DE3000802A1 - Silicon prodn. by decomposition or redn. of silicon cpd. in plasma - produced in carrier gas stream gives pure silicon at very low cost - Google Patents

Abstract

In Si prodn., a plasma (3) is produced in a gas stream (1) and a Si cpd. (2) is introduced. This is then decomposed or reduced to Si, which is transported away from the plasma by the gas stream. The plasma is pref. produced with a d.c. or a.c. current or by absorption of intensive electromagnetic or ionising radiation in the gas stream. The Si can be deposited on a substrate, pref. of monocrystalline Si, a metal, an insulator, an inert liq. e.g. liq. MgC12 or Pb at 750 deg.C, or a heated substrate (e.g. graphite or ceramic at 1000 deg. C) covered with a thin film of inert liq. e.g. NaF or Sn. Deposition is carried out in an 02-free atmos. opt. in vacuo. The plasma spraying equipment may have a gas- or water-stabilised plasma. The gas stream consists of H2, noble gas, N2, hydrocarbon, C0and/or steam, whilst the Si cpd. can be an O-free cpd., e.g. SiH4, SiCl4, SiHCl3, SiH2Cl2 etc. or a cpd. contg. 0, e.g. SiO2, a silicate or an organo-Si cpd. Gp. III or gp. V dopants can be added to the gas stream. Specified combinations of gas and Si cpd. are H2 and Si chloride; noble gas or H2 and silane; H2 and SiO2; or a mixt. of noble gas or H2 and a hydrocarbon cpd. and SiO2. The process is specified for the prodn. of mono- or polycrystalline Si, pref. wafers, Si solar cells, Si transistors with p- and n-zones and pn-junctiions, Si power and silicides by further reaction of the Si formed in the plasma. Pure Si is produced at very low cost.

Description

Process for the production of silicon

The element silicon is used to a considerable extent as an alloy additive in metallurgy and in very pure form in increasing quantities in the semiconductor industry consumed. The need for silicon for the production of solar cells for direct The use of solar energy will increase sharply in the future.

After oxygen, silicon is the most abundant in the earth's crust occurring element. It is - bound in quartz, in silicates, but also in many other minerals - present practically everywhere.

The technical representation of silicon is based on quartz sand, for example from that by coal or by metals like aluminum, magne # ium or sodium Silicon can be reduced. For the semiconductor industry this is raw silicon cleaned and, for example, converted to SiC14 with the help of chlorine gas at an elevated temperature. SiCl4 allows further purification by fractional distillation.

By pyrolysis, i.e. by decomposing e.g. a mixture of H2 and SiCI, for example on a hot silicon rod, allows elemental silicon to be very pure win in policrystalline form. By so-called "single pulling" or ~ crucible pulling " the polycrystalline silicon can be converted into monocrystalline rods. "Endowed", i.e. silicon single crystal rods provided with targeted impurities become Sawed up slices. These are the most important raw material for the Haloieiter industry, Pol ikristal 1 ne silicon wafers can also be used for silicon solar cells whose manufacturing costs are significantly lower than the manufacturing costs of Single crystal disks.

Even lower manufacturing costs can be expected from 5 i 1 icon solar cells, where only a thin silicon film on a suitable carrier, for example by pyrolytic Decomposition of a suitable silicon compound such as SiH4 is generated.

All known processes for the production of silicon, silicon wafers or have silicon layers specially designed for the production of cheap Solar cells with high efficiency still have two disadvantages: 1. Silicon wafers. or - Layers of sufficiently pure silicon with good crystal quality are still there relatively expensive and 2. are sufficiently cheap wafers or layers made of silicon their quality is usually not sufficient for good solar cells.

These disadvantages arise from the fact that after the reduction of the Silicon too many subsequent processing steps up to the silicon wafer or -Shift are necessary. On the other hand, there are also the processes of purification and reduction policrystalline silicon processes are relatively complex. Liquid silicon is in addition, a material that requires a lot of energy and material and which by practically all materials with which it is at high temperature mechanical contact has contaminated (e.g. crucible or substrate materials) will.

The present invention aims to keep silicon as low as possible Generate costs. It solves this problem in that a gas flow is provided is that a plasma is generated in this gas flow, that means are provided, through which the gas flow is loaded with at least one silicon compound, that in the plasma of the gas stream the silicon compound to silicon is decomposed or reduced, and that the silicon together with the reaction products is transported out of the plasma by the gas flow. That through the gas stream Silicon transported away can be deposited on a Sud'trat as a cohesive layer or precipitated or deposited as a solid crystal. However, it can also condense as a powder and be deposited.

A plasma can be generated in a gas stream e.g. by An electric arc burns in the gas flow between cooled electrodes. -This creates an arc plasma in the gas flow. The electric plasma in the However, gas flow can also be generated by using a suitable electromagnetic Alternating field is applied to the gas stream. If the gas flow is e.g. A high-frequency coil is led in an enclosed space, an induction plasma can be generated in gas electricity. Also by absorbing electromagnetic radiation high intensity, e.g. LASER radiation, or very intense ionizing radiation E.g. c ~ or # radiation, a plasma can be generated in the gas flow.

The manufacturing process is particularly simple and easy to use Carry out technical of silicon according to the invention, if a so-called.

Plasma spray system (also plasma flame, plasma spray, plasma jet or plasma powder welding system) is used. Such systems for plasma spraying and plasma build-up welding of metallic and ceramic Materials are available in the market. In the case of a plasma spray system with "gas-stabilized" Plasma is in a chamber between a z. B. thoriated Wolfram-Kathoje and a water-cooled nozzle as / anode creates a direct current arc that passes through a gas stream e.g. from H2 gas - is propelled through the nozzle. The outer one The rapid gas jacket of the gas stream keeps the arc from the cooled nozzle wall distant, while the central one is slower Hydrogen gas in plasma is converted. As the distance from the cathode increases, the flow becomes slower Plasma core of the gas stream mixed with the outer fast gas jacket and through the reversing arc in the direction is additionally heated, so that the entire gas flow heats up and forms an elongated plasma. Be in the plasma Temperatures of up to 30,000 C reached. You blow a metal or ceramic powder into it the gas flow, then this is heated well above its melting point and at a higher rate Speed (e.g. a few 100 meters per second) applied to a workpiece.

In plasma powder build-up welding, a constricted arc burns between a water-cooled electrode and the workpiece to be coated. That Powder to be applied is fed into the arc in precisely dosed quantities and melted into the surface of the workpiece. Extreme electrical performances in plasma and orders of magnitude higher order rates are achieved when using achieved by plasma spray systems with "water-stabilized" plasma. The stabilization and the arc is constricted by water.

The gas stream consists of water plasma, which the electric arc consists of Self-produced water.

Plasma spray systems of the type described can be used directly or after relatively minor modification for the production of silicon according to FIG Use invention.

By U.S. Patent No. 4,003,770 of 1 ~ 5. It is already January 1977 known, p- or n-doped silicon particles by injection in a plasma beam heat up and deposit on a substrate as a policrystalline film. That However, silicon becomes the plasma beam in its elementary and doped form fed. A generation of elemental silicon by decomposition or reduction a silicon compound in plasma is not disclosed in this patent.

The gas flow through the arc consists of a plasma spray system according to the invention preferably from hydrogen, noble gas, nitrogen, halogen, hydrocarbon, Carbon monoxide, water vapor, or a mixture or combination of these gases.

The silicon compound with which the gas stream is loaded can be an oxygen-free compound, such as SiH4, SiCl4, SiHCl31, SiH2Cl2 or You can use a different hydrogen, halogen or hydrogen-halogen compound but also an oxygen-containing compound of silicon such as Sir2 Silicate or an organic or silicon-organic compound. At temperatures above 2000 C, SiO2 is reduced to silicon by hydrogen.

In addition to the silicon compound, the gas flow can also contain a dopant for silicon e.g. from the third or fifth group of the periodic table of Elements are mixed in. By adding B, Al, Ga, In or beryllium or also of chemical compounds of these elements such as B2H6, AlCl3 etc. The silicon can be deposited in a defined quantity in a p-doped manner.

Defined admixtures of P, As, Sb or vanadium or else of connections of these elements like e.g. PH3, Asc3, VC14 etc. allow the To deposit silicon doped n-doped.

According to the invention, the gas flow can also contain silicon powder particles be loaded to z. B. the nucleation speed for the reduced silicon or to increase the amount of silicon deposited.

The gas flow can, however, also contain carbon powder particles loaded, e.g. to increase the reducing effect of the gas flow.

In a preferred embodiment of the invention, there is Gas stream from hydrogen and the silicon compound from silicon tetrachloride, or a halosilane.

In another preferred embodiment, there is gas flow from noble gas or hydrogen and as a silicon compound is silicon hydrogen (Silane such as SiH4, Si2H6 etc.) is used.

In a further preferred embodiment there is the gas flow from hydrogen and the silicon compound is SiC2 e.g. in powder form.

However, according to the invention, the gas stream can also consist of a mixture of Noble gas with a hydrocarbon compound or a mixture of hydrogen with a hydrocarbon compound, while the silicon compound SiO2 powder or silicate powder.

The SiO2 powder or the silicate powder can also be used Be added carbon powder particles.

The gas stream can also consist of noble gas, nitrogen or carbon monoxide exist, and the silicon compound (e.g. SiO2 or a silicate) can be other Chemicals (such as a metal powder) must be added.

The silicon produced according to the invention can be on a monocrystalline Silicon surface can be deposited or deposited.

If the temperature of the silicon surface is high enough, it can deposited or precipitated silicon single crystal in grow up.

However, the silicon can also be placed on a metallically conductive surface, e.g. on a metal surface or on a metallically conductive one layer being isolated or dejected.

Also on an insulator surface, e.g. on ceramic, glass or organic Material can be applied to the silicon. Since the plasma cools down very quickly, leave it Conditions arise for the precipitation or deposition of the silicon, where the collecting surface is not heated to more than 200 ° C.

According to the invention, the silicon can also be applied to a liquid surface precipitate that does not chemically react with the silicon, such as external liquid MgCl2 or lead at around 750 ° C.

Also on a heated carrier (such as graphite at 1000 ° C), the is covered with a liquid film (e.g. from NaF), the silicon deposit. Silicon layers are obtained, which are monocrystalline in larger areas are.

In a preferred embodiment, the silicon is on a metallically conductive liquid surface or on a metallically conductive Liquid film deposited. As metals that are with the silicon also in liquid Phase do not react, tin, lead, zinc, bismuth, cadmium are particularly suitable, Thallium, mercury, gallium, indium and antimony and mixtures of these elements.

When depositing the silicon on a substrate, which is in an oxygen-free atmosphere, one obtains oxide-free silicon.

According to the invention, it is also advantageous to use the plasma and the gas' to blow electricity into a room with strong negative pressure or into a vacuum. Leave it at that gas speeds up to a multiple of the shell speed can be achieved. A deposition of the silicon according to the invention in an oxygen-free vacuum results Oxide-free compact silicon of particularly good crystal quality itat.

The method according to the invention is suitable for inexpensive Production of monocrystalline and polycrystalline silicon.

It can also be used for the direct production of single crystal or polycrystalline silicon plates, discs or layers are used, without any intermediate step, directly in the manufacturing process of the silicon according to the Invention are generated.

The method is therefore also particularly well suited for production of silicon solar cells and silicon components.

Both the n-zone and the p-zone and the p / n junction of a component or a solar cell can be produced according to the method of the invention by that a corresponding loading of the gas stream takes place with doping material. P / n structures can be produced in a continuous deposition process will. However, P / n junctions can also occur in two separate deposition processes be generated. However, the solar cell can also be equipped with a heterojunction (e.g. a SnO2 layer or SnO2 + 1 n203 layer on n- or p-silicon) or a Schottky junction be designed for charge separation. Also their production as a SIS structure or Ml S structure is possible in a manner known per se.

With the help of a suitable process management (appropriate distance between Arc and collecting surface) can also be used with the method according to the invention Manufacture silicon powder.

According to a development of the invention, this can be done in the Use the arc zone generated silicon still in the gas flow to form a silicide, which is then deposited in place of the silicon.

Silicon carbide, silicon nitride and metal silicides can be broken down into the form of compact crystals, plates, disks or layers or also in form of powder generate.

The method of manufacturing silicon allows manufacturing of pure silicon, the purity of which depends solely on the purity of the used Gases and chemicals. There is no contamination in the manufacturing process.

It is particularly inexpensive because it is what you want in the end Form of pure silicon (plate, disk or layer) in a single high-temperature process is generated: Reduction in the plasma with subsequent targeted deposition on any substrate.

In the following the invention on the basis of 9 exemplary embodiments be explained in more detail.

Embodiment 1 gives the principle of production according to the invention of silicon with arc plasma and again with induction plasma.

Embodiment 2 describes the production of silicon by Breakdown of SiH4 in an induction plasma and the deposition of silicon as a single crystal layer.

Embodiment 3 shows the reduction of silicon tetrachloride ir a plasma generated by a direct electric current to produce a Silicon wafer, embodiment 4 describes the reduction of SiO2 in one Arc plasma for the production of a pol crystalline silicon layer on a Iron substrate.

Embodiment 5 describes the plasma reduction of SiG2 for Manufacture of a silicon ribbon.

Embodiment 6 shows the structure of a silicon solar cell in cross section again, the silicon layers of which are produced by the method of the invention.

Embodiment 7 describes the production of silicon powder by reducing quartz sand with methane in the plasma.

Embodiment 8 shows the production of silicon carbide layers again, those formed from the reaction of silicon generated in the plasma with carbon are.

Embodiment 9 describes the production of a layer of molybdenum silicide, which is formed by the reaction of silicon generated in the plasma with molybdenum is.

Embodiment 1 In Fig. 1, 1 denotes a gas flow which is loaded with a silicon compound 2. With the help of an electrical direct current (a) - between the cathode 4 and the anode 5 - or with the help of an electrical Alternating current (b) - induced via the high-frequency coil 6 - is the gas current 1 heated up and transformed into plasma 3. The silicon compound 2 is in the plasma 3 broken down into elemental silicon or reduced. 7 is the housing of the assembly.

Embodiment 2 In FIG. 2, 3 is a plasma zone which passes through High frequency heating of an argon gas beam is generated. The argon gas jet is loaded with silane, which in the plasma 3 in elemental silicon The following is broken down: SiH4 + Ar = Si + 2H2 + Ar The SiH4 still contains a small amount of phosphine added so that the silicon formed in the plasma 3 on the substrate 9 as n-silicon layer 10 is deposited. The substrate 9 is a monocrystalline silicon wafer, which has a temperature of 900 OC and is in vacuum 8. The downcast The n-conducting silicon layer 10 is therefore also monocrystalline.

Embodiment 3 In Fig. 3, the plasma 3 is through a direct current arc generated in a hydrogen stream. The hydrogen stream is with silicon tetrachloride loaded so that the reaction takes place in plasma 3: 2 H2 + SiCL = - Si +4 HCI Dem SiC1 4 a small dose of BC13 is added. The substrate 9 is a carbon plate, which is heated in the vacuum 8 by the heater 13 to a temperature of 1000 C. It is coated on its surface with a liquid film 12 made of sodium fluoride. The silicon reduced in the plasma 3 becomes a p-conductive, very coarse crystalline layer 11 down on the NaF liquid fi Im 12.

Embodiment 4 In FIG. 4 the burns in a hydrogen stream Plasma 3. The hydrogen stream is with a mixture of quartz powder with p-doped Load silicon powder. The reaction takes place in the plasma: SiG2 + 3 H2 + Si = 2 Si + H20 + H2 On an iron sheet 9, which has an aluminum layer 74 is coated, the p-silicon layer 11 is deposited in a vacuum 8.

Embodiment 5 In Fig. 5, the head of a plasma spray system 16 flows through argon gas 1. This gas stream 1 is mixed with a powder 2 made of SiO2 powder with a very low B2O3 content and loaded with graphite powder. Between the cathode 4 and the anode 5 burns an arc in the argon gas stream 1, which Plasma 3 generated. Cathode 4 and anode 5 are water-cooled 17. In the plasma 3 takes place the reduction of SiO2 according to the equation SiO2 + 2 C + Ar = Si + 2 CO + Ar The elementary Silicon is used as a p-type silicon layer 11 on the surface 9 of molten lead deposited as a substrate. Through the heater 13, the crucible 18 with the lead 9 heated to 600 C. The silicon layer 11 is as a band with the constant Speed 15 deducted from the lead surface 9. That with the reduction of the SiO2 produced CO is captured and stored just like argon.

Embodiment 6 In Fig. 6 is a silicon film solar cell shown in cross section, the p- and n-silicon layers 1s1 and 10 after a Methods of the invention are made. The p-silicon layer 11 is through reduction of very pure SiO2 powder (with a defined B 0 addition) and 23 the n-silicon layer 10 by reducing very pure SiO2 powder (with # AS2O3 addition) in the plasma zone of a gas stream of carbon monoxide according to the reaction equation generated: SiO2 + 2 CO = Si + 2 CO2 The p-silicon layer 11 is on the tin layer 19 dejected. The tin layer 19 (which contains 0.5%, aluminum) is located on the surface of the ceramic substrate 9. It was when the Silicon layer 11 is liquid. The n-silicon layer 10 is structured with a Contact layer 20 made of zinc, to which the front-side contact 22 of the Solar cell is welded.

The rear side contact 21 of the solar cell is to the tin layer 19 appropriate. The solar cell is made with the help of a Heil3-Preß process with a translucent Polycarbonate mass 23 was encapsulated. To increase the weather resistance the entire surface is then covered with a plasma-sprayed aluminum oxide layer Under the solar radiation 25, the photo voltage of the solar cell lies between the contacts 21 and 22 Embodiment 7 In Fig. 7, 7 is a housing with a square Cross-section. An extensive water jet flows out of the nozzle 26, which flows into the housing 7 forms a water curtain 27 (filling the cross-section). Against this curtain of water 27 blows a hydrogen gas plasma 3. In the plasma 3, the reduction of very takes place fine quartz powder according to the reaction equation 2 H2 + SiO2 = Si + 2 H2O that produced Silicon is flushed with the water curtain 27 into the drain 2n and filtered of the water obtained as a powder.

Embodiment 8 In Fig. 8, 3 is a plasma in an argon gas beam mixed with methane. This mixed gas jet is with silicon tetrachloride loaded. The reaction initially takes place in the plasma: SiC14 + CH4 + Ar = Si + 4 HCI + C + Ar The elements Si and C react further under suitable conditions Silicon carbide: Si + C = SiC on a silicon substrate 9 by the heater 13 is heated to 1200 ° C., the SiC formed in the plasma 3 becomes a layer 29 dejected. The substrate 9 is located in a room 8 which is evacuated will.

Embodiment 9 In FIG. 9, 16 is the spray head of a plasma spray system. 1 is a hydrogen gas stream in which between the cathode 4 and the anode 5 an arc burns, which generates the plasma 3. The gas stream 1 is with a Loaded powdery mixture 2 of SiO2 and MoG 3. 17 is the water cooling of the Spray head 16. In plasma 3, according to the equation 7, H2 + 2 SiO2 + MoO3 = 2 Si + 7 H2O + Mo silicon and molybdenum are formed. Both elements react under appropriate conditions Conditions in the plasma continue to molybdenum disilicide: 2 Si + Mo = MoSi2 This MoSi2 is deposited as a layer 30 on an iron strip 9, which is moved at the speed 15 under the plasma beam 3. The iron band 9 is heated to 1000 ° C. by the heater 13 in a vacuum 8.

Process for the production of silicon reference numbers 1 gas flow 2 silicon compound 3 plasma 4 cathode 5 anode 6 high frequency coil 7 housing 8 vacuum 9 substrate 10 n-silicon layer 11 p-silicon layer 12 liquid layer on the substrate 9 13 heater 14 aluminum layer 15 speed 16 plasma spray head 17 water cooling 18 crucible 19 tin layer 20 front side metal 1 is eration 21 back side contact 22 Front contact 23 Plastic compound 24 Aluminum oxide layer 25 Solar radiation 26 Water nozzle 27 Water curtain 28 Water drain 29 Silicon carbide layer 30 Molybdenum si 1 izid layer Blank page

Claims (30)

Process for the production of silicon Claims 1. Process for the production of silicon, characterized in that a gas flow (1) is provided is that in this gas flow (1) a plasma (3h is generated, that means are provided are, through which the gas flow (1) with at least one silicon compound (2) is loaded that in the plasma (3) of the gas stream (1) the silicon compound (2) to Silicon is decomposed or reduced, and that the silicon together with the reaction products is transported out of the plasma (3) by the gas stream (1). 2. A method for producing silicon according to claim 1 thereby characterized in that the plasma (3) by electrical direct current or alternating current is generated. 3. A method for producing silicon according to claim 1 thereby characterized in that the plasma (3) by absorption of intense electromagnetic or ionizing radiation is generated in the gas stream (1). 4. Process for the production of silicon according to one of the preceding Claims characterized in that the silicon generated in the plasma (3) on one Substrate (9) is deposited. 5. Process for the production of silicon according to one of the preceding Claims characterized in that a plasma spray system with gas-stabilized Plasma (3) is used to produce silicon. 6. Process for the production of silicon according to one of the preceding Claims characterized in that a plasma spray system with water-stabilized Plasma (3) is used. 7. A method for the produc- tion of silicon according to one of the preceding Claims characterized in that the gas stream (1) consists of hydrogen, noble gas, Nitrogen, halogen, hydrocarbon, carbon monoxide, water vapor or a mixture or there is a connection between these gases. 8. Process for the production of silicon according to one of the preceding Claims characterized in that the silicon compound (2) is an oxygen-free Silicon compounds such as SiH4, SiOl4, SiHC13, SiH2CI and others. 9. Process for the production of silicon according to one of the preceding Claims characterized in that the silicon compound (2) is an oxygen-containing Silicon compound such as SiO2, a silicate or a silicon-organic compound is. 10. Process for the production of silicon according to one of the preceding Claims characterized in that the gas flow (1) is additionally coated with a dopant is loaded from the third or fifth group of the periodic table. 11. Process for the production of silicon according to one of the preceding Claims, characterized in that the gas stream (1) also contains silicon powder particles is loaded. 12. Process for the production of silicon according to one of the preceding Claims, characterized in that the gas stream (1) is additionally also containing carbon powder particles is loaded. 13. Process for the production of silicon according to one of the preceding Claims characterized in that the gas stream (1) consists of hydrogen and that silicon chloride is used as silicon compound (2). 14. Process for the production of silicon according to one of the preceding Claims characterized in that the gas stream (1) consists of noble gas or hydrogen exists and that silicon hydrogen is used as silicon compound (2) 15th Method for producing silicon according to one of the preceding claims thereby characterized in that the gas stream, m (t) consists of hydrogen and that the silicon compound (2) consists of SiO2. 16. Process for the production of silicon according to one of the preceding Claims characterized in that the gas stream (1) consists of a mixture of noble gas with a hydrocarbon compound or from a mixture of hydrogen with a hydrocarbon compound and that the silicon compound (2) SiO2 is. 17. Process for the production of silicon according to one of the preceding Claims characterized in that the gas stream (1) consists of hydrogen or noble gas or a mixture of these gases, and that the gas stream (1) zeitzSi with SiO2 powder particles (2) and is additionally loaded with carbon powder particles. 18. Process for the production of silicon according to one of the preceding Claims characterized in that the silicon is on a monocrystalline silicon surface (9) is knocked down. 19. Process for the production of silicon according to one of the preceding Claims characterized in that the silicon on a metallically conductive Surface (9) such as on a metal surface or on a metallically conductive one Layer is knocked down. 20. Process for the production of silicon according to one of the preceding Claims characterized in that the silicon on an insulator surface (9) being knocked down. 21. Process for the production of silicon according to one of the preceding Claims characterized in that the silicon is on a liquid surface (9) that does not chemically react with the silicon, e.g. liquid MgCl2 or lead at 750 ° C. 22. Process for the production of silicon according to one of the preceding Claims, characterized in that the silicon on a heated carrier (9) (e.g. graphite or ceramic to 1000 ° C) is precipitated with a thin Liquid film (12) which does not react with the silicon - e.g. a NaF film or a tin film - is coated. 23. Process for the production of silicon according to one of the preceding Claims characterized in that the silicon is deposited in an atmosphere or is knocked down that is oxygen-free. 24. Process for the production of silicon according to one of the preceding Claims characterized in that the gas flow (1) with the silicon in one Space with negative pressure or flows into a vacuum and that the silicon is deposited in a vacuum or being knocked down. 25. Process for the production of silicon according to one of the preceding Claims characterized in that it is used for the production of monocrystalline or policrystalline silicon is used. 26. Process for the production of silicon according to one of the preceding Claims characterized in that it is used for the production of monocrystalline or policrystalline silicon plates or layers is used. 27. Process for the production of silicon according to one of the preceding Claims characterized in that it is used for the production of silicon solar cells is used. 28. Process for the production of silicon according to one of the preceding Claims characterized in that it is used for the production of silicon components is used and that both the p-zones and the n-zones and the p / n junctions are produced by the method of the invention. 29. Process for the production of silicon according to one of the preceding Claims characterized in that it is used for the production of silicon powder is. 30. Process for the production of silicon according to one of the preceding Claims characterized in that the silicon formed in the plasma (3) is below Formation of a silicide reacts further.