TWI743360B - The method of electrochemical production of germane - Google Patents

Abstract

A method of electrochemically manufacturing germane is in an electrochemical cell with a diaphragm, an anode and a cathode containing silver, and an electrolyte containing a germanium compound is energized to generate germane at the cathode.

Description

Method of producing germane electrochemically

The present invention relates to a method of electrochemically producing germane.

In the past, high-speed and low-power consumption of semiconductor devices can be achieved by miniaturization of the device. However, as a technology for further high-speed and low-power consumption, strained silicon such as SiGe substrates is available. By the attention. _{Germane (GeH 4} ) is used as the raw material for manufacturing the SiGe substrate. As the use of SiGe substrates increases, it is predicted that the amount of _{GeH 4 used will increase.}

As a _{method for producing such GeH 4} , for example, Patent Document 1 describes that by using Cu alloy or Sn alloy as a cathode, GeH ₄ can be produced electrochemically with high current efficiency.

In addition, Non-Patent Document 1 describes the results of screening Pt, Zn, Ti, graphite, Cu, Ni, Cd, Pb, Sn as a cathode _{used in the electrochemical production of GeH 4, and from the viewpoints of current efficiency and pollution, etc.} Cd or Cu are most suitable.

Furthermore, Non-Patent Document 2 discloses that _{it is used as a cathode for electrochemical production of GeH 4} , and as a result of investigating a plurality of cathodes, when Hg is used as the cathode, the hydrogenation rate becomes 99% or more. [Prior Technical Documents] [Patent Documents]

[Patent Document 1] JP 2012-52234 A [Non-Patent Document]

[Non-Patent Document 1] Turygin et. al., Inorganic Materials, 2008, vol.44, No.10, pp.1081-1085 　　 [Non-Patent Document 2] Djurkovic et. al., Glanik Hem. Drustva, Beograd, 1961 , vol.25/26, pp.469-475

[The problem to be solved by the invention]

The conventional electrochemical manufacturing _{method of GeH 4} described in the aforementioned document, for example, the cathode (bronze manufactured by McMaster-Carr Company) used in the example of the aforementioned Patent Document 1 is difficult to use methods that only have effective elements on the surface such as electroplating or coating. Application, or because of the high toxicity of the cathode (Hg) used in Non-Patent Document 2, is unfavorable as a method _{for industrially producing GeH 4.}

An embodiment of the present invention provides an industrially advantageous method as a method for electrochemically producing GeH ₄ . [Means to solve the problem]

The inventors of the present invention have actively studied to solve the aforementioned problems, and found that the aforementioned problems can be solved according to the following manufacturing method and the like, thus completing the present invention.　　 The configuration example of the present invention is as follows.

[1] A method of electrochemically producing germane, in an electrochemical cell having a separator, an anode, and a cathode containing silver, an electrolyte containing a germanium compound is energized to generate germane at the cathode.

[2] The manufacturing method of [1], wherein the electrolyte is an electrolyte containing germanium dioxide and an ionic substance.　　[3] The manufacturing method as in [2], wherein the aforementioned ionic substance is potassium hydroxide or sodium hydroxide.　　[4] The manufacturing method of [2] or [3], wherein the aforementioned ionic substance is potassium hydroxide, and the concentration of potassium hydroxide in the aforementioned electrolyte is 1-8 mol/L.

[5] The manufacturing method of any one of [1] to [4], wherein the current density of the cathode when energized is 30 to 500 mA/cm ² . [6] The manufacturing method of any one of [1] to [5], wherein the reaction temperature when the germane is produced is 5-100°C. [Effects of the invention]

_{According to an embodiment of the present invention, GeH 4} can be produced by an industrially advantageous method, particularly high current efficiency electrochemical production.

＜＜Method of electrochemically producing GeH _{4 ＞＞ The method of electrochemically producing GeH 4} according to an embodiment of the present invention (hereinafter also referred to as "the method") is in an electrochemical cell having a separator, an anode, and a cathode containing silver , the energization of the electrolytic solution of the compound containing germanium, to produce a cathode GeH _4, electrochemically manufactured GeH _{4. According to this method, GeH 4} can be produced by industrially advantageous methods, especially high current efficiency electrochemistry. Therefore, by using the GeH ₄ obtained by this method, it is also advantageous for the industrial manufacturing of SiGe substrates.

As an example of such an industrial reaction, for example, an electrolyte with a capacity of 500 to 2500L, a number of units of 30 to 150, and a current used in a scale of 100 to 300A are exemplified.

_{According to this method, GeH 4} can be manufactured with a current efficiency of preferably 10 to 90%, more preferably 12 to 40%. In addition, the aforementioned current efficiency can be specifically measured by the method described in the following Examples.

<Electrochemical cell> ""As the electrochemical cell, if it has a separator, an anode, and the cathode, it is not particularly limited, and a conventionally known cell can be used. A specific example of the unit is a unit that uses a diaphragm to separate an anode compartment containing an anode and a cathode compartment containing a cathode.

<Cathode> 　　 If the aforementioned cathode contains Ag, it is not limited.　　The cathode can be an electrode made of metallic Ag or an electrode made of Ag-based alloy with Ag as the main component, or an electrode made of electroplating or coated with metallic Ag or Ag alloy. "" As the aforementioned electroplated or coated electrode, for example, electroplated or coated metal Ag or Ag alloy electrode on a Ni substrate or the like.　　 Among these, metal Ag is expensive, so based on cost, it is preferably an electrode plated or coated with metallic Ag or Ag alloy.

The shape of the foregoing cathode is not particularly limited, and it may be any of a plate shape, a column shape, a hollow shape, and the like. "And the size and surface area of the aforementioned cathode are not particularly limited.

<Anode> As the aforementioned anode, there is no particular limitation. As long as the anode used in the electrochemical production of GeH ₄ is used, it is preferably an electrode made of a conductive metal such as Ni and Pt. An electrode made of an alloy with a main component, etc., is preferably an electrode made of Ni based on cost. In addition, the anode, like the cathode, can be electroplated or coated with the conductive metal or an alloy containing the metal. The shape, size, surface area, etc. of the foregoing anode are also not particularly limited as the foregoing cathode.

<Diaphragm> ""The above-mentioned membrane is not particularly limited, as long as it is used in an electrochemical cell that can separate the anode chamber and the cathode chamber.　　As such a separator, various electrolyte membranes or porous membranes can be used. """ As an electrolyte membrane, a polymer electrolyte membrane such as an ion exchange solid polymer electrolyte membrane is exemplified, specifically NAFION (registered trademark) 115, 117, NRE-212 (manufactured by SIGMA ALDRICH), and the like.　　As the porous membrane, porous ceramics such as porous glass, porous alumina, and porous titanium oxide, and porous polymers such as porous polyethylene and porous propylene can be used.

In one embodiment of the present invention, since the electrochemical cell is divided into an anode chamber and a cathode chamber by a diaphragm, the O _{2 gas generated at the anode and the GeH 4} generated at the cathode will not be mixed, and can be separated from each electrode chamber Take out the exit. When the _gas is mixed with ₄ GeH O, O ₂ gas and the GeH ₄ reaction tends to decrease the yield of GeH _4.

<Electrolyte containing germanium compound> In this method, GeH _{4 is} produced from an electrolyte containing germanium compound. The electrolyte is preferably an aqueous solution.

The germanium compound is preferably GeO ₂ . _{The higher the concentration of GeO 2} in the foregoing electrolyte, the faster the reaction rate, and the efficient synthesis of GeH _4. Therefore, the solvent is preferably set to a saturation concentration relative to water.

In order to improve the conductivity of the electrolyte and promote _{the solubility of GeO 2} in water, the aforementioned electrolyte preferably contains ionic substances. As the ionic substance, conventionally known ionic substances used in electrochemistry can be used, but from the viewpoint of the aforementioned excellent effects, etc., KOH or NaOH is preferred. Among them, the conductivity of the KOH aqueous solution is superior to that of the NaOH aqueous solution, so KOH is preferred.

The KOH concentration in the aforementioned electrolyte is preferably 1-8 mol/L, more preferably 2-5 mol/L. When the KOH concentration is within the aforementioned range, it is easy to obtain _{an electrolyte solution with a high GeO 2 concentration, and GeH 4} can be efficiently produced with high current efficiency. When the KOH concentration does not reach the lower limit of the aforementioned range, the conductivity of the electrolyte tends to be low, and high voltage is required _{for the production of GeH 4. In addition, the amount of GeO 2} dissolved in water tends to decrease, which may cause the reaction Conditions of reduced efficiency. On the other hand, when the KOH concentration exceeds the upper limit of the aforementioned range, there is a tendency that the electrode or cell material must be a material with high corrosion resistance, which may increase the cost of the device.

<Reaction conditions> In this method, the current magnitude (current density) per unit area of the cathode at the time of _{manufacturing GeH 4} (at the aforementioned energization) is preferable based on the viewpoint that the _{reaction rate is excellent and GeH 4 can be manufactured with high current efficiency.} It is 30~500mA/cm ² , more preferably 50~400mA/cm ² . When the current density is in the aforementioned range, the rate of GeH ₄ generation per unit time or the reaction efficiency will not decrease, and the amount of hydrogen generated by the electrolysis of water can also be suppressed to an appropriate level.

The reaction temperature for producing GeH ₄ (produced GeH ₄₎ of, based on the reaction rate is excellent, can be manufactured at low cost viewpoint GeH _4, etc., preferably 5 ~ 100 ℃, more preferably 10 ~ 40 ℃. If the reaction temperature is within the aforementioned range, the reaction efficiency will not decrease, and the power consumption for unit heating can also be suppressed to an appropriate level.

The reaction environment (the gas phase part of the anode chamber and the cathode chamber) in the production of GeH ₄ is not particularly limited, but is preferably an inert gas environment, and the inert gas is preferably nitrogen.

In this method, the aforesaid electrolyte in the electrochemical cell can be in a static state, can also be stirred, or other liquid tanks can be additionally provided and circulated. When other liquid tanks are installed and circulated as described above, the change in the concentration of the reaction solution is relatively small, the current efficiency can be expected to stabilize, and the GeO ₂ concentration on the electrode surface can be kept high, and the reaction rate can be expected to increase. Therefore, the aforementioned electrolyte in the electrochemical cell is better circulated.

<GeH ₄ manufacturing apparatus> This method is not particularly limited if the aforementioned electrochemical cell is used, but in addition to the cell, a power source and measuring means (FT-IR, pressure gauge (PI) as shown in Fig. 1 can be used. , Accumulator, etc.), nitrogen (N ₂ ) supply path, mass flow controller (MFC), exhaust path and other conventionally known components. In addition, a device having the aforementioned circulation flow path not shown in the figure can also be used. [Example]

Examples are listed below to specifically illustrate the present invention, but the present invention is not limited to these examples.

[Example 1] Using the following materials, as shown in FIG. 1, an electrochemical cell made of vinyl chloride in which the anode chamber and the cathode chamber were separated by a diaphragm was fabricated.・Cathode: Ag plate of 0.5cm×0.5cm×thickness 0.5mm ・Anode: Ni plate of 2cm×2cm×thickness 0.5mm ・Separator: NAFION (registered trademark) NRE-212 (manufactured by SIGMA ALDRICH) ・Electrolyte: in _{A liquid that dissolves GeO 2} at a concentration of 90g/L in a 4mol/L KOH aqueous solution. ・The amount of electrolyte introduced into the cathode chamber: 100mL ・The amount of electrolyte introduced into the anode chamber: 100mL ・Standard electrode: Silver-chloride is installed on the cathode Silver electrode

After the gas phase part of the anode and cathode chambers in the obtained electrochemical cell is _{blown with nitrogen (N 2} ), use Hz-5000 manufactured by Beidou Electric Co., Ltd. as a power source, and flow a current of -57mA for 10 minutes to electrochemically produce GeH ₄ . The current density at this time is 99 mA/cm ² . In addition, the temperature of the electrochemical cell was not controlled when the current was flowing, and as a result, the reaction temperature was 14°C. By using an accumulator to measure the outlet gas of the cathode chamber, the total amount of outlet gas produced by the reaction (including GeH ₄ and hydrogen gas) is measured, and the FT-IR is used to measure the GeH ₄ concentration in the total outlet gas. From these measurement results, the amount of _{GeH 4 produced was calculated.}

_{After the current is applied, the current efficiency is calculated based on the following formula from the amount of GeH 4} generated between 0 and 10 minutes and the amount of current applied. The current efficiency is set as the current efficiency for a reaction time of 10 minutes. The results are shown in Table 1. Current efficiency (%) = (equivalent to the amount of electricity (C/min) × 10 (min) × 100 _{that produces the aforementioned amount of GeH 4 (mmol/min)} min)]

[Comparative Example 1] "The reaction was carried out under the same conditions as in Example 1, except that a 0.5 cm × 0.5 cm × 0.5 mm thick Cu plate was used as the cathode and the applied current was changed to -85 mA for 10 minutes. The results are shown in Table 1.

[Comparative Example 2] 　　 The reaction was carried out under the same conditions as in Example 1, except that a 0.5 cm × 0.5 cm × 0.5 mm thick Cd plate was used as the cathode and the applied current was changed to -55 mA for 10 minutes. The results are shown in Table 1.

[表1]

[Table 1]

Fig. 1 is a schematic diagram of the device used in the embodiment.

Claims (4)

A method of electrochemically producing germane, in an electrochemical cell with a diaphragm, an anode, and a cathode containing silver, the electrolytic solution containing germanium dioxide and ionic substances is energized, and the germanium gas is generated at the cathode Alkane, the ionic substance is potassium hydroxide or sodium hydroxide, and the concentration of the ionic substance in the electrolyte is 1-8 mol/L. The method for manufacturing germane according to claim 1, wherein the aforementioned ionic substance is potassium hydroxide. Such as the method of manufacturing germane in claim 1, wherein the cathode current density when the current is energized is 30~500mA/cm ² . The method for producing germane according to any one of claims 1 to 3, wherein the reaction temperature when the germane is produced is 5-100°C.

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