DE1467143A1 - Process for the pyrolytic deposition of crystalline, preferably monocrystalline silicon - Google Patents

Description

Process for the pyrolytic deposition of crystalline, preferably monocrystalline Silicon.

The invention is concerned with the production of highly rejptem, silicon suitable for use in semiconductor technology by deposition from the grass phase using a silicon halides mixed with hydrogen, in particular SiHCla or SiCl., as a reaction gas that is present on the surface a heated carrier body consisting of high-purity silicon is implemented with the deposition of silicon on the surface of this carrier body.

Such a method is for example in US Pat. No. 3,016,291 and in German Pat. No. 1,047,181 described. According to the explanations of German patent 1.047.181, small amounts of argon can be added to the reaction gas in addition to the hydrogen.

The deposition of crystalline silicon suitable for semiconductor purposes on a substrate made of silicon Experience has shown that a deposition temperature of approx 1100 - 1300 ° 0. In addition, when using halogen-containing reaction gases such. B. from SiHOl, or SiOl., The Reaction gas normally contain more than 90 MoljC hydrogen, if the silicon halide made available even only should be used to some extent. The maximum possible yield is then about 15 ^. The example disclosed in German patent specification 1.047.181 shows that from 10-12 kg SiGl ,, d. H. buckets of expenditure of 2 kg silicon, only 31 - 33 g slIi * cium will get »· where is how according to the present

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Invention recognizes an additional admixture of an appropriately selected inert gas entirely suited to the reaction gas, such as argon to increase the yield. The reason for the low yield of only $ 2> with the acquaintance is too low a hydrogen content and possibly also an inadequate admixture of the inert gas components. In contrast, the application of the following guarantees . defining a yield of at least 22 # silicon.

The invention relates to a process for the pyrolytic deposition of crystalline, preferably monocrystalline silicon from a reaction path consisting of a gaseous silicon-halogen compound, hydrogen and an inert gas mixed on a heated silicon crystal, which is according to the invention characterized in that in the Reaction gas mixture a molar hybrid ratio of Y / hydrogen to inert gas lying between 0.1 and 3.0 and a _{molar mixing ratio in the range of O 1} ,;) - 2.0 lying between the silicon compound and Y / hydrogen is established and maintained.

For the production of doped Siliciim Teuxui änu F_ear: i; ± onsgagmixture gaseous doping material can be added in the form of a compound. Experience has shown that the additions required for the doping are so small that oils do not have any effect on the weight of the silicon content.

Further singularities go from the Besohreitiiag of the]? Igui * cv3i 1 and 2 as well as from your exemplary embodiment *

In Hg. 1 is a suitable for Durchführuiig äzu Verfahi-emt-i gi Anordnmig invention is shown. " In eiii Qüer there is a noisy rod 2 made of high-purity silicon oily spar / üt * Sui * holder serves, the electrodes 3 and 13 * The silicon trough is built by direct current supply to the Hiöilertselilögct VOÄ for example 1200 ° C. To this zwz ^ k electrodes 3 and 13 lait a Spaisxiungaquelle 4 vermmden Reg is "slu2ig Heiastromö of the V / idex-staiaä" 5 "Q The barrel 1 is provided with äeat Vaiitilvsit 6 uad-16 auu ^^ bat-ust aiii BZV /. Derive äea HeaktioiisgasgaMiRPhea dieaan. Τά · ΐ ::

There is also a liquid Silloochloroforai 17, the QC

through a heat bath 8 Verdäiapfi is imd ub & r Als -Sxileituag 9 iu

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the reaction vessel 1 arrives. The funnel 10 is provided for refilling the liquid silicon compound. Through the Feed line 11 is highly purified hydrogen, which is mixed with inert gas according to the teaching of the invention, into the Evaporator vessel 7 initiated. There the hydrogen mixes with the vaporous silicon compound and becomes together introduced into the reaction vessel 1 with it. The supply of hydrogen and inert gas can either be by means of a joint Supply line or through two different supply lines. Should the reaction vessel be used at the beginning of the deposition process and the silicon rod located therein is annealed, so it is advisable to initially only add hydrogen to the apparatus as otherwise silicon nitride could be formed when nitrogen is used as an inert gas additive.

In Pig. 2 shows another arrangement for the method according to the invention. A heater is located in a quartz vessel 21 arranged, which is attached to the electrodes 25 and 33 and connected via the terminals 24 and 34 to a voltage source is »On the heater 22 there are disc-shaped support bodies 25 made of monocrystalline silicon. The reaction vessel 21 is again via a valve 26 with an evaporation device connected similarly to that in the arrangement described above. The reaction gas mixture is generated in the same way as in FIG. 1 described, generated and introduced into the reaction vessel. The valve 36 is provided for discharge.

In one embodiment of the method according to the invention, a mixture of silicochloroform and hydrogen is with a molar ratio = 0.2 is used. The hydrogen / inert gas molar ratio corresponds to the value of 3.0. With this composition of the reaction gas, it becomes the deposition intended carrier heated to approx. 1200 ° 0. If nitrogen is used as an inert gas additive, a reaction temperature should be used voa 1200 ° 0 must not be exceeded. When using argon, the limitation of the temperature range is less narrow. The flow rate of the reaction gas is about 1000 l / h. The yield in this embodiment is Process about 15 56 The molar ratio silicochloroform / However, hydrogen can be increased to 2.0. In this case, the hydrogen / nitrogen mixing ratio becomes 0.1

809813/1006 ^ropY

used · The reaction temperature is also 1200 ° 0 and must not be exceeded when using nitrogen as an inert gas additive. The yield here is 12 15 J *. The flow rate is about 500 l / o.

Sometimes it is useful to do this on silicon rods accordingly Fig. 1 to convert silicon obtained by zone melting into the monocrystalline form.

6 claims,
2 figures.

809813/1006

Claims (2)

Claims Process for the pyrolytic deposition of crystalline, preferably monocrystalline silicon from one of a gaseous silicon-halogen compound, hydrogen and one inert gas existing reaction gas mixture on a heated silicon crystal, characterized in that a molar between 0.1 and 3.0 in the reaction gas mixture Mixing ratio of hydrogen to inert gas and a molar mixing ratio in the range of 0.3 - 2.0 of the silicon-halogen compound to the hydrogen is adjusted and maintained. 2.) The method according to claim 1, characterized in that as Reaction gas is a mixture of SiHOl and hydrogen and, as a further component, an inert gas, ζ · Β. Nitrogen or argon, used and added in such an amount that the molar mixing ratio hydrogen / inert gas between 0.1 and 3.0 is 3.) Process according to claim 2, characterized in that the molar ratio of SiHCl and H _{2 is set} to 0.2, the molar ratio of Hg / inert gas is set to 3 * 0 and the support provided for the deposition is heated to about 1200 ° C. 4 ·) Process according to claim 2, characterized in that the molar ratio of silicochloroform / hydrogen to 2.0, the Hydrogen / nitrogen molar ratio adjusted to 0.1 and the temperature of the substrate intended for deposition is adjusted to about 1200.degree. 5 ·) Method according to one of claims 1-4 »characterized in that the temperature of the carrier provided for deposition increases when nitrogen is used as the inert gas additive a maximum of 1200 ° 0 is set 6 ·) Method make buckets of claims 1-5, characterized in that the support provided for the deposition is annealed in pure hydrogen immediately before the start of the deposition will. «09813/1006