WO2024133713A1

WO2024133713A1 - Inorganic compounds

Info

Publication number: WO2024133713A1
Application number: PCT/EP2023/087306
Authority: WO
Inventors: Nicholas RAU; Wolf SCHORN
Original assignee: Umicore Ag & Co. Kg
Priority date: 2022-12-23
Filing date: 2023-12-21
Publication date: 2024-06-27

Abstract

The invention relates to a method for generating HGeCl₃ from the homogeneous gas phase reaction between GeCl₄ and H₂ according to (I).

Description

Inorganic Compounds

Description

For germanium-based electronic components ("germanium stibium telluride" or germanium antimony telluride, Ge_x Sb_yTe_x+i.5y, abbreviated as GST) germanium precursors are sought that release Ge(II) in the deposition processes. These compounds are used in vapor phase depositions, which is why the germanium precursors must have high volatility. One of the germanium compounds that is considered particularly attractive is HGeCh (trichlorgermane or germanochloroform, CAS No. : 1184-65-2). It has a boiling point of 75°C and is a liquid at room temperature. In addition, it has a high germanium content (approx.40 m%), ensuring a high germanium concentration in the gas phase. This is necessary to enable a high deposition rate.

The academic literature describes the following reactions:

1) wet chemical i) Reduction of GeCl4 in aqueous with phosphites. ii) Reduction of GeCl4 in organic solvents with silanes.

2) heterogeneous gas-phase reactions (HGR): i) Reaction of elemental germanium with dry HCI

Ge + 3 HCI -> HGeCh + H₂ (idealized reaction equation) ii) Reaction of GeCI₂ with gaseous and dry HCI.

GeCI₂ + HCI -> HGeCh iii) Reaction of GeS with gaseous and dry HCI.

GeS + 3 HCI -> HGeCh + H₂ S

Wet chemical :

Wet chemical syntheses are known, but these are used to generate HGeCh in situ and in solution: no one has reported isolation of the labile HGeCh from solution. Medicinal Chemistry, 2009, 5, 382-384 describes the in situ synthesis of HGeCI3 in an aqueous medium starting from GeCI4 or GeO2 by HCI/NaH2PO2, but does not describe the isolation. The HGeCI3 obtained is directly reacted further. Also, HGeCh , which is produced wet-chemically, is not used in the semiconductor industry, but usually in wet-chemical, (metal)organic chemistry and pharmaceuticals; in "Encyclopedia of reagents for organic syntheses", C. A. Roskamp et al. describe the synthesis of HGeCI3 starting from GeCI4 and tetramethyldisiloxane. However, the product is not isolated, but the HGeCI3 formed is further reacted at the reaction temperature to give the dioxane complex GeCI2(dioxane).

Consequently, this class of reactions was considered unsuitable for the intended purpose as set out above and not further investigated.

As for heterogeneous gas-phase reactions, Reaction 2. i was described for the first time in 1886. C. Winkler, J. prakt. Chem. 1886, 34, 177-229 shows the synthesis of HGeCI3 starting from Ge + HCI at red heat.

"Handbook of Preparative inorganic Chemistry" by Georg Brauer describes on page 721 that a synthesis of HGeCI3 starting from Ge + HCI is possible.

"Journal of Physical Chemistry, 1926, 30, 1049-1054", L. M. Dennis also describes the synthesis of HGeCI3 starting from Ge + HCI.

Various literatures exist according to which neat HGeCI3 can be obtained from this mixture by derivatization and subsequent workup of the intermediate isolated derivative. Since the last step requires distillation under reduced pressure, this step is associated with a yield loss (81% based on the derivative). This procedure involves dissolving the raw mixture in diethyl ether, separation of the formed two layer system and cracking of the intermediate trichlorgermane diethyl ether complex with aluminium trichloride.

L. M. Dennis Journal of Physical Chemistry, 1926, 30, 1049-1054 and "Handbook of Preparative inorganic Chemistry" by Georg Brauer on page 721 reported Reaction 2. ii as an alternative to reaction 2.i, taking advantage of the equilibrium shown below. The problem here is that the GeCh used is temperature sensitive and tends to decompose above room temperature to form so-called germanium subchlorides. GeCI₂ — GeCl_x + GeCI^

(x < 2), so that with progressive decomposition only germanium and germanium tetrachloride remain at the end.

"Handbook of Preparative inorganic Chemistry" by Georg Brauer on page 721 describes that the synthesis of HGeCI3 starting from GeCI2 + HCI is possible.

L. M. Dennis Journal of Physical Chemistry, 1926, 30, 1049-1054, also describes the synthesis of HGeCI3 starting from GeCI2 + HCI and states that both the synthesis of GeCh and the subsequent reaction with HCI take place above room temperature, so that the GeCh used is always contaminated with subchlorides, which has considerable disadvantages.

Reaction 2. iii has been described as an alternative to reaction 2. ii in "Handbook of Preparative inorganic Chemistry" by Georg Brauer on page 721 and in C. W. Moulton et al., JACS 1956, 78, 2702-2704. Yields of about 40% based on GeS have been obtained and stated that it is the preparatively simplest (stable reactant GeS) as well as the cleanest synthesis route with no GeCl4 as side product. However, the H2S occurring in the synthesis might cause problems because the sulfur is chemically similar to the tellurium in GST. Consequently, sulfur contained in the GST can be expected to impair the functionality of electronic components, so it was concluded by the Inventors that sulfur must not be present in the final product HGeCh.

As mentioned above, compounds that release Ge(II) are particularly in demand. HGeCI3, although formally a Ge(IV) compound, is capable of this, since it decomposes already at room temperature (and faster at higher temperature or reduced pressure) according to

HGeCI₃ — HCI f + GeCI₂|

This advantage in application is at the same time disadvantageous for synthesis on a larger scale: HGeCh is a liquid, HCI is a gas and GeCL is a solid (in each case at room temperature and normal pressure), accordingly HCI slowly outgases, while GeCh remains as a solid. The problem is obtaining a product from a stable process, which product is of consistent quality and high purity, which is required for use in the semiconductor device industry.

The problem is solved by a method for generating HGeCh from the homogeneous gas phase reaction between GeCl4 and H₂ according to

GeCI₄ + H₂ - HGeCI₃ + HCI

It was shown in various experiments that the careful reduction, i.e. close to equimolar amounts of hydrogen in the reduction reaction of GeCl4 with hydrogen can indeed selectively lead to the desired product HGeCh.

It was surprisingly found and totally unexpected in view of the fact that in the reaction system Ge/GeCl4 /HGeCh /H₂ /HCI all components are in equilibrium with each other that this reaction provides a solution to the problem of the Invention.

Moreover, the proportion of the starting material GeCl4 is so small that this synthesis method, which has not been described before, yields HGeCh with a very high purity (in terms of GeCl4 as a minor component) comprising 80% of the desired trichlorogermane (HGeCh), which is significantly higher than in the other methods described in literature. The product obtained directly from the process can be used for applications in the semiconductor device industry without further purification.

In general, the above methods employing a heterogeneous gas-phase syntheses are less suitable to be run in a continuous process, or only with difficulty, due to the use of solid starting materials.

The advantage of the present invention is that both GeCl4 (volatile and liquid) and hydrogen (gaseous) can be easily introduced into the reaction, thus facilitating a continuous process.

The inventors found that the gas phase reaction particularly yields the desired product when the gas phase reaction proceeds in a furnace, preferably a tube furnace, and the flux of hydrogen through said furnace is not higher than 0.5 L.mimTcrm², preferably not higher than 0.4 L.mimTcrm², and more preferably not higher than 0.3 L.min ⁴.cm‘². Also, it is preferred that said flux is higher than 0.1 L.min Tcnr².

Further, it was found that when gas phase reaction proceeds in a furnace, preferably a tube furnace, hydrogen (H2) and germanium tetrachloride (GeCl4) are provided to said furnace preferably in a molar ratio of hydrogen (H₂) to germanium tetrachloride (GeCl4) of between 1 : 1 and 30: 1, preferably between 2: 1 and 25: 1.

Also, it was found that the reaction product containing trichlorogermane obtained from said gas phase reaction is preferably condensed at a temperature below -80°C, more preferably at a temperature between -80°C and - 200°C.

In general, the reaction of germanium tetrachloride (GeCk) with hydrogen

(H2) to yield the desired product trichlorogermane (HGeCk) was found to be a very robust reaction that can be carried out at temperatures of from 600°C to 1200°C, more specifically at temperatures of from 800°C to 1200°C .

Suitable pressures can be applied over an extended range as well and in general reaction pressures of from 100 mbar to 10.000 mbar, more specifically reaction pressures from 800 mbar to 2000 mbar have been found suitable, in particular pressures of about 1000 mbar.

In general, the method comprises a step wherein a gaseous mixture of germanium tetrachloride (GeCk) and a carrier gas is being generated.

This can, for example, be effected by exposing germanium tetrachloride (GeCk) to temperature and pressure conditions sufficient to create gaseous germanium tetrachloride (GeCk) and passing a stream of carrier gas through the gaseous germanium tetrachloride (GeCk), thus generating a carrier gas stream comprising gaseous germanium tetrachloride. In another embodiment a stream of carrier gas is passed through liquid germanium tetrachloride (GeCk) which is exposed to conditions sufficient to allow generation of a carrier gas stream comprising gaseous germanium tetrachloride (GeCk). In this embodiment, it can be advantageous to heat the germanium tetrachloride (GeCk) to a temperature of less than the boiling point at ambient pressure. In particular, the germanium tetrachloride (GeCk) is heated to a temperature of 30°C to 100°C, preferably of 40°C to 100°C, and more preferably of 50°C to 100°C, particularly to 50°C to 80°C at ambient pressure.

Other means for generating a carrier gas stream comprising gaseous germanium tetrachloride might be useful as well.

The carrier gas may be an inert gas or hydrogen, more specifically the carrier gas is selected from nitrogen, hydrogen, helium, neon, argon, hydrogen chloride, xenon or combinations thereof.

If the carrier gas comprising germanium tetrachloride (GeCk) is different from hydrogen, then hydrogen as the reactant must be added, which can be effected by mixing with hydrogen.

In another embodiment the carrier gas is hydrogen. Consequently, no efforts need to be taken to add hydrogen to the carrier gas stream comprising gaseous germanium tetrachloride.

The carrier gas stream comprising gaseous germanium tetrachloride is subsequently heated to a temperature of preferably 600°C or above, in particular a temperature of 600°C to 1200°C or 800°C to 1000°C, more specifically to about 1000°C.

This can be effected, for example, by passing the carrier gas stream comprising gaseous germanium tetrachloride through a heat exchanger. In a simple case of this embodiment the carrier gas stream comprising gaseous germanium tetrachloride is passed through a tube placed in a tube furnace. The ratio of hydrogen (H2) : germanium tetrachloride (GeCk) is from about 1 : 1 to about 30: 1, more specifically from about 2 : 1 to about 22: 1.

In general, a tube furnace setup has been found sufficient that may comprise, for example, a quartz glass tube with an inner diameter of 1.8 cm and a length of 55 cm, wherein 16.5 cm of the tube being heated externally. This heated area is called the reaction zone.

In general, the gas stream can be adjusted in the range of about 0,76 b/min to about 1,14 b/rnin, thus the reaction mixture remains in the reaction zone for 2-3 seconds. Both the flow rate and the time in the reaction zone can be adapted to the length and diameter of the glass tube and the length of the reaction zone within the tube.

Additionally it was found that a static mixing element such as a glass wool plug can be inserted before or into the reaction zone because it has a positive influence on the purity of the product, most likely due to improved mixing of the reactants.

Under these conditions the reaction between the (gaseous) germanium tetrachloride with hydrogen commences and will rapidly result in creation of the desired product trichlorogermane, thus generating a carrier gas stream comprising gaseous trichlorogermane.

The carrier gas stream comprising gaseous trichlorogermane is subsequently exposed to conditions allowing the collection of trichlorogermane and its separation from gaseous educts and byproducts, in particular to suitable temperatures and pressures.

Generally, working at ambient pressure and cooling to a temperature of less than 75°C, which is the boiling point of trichlorogermane, is sufficient. More specifically the carrier gas stream comprising gaseous trichlorogermane can be cooled to a temperature of less than 0°C, in particular less than -30°C, which can be advantageous because at temperatures that low the decomposition to germanium chloride and hydrogen chloride can be suppressed. In particular cooling to a temperature of less than -71°C, which is the melting point of trichlorogermane, can be advantageous, even more so at temperatures of -78°C or less. So in general, the carrier gas stream comprising gaseous trichlorogermane is cooled to a temperature of from -80°C to 75°C, - 80°C to -71°C or -80°C to -30°C, in particular to -78°C to 0°C or -78°C to - 30°C or -78°C to -71°C. In another embodiment it was found practical to effect cooling with liquid nitrogen, so the carrier gas stream comprising gaseous trichlorogermane can be cooled to temperature lower than -80°C, preferably lower than -120°C, and preferably not lower than -200°C. Yet alternatively, the carrier gas stream comprising gaseous trichlorogermane can be cooled to temperature of from -200°C to 75°C, -196°C to -71°C or - 196°C to -30°C.

In one embodiment, the method is comprising the steps of

- providing a carrier gas stream comprising hydrogen;

- contacting the carrier gas stream with a germanium tetrachloride (GeCk) source under conditions sufficient to at least partially saturate the carrier gas stream with germanium tetrachloride (GeCk);

- exposing the carrier gas stream to conditions sufficient to effect the reaction of germanium tetrachloride (GeCk) with hydrogen (H2).

In this embodiment, the step of contacting the carrier gas stream with a germanium tetrachloride (GeCk) source can be carried out by passing a stream of hydrogen through germanium tetrachloride at a temperature of from 20°C to 100°C, in particular 20°C to 60°C or 23°C to 40°C before subsequently being heated under inert conditions to a reaction temperature of 600°C or above. It should be noted that, in the entirety of this description, the expression "under inert conditions" is to be understood to be under conditions under absence or at least minimized presence of both oxygen and water and not broadly as being free of any reactive components.

In another embodiment, the method is comprising the steps of - providing a carrier gas stream comprising hydrogen;

- providing a stream of germanium tetrachloride (GeCk);

- combining both the carrier gas stream and the stream of germanium tetrachloride (GeCk);

- exposing the combined carrier gas stream and stream of germanium tetrachloride (GeCk) to conditions sufficient to effect the reaction of germanium tetrachloride (GeCk) with hydrogen (H2).

In the two embodiments mentioned hereinabove, the stream of germanium tetrachloride (GeCk) can be liquid or gaseous.

In the two embodiments mentioned hereinabove, both the step of combining both the carrier gas stream and the stream of germanium tetrachloride (GeCk) and the step of exposing the combined carrier gas stream and stream of germanium tetrachloride (GeCk) to conditions sufficient to effect the reaction of germanium tetrachloride (GeCk) with hydrogen (H2) are carried out simultaneously. That means that during combination of the carrier gas stream and the stream of germanium tetrachloride (GeCk) the temperature is preferably above 600°C and/or the pressure is preferably between 100 mbar and 10.000 mbar.

The step of combining both the carrier gas stream and the stream of germanium tetrachloride (GeCk) can be carried out by injecting the stream of germanium tetrachloride (GeCk) into the carrier gas stream by means of a nozzle.

As mentioned above, the conditions sufficient to effect the reaction of germanium tetrachloride (GeCk) with hydrogen (H2) are comprising a reaction temperature of greater than 600°C, in particular the reaction temperature is from 600°C to 1200°C or the reaction temperature is from 1000°C to 1200°C, and/or are comprising a reaction pressure of from 100 mbar to 10.000 mbar.

Method of any of the preceding claims, wherein the carrier gas stream comprising gaseous germanium tetrachloride (GeCk) and hydrogen is passed through a static mixing element before or while being exposed to conditions sufficient to effect the reaction of germanium tetrachloride (GeCk) with hydrogen (H2).

In another, more specific embodiment, the reaction can be conducted under direct liquid injection conditions, where a gas stream (consisting of hydrogen or a mixture of hydrogen and hydrogen chloride or a mixture of hydrogen and an inert gas or a mixture of hydrogen, hydrogen chloride and an inert gas) is led through a tube furnace and GeCk in pure form is introduced via a nozzle into the gas stream under conditions sufficient to allow the reaction of germanium tetrachloride (GeCk) with hydrogen.

The gas stream thus carries out the functions of reactant and carrier gas at the same time, allowing it to react hydrogen with GeCk to the product HGeCk and propelling it through the furnace to a location where the gas stream is allowed to cooled, allowing condensation of the product where it can be collected.

The conditions of the condensation and reaction are basically the same as mentioned above, where a gas stream is bubbled through pure GeCk in order to create a GeCk saturated gas stream.

The invention also relates to Trichlorogermane (HGeCk) directly obtained by the method of the invention, in particular a Trichlorogermane (HGeCk) raw product comprising at least 70% of trichlorogermane, preferably at least 75% and more preferably at least 80% of Trichlorogermane (HGeCk).

General experimental procedure for the preparation of HGeCh from GeCl4 and H2:

The corresponding parameters T_B, JH2, TR, tR and the coolants/others used can be taken from Table 1.

The tube furnace setup consisted of a 550 mm quartz glass tube (inner diameter: 18 mm). 165 mm of the tube was heated externally, defining the reaction zone. The gas stream was adjusted between 0,76 L/min and 1,14 b/min, thus the reaction mixture remained in the reaction zone for about in 2-3 seconds. Additionally, it was found, that a glass wool plug inserted into the reaction zone had a positive influence on the purity of the product, most likely due to better mixing of the reactants. Experiments where a glass wool plug was used are marked in Table 1 accordingly.

• GeCl4 was placed in a stainless steel bubbler and this bubbler was preheated to the specific temperature T_B.

• Pure hydrogen was passed through this bubbler at a flow rate JH2, producing an H₂ stream saturated with GeCl4.

• This GeCl4 /H₂ mixture was passed through the glass tube that was placed in the tubular furnace heated to a certain temperature T_R.

• The reaction was carried out for a certain time (t_R).

• The reaction product was condensed out at the tube outlet, using either dry ice or liquid nitrogen as the condensing agent.

• In some experiments, a glass wool plug was introduced into the reaction zone for better mixing of the reactants. Table 1 : Overview of the tests and the selected parameters.

Trial Bubbler Hydrogen Reaction Reaction Coolant

No. temperature flow ^b) JH₂ temperature time TB /°C / L/min TR /°C tR /min

1 23 1,14 1000 15 Dry ice

2 40 1,14 1000 15 Dry ice

3 60 1,14 1000 15 Dry ice

4 60 0,76 1000 15 Dry ice

5 60 0,76 800 15 Dry ice

6 ^a) 60 0,76 1000 15 Dry ice

7 23 1,14 1000 35 Dry ice

8 60 0,76 1000 15 Liquid N2

9 ^a) 23 0,76 1000 32 Liquid N2 a⁾ Reaction in presence of glass wool plug. b⁾ Hydrogen flow JH2 of 1.14 L.min ¹ corresponds to hydrogen flux 4>H2 0.45 L.min Tern^-2; Hydrogen flow J H2 of 0.76 L.min ¹ corresponds to hydrogen flux 4>H2 0.30 L.min Tcnr².

The results of the tests are summarized in Table 2:

• When choosing the parameters or the experimental procedure, care was taken to ensure that only one parameter was ever changed from one experiment to the next (experiments 1-8).

• The gas phase concentration of GeCl4 was affected by means of bubbler temperature.

• In the first three experiments, it was shown that a high hydrogen to GeCl4 ratio has a positive effect on the content of HGeCh. The H₂:GeCl4 ratio is calculated using the following parameters: Current velocity J H2 * Reaction time 1R = Reaction volume H₂, Reaction volume gives the amount of substance of hydrogen used via ideal gas equation p*V = n*R*T. The amount of GeCl4 is obtained by weighing the GeCl4 bubbler before and after the reaction.

• This can be explained by the fact that the reaction GeCl4 + H₂ <-> HGeCh + HCI is an equilibrium reaction and is on the right side with increasing hydrogen content. It was also shown here that as the bubbler temperature increases, the GeCl4 consumption increases as well as the isolated amount of product, which is a direct effect of the increased evaporation rate of the GeCl4 (due to the higher vapor pres- sure/higher bubbler temperature).

• Experiments 3 and 4 show that the higher flow rates JH2 of the hydrogen stream have a negative influence on the purity of the product: This can be explained by the shorter residence time of the reaction mixture in the reaction zone. Since at higher temperatures the equilibrium is on the right side, the product side is thus favored, since the equilibrium can be better established by remaining longer in the hot reaction zone. At the same time, less GeCl4 is discharged and also less crude product is isolated, which can be explained by the lower stock flow from the bubbler.

• Experiments 4 and 5 clearly show the influence of the reaction temperature T_R on the HGeCh content of the crude product: the lower the reaction temperature, the lower the content of HGeCh. Since the equilibrium of the reaction GeCl4 + H2 <-> HGeCh + HCI is on the right side for high temperatures, the equilibrium is shifted towards the reactants GeCl4 and H₂ at lower temperatures.

• Experiments 1 and 7 show that with a longer reaction time, the GeCl4 output increases (as expected), as does the amount of crude product isolated (also expected). Interestingly, the purity also increases, possibly due to the fact that forming GeCI₂ (by-product in the reaction) enters the collection vessel and reacts there with HCI (also by-product of the reaction) again to form HGeCh.

• Experiments 4 and 8 show that the temperature at which the product is condensed out has an effect on the discharge of GeCl4, the amount of crude product isolated, and the purity of the crude product: If the crude product is condensed out at -196°C instead of -78°C, the discharge of GeCl4 increases as well as the isolated amount of crude product; in addition, the content of HGeCh in the crude product increases. The increased discharge is probably due to the fact that the significantly lower condensation temperature also simultaneously generates a strong negative pressure, which draws more GeCl4 out of the bubbler. The increased crude yield is directly due to the fact that at - 196°C the vapor pressure of the product is significantly lower than at -78°C and, accordingly, less material is discharged from the cooling trap with the reaction gas stream from the collection vessel. The increased HGeCh content is probably a result of HCI freezing out, which occurs at -196°C but not at -78°C. Since GeCh is considered one of the main impurities in the crude product, when it enters the collection vessel, it may react with the HCI condensed out there to form HGeCh, which may explain the increased HGeCh content.

• Experiments 4 and 6 show that the use of a glass wool plug in the reaction zone slightly increases the GeCl4 yield, the isolated amount of crude product and the HGeCh content. While the GeCl4 output (and thus the increased crude yield) can be explained by statistical fluctuations when adjusting the H2 flow, the increased HGeCh content may be a consequence of the glass wool plug, which ensures better mixing of the reactants and better heat transfer from the heated tube outer wall to the center of the tube.

• In the last experiment it can be seen that combination of all parameters that had shown a positive influence on the reaction during the first 8 experiments result in a further improvement of the result.

Table 2: Overview of the tests and the results obtained.

Trial con- isolated Amount Ratio Raw number sumed product product H₂:GeCl4 yield

GeCh /g /g /% /%

1 7,5 2,6 82,7 21,83 34,7

2 23,2 12,6 78,4 7,1 54,3

3 68,6 43,4 75,1 2,4 63,3

4 44,3 30,9 80,5 2,5 69,8

5 46,1 30,9 32,7 2,4 67,0

6 46,8 31,7 82,8 2,3 67,7

7 29,6 17,3 86,7 12,9 58,4

8 50,3 38,3 87,3 2,2 76,1

9 20,3 13,5 11,5 66,5

Claims

1. Method for producing Trichlorogermane (HGeCk) by a gas phase reaction of germanium tetrachloride (GeCk) and hydrogen (H2).

2. Method of claim 1, whereby said gas phase reaction proceeds in a furnace, and whereby the flux of hydrogen through said furnace is not higher than 0.5 L.min Tcm^-2.

3. Method of claim 1 or 2, whereby said gas phase reaction proceeds in a furnace, and whereby hydrogen (H2) and germanium tetrachloride (GeCk) are provided to said furnace in a molar ratio of hydrogen (H2) to germanium tetrachloride (GeCk) of between 2 and 25.

4. Method of any of claims 1 to 3, whereby the reaction product obtained from said gas phase reaction is condensed at a temperature below - 80°C and not lower than -200°C.

5. Method of any of claims 1 to 4, comprising the steps of

- providing a carrier gas stream comprising hydrogen;

6. Method of any of claims 1 to 5, comprising the steps of

- providing a carrier gas stream comprising hydrogen; providing a stream of germanium tetrachloride (GeCk); combining both the carrier gas stream and the stream of germanium tetrachloride (GeCk);

7. Method of any of claims 1 to 6,, wherein the stream of germanium tetrachloride (GeCk) is liquid or gaseous.

8. Method of any of claims 1, 6 and 7, wherein both the steps of combining both the carrier gas stream and the stream of germanium tetrachloride (GeCk) are carried out simultaneously with the step of exposing the combined carrier gas stream and stream of germanium tetrachloride (GeCk) to conditions sufficient to effect the reaction of germanium tetrachloride (GeCk) with hydrogen (H2).

9. Method of any of claims 1 and 6 to 8 wherein the step of combining both the carrier gas stream and the stream of germanium tetrachloride (GeCk) is carried out by injecting the stream of germanium tetrachloride (GeCk) into the carrier gas stream by means of a nozzle.

10. Method of any of claims 1 to 9, wherein the conditions sufficient to effect the reaction of germanium tetrachloride (GeCk) with hydrogen (H2) are comprising a reaction temperature of greater than 600°C.

11. Method of any of the preceding claims, wherein the reaction temperature is from 600°C to 1200°C.

12. Method of any of the preceding claims, wherein the reaction temperature is from 1000°C to 1200°C.

13. Method of any of any of the preceding claims, wherein the conditions sufficient to effect the reaction of germanium tetrachloride (GeCk) with hydrogen (H2) are comprising a reaction pressure of from 100 mbar to 10.000 mbar.

14. Method of any of the preceding claims, wherein the reaction pressure is from 800 to 2000 mbar.

15. Method of any of the preceding claims, the method comprising a step wherein a gaseous mixture of germanium tetrachloride (GeCk) and a carrier gas is being generated.

16. Method of any of the preceding claims, in particular any of claims 1 or 2, wherein the germanium tetrachloride (GeCk) is exposed to temperature and pressure sufficient to create gaseous germanium tetrachloride (GeCk) and passing a stream of carrier gas through the gaseous germanium tetrachloride (GeCk).

17. Method of any of the preceding claims, in particular any of claims 1 or 2, wherein a stream of carrier gas is passed through liquid germanium tetrachloride (GeCk) which is exposed to conditions sufficient to allow generation of a carrier gas stream comprising gaseous germanium tetrachloride (GeCk).

18. Method of any of the preceding claims, wherein the carrier gas is an inert gas or hydrogen.

19. Method of any of the preceding claims, wherein the carrier gas is selected from nitrogen, hydrogen, helium, neon, argon, hydrogen chloride, xenon or combinations thereof.

20. Method of any of the preceding claims wherein the carrier gas comprising germanium tetrachloride (GeCk) is mixed with hydrogen.

21. Method of any of the preceding claims, wherein the carrier gas is hydrogen.

22. Method of any of the preceding claims, wherein a stream of hydrogen is passed through germanium tetrachloride at a temperature of from 20°C to 100°C and then heated under inert conditions to a reaction temperature of 600°C or above.

23. Method of any of the preceding claims, wherein the gas stream is passed through a cold trap at a temperature of less than -50°C to obtain the solid product Trichlorogermane (HGeCk).

24. Method of any of the preceding claims, wherein the carrier gas stream comprising gaseous germanium tetrachloride (GeCk) and hydrogen is passed through a static mixing element before or while being exposed to conditions sufficient to effect the reaction of germanium tetrachloride (GeCk) with hydrogen (H2).

25. Trichlorogermane (HGeCk) directly obtained by a method of any of the preceding claims.

26. A Trichlorogermane (HGeCk) raw product directly obtained by a method of any of the preceding claims comprising at least 80% of Trichlorogermane (HGeCk).