CN110612366B

CN110612366B - Method for electrochemically producing germane

Info

Publication number: CN110612366B
Application number: CN201880031037.7A
Authority: CN
Inventors: 铃木淳
Original assignee: Showa Denko KK
Current assignee: Resonac Holdings Corp; Resonac Corp
Priority date: 2017-05-19
Filing date: 2018-05-07
Publication date: 2022-04-05
Anticipated expiration: 2038-05-07
Also published as: WO2018212005A1; CN110612366A; KR20190140029A; JP7030114B2; TWI689626B; JPWO2018212005A1; TW201905241A; KR102305936B1

Abstract

In a method for electrochemically producing germane, in an electrochemical cell having a separator, an anode, and a cathode containing palladium, an electrolyte solution containing a germanium compound is energized, and germane is produced at the cathode.

Description

Method for electrochemically producing germane

Technical Field

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

Background

Conventionally, the speed and power consumption of semiconductor devices have been increased by miniaturization of the devices, and strained silicon such as a SiGe substrate has been drawing attention as a technique for further increasing the speed and power consumption.

Germane (GeH) is used as a raw material for fabricating the SiGe substrate₄) GeH is expected to accompany the increase in the use of SiGe substrates₄The amount of (2) used also increases.

As such GeH₄For example, patent document 1 describes the following manufacturing method: GeH can be electrochemically produced at high current efficiency by using a Cu alloy or a Sn alloy as a cathode₄。

In addition, theNon-patent document 1 describes the following: as a process for electrochemically producing GeH₄The cathode used in the method screens Pt, Zn, Ti, graphite, Cu, Ni, Cd, Pb and Sn, and the result shows that Cd or Cu is optimal in the aspects of current efficiency, pollution and the like.

Further, non-patent document 2 discloses the following: as a process for electrochemically producing GeH₄As a result of examining many cathodes used in the above process, the hydrogenation rate was 99% or more when Hg was used as a cathode.

Prior art documents

Patent document

Patent document 1: japanese laid-open patent 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

Disclosure of Invention

The cathode (bronze manufactured by McMaster-Carr) used in the examples of patent document 1 is difficult to apply to a method of forming only effective elements on the surface by plating, coating, or the like, and is not suitable for industrial GeH₄The manufacturing of (1).

Further, when Cd and Cu used in the above non-patent document 1 are used as a cathode, the current efficiency is lowered in a long-term reaction, and thus the method is not suitable for an industrial continuous reaction.

The cathode (Hg) used in the above non-patent document 2 is highly toxic and cannot be used for industrial reactions.

One embodiment of the present invention provides electrochemical production of GeH with stable current efficiency for a long period of time₄The method of (1).

The present inventors have conducted extensive studies to solve the above problems, and as a result, have found that the above problems can be solved by the following production method and the like, and have completed the present invention.

The constitution of the present invention is as follows.

[1] In an electrochemical cell having a separator, an anode, and a cathode containing palladium, an electrolyte containing a germanium compound is energized, and germane is produced at the cathode.

[2] The production method according to [1], wherein the electrolyte solution is an electrolyte solution containing germanium dioxide and an ionic substance.

[3] The production method according to [2], wherein the ionic substance is potassium hydroxide or sodium hydroxide.

[4] The production method according to [2] or [3], wherein the ionic substance is potassium hydroxide, and the concentration of potassium hydroxide in the electrolyte is 1 to 8 mol/L.

[5]According to [1]～[4]The method according to (1), wherein the current density of the cathode during the energization is 30 to 500mA/cm²。

[6] The production method according to any one of [1] to [5], wherein the reaction temperature at the time of germane generation is 10 to 100 ℃.

According to one embodiment of the present invention, GeH can be electrochemically produced with stable current efficiency for a long period of time₄。

Drawings

Fig. 1 is a schematic illustration of the apparatus used in the examples.

FIG. 2 is a graph showing the relationship between the reaction time and the current efficiency in the production method of example 1.

FIG. 3 is a graph showing the relationship between the reaction time and the current efficiency in the production method of comparative example 1.

Detailed Description

Electrochemical production of GeH₄Methods of (1)

GeH electrochemical production according to one embodiment of the present invention₄In an electrochemical cell (electrochemical cell) having a separator, an anode and a cathode containing palladium, an electrolytic solution containing a germanium compound is electrified, and GeH is supplied to the cathode₄Generation thereby electrochemically producing GeH₄。

According to the method, the device can be used for a long timeStable current efficiency efficient electrochemical production of GeH₄. Thus, by using GeH obtained by the present method₄The SiGe substrate can be efficiently manufactured.

The present method can be advantageously used for industrial continuous reaction because the above effects are obtained.

Examples of such industrial reactions include reactions with a scale of 500 to 2500L of electrolyte capacity, 30 to 150 cell(s) and 100 to 300A of current used.

The continuous reaction is preferably carried out for 20 to 200 hours, more preferably 30 to 120 hours.

According to the method, GeH can be produced with a current efficiency of preferably 10 to 90%, more preferably 12 to 40%₄。

Further, according to the present method, for example, in the case of a continuous reaction for 30 hours, when the current efficiency at a reaction time of 10 hours, at which the reaction is substantially in a stable region, is set to 100%, the current efficiency at the reaction time of 30 hours can be maintained at preferably 95% or more, more preferably 99% or more.

The current efficiency can be measured specifically by the method described in the following examples.

< electrochemical cell >

The electrochemical cell is not particularly limited if it includes a separator, an anode, and a cathode, and conventionally known cells can be used.

Specific examples of the cell include a cell in which an anode chamber including an anode and a cathode chamber including a cathode are separated from each other by a separator.

< cathode >

The cathode is not particularly limited if it contains Pd.

The cathode may be an electrode made of metal Pd, an electrode made of a Pd-based alloy containing Pd as a main component, or an electrode plated or coated with metal Pd or a Pd alloy.

Examples of the plated or coated electrode include an electrode obtained by plating a base material such as Ni or coating a metal Pd or Pd alloy.

Among them, since metal Pd is expensive, an electrode plated or coated with metal Pd or a Pd alloy is preferable from the viewpoint of cost.

The shape of the cathode is not particularly limited, and may be any of plate-like, columnar, hollow, and the like.

The size, surface area, and the like of the cathode are not particularly limited.

< Anode >

The anode is not particularly limited, and GeH is produced electrochemically by the conventional method₄The anode used in the case may be any one, but is preferably an electrode made of a conductive metal such as Ni or Pt, an electrode made of an alloy containing the conductive metal as a main component, or the like, and is preferably an electrode made of Ni in terms of cost.

In addition, as the anode, an electrode plated or coated with the conductive metal or an alloy containing the conductive metal may be used similarly to the cathode.

The shape, size, surface area, and the like of the anode are also not particularly limited, as are the cathodes.

< diaphragm >

The separator is not particularly limited, and a separator that can separate an anode chamber from a cathode chamber, which has been conventionally used in an electrochemical cell, may be used.

As such a separator, various electrolyte membranes and porous membranes can be used.

The electrolyte membrane may be a polymer electrolyte membrane, for example, an ion-exchange solid polymer electrolyte membrane, specifically NAFION (registered trademark) 115 and 117, NRE-212 (manufactured by シグマアルドリッチ) or the like.

As the porous film, porous glass, porous ceramic such as porous alumina and porous titania, porous polyethylene, porous polymer such as porous propylene, or the like can be used.

In one embodiment of the present invention, the electrochemical cell is divided into an anode chamber and a cathode chamber by a diaphragm, so that the electrochemical cell can be prevented from being exposed to the sunExtremely produced O₂Gas and GeH produced at the cathode₄Mixed and withdrawn from separate outlets of the respective electrode chambers.

If O is₂Gas and GeH₄Mixed if O is present₂Gas and GeH₄Is reacted to GeH₄The yield of (2) tends to be low.

< electrolyte containing germanium compound >

In the method, GeH is produced from an electrolyte containing a germanium compound₄。

The electrolyte is preferably an aqueous solution.

As the germanium compound, GeO is preferable₂。

GeO in the above electrolyte₂High reaction speed, and efficient synthesis of GeH₄Therefore, it is preferable to set the concentration to be saturated with respect to the solvent, preferably with respect to water.

In order to improve the conductivity of the electrolyte and promote GeO₂The electrolyte preferably contains an ionic substance because of its solubility in water.

As the ionic substance, a conventionally known ionic substance used in electrochemistry can be used, but KOH or NaOH is preferable in terms of excellent effects. Among these, KOH is preferable because KOH aqueous solution is superior in conductivity to NaOH aqueous solution.

The concentration of KOH in the electrolyte is preferably 1 to 8mol/L, and more preferably 2 to 5 mol/L.

When the KOH concentration is in the above range, GeO can be easily obtained₂High concentration electrolyte solution, and high current efficiency₄。

When the concentration of KOH is less than the lower limit of the above range, the conductivity of the electrolyte tends to be low, and GeH may be used₄The production of (2) requires a high voltage, and in addition, GeO is present₂The amount of the compound dissolved in water tends to decrease, and the reaction efficiency may decrease. On the other hand, when the concentration of KOH exceeds the upper limit of the above range, a material having high corrosion resistance tends to be required as a material for electrodes and cells,the cost of the apparatus may become high.

< reaction conditions >

In the method, GeH can be produced with excellent reaction speed and high current efficiency₄Starting from the same point, GeH is produced₄The magnitude of the current per unit area (current density) of the cathode is preferably 30 to 500mA/cm in the above-mentioned energization²More preferably 50 to 400mA/cm²。

If the current density is in the above range, it is possible to prevent GeH per unit time₄The production rate and reaction efficiency are reduced, and the amount of hydrogen produced by electrolysis of water is appropriately controlled.

Excellent in reaction rate and capable of producing GeH at low cost₄Starting from the same point, GeH is produced₄When (make GeH)₄During generation), the reaction temperature is preferably 10 to 100 ℃, and more preferably 15 to 40 ℃.

If the reaction temperature is in the above range, the power consumption for heating the cell can be appropriately controlled without lowering the reaction efficiency.

Manufacture of GeH₄The reaction atmosphere (gas phase portion of the anode chamber and the cathode chamber) in the case of using the above-mentioned catalyst is not particularly limited, but is preferably an inert gas atmosphere, and nitrogen is preferable as the inert gas.

In the method, the electrolyte in the electrochemical cell may be left at rest, may be stirred, or may be circulated by separately providing another liquid tank.

When the other liquid tank is provided and circulated, the change in the concentration of the reaction solution is relatively small, and stabilization of the current efficiency can be expected, and the GeO on the surface of the electrode can be kept high₂The concentration is expected to improve the reaction rate. Therefore, the electrolyte solution in the electrochemical cell is preferably circulated.

＜GeH₄Manufacturing apparatus of (1) >

In the method, the electrochemical cell is not particularly limited as long as it is used, and a power supply or a measuring cell (FT-IR) having a structure shown in FIG. 1, for example, can be used in addition to the above cellPressure gauge (PI), Integrator, etc.), nitrogen (N)₂) A supply path, a Mass Flow Controller (MFC), an exhaust path, and the like.

Further, a device having the aforementioned circulation channel or the like, which is not shown, may be used.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[ example 1]

An electrochemical cell made of vinyl chloride, in which an anode chamber and a cathode chamber were separated by a diaphragm as shown in fig. 1, was fabricated using the following materials.

Cathode: 0.5cm Pd plate with thickness of 0.5mm

Anode: ni plate 2cm x 0.5mm thick

A separator: ナフィオン (registered trademark) NRE-212(シグマアルドリッチ Co., Ltd.)

Electrolyte solution: by reacting GeO₂A solution obtained by dissolving KOH in a concentration of 90g/L in a 4mol/L aqueous solution

Introduction amount of electrolyte into cathode chamber: 100mL

Introduction amount of electrolyte into anode chamber: 100mL

Standard electrodes: arranging a silver-silver chloride electrode on the cathode

The gas phase parts of the anode chamber and cathode chamber in the obtained electrochemical cell are treated with nitrogen (N)₂) After the removal, Hz-5000 manufactured by BeiDou electrician (Ltd.) was used as a power source, and a current was applied at-100 mA for 37 hours to electrochemically manufacture GeH₄. The current density at this time was 174mA/cm²。

Furthermore, the temperature of the electrochemical cell is not controlled while applying the current, resulting in a reaction temperature of 15 to 22 ℃.

The total amount of the outlet gas (including GeH) generated by the reaction was measured by measuring the outlet gas of the cathode chamber with an integrator₄And hydrogen gas) and measured for GeH in the total amount of the outlet gas using FT-IR₄And (4) concentration. From these measurementsDetermining the result to calculate GeH₄The amount of production of (c).

From the last 1 hour of GeH at a particular reaction time₄The current efficiency was calculated based on the following equation, and the current efficiency was defined as the current efficiency at a reaction time of 1 hour. The current efficiency was calculated for each reaction time in the same manner. The results are shown in FIG. 2.

According to the results of fig. 2, no decrease in current efficiency was seen in the reaction for 37 hours.

Current efficiency (%) (-) with GeH producing the above-mentioned amount of production (mmol/min)₄Corresponding electric quantity (C/min) x 60(min) x 100]/[ Total amount of electricity applied (C/min) × 60(min)]

Comparative example 1

A reaction was carried out under the same conditions as in example 1 except that a Cd plate having a thickness of 1 cm. times.1 cm. times.0.5 mm was used as a cathode and the applied current was changed to-200 mA for 24 hours.

Fig. 3 shows the results of the current efficiencies calculated in the same manner as in example 1.

According to the results of fig. 3, when the reaction time exceeded 12 hours, no decrease in current efficiency was observed.

From fig. 2, it can be determined that the current efficiency is about 16% (when the reaction time is about 10 hours, at which the reaction becomes a stable region) at the time of the ordinary reaction, and the current efficiency does not decrease even if the reaction time exceeds 30 hours.

On the other hand, fig. 3 is a graph of a mountain shape having a peak of current efficiency with a reaction time of 10 hours, and when the reaction time exceeds 10 hours, the current efficiency continues to decrease. Therefore, the cathode (Cd plate) used in comparative example 1 could not withstand a long-term reaction, and it was necessary to increase the frequency of replacing the cathode and the frequency of maintaining the cathode, and thus the Cd plate was considered to be unsuitable for an industrial reaction.

In comparative example 1, the current load per unit area of the cathode plate, that is, the current density (200mA/(1 cm)²+1cm²+(1×0.05×3))＝93mA/cm²) Same as example 1(100mA/(0.25 cm)²+0.25cm²+(0.5×0.05×3))＝174mA/cm²) In contrast, although comparative example 1 has mild conditions compared to example 1, the current efficiency continues to decrease from about 10 hours of the reaction time, but the current efficiency does not decrease even after 30 hours or more has elapsed in example 1.

In the calculation of the current density, "× 3" is because one surface is hidden by the fixing jig.

Claims

1. A method for electrochemically producing germane, wherein in an electrochemical cell having a separator, an anode, and a cathode containing palladium, electricity is applied to an electrolyte solution containing a germanium compound, and germane is generated at the cathode.

2 . The manufacturing method according to claim 1 , wherein the electrolytic solution is an electrolytic solution containing germanium dioxide and an ionic substance. 3 .

3. The production method according to claim 2, wherein the ionic substance is potassium hydroxide or sodium hydroxide.

4 . The method according to claim 2 , wherein the ionic substance is potassium hydroxide, and the concentration of potassium hydroxide in the electrolytic solution is 1 to 8 mol/L. 5 .

5 . The production method according to claim 1 , wherein the current density of the cathode at the time of energization is 30 to 500 mA/cm ² .

6 . The production method according to claim 1 , wherein the reaction temperature at the time of generating the germane is 10 to 100° C. 7 .