TW201900931A - Method for electrochemically producing decane - Google Patents

Abstract

Provided is a method for electrochemically producing germane by applying an electric current to a germanium compound-containing electrolytic solution in an electrochemical cell having a barrier membrane, an anode, and a silver-containing cathode to cause the generation of germane in the cathode.

Description

Method for producing germane by electrochemical method

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

In the past, high-speed and low-power consumption of semiconductor devices can be achieved by miniaturization of the device, but as a technology for further high-speed and low-power consumption, strained silicon such as SiGe substrates has been prepared. By the attention. As a raw material when manufacturing the SiGe substrate, germane (GeH ₄ ) is used. As the use of SiGe substrates increases, the amount of GeH ₄ used is expected to increase.

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

Furthermore, Non-Patent Document 1 describes the results of screening Pt, Zn, Ti, graphite, Cu, Ni, Cd, Pb, and Sn as cathodes used in the electrochemical production of GeH ₄ from the viewpoints of current efficiency and pollution, Cd or Cu is most suitable.

In addition, Non-Patent Document 2 discloses the results of investigating a plurality of cathodes as cathodes used for electrochemical production of GeH _4. When Hg is used as the cathode, the hydrogenation rate becomes 99% or more. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Publication No. 2012-52234 [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

[Questions to be Solved by the Invention]

The conventional method for electrochemically manufacturing GeH ₄ as described in the aforementioned documents, for example, the method in which the cathode (Bronze manufactured by McMaster-Carr) used in the example of the aforementioned Patent Document 1 only has effective elements on the surface by plating or coating is difficult It is unfavorable as a method for industrially manufacturing GeH ₄ due to its application, or because of the high toxicity of the cathode (Hg) used in the aforementioned Non-Patent Document 2.

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

As a result of an active review by the present inventors to solve the aforementioned problems, they have found that the aforementioned problems can be solved according to the following manufacturing methods and the like, and have completed the present invention. The configuration examples of the present invention are as follows.

[1] A method for electrochemically producing germane is based on an electrochemical cell having a separator, an anode, and a cathode containing silver. The electrolytic solution containing a germanium compound is energized to generate germane at the cathode.

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

[5] The manufacturing method according to any one of [1] to [4], wherein the cathode current density when the current is applied is 30 to 500 mA / cm ² . [6] The method according to any one of [1] to [5], wherein the reaction temperature when the aforementioned germane is generated is 5 to 100 ° C. [Inventive effect]

According to one embodiment of the present invention, GeH ₄ can be electrochemically manufactured by industrially advantageous methods, particularly with high current efficiency.

A method for producing an electrochemical <<>> GeH ₄ of the embodiment of the present invention, a method of manufacturing an electrochemical aspect of GeH ₄ (hereinafter also referred to as "the present method") based on a septum, an electrochemical cell comprising a cathode and an anode of silver in , 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 electrochemically produced by an industrially advantageous method, particularly with high current efficiency. Therefore, by using GeH ₄ obtained by this method, SiGe substrates can also be manufactured industrially.

As such an industrial reaction, for example, a reaction having a scale of an electrolytic solution capacity of 500 to 2500 L, a number of units of 30 to 150, and a current of 100 to 300 A is used.

According to this method, GeH ₄ can be manufactured with a current efficiency of preferably 10 to 90%, more preferably 12 to 40%. The current efficiency can be specifically measured by the method described in the following examples.

<Electrochemical cell> As the electrochemical cell, a separator, an anode, and the cathode are not particularly limited, and conventionally known cells can be used. As a specific example of the unit, a unit that uses a separator to separate an anode chamber including an anode and a cathode chamber including a cathode is used.

<Cathode> The cathode is not limited as long as it contains Ag.阴极 The cathode can be an electrode made of metal Ag or an Ag-based alloy with Ag as the main component, or an electrode plated or coated with metal Ag or Ag alloy. (2) Examples of the aforementioned electrode to be plated or coated include an electrode to be plated or coated with metallic Ag or an Ag alloy on a substrate such as Ni. Among these, since metal Ag is expensive, based on the cost, it is preferable to electrode plate or coat metal Ag or Ag alloy.

The shape of the cathode is not particularly limited, and may be any of a plate shape, a column shape, and a hollow shape. In addition, the size, surface area, etc. of the foregoing cathode are not particularly limited.

<Anode> The anode is not particularly limited, and any anode that has been conventionally used in the electrochemical production of GeH ₄ may be used, but an electrode made of a conductive metal such as Ni, Pt, or the like is preferred. An electrode made of an alloy containing a main component is preferably an electrode made of Ni based on cost. In addition, the anode and the cathode may be electrodes that are plated or coated with the conductive metal or an alloy containing the metal. The shape, size, surface area, and the like of the anode are also not particularly limited similarly to the cathode.

<Separator> The separator is not particularly limited as long as it is used as a separator that can be used to separate the anode chamber and the cathode chamber, which has been conventionally used in electrochemical cells.此种 As such a separator, various electrolyte membranes or porous membranes can be used. Examples of the electrolyte membrane include polymer electrolyte membranes such as ion exchange solid polymer electrolyte membranes, and specifically, NAFION (registered trademark) 115, 117, NRE-212 (manufactured by SIGMA ALDRICH), and the like. As the porous film, porous glass, porous alumina, porous titanium oxide, and other porous ceramics, porous polyethylene, and porous polymers such as 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 are not mixed, and can be independent from each electrode chamber. Take out the exit. When O ₂ gas and GeH _{4 are} mixed, O ₂ gas and GeH ₄ react, and the yield of GeH ₄ tends to decrease.

<An electrolytic solution containing a germanium compound> This method is to produce GeH ₄ from an electrolytic solution containing a germanium compound. The electrolytic solution is preferably an aqueous solution.

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

In order to improve the conductivity of the electrolytic solution and promote the solubility of GeO ₂ to water, the electrolytic solution preferably contains an ionic substance. As the ionic substance, a conventionally known ionic substance used in electrochemistry can be used, but from the viewpoint of excellent effects as described above, KOH or NaOH is preferred. Among these, KOH aqueous solution is more excellent in electrical conductivity than NaOH aqueous solution, so it is preferably KOH.

The KOH concentration in the electrolyte is preferably 1 to 8 mol / L, and more preferably 2 to 5 mol / L. When the KOH concentration is within the aforementioned range, an electrolyte having a high GeO ₂ concentration is easily obtained, 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 electrolytic solution tends to decrease, a high voltage is required in the production of GeH ₄ , and the solubility of GeO ₂ in water tends to decrease, leading to a reaction. Cases of reduced efficiency. On the other hand, when the KOH concentration exceeds the upper limit of the above range, the electrode or unit material tends to be a material with high corrosion resistance, and the cost of the device may increase.

<Reaction conditions> In this method, the current per unit area (current density) of the cathode at the time of manufacturing GeH ₄ (at the time of the aforementioned energization) is excellent from the viewpoint that the reaction speed is excellent and GeH ₄ can be manufactured at high current efficiency. It is 30 to 500 mA / cm ² , more preferably 50 to 400 mA / cm ² . When the current density is in the aforementioned range, the generation rate or reaction efficiency of GeH ₄ per unit time does not decrease, and the amount of hydrogen generated due to the electrolysis of water can be suppressed to a moderate 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 does not decrease, and the power consumption for unit heating can be suppressed to a moderate level.

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

In this method, the aforementioned electrolyte in the electrochemical unit may be in a static state, or it may be stirred, or other liquid tanks may be provided and circulated. When other liquid tanks are provided and circulated as described above, the change in the concentration of the reaction solution is relatively small, and the stability of the current efficiency can be expected, and the GeO ₂ concentration on the electrode surface can be kept high, and the reaction speed can be expected to increase. Therefore, the aforementioned electrolyte in the electrochemical cell is preferably circulated.

<Manufacturing apparatus for GeH ₄ > This method is not particularly limited if the aforementioned electrochemical cell is used, but other than this cell, a power source and a measuring means (FT-IR, pressure gauge (PI), etc.) as shown in FIG. 1 can be used, for example. , Accumulators, etc.), a conventionally known device such as a nitrogen (N ₂ ) supply path, a mass flow controller (MFC), and an exhaust path. Further, a device having the aforementioned circulation flow path and the like (not shown) may be used. [Example]

The following examples specifically illustrate the present invention, but the present invention is not limited to these examples.

[Example 1] As shown in FIG. 1, the following materials were used to produce an electrochemical cell made of vinyl chloride with a separator separating an anode chamber and a cathode chamber.・ Cathode: 0.5cm × 0.5cm × 0.5mm thick Ag plate ・ Anode: 2cm × 2cm × 0.5mm thick Ni plate ・ Separator: NAFION (registered trademark) NRE-212 (manufactured by SIGMA ALDRICH) A 4 mol / L KOH aqueous solution dissolves GeO ₂ at a concentration of 90 g / L. ・ The amount of electrolyte introduced into the cathode compartment: 100 mL Silver electrode

After the gas phase portions of the anode chamber and the cathode chamber in the obtained electrochemical cell were purged with nitrogen (N ₂ ), a current of -57 mA was flowed for 10 minutes at a frequency of -57 mA using a power source of Hz-5000 manufactured by Beidou Electric Co., Ltd. to electrochemically manufacture GeH ₄ . The current density at this time was 99 mA / cm ² . In addition, the electrochemical cell temperature when the current was flowing was not controlled, and the reaction temperature was 14 ° C. The total outlet gas (gas containing GeH ₄ and hydrogen) generated by the reaction is measured by using an accumulator to measure the outlet gas of the cathode chamber, and the concentration of GeH ₄ in the total outlet gas is measured using FT-IR. From these measurement results, the amount of GeH ₄ produced was calculated.

After the current was applied, the current efficiency was calculated based on the following formula from the amount of GeH ₄ generated and the applied current between 0 to 10 minutes, and the current efficiency was set to the current efficiency of 10 minutes for the reaction time. The results are shown in Table 1. Current efficiency (%) = [Equivalent to the amount of GeH ₄ generated (mmol / min) (C / min) × 10 (min) × 100] / [Total applied amount (C / min) × 10 ( min)]

[Comparative Example 1] A reaction was performed under the same conditions as in Example 1 except that a Cu plate having a thickness of 0.5 cm × 0.5 cm × 0.5 mm 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] 反应 Reaction was performed under the same conditions as in Example 1 except that a Cd plate of 0.5 cm x 0.5 cm x 0.5 mm thickness was used as a cathode, and the applied current was changed to -55 mA for 10 minutes. The results are shown in Table 1.

[Table 1]

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

Claims (6)

A method for electrochemically manufacturing germane is based on an electrochemical cell having a separator, an anode, and a cathode containing silver. The electrolytic solution containing a germanium compound is energized to generate germane at the cathode. The method for producing germane according to claim 1, wherein the aforementioned electrolytic solution is an electrolytic solution containing germanium dioxide and an ionic substance. The method for producing germane according to claim 2, wherein the ionic substance is potassium hydroxide or sodium hydroxide. The method for producing germane according to claim 2, wherein the ionic substance is potassium hydroxide, and the potassium hydroxide concentration in the electrolyte is 1 to 8 mol / L. The method for producing germane according to any one of claims 1 to 4, wherein the aforementioned cathode current density at the time of energization is 30 to 500 mA / cm ² . The method for producing germane according to any one of claims 1 to 4, wherein the aforementioned reaction temperature when producing germane is 5 to 100 ° C.