DE1619987A1 - Process for making crystals, particularly for semiconductor devices - Google Patents

Description

Anrn? ¹¹ ■: IVJi: L ^ V ^ LOtH ^ FABRIEKE »/ r vO / wo.

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Registration dated: 3. Ck "fc. 1967

"Process for making crystals, particularly for semiconductor devices ¹¹ .

The invention relates to the production of crystals, in particular for half-lead devices.

Eb is known that semiconductor crystals are produced by it be able to be that a seed crystal is brewed in contact with a Sohmelse of the semiconductor material and thereby a temperature gradient is maintained in the Granso layer, so that the seed crystal grows.

Katurgem & ss only uses this procedure for substances with acceptable temperatures can be brewed to Sohmelsen, such as Silicium and Qermaniua, in question.

It is also known that silicon carbide can grow on a vaccine crystal at an acceptable temperature from a geaohmolic, saturated solution in ^ ₁ chromium.

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Solvents can be used, since silicon carbide is readily soluble in it and this solvent does not interfere with the crystal is recorded. This process takes place at atmospheric pressure carried out in an inert gas at a temperature slightly exceeding the melting point of the solution - namely at about 1800 C. As a result the small temperature difference as well as the seed crystal and the The solution was the speed of the crystal in disruptive hatred low. '

This can be significantly improved in that the Crystallization is carried out under a reduced gas pressure at which the solvent evaporates. In the surface layer, with which the seed crystal is in contact, then becomes a supersaturation Bustand, which causes a much faster growth of the crystal caused.

It is also known that such a process is also of interest to semiconductors other than silicon carbide. This applies nioht on semiconductor compounds such as gallium phosphide, which can be crystallized very difficult to directly from a son Else not or w, but also for semi-conductive · Elementaretoffβ such as silicon ,, the ltnismassig low in solution in a low sohoelsenden solvent, BB tin, at RELATIONSHIP Temperatures are crystallizable.

The solvent does not only have to be used, as above mentioned, have an · acceptable · solubility of the semiconductor substance and are not absorbed into the crystal to a disturbing degree, but rather even at the Sohmel temperature they have a high vapor pressure, since if necessary, when the pressure is down, a sufficient level can be seen.

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Evaporation of the solvent and a rapid force;

The latter JaifoT has fertilizer with regard to the solvent;

As a result, the choice of a Lascivious tool for learning about the problem oine3 beatirit * th semiconductor very beephrUnlet Afird Wid sometimes even usable safety equipment will be available.

The purpose of the invention is to counteract the unheard of » The discovery is based on the knowledge that the over ^

instead of. dt? rch physical removal of _ λ

duroh evaporation, possibly vinter reduced tem "Dxv: ck _t in a simple" way on chemiechem ¥ ogo can be redeemed.

The invention relates to a process for the production of crystals, for example crystals for semiconductor devices, in which an infeed of a molten, saturated lion is brought into contact with a semiconductor; so that the seed crystal grows and points the indicator that a gas is supplied to the atmosphere above the solution, which reacts with the solvent at the temperature of the bean oil and creates a volatile compound

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Forms that the surface of the skin is removed from the fertilizer and in this an excess saturation is brought about.

This way of removing the solvent has a ... less restrictive or at least otherwise; In the sense of a limiting influence on the choice of the release agent than in the event that this may be reduced by a pressure due to evaporation. Most of them can be used as solvents. iliziurakarbii and ZAxui for silicon, naralieh have low melting point requests;. *. '| l ^^ td ^ Qk ^ aü ^ -' * 0hi9.m _f dä9 ^: -.a '}: ip % &% && $ &? -. ~ \

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In this respect, many of the solvents in question easily form volatile compounds with gaseous reagents such as oxygen, sulfur and halogens, which means that solvents can be quickly removed from the solution « Example 1

As shown in the drawing, a seed crystal 1 of gallium phosphide is placed on the surface of a saturated solution 2 of 4 col, # gallium phosphide in QaIIiUm, the graphite vessels 3 housed in a quartz tube 4 in argon at atmospheric pressure with the aid of the furnace 5 "at a temperature of 105O ⁰ G is kept molten. '

A chlorine flow of 50.00 m per kinute is then passed through the quartz tube 4. As a result, solvent (gallium) is withdrawn from the melt with the formation of volatile gallium chloride, so that "the surface layer becomes oversaturated and the gallium phosphide seed crystal softens at a rate of more than 30 μm per hour.
Example 2

Using a device of the type described in Example 1, a solution of 5 At ·? » Held silicon melted in a quartz vessel in tin at 900 ⁰ C.

When passing hydrochloric acid gas with atmospheric pressure a speed of 100 ecm per hour wanks on the solution placed silicon seed crystal at a speed of 25 / un per hour. This growth occurs because of the oversaturation in the Surface chioht, which is brought about by the fact that "solvent

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(Tin) is withdrawn from the L3aun £ in the form of volatile tin chloride.

If the solution is by evaporation in an argon atmosphere "Removing solvent at a pressure of 10 mm is achieved at the same temperature only one kriatallwuqhs of to / um per hour.

Sohliesslich be noted that _f daee method of the invention also can be carried out such that the seed crystal is fixed relative to the graphite cup, 'wherein the seed crystal DA> by increase "can vereohwindet that the solvent and,

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Claims (3)

-6- PHII. 2009 PATIUTANSP KITCHEN 1. Process for the production of crystals; for example crystals for semiconductor devices in which a seed crystal with an ohm-melted saturated solution of a semiconductor material is, when the seed crystal grows, characterized in that that a gas is supplied to the atmosphere above the solution, which at the temperature of the melt reacts with the solvent and thereby forms a volatile compound, so that solvent is removed from the surface layer and a supersaturation condition is brought about in this. 2. Crystals _f preferably semiconductor crystals which are produced according to claims 1 3. A semiconductor device comprising a semiconductor crystal according to claim 2. BAD ORiQfNAL ΟΟ90Υ3- / Ϊ47-1