removed from the surface and wear of the conveyor is minimized. The sorted particles are divided into three groups. The sorted particles above the maximum target size are transferred into a post-processing step in which the particulate silicon material above the maximum target size is collected in a collecting container and then transferred back into the process container for further comminution in the high-voltage pulse grinder. The sorted particles below the minimum target size are disposed of as waste. The sorted particles within a target size window are mechanically collected in a perforated polymer basket and transported to an automatic cleaning and etching system.The inventors have discovered a method for cleaning the particulate material, wherein the cleaning occurs in a clean room area at ISO 6 or below, in which the vessel containing the particles is flushed by baths with optional cleaning in one or more optionally heated baths containing an caustic detergent and high purity (typically 18 Mohm-cm) deionized water having a pH > / = 10; flushing in one or more baths with high purity (typically 18 Mohm-cm) deionized water; Etching in one or more acid baths containing a mixture of one or more acids, e.g., HF (e.g., 49% by weight) / HNO 3( e.g., 68-77% by weight) to dissolve the top surface of the silicon particles and the impurity introduced during the comminution process; rinsing in one or more baths with high purity (typically 18 Mohm-cm) deionized water; optionally immersing in a mixture of ozone (e.g., 1-5% ozone) and high purity (typically 18 Mohm-cm) deionized water; and rinsing in a high temperature (e.g., > / = 20°C) and high purity (typically 18 Mohm-cm) deionized water bath.The polymeric basket containing the particles / platelets is dried in a drying chamber where a vacuum prevails to produce a reduced pressure, and dried in a second drying chamber with a heated (e.g., > / = 30° C.), high air flow and a relative air humidity (e.g., < / = 34%) to accelerate the drying process.The packaging steps, which take place in a clean room according to ISO 5 or in a clean room according to ISO 4, comprise the transfer of the high-purity silicon particles into polyethylene / polymer bags, the heat sealing of the bags, the labeling of the heat-sealed bags and the depositing of the heat-sealed bags in a box. After packaging, the high purity silicon particulate material is sampled in a pouch and can optionally be tested for surface contaminants.The process developed by the present invention has unexpectedly shown that the process can be used to produce particles of high purity silicon material having a controlled size range, very low aspect ratio, and very low surface and bulk impurities from iron, nickel, copper and carbon, which particles have high consistency and low variability.The high purity silicon particulate material comprises silicon particulate material having a polycrystalline structure; wherein the silicon particulate material has a particle size distribution in a range of greater than or equal to 3 mm and less than or equal to 75 mm; wherein the silicon particulate material has an average aspect ratio of less than or equal to 1.55; and wherein the silicon particulate material comprises combined surface contaminants and bulk contaminants that overall result in an iron impurity of less than or equal to 20 pptw, a total nickel impurity of less than or equal to 4 pptw, and a total copper impurity of less than or equal to 4 pptw.Validation of the surface metal impurity content is by methods such as that described in WO2016051761A1, which is incorporated herein by reference in its entirety. Therein, the dissolution of the surface of the silicon pieces with HF / HNO 3 and the preparation of a suitable sample for the examination with ICP-MS methods in graphite furnaces are described. Due to the very low impurities, the ICP-MS tests must have a minimum detection limit of at most 10 ppta, at most 1 ppta. The surface contaminant testing is performed in an ISO-4 clean room environment. The validation of the surface carbon is measured in a clean room environment according to ISO 5 or below with a LECO RC193 system. The total elemental impurity in the high purity particulate silicon material is determined by adding the bulk and surface area values for the particular element.When the high purity polycrystalline silicon particulate is used for growing a silicon crystal by the CZ method and the replenishment method, many consecutive large silicon crystals (diameter >200 mm and mass >350 kg) having very small impurities lower than that of the high purity silicon particulate as a starting material can be produced. The silicon crystals produced are useful for the production of silicon wafers having very low metal impurities lower than that of the high purity particulate silicon material.Other features and advantages of the present invention will become apparent from the following detailed description, examples and figures. It should be understood, however, that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description.BRIEF DESCRIPTION OF THE DRAWINGSThe following drawings form a part of the present specification and serve to further illustrate certain aspects of the present disclosure, the inventions of which may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments herein. FIG. 1 shows the historical process sequence for converting silicon rods produced by CVD into high-purity silicon particles. FIG. 2 shows the process flow currently being practiced for converting CVD silicon rods into high-purity silicon particles. FIG. 3 shows the process sequence according to the invention for converting silicon rods produced by CVD into high-purity silicon particles.DETAILED DESCRIPTION OF THE INVENTIONFor a better understanding of the present subject matter, reference is made to the following detailed description that forms a part of this disclosure. It is to be understood that this invention is not limited to the specific products, methods, conditions, or parameters described and / or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention as claimed.The object of this invention is to provide a method and material which satisfies the requirements of cost, consistency and purity in the production of high purity silicon particles which meet the current and future requirements for the production of silicon crystals and silicon wafers. The method according to the invention aims to eliminate the fluctuations and costs associated with manual and mechanical comminution and at the same time to minimize the concentrations of impurities in and on the silicon particles.Unless defined otherwise herein, scientific and technical terms used in connection with the present application have the meaning that is common to those skilled in the art. Unless the context requires otherwise, the singular includes the plurality and the plurality includes the singular.As used above and throughout the disclosure, and unless otherwise indicated, the following terms and abbreviations have the following meaning.PPMA stands for part per million atomic and refers to a concentration of impurity atoms defined as the ratio of the number of impurity atoms to the total atoms in the material and multiplied by 1E6 (i.e., 1,000,000 or 10 6).PPBA stands for part per billion atomic (part per billion atoms) and refers to a concentration of impurity atoms, which is defined as the ratio of the number of impurity atoms to the total atoms of the material and multiplied by 1E9(i.e., 1,000,000,000 or 10 9).PPTA stands for part per drilling atomic and refers to a concentration of impurity atoms defined as the ratio of the number of impurity atoms to the total number of atoms in the material and multiplied by 1E12 (i.e., 1,000,000,000,000 or 10 12).PPMW stands for part per million weight (parts per million weight) and refers to a concentration of impurity atoms, defined as the ratio of the weight of the impurity atoms to the total weight of the material, multiplied by 1E6(i.e., 1,000,000, or 10 6).PPBW is a weight part per billion and refers to a concentration of impurity atoms defined as the ratio of the weight of the impurity atoms to the total weight of the material and multiplied by 1E9(i.e., 1,000,000,000 or 10 9).PPTW stands for part per trillion weight (part per billion weight) and refers to a concentration of impurity atoms defined as the ratio of the weight of impurity atoms to the total weight of the material and multiplied by 1E12(i.e., 1,000,000,000,000 or 10 12).The particle size is the longest straight line between two points on the particle (e.g., for a sphere, the diameter is the particle size).The concentrations of silicon contaminants, such as the relative units of ppmw, ppbw, etc., are often stated in various units of the SEMI standards. The document SEMI AUX02 0611 Conversion of Units for Impurity Concentrations in Silicone is incorporated in its entirety by reference.The term "aspect ratio" is defined as the ratio between the longest and the shortest dimension measured on a particle. A sphere has an aspect ratio of 1. an ellipsoid may have an aspect ratio of greater than 1, e.g., 1.55.The ranges described herein include both the endpoints and all that are included therein. For example, range 7-20 includes both 7 and 20, and 8, 15, 17, 19, 6, etc. Moreover, the designation of a range, e.g., 7-20, also includes ranges within that range, e.g., 8-15, 9, 9-17, 4, etc.If the term "at least" stands in front of an ISO space number, then this ISO space number contains the highest permissible degree of contamination, e.g. "at least ISO 5" may be ISO 5, ISO 4, ISO 3, ISO 2 or ISO 1.Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.In the present disclosure, the singular forms "a", "an" and "the" include the plural form, and reference to a specific numerical value includes at least this specific value unless the context clearly indicates otherwise. For example, reference to "a material" is reference to one or more such materials and their equivalents known to those skilled in the art, etc. When a range of values is given, another embodiment encompasses the range from one particular and / or to the other particular value. When values are expressed as approximate values, it is expressed by using the prefix "about" that the determined value represents another embodiment. All ranges include the end points and can be combined.As mentioned above, the invention provides a method and material that satisfies the requirements of cost, constancy and purity in the production of high purity silicon particles that can be used to produce silicon crystals and silicon wafers.The object of this invention is achieved in one embodiment with the high purity silicon particulate material comprising silicon particulate material having a polycrystalline structure, wherein the silicon particulate material has a particle size distribution in a range of greater than or equal to 3 mm and less than or equal to 75 mm. The high purity particulate silicon material has a round or ellipsoidal shape, resulting in a low aspect ratio of the particles and a reduction in surface area. Silicon particles with a lower surface area reduce the inclusion of fines and dust contaminants, thus reducing the amount of contaminants added to the silicon particles during conveyance. The average aspect ratio of a collection of silicon particles is less than or equal to 1.55, and the total (combined surface and bulk) iron impurity is < / = 20 pptw, the total nickel impurity is < / = 4 pptw, and the total copper impurity is < / = 4 pptw.In various embodiments, the particulate silicon material may have bulk impurities of iron< / = 10 pptw, of nickel< / = 4 pptw, and of copper< / = 4 pptw; and the iron, nickel, and copper surface impurities on the particulate silicon material are evaluated by acid extraction and inductively coupled mass spectrometry (ICP-MS) analysis with minimum detection limits of < / = 4 pptw, e.g., less than 1 pptw. The silicon rod can be produced by the Siemens process.In some embodiments, the particulate silicon material is a product of a silicon rod made by the Siemens process.In certain embodiments, the particulate silicon material has bulk impurity levels of iron< / = 10 pptw, nickel< / = 4 pptw, and copper< / = 4 pptw.In another embodiment, the surface contaminants of iron, nickel and copper on the particulate silicon material are studied by acid extraction and inductively coupled mass spectrometry (ICP-MS) analysis.In various embodiments, the particulate silicon material is a product of a silicon rod made by the Siemens process and having a bulk impurity level of iron< / =10 pptw, nickel< / =4 pptw, and copper< / =4 pptw.In various embodiments, the particulate silicon material is a product of a silicon rod made by the Siemens process and having a bulk impurity level of iron< / = 10 pptw, nickel< / = 4 pptw, and copper< / = 4 pptw; and the iron, nickel, and copper surface impurities on the particulate silicon material are evaluated by acid extraction and inductively coupled mass spectrometry (ICP-MS) analysis.In some embodiments, the particulate silicon material is a product of a silicon rod made by the Siemens process and having a bulk impurity level of iron< / = 10 pptw, nickel< / = 4 pptw, and copper< / = 4 pptw; and the iron, nickel, and copper surface impurities on the particulate silicon material are evaluated by acid extraction and inductively coupled mass spectrometry (ICP-MS) analysis with minimum detection limits of < / = 4 pptw.In certain embodiments, the invention provides a product selected from an integrated circuit and a power device comprising a silicon wafer containing silicon particulate material of any of the foregoing embodiments or a combination thereof.In further embodiments, the invention provides a product selected from an integrated circuit and a power device fabricated from a wafer fabricated from the particulate silicon material of one or a combination of the foregoing embodiments.In various embodiments, the invention provides a monocrystalline silicon material comprising the particulate silicon material of one or a combination of the preceding embodiments.In certain embodiments, the invention provides a monocrystalline silicon material made from the particulate silicon material of one or a combination of the foregoing embodiments.In some embodiments, the invention provides a product selected from a silicon wafer, a solar cell, and a photovoltaic panel comprising the monocrystalline silicon material of any one or a combination of the foregoing embodiments.In certain embodiments, the invention provides a product selected from a silicon wafer, a solar cell, and a photovoltaic panel made from the monocrystalline silicon material of any one or a combination of the foregoing embodiments.In some embodiments, the invention provides a particulate silicon material of any one or a combination of the foregoing embodiments for use in an integrated circuit and / or a power device.In various embodiments, the invention provides a monocrystalline silicon material from one or a combination of the preceding embodiments for use in a silicon wafer, a solar cell and / or a photovoltaic panel.In certain embodiments, the invention provides a silicon material comprising the particulate silicon material of any one or a combination of the foregoing embodiments.In some embodiments, the invention provides a particulate silicon material for use in the manufacture of a silicon wafer, wherein the silicon wafer may be used for the manufacture of an integrated circuit and / or a power device.In various embodiments, the invention provides a monocrystalline silicon material for use in the production of a silicon crystal, wherein the silicon crystal can be used for the production of a silicon wafer serving for the production of a solar cell and / or a photovoltaic panel.A further aspect of the invention is the production of a fully automatic and contactless method for comminution, sorting, rinsing, cleaning and packaging of highly pure particulate silicon material from silicon rods, it being possible for the silicon rods to be produced by the Siemens CVD method. The term "contactless process" refers to an automated process flow in which a human need not grasp silicon during normal execution of the process flow.In one embodiment, the process flow of the method according to the invention is illustrated in FIG. 3.The process flow in FIG. 3 is divided into a series of processing areas or spaces that may be connected by vibration promoters. A silicon rod produced by a CVD method such as the Siemens CVD method is supplied into the first room, which is a clean room with particle control according to ISO 7. The silicon rod is broken down into particles by particle crushing methods such as the high voltage pulse crushing method (HVPC). In this comminution method, a silicon rod is completely immersed in a process container filled with high-purity deionised water. Metal electrodes are mounted near the top and bottom of the rod and a high voltage is generated across the electrodes causing an electric arc discharge. This discharge generates a high pressure shock wave in the vessel which decomposes the silicon rod into particles. The CVD rods must initially have a sufficiently low content of bulk impurities to meet the requirements of the semiconductor silicon crystal growth process and should therefore have bulk impurity values that meet the requirements of the silicon particles. Typical concentration values for bulk impurities are: iron< / = 10 pptw, nickel< / = 4 pptw and copper< / = 4 pptw.After comminution by high-voltage pulse comminution (HVPC), the particles are conveyed mechanically from the process container onto a conveyor belt in a clean room which is operated at least with particle control according to ISO 7 and do not come into contact with metallic materials. During transport on the conveyor belt, the discharged silicon particles from the process vessel are sprayed / rinsed with high purity (e.g., > / = 10-18 Mohm-cm) deionized water. The Applicant has unexpectedly found that the particles are kept wet from the process vessel by spraying / flushing the particles during transport, thereby removing fines and dust adhering to larger particles as well as other contaminants generated during comminution. Moreover, the applicant has unexpectedly found that spraying / flushing the particles to remove the contaminants makes the process more efficient and effective by preventing accumulation of contaminants on the conveyor that can rub off the conveyor and add carbon contaminants to the particles. In the next step, the particles are sorted into three groups to separate the excessively small and the excessively large pieces from the pieces whose size is in the target area. The sorting is done by conveying the silicon particles over vibrating solid polymer screens while spraying them with high purity deionized water. The Applicant has surprisingly found that spraying the particles during screening makes screening more effective because the water acts as a lubricant so that the particles do not rub the screens. The applicant's novel method of spraying the particles during transport and screening thus also minimizes the need to interrupt the process to clean and repair the damage caused by the accumulation of contaminants.After screening, the sub-target size silicon particles are removed from the process stream, the sub-target size silicon particles are collected in a solid polymer collection vessel. The oversized particles are collected in a solid polymer collection container and finally returned to the HVPC comminution step for comminution.The silicon particles within the target size window are separated off by known methods. In this embodiment, the silicon particles are transported via a conveyor belt to a step in which they are loaded into perforated solid polymer baskets. The baskets with the silicon particles are fed to a wet cleaning plant where they pass through separate cleaning baths to remove surface contaminants. The wet cleaning system is operated in a separate clean room which ensures at least the particle control according to ISO 6.The wet cleaning system comprises the following steps:The basket containing the silicon particles is optionally immersed in one or more vessels containing baths containing an caustic detergent (i.e., any detergent formulation having a pH > / = 10) and high purity deionized water, wherein the bath or baths can optionally be heated to a temperature > / = 20°C, e.g., between 20°C and 90°C, or between 20°C and 40°C. The heated water accelerates the cleaning action and permits more rapid cleaning of the particulate silicon material. During the high-voltage pulse comminution, very fine silicon dust is produced from the comminution of the silicon rod and iron dust from the erosion of the electrode as a result of the arc discharge, both of which dust are embedded in the water of the process container. It is also known that arc discharge generates ozone and hydrogen peroxide in water. The ozone and hydrogen peroxide lead to hydrolysis reactions with the iron and silicon particles and form a polymer. The iron-oxygen-silicon hydroxide polymers deposit as an impurity on the surface of the larger silicon particles in the process vessel. The polymer surrounds the silicon particles and the presence of the polymer inhibits the etching of the silicon particles by acids. Thus, the Anmeldin has unexpectedly found that flushing the particles in caustic detergent in the HVPC process is particularly useful because it breaks bonds of the polymeric material and thus allows some of the iron to be removed from the particles before the particles enter the acid bath and allow the silicon particles to react with the acid. Although the level of iron contamination has long been a factor known to degrade the quality of silicon particles, prior HVPC processes for producing high purity silicon particles have not successfully resulted in the removal of the iron contaminants to achieve the low level of iron contamination in the silicon particles that applicant has reached.The basket with the silicon particles is immersed in one or more vessels containing a mixture of nitric acid (e.g., 70% w / w) and hydrofluoric acid (e.g., 49% w / w). By this step, the surface of the silicon particles is etched and the impurities are emitted from the surface of the silicon particles into the acid.The basket containing the silicon particles is immersed in one or more vessels filled with high purity deionized water, typically 18 Mohm-cm, to remove any acid from the previous cleaning steps.The basket containing the silicon particles is optionally immersed in a vessel containing a mixture of high purity deionized water, typically 18 Mohm-cm, and 1-5% ozone. The ozone coats the particles to form a silicon oxide film that makes the surface of the silicon particles hydrophilic. This step inhibits the attraction of new particles to the silicon particles.The basket containing the silicon particles is immersed in a vessel filled with high purity deionized water (typically 18 Mohm-cm) that is heated to a temperature of at least 20°C, e.g., in the range of 50-80°C. The hot water heats the polysilicon, so that the drying step is more efficient.After the cleaning steps, the basket with the silicon particles is conveyed into a drying chamber. The drying process consists of a first chamber in which the pressure is reduced to a vacuum sufficient to evaporate water from the surface of the particles. The basket with the particles is then conveyed via a conveyor belt into a second chamber, in which the particles are exposed to heated dry air at high speed (forced) to assist in evaporation. A relative air humidity of < / =34% and an air temperature of > / =30° C. prevail in this chamber, both of which support the drying process for productivity reasons. The drying process is carried out in a clean room which is subjected at least to the particle control according to ISO 6 in order to control the level of the particles and to reduce the contamination.Following the cleaning process, the basket with the high-purity silicon particles is brought into another clean room in which at least one particle control according to ISO 5 is carried out. The basket is emptied into a collecting container. A bag, typically a polyethylene bag, is placed under the collection vessel. The bag is filled with a target weight of silicon particles (e.g., 5 kg + / - 50 g) and sealed with a heat sealer. A label containing the product information is applied to the bag in a contactless manner. Optionally, the pouch containing the silicon particles is placed in a second pouch, the pouch is sealed and then also labeled. A robot removes the bag and places it on a conveyor belt where it is then transferred by another robot into a box.In certain embodiments, a method of making a particulate silicon material comprises crushing silicon to produce particulate silicon material and cleaning the surface of the particulate silicon material, wherein the cleaning comprises dipping a perforated polymeric basket containing the particulate silicon material into separate baths comprising: optionally dipping into one or more vessels containing a mixture comprising an caustic cleaning agent and high purity deionized water at a pH greater than or equal to 10; dipping into one or more vessels containing a mixture comprising one or more acids; dipping into one or more vessels containing high purity deionized water; optionally dipping into a vessel containing a mixture comprising ozone and high purity deionized water; and immersed in one or more vessels containing high purity deionized water at a temperature greater than 20°C.In some embodiments, the method of manufacturing a silicon particulate material further comprises transferring the silicon particulate material to a vibrating screen belt.In various embodiments, the method of making a particulate silicon material further comprises rinsing the particulate silicon material with high purity deionized water and simultaneously sorting the particulate silicon material over a vibrating screen belt, wherein the particulate silicon material is screened in material 1) below the minimum target size, 2) within the target size window, and 3) above the maximum target size.In some embodiments, the method of making a particulate silicon material further comprises transferring the particulate silicon material below the minimum target size to a collection vessel, transferring the particulate silicon material above the maximum target size to a holding vessel, and transferring the particulate silicon material within the target size window in batches of predefined amounts to perforated polymer baskets.In various embodiments, the cleaning steps comprise immersing the basket containing the silicon particles in one or more vessels containing a mixture of one or more acids, in one or more vessels filled with high purity deionized water, and in a vessel filled with high purity deionized water, optionally heated to a temperature of 20° C. or more.In some embodiments, the cleaning steps comprise dipping the basket containing the silicon particles into one or more optionally heated baths of caustic cleaning agent, into one or more vessels containing a mixture of one or more acids, into one or more vessels filled with high purity deionized water, and into a vessel filled with high purity deionized water, which is optionally heated to a temperature of 20°C or more.In certain embodiments, the cleaning steps comprise immersing the basket containing the silicon particles in one or more optionally heated baths of caustic cleaning agent, in one or more vessels containing a mixture of one or more acids, in one or more vessels filled with high purity deionized water, in a vessel containing a mixture of high purity deionized water and 1-5% ozone, and in a vessel filled with high purity deionized water optionally heated to a temperature of 20°C or more.In various embodiments, the cleaning steps comprise immersing the basket containing the silicon particles in one or more vessels containing a mixture of one or more acids, in one or more vessels filled with high purity deionized water, in a vessel containing a mixture of high purity deionized water and 1-5% ozone, and in a vessel filled with high purity deionized water that is optionally heated to a temperature of 20° C. or more.In some embodiments, the method of making a particulate silicon material further comprises drying the particulate silicon material in a vacuum chamber.In various embodiments, the method of making a particulate silicon material further comprises drying the particulate silicon material in a vacuum chamber at subatmospheric pressure.In certain embodiments, the method of making a particulate silicon material further comprises drying the particulate silicon material in a chamber with a vacuum sufficient to evaporate water from the surface of the particles.In various embodiments, the method of making a particulate silicon material further comprises drying the particulate silicon material in a chamber with blower air supplied with controlled relative humidity and controlled air temperature.In some embodiments, the silicon is polycrystalline silicon.In various embodiments, the polycrystalline silicon is a polycrystalline silicon rod.In certain embodiments, the polycrystalline silicon rod is a Siemens-made polycrystalline silicon rod.In some cases, the silicon is monocrystalline silicon.In various embodiments, the comminution is effected by high-voltage pulse comminution (HVPC).In certain embodiments, the comminution takes place in a process container.In various embodiments, the silicon rod is partially immersed in a process vessel filled with high purity deionized water.In some embodiments, the high purity deionized water is > / =16 Mohm-cm high purity deionized water.In some embodiments, the high purity deionized water is > / =18 Mohm-cm high purity deionized water.In certain embodiments, the temperature of the high purity deionized water is > / = 20°C.In some embodiments, the temperature of the high purity deionized water is > / = 20°C, e.g., in the range of 50-80°C.In various embodiments, the mixture containing one or more acids comprises one or more of the following acids: nitric acid, hydrofluoric acid, hydrogen peroxide and / or hydrochloric acid.In certain embodiments, the mixture of one or more acids comprises nitric acid and hydrofluoric acid.In some embodiments, the mixture of one or more acids comprises nitric acid (e.g., 68-77% w / w) and hydrofluoric acid (e.g., 49% w / w).In certain embodiments, the mixture of one or more acids comprises nitric acid (e.g., 68-70% w / w) and hydrofluoric acid (e.g., 49% w / w).In various embodiments, the process is carried out in a consecutive series of clean rooms operating in the range of ISO 7 to ISO 1.In some embodiments, the process is carried out in a series of successive clean rooms operating in the range of ISO 7 to ISO 4.In certain embodiments, the relative humidity in the drying chamber is < / =34%.In various embodiments, the air temperature in the drying chamber is > / = 30° C.In some embodiments, the method further comprises subjecting the silicon particulate material above the maximum target size accumulated in the holding vessel to post-processing steps, the post-processing steps comprising: transferring the silicon particulate material above the maximum target size to a crushing station; and crushing the silicon particulate material above the maximum target size.In various embodiments, the comminution station may be a process container.In certain embodiments, the method further comprises transferring the dried silicon particulate material into a pouch of polymeric material, heat sealing the pouch, labeling the heat sealed pouch, and placing the heat sealed and labeled pouch in a carton.In various embodiments, the method further comprises manufacturing an integrated circuit and / or a power device from a wafer made from a crystalline silicon block made of the particulate silicon material.In some embodiments, the method further comprises preparing a monocrystalline silicon material from the particulate silicon material.In certain embodiments, the method further comprises preparing a monocrystalline silicon material according to the Czochralski (CZ) crystal growth method.In various embodiments, the method further comprises the production of a silicon wafer, a solar cell and / or a photovoltaic panel from monocrystalline silicon material.In some embodiments, a particulate silicon material is produced by the method of any of the above embodiments.The accuracy of the process can be evaluated offline for quality control. For example, a bag of silicon particles is removed from a carton. The contents of the bag are checked for surface contaminants and particle size distribution. Validation of the surface metal impurity content is done by methods such as that described in ASTM 1724-96, in which the surface of the silicon particles is dissolved with HF / HNO 3- mixtures and a suitable sample is prepared for testing with a graphite furnace (GFAAS), or alternatively with ICP-MS methods. The surface contaminants are tested in a clean room environment which corresponds at least to the particle control according to ISO 4. Because of the very low impurities, the surface tests must have a minimum detection limit of < / =4 pptw.The surface impurity testing can be repeatedly performed on the same sample, and after sufficient repetition of the surface etching, the measured impurities should not change, so that the values are representative of the concentration of the impurities in the mass of the particles.Surface carbon validation is measured in an ISO-5 clean room environment with a LECO RC193 system (LECO Corporation, 3000 Lakeview Ave., St. Joseph, MI 49085).To confirm that the particles conform to the desired size range, samples of the particles are tested using a machine that passes the silicon particles past a camera (e.g., Canty Tiltizer, JM Canty, Inc., Buffalo, NY) that images particles and then determines the particle size metrics such as distributions according to linear dimensions (minimum length, maximum length), volume, and aspect ratio.The distribution of the particles can be evaluated with a camera-based particle sorting system, which can determine the largest and smallest linear dimensions of the particles and can calculate the aspect ratio on the basis of these data:Aspect ratio = maximum linear dimension / minimum linear dimension.Unexpectedly, the HVPC comminution method results in silicon particles with a lower aspect ratio compared to comminution methods such as human hammer or mechanical comminution. In order to provide high-purity silicon particles which meet the ever-increasing requirements of the semiconductor industry, new and improved methods for producing high-purity silicon particles are required.In addition, the Applicant has unexpectedly discovered that the process of the present invention can be used to produce particles of high purity silicon material having a controlled size range and very low aspect ratio, high consistency and low variability, and with very low surface contaminants comprising iron, nickel, copper and carbon.This method of the invention minimizes additional contamination of the silicon by an automated process in which no human contacts the silicon rod once it is delivered to feed the comminution process. Preferably, grinding methods are used in which the silicon is ground in high purity water and then kept moist during conveyance and sorting and until automatic loading into baskets for etching. To ensure the highest contamination control, the automated process is carried out in increasingly controlled clean room environments, starting with a control of at least ISO 7 during comminution and up to a control of at least ISO 5 during packaging in bags.In addition, this method minimizes the additional contamination of the silicon, since no rods with mechanical contact or particle comminution are used. During the comminution of silicon, the silicon material can come into contact with other materials, in particular with metallic materials, and absorb metallic impurities which contaminate the silicon material. Manual comminution with hammers can not only result in pieces of different size distribution but also entail additional impurities (iron, tungsten, cobalt) on the surface of the silicon material. Roller crushers and jaw crushers can also contribute to undesired metallic impurities on the surface of the silicon material. In this method, since the high voltage pulse crushing does not require mechanical contact with impact or crushing surfaces which are liable to be torn and adhered to the silicon particles, the silicon is less likely to be contaminated with such materials.EXAMPLESThe following examples serve to better illustrate certain embodiments of the invention. However, they should not be construed as limiting the broad scope of the invention in any way.Example 1: Preparation of Silicon Particulate MaterialSilicon (polysilicon) rods having diameters of 125-145 mm were prepared by first removing the carbon ends with the graphite bases (125-150 mm from each leg) by hand and then separating the bridge portion connecting the two legs with a tungsten carbide hammer. The two legs were then broken to a length of 750-900 mm approximately half. Each leg section was placed in a rectangular polymer process vessel filled with deionized water and then individually processed in a HVPC line with the following parameters: voltage of 180-190 kV, frequency of 3-5 Hz, speed of 6-12 mm / s, and water gap of 25 mm. After the HVPC treatment, most of the process water was drained from the process vessel. The crushed silicon particles were then manually removed and manually sorted using a bullseye sort map for the upper limit of 65 mm and a 20 mm round hole hand screen for the lower limit. The sorted silicon particles were then either air dried or wet packaged.After sorting the material to collect the particles in the desired size range, the material was divided into 5 kg batches. The contents of a 5 kg bag were used to fill a perforated polymeric basket. Selected 5 kg samples were then subjected to various purification procedures (see Table 1). Selected samples were chemically cleaned in an caustic cleaner having a pH of 12 and then agitated in multiple baths with deionized water. Selected samples were etched in a solution of 6 parts 70% HNO 3 to 1 part 49% HF. After chemical cleaning, all samples were rinsed in 18 Mohm-cm deionized water and dried. For surface contamination testing, a 10 mm chip was taken from the etched sample and tested according to the general method of WO2016051761A1 (fully incorporated herein) to determine surface metal concentrations using ICP-MS. Surface metal contamination was determined by etching the 10 mm sample with a mixture of HNO 3 / HF for a period of time resulting in a 5 μm etch on a polished crystalline silicon wafer. Metal contamination was determined by etching the 10 mm sample with a mixture of HNO 3 / HF for a period of time resulting in a 25 μm etch on a polished crystalline silicon wafer. After etching, the sample is removed, the acid evaporated, the residue reconstituted and then assayed by ICP-MS. The detection limit for the contamination tests was <4 pptw. TABLE 1 - Contamination Level of Silicon Particles with and without Acid Etch TABLE 1 - Contamination Level of Silicon Particles with and without Acid EtchNo clean5Surface Surface Surface7900k.A.k.A.Immersion in caustic detergents, not acid etching5Surface Surface Surface3800<4<4Immersion in caustic detergents, not acid etching25Bulk6.6<4<4Immersion in caustic detergents, not acid etchingOverall, the total is3806<4<4Acid Only Etching5Surface Surface Surface13<4<4Acid Only Etching25Bulk<4<4<4Acid Only EtchingIntegrated mt<17<4<4Immersion in an caustic cleaner, then acidic etching5Surface Surface Surface12<4<4Immersion in an caustic cleaner, then acidic etching25Bulk<4<4<4Immersion in an caustic cleaner, then acidic etchingOverall, the total is<16<4<4Example 2: Comparative ExampleSamples of silicon particles were prepared in a similar manner to Example 1, except that instead of HVPC comminution was performed with a) a tungsten carbide manual hammer and b) a tungsten carbide manual hammer followed by a tungsten carbide roller breaker, and then washed with a solution of deionized water containing 1% HF and H 2 O 2. The resulting surface and bulk metal contamination was examined using the sample methods described in Example 1. TABLE 2 - Contamination level of the particulate silicon material depending on the crushing process and the washing agent used TABLE 2 - Contamination level of the particulate silicon material depending on the crushing process and the washing agent usedHammer5Surface Surface Surface130<4<4Hammer15Bulk<4<4<4HammerOverall, the total is<134<4<4Hemmer, Crush, Wash acids5Surface Surface Surface18<4<4Hemmer, Crush, Wash acids15Bulk5<4<4Hemmer, Crush, Wash acidsOverall, the total is23<4<4Example 3: Preparation of Particulate Silicon MaterialSilicon rods having diameters of 127-144 mm were prepared for HVPC comminution by first removing the carbon ends with the graphite bases (125-150 mm from each leg) manually with a tungsten carbide hammer. The bridge member connecting the two legs was then broken approximately midway. One leg and half of the bridge were loaded into the process vessel by means of a vacuum lifter. The length of the leg and half bridge was between 1775 and 1900 mm. The maximum permissible length in the process vessel was 2,100 mm. Each leg and half bridge portion was individually processed in the HVPC process vessel with the following parameters: voltage of 175-200 kV, frequency of 3-5 Hz, speed of 10-15 mm / s, and water gap of 15-25 mm. The resistance of the deionized process water was between 17 and 18 mohm-cm. After the HVPC treatment, most of the process water was drained from the process vessel. The HVPC silicon particles were sorted with a vibratory separator using two sets of perforated polyurethane screens to obtain a particle size range of 8-65 mm (maximum length). The sorted silicon particles were then spread on polyurethane sheets and air dried with a fan.After the sorting, the HVPC particles were divided into 5 kg batches. Five bags were characterized with a CANTY Tiltsizer to measure the aspect ratio of the silicon particles. Five samples of commercially available silicon particles crushed with a roller or jaw crusher were also characterized with a CANTY Titsizer to measure the aspect ratio of the silicon particles. TABLE 3 - Measurement of the aspect ratio of silicon particles after HVPC or mechanical comminution TABLE 3 - Measurement of the aspect ratio of silicon particles after HVPC or mechanical comminutionHVPC 11,560,461,57HVPC 21,550,42HVPC 31,540,41HVPC 41,570,48HVPC 51,530,38Average Average1,55Roller / Jaw Crusher 11,670,561,67Roller / Jaw Crusher 21,570,46Roller / Jaw Crusher 31,620,48Roller / jaw crusher 41,550,43Roller / Jaw Crusher 51,520,39Average Average1,59While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will occur to those skilled in the art that are conventional in the art. It is therefore to be understood that the appended claims are intended to cover all modifications and changes which come within the true spirit of the invention.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Cited Non-Patent LiteraturePorrini, M., et al., Solid State Phenomena, Vols. 108-109 (2005), pp. 591-596

[0009] CANTY Tiltizer, JM Canty, Inc., Buffalo, NY

[0019] Canty Tiltizer, JM Canty, Inc., Buffalo, NY

[0129]

Claims

A method of making a particulate silicon material comprising: a) crushing silicon to produce silicon particles; and b) rinsing the particulate silicon material with deionized water; c) cleaning a surface of the particulate silicon material, wherein the cleaning comprises dipping a perforated polymeric basket containing the particulate silicon material into separate baths: i) optionally dipping into one or more vessels containing a mixture of caustic detergent and high purity deionized water having a pH of 10 or more; ii) dipping into one or more vessels with a mixture of one or more acids; iii) dipping into one or more vessels with high purity deionized water; iv) optionally dipping into a vessel containing a mixture of ozone and high purity deionized water; and v) immersion in one or more vessels of high purity deionized water at a temperature of at least 20°C.The method of claim 1, wherein the silicon particulate material is transferred to a vibrating screen belt.The method of claim 2, further comprising sorting the silicon particulate material via the vibratory screen conveyor, wherein the screening separates the silicon particulate material into three groups, the three groups 1 ) being below the minimum target size, 2 being within a target size window, and 3 being above the maximum target size.The method of claim 3, further comprising transferring the silicon particulate material below the minimum target size into a collection vessel, the silicon particulate material above the maximum target size into a holding vessel, and the silicon particulate material within the target size window in batches of predefined amounts into perforated polymer baskets.The method of claim 1, further comprising drying the wet particulate silicon material in a chamber in which a vacuum is applied to create a pressure below atmospheric pressure.The method of claim 1, further comprising drying the particulate silicon material in a chamber with blower air supplied with controlled relative humidity and controlled air temperature.The method of claim 1, wherein the silicon is polycrystalline silicon.The method of claim 7, wherein the polycrystalline silicon is a polycrystalline silicon rod.The method of claim 8, wherein the polycrystalline silicon rod is a Siemens polycrystalline silicon rod.Method according to claim 1, wherein the comminution is carried out using high-voltage pulse comminution (HVPC).The method of claim 1, wherein the mixture contains nitric acid and hydrofluoric acid.The process according to claim 1, wherein the process is carried out in clean rooms operating in the range of ISO 7 to ISO 1.The process according to claim 1, wherein the process is carried out in clean rooms operating in the range of ISO 7 to ISO 4.The method of claim 6, wherein the relative humidity in the drying chamber is less than or equal to 34%.The method of claim 6, wherein the air temperature in the drying chamber is greater than or equal to 30°C.The method of claim 4, further comprising subjecting the particulate silicon material above the maximum target size accumulated in the holding container to post-processing steps, the post-processing steps comprising: i) delivering the particulate silicon material above the maximum target size to a crushing station; and ii) crushing the particulate silicon material from step i.The method of claim 1, further comprising: a) transferring the particulate silicon material into a pouch of polymeric material; b) heat sealing the pouch; c) labeling the heat sealed pouch; and d) placing the heat sealed and labeled pouch in a carton.The method of claim 1, further comprising fabricating an integrated circuit and / or a power device from a wafer made from a crystalline silicon block comprised of the particulate silicon material.A silicon material produced by the method of claim 1.A particulate silicon material comprising: a) a polycrystalline structure; and b) a particle size distribution in a range of greater than or equal to 3 mm and less than or equal to 75 mm; and c) an average aspect ratio of 1.55 or less; and d) combined surface impurity and bulk impurity of a total of less than or equal to 20 pptw iron impurity, a total of less than or equal to 4 pptw nickel impurity, and a total of less than or equal to 4 pptw copper impurity.The particulate silicon material of claim 20, wherein the particulate silicon material has bulk impurities of iron of less than or equal to 10 pptw, total nickel impurity of less than or equal to 4 pptw, and copper of less than or equal to 4 pptw nickel.The particulate silicon material of claim 20, wherein the particulate silicon material is a product of a polycrystalline silicon rod according to the Siemens processThe particulate silicon material of claim 20, wherein the iron, nickel and copper surface contamination in the particulate silicon material is evaluated using acid dissolution and ICP-MS.A product selected from an integrated circuit and a power device comprising a silicon wafer comprising the particulate silicon material of claim 20.A product selected from an integrated circuit and a power device fabricated from a wafer fabricated from the particulate silicon material of claim 20.A silicon material comprising the particulate silicon material of claim 20.The particulate silicon material of claim 20 for use in the manufacture of a silicon wafer, wherein the silicon wafer is usable for the manufacture of an integrated circuit and / or a power device.

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