JP4710002B2 - Membrane manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a membrane. Specifically, the present invention relates to a method for manufacturing a film made of a group 14 element of carbon, silicon, and germanium.

  Diamond-like carbon (DLC) is an amorphous carbon film having properties similar to diamond and a smooth surface containing hydrogen. Among amorphous carbon thin films mainly composed of carbon, those having high strength and low friction coefficient are indicated. It is attracting attention as a highly functional film because it has excellent mechanical strength such as high hardness, wear resistance, and low friction coefficient, and excellent electrical and chemical properties. Up to now, it has been used for sliding parts of machine parts, but in recent years its application fields have been greatly expanded. Application to LSI interlayer insulation films and PDP (Plasma Display Panel) electron-emitting devices using insulation and low dielectric constant, application to coating materials for molds using corrosion resistance and low adhesion, and gas barrier properties Application to coating materials for PET bottles and the like can be mentioned. In addition, since it is a carbon material, its biocompatibility is good and applied research in the medical field is actively conducted.

  Conventionally, as a method for producing a diamond-like carbon film, for example, a plasma CVD method which is a kind of chemical vapor deposition method as shown in (Patent Document 1) is known. However, the plasma CVD method has a problem that a dense and dense film cannot be formed. For this reason, it has been difficult to change the characteristics of the diamond-like carbon film according to various uses.

  Further, although the plasma CVD method is used as a method for producing a silicon film, a germanium film, etc., there is a problem that a dense and dense film cannot be formed as in the case of producing a diamond-like carbon film.

JP 08-217596 A

  An object of the present invention is to provide a film manufacturing method for forming a high-density diamond-like carbon film, a silicon film, a germanium film, or the like in view of the above-described conventional situation.

  In order to solve the above-mentioned problems, a film manufacturing method according to the present invention includes, as claimed in claim 1, a plasma discharge in a mixed system of a compound containing a group 14 element and a reaction solvent in a supercritical state. A film is formed.

  According to the above means, a uniform mixed system is formed by supplying the raw material compound in a supercritical fluid having both the liquid property of high concentration and high solubility and the gas property of high diffusibility and low viscosity, A dense and high-density film can be formed.

  In order to solve the above-mentioned problems, the film manufacturing method according to the present invention includes, as claimed in claim 2, a mixed system in which a mixed system of a compound containing a group 14 element and a reaction solvent is in a supercritical state. A film is formed on a substrate by performing plasma discharge.

  According to the above means, the mixed system of the reaction solvent and the compound containing a group 14 element is brought into a supercritical state having both liquid properties of high concentration and high solubility and gas properties of high diffusibility and low viscosity. Therefore, it is possible to supply the raw material compound uniformly at a high concentration and to form a high-density film.

  A third aspect of the present invention is characterized in that in the film manufacturing method of the first or second aspect, the group 14 element is carbon, and the formed film is a diamond-like carbon film.

  According to the above means, a diamond-like carbon thin film having characteristics such as high strength and a low friction coefficient can be obtained.

  Further, according to a fourth aspect of the present invention, in the film manufacturing method according to the third aspect, the compound containing carbon element is selected from saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, and ethers. It is 1 type or 2 types or more, It is characterized by the above-mentioned.

  Furthermore, claim 5 is the film manufacturing method according to claim 3, wherein the compound containing carbon element is selected from saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, and aromatic hydrocarbons. It is characterized by more than seeds.

  Furthermore, claim 6 is the film manufacturing method according to claim 5, wherein the saturated aliphatic hydrocarbon is one or more selected from compounds having 1 to 20 carbon atoms.

  Furthermore, claim 7 is the method for producing a film according to claim 5, wherein the unsaturated aliphatic hydrocarbon is one or more selected from compounds having 1 to 20 carbon atoms. .

  According to the above means, an optimum compound is selected for forming a diamond-like carbon film.

  Further, an eighth aspect is characterized in that in the film manufacturing method according to the first or second aspect, the group 14 element is silicon and the formed film is a silicon film.

  According to the above means, a silicon thin film used for an integrated circuit silicon wafer or the like can be obtained.

Furthermore, a ninth aspect is characterized in that in the film manufacturing method according to the eighth aspect, the compound is at least one selected from SiH ₄ and Si ₂ H ₆ .

  According to the above means, the optimum compound for forming the silicon film is selected.

  A tenth aspect of the present invention is the film manufacturing method according to the first or second aspect, wherein the group 14 element is a germanium element and the formed film is a germanium film.

  According to the above means, a germanium thin film used for a germanium wafer for an integrated circuit or the like can be obtained.

Further, according to an eleventh aspect, in the film manufacturing method according to the tenth aspect, the compound is at least one selected from GeH ₄ and Ge ₂ H ₆ .

  According to the above means, the optimum compound for forming the germanium film is selected.

  A twelfth aspect is characterized in that, in the film manufacturing method according to any one of the first to eleventh aspects, the reaction solvent is carbon dioxide.

  According to the above means, since carbon dioxide is selected as the supercritical fluid, there are advantages that it is inexpensive, non-toxic, flame retardant, and critical temperature is close to room temperature.

  According to the present invention, since a supercritical fluid having both liquid properties of high concentration and high solubility and gas properties of high diffusibility and low viscosity is used, the raw material compound can be supplied at a high concentration. Since the concentration of the raw material compound can be selected widely from a low concentration to a high concentration, a diamond-like carbon, silicon, or germanium film having characteristics corresponding to various applications can be produced.

  Hereinafter, the present invention will be described in detail based on the best mode for carrying out the invention.

  First, the embodiment (1) will be described. In the film manufacturing method according to Embodiment (1), a compound B containing a carbon element is used as a carbon raw material, and plasma discharge is performed in a mixed system of the carbon raw material and the reaction solvent A. By causing plasma discharge, the compound B containing the carbon element is decomposed, and a diamond-like carbon film is deposited on the substrate.

  FIG. 1 shows an embodiment of a film manufacturing apparatus used in the film manufacturing method of the present invention. The manufacturing apparatus 1 in FIG. 1 includes a pressure-resistant reactor 10 in a thermostatic chamber 21, and plate-like electrodes 11 and 12 are arranged inside the reactor 10 so as to face each other. The substance enclosed in the cylinder 22 is configured to be introduced into the reactor 10 via the liquid feed pump 24 and the pressure regulating valve 25. The reactor 10 is kept at a constant temperature by a thermostatic chamber 21. The liquid feed pump 24 is cooled using a cooler 23. Further, the pressure in the reactor 10 is adjusted by the exhaust pressure adjusting valve 26. Further, a high frequency power source 27 for supplying power for performing plasma discharge is connected to the electrodes 11 and 12 via a matching unit 28.

  As the electrodes 11 and 12, any material capable of plasma discharge can be used. Specifically, platinum, gold, galvanized iron, iron, brass electrodes, and the like can be used. Further, the distance between the electrodes is not particularly limited because it varies depending on the temperature, pressure, or discharge conditions in the reactor 10, but is usually set to about 0.1 to 1.0 mm.

  Next, a method for manufacturing a film using the above-described film manufacturing apparatus will be described.

  First, the reaction solvent A is pressurized to a critical pressure or higher using the liquid feed pump 24 and supplied to the reactor 10. At this time, the pressure of the substance to be supplied is adjusted using the pressure adjustment valve 25 and the exhaust pressure adjustment valve 26. In addition, when supplying the reaction solvent A, the liquid feed pump 24 is cooled using the cooler 23. Thereby, it can pressurize rapidly to the target pressure and can stabilize a pressure. And the temperature inside the reactor 10 is raised using the thermostat 21, and it is made more than critical temperature.

  The reaction solvent A refers to a substance that dissolves a reaction product when forming a film. The reaction solvent A is not particularly limited, and can be appropriately selected from conventionally known gases and liquid substances in consideration of the critical temperature and critical pressure inherent to the substance. Specific examples include carbon dioxide, trifluoromethane (fluoroform), ethane, propane, butane, benzene, methyl ether, chloroform and the like. Among these, carbon dioxide is most preferably used in terms of cost, safety, critical conditions, and the like. For example, carbon dioxide has a critical temperature of 304.5K and a critical pressure of 7.38 MPa, and transitions to a supercritical state in a range higher than that. Further, when carbon dioxide is used, it also serves as a carbon raw material for forming a diamond-like carbon film.

  Further, the compound B containing carbon element is introduced into the reactor 10 in advance, or mixed with the reaction solvent A and supplied into the reactor 10. And the inside of the reactor 10 becomes a mixed system of the compound B containing the carbon element and the reaction solvent A.

  The compound containing carbon is not particularly limited as long as it has solubility in the reaction solvent A, and various compounds such as saturated aliphatic hydrocarbon, unsaturated aliphatic hydrocarbon, aromatic hydrocarbon, alcohol, ether, etc. Organic compounds can be used.

  Examples of saturated aliphatic hydrocarbons include chain saturated aliphatic hydrocarbons and cyclic saturated aliphatic hydrocarbons. As the chain saturated aliphatic hydrocarbon, those having 1 to 20 carbon atoms are preferably used. Specifically, from methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, icosane, isobutane, isopentane, One or more compounds selected. Of these, ethane, propane, butane, pentane, and hexane, which are inexpensive and easy to handle, are particularly preferably used. When the number of carbon atoms is 21 or more, thermal decomposition occurs below the critical temperature, and it may be difficult to form a diamond-like carbon film.

  Moreover, as a cyclic | annular saturated aliphatic hydrocarbon, a C1-C20 thing is used preferably. Specifically, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, or aliphatic hydrocarbons containing them as a structure, such as methylcyclopropane, ethylcyclopropane, dimethylcyclopropane, trimethyl Cyclopropane, propylcyclopropane, butylcyclopropane, methylethylcyclopropane, triethylcyclopropane, tripropyllcyclopropane, tributylcyclopropane, methylcyclobutane, ethylcyclobutane, dimethylcyclobutane, trimethylcyclobutane, tetramethylcyclobutane, diethylcyclobutane, triethyl Cyclobutane, tetraethylcyclobutane, dipropylcyclobutane, tripropylcyclobutane, Trapropylcyclobutane, propylcyclobutane, butylcyclobutanemethylethylcyclobutane, methylcyclopentane, ethylcyclopentane, dimethylcyclopentane, trimethylcyclopentane, tetramethylcyclopentane, pentamethylcyclopentane, diethylcyclopentane, triethylcyclopentane, tetraethylcyclopentane , Pentaethylcyclopentane, dipropylcyclopentane, tripropylcyclopentane, tetrapropylcyclopentane, pentapropylcyclopentane, propylcyclopentane, butylcyclopentane, methylethylcyclopentane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, trimethyl Cyclohexane, tetramethylcyclohexane, pen Methylcyclohexane, hexamethylphosphoric cyclohexane, propyl cyclohexane, butyl cyclohexane, which is one or more compounds selected from methyl ethyl cyclohexane. Among these, cyclopropane, cyclobutane, cyclopentane, and cyclohexane are particularly preferable. When the number of carbon atoms is 21 or more, thermal decomposition occurs below the critical temperature, and it may be difficult to form a diamond-like carbon film.

  The unsaturated aliphatic hydrocarbon is preferably one having 1 to 20 carbon atoms, specifically, ethene, propene, butene, pentene, hexene, heptene, octene, nonene, deken, butadiene, pentadiene, hexadiene. 1 type, or 2 or more types selected from heptadiene, octadiene, nonadiene, hexatriene, heptatriene, octatriene, nonatriene is used. When the number of carbon atoms is 21 or more, pyrolysis and side reactions occur below the critical temperature, which may make it difficult to form a diamond-like carbon film.

  The mixing ratio of the reaction solvent A and the compound B containing the carbon element is not particularly limited, and can be appropriately set according to the characteristics of the target diamond-like carbon film.

  The conditions of temperature and pressure can be appropriately set except that the reaction solvent A is in a supercritical state and mixed with the compound B containing carbon element and made to react, but the reaction solvent A and carbon element are included. It is particularly preferable to react the mixed system of compound B in a supercritical state. FIG. 2 shows an example of a vapor-liquid equilibrium curve of compound B containing reaction solvent A and carbon element. C. In FIG. p. (A) is the critical point of reaction solvent A, c. p. (B) represents the critical point of the compound B containing a carbon element. The curve represents the phase diagram of the mixed system, the low temperature side curve is the boiling point curve, and the high temperature side curve is the dew point curve. Moreover, VL represents the mixed system critical curve of the reaction solvent A and the compound B containing a carbon element. In this case, the mixed system critical point in the two-component system composed of the reaction solvent A and the compound B containing the carbon element varies depending on the mixing ratio of the two components. Therefore, in these mixed systems, the reaction solvent A and the compound B containing the carbon element are both in a supercritical state and uniformly mixed at a temperature and pressure higher than the mixed system critical curve shown in FIG.

  For example, the case where carbon dioxide and heptane are selected as the reaction solvent A and the compound B containing carbon element will be described. Carbon dioxide has a critical point of 304.5 K (31.1 ° C.) and a pressure of 7.387 MPa, and pentane has a critical point of 470 K (196.7 ° C.) and a pressure of 3.36 MPa. These mixed systems show a phase diagram as shown in FIG. 2, and carbon dioxide and pentane are in a supercritical state and uniformly mixed at a higher temperature and higher pressure than the mixed system critical curve.

  Subsequently, power is applied between the electrodes 11 and 12 by the high frequency power source 27 to perform plasma discharge. The discharge conditions at that time vary depending on the distance between electrodes and pressure, but for example, the frequency of the power source is set to 1 to 50 MPa and the power is set to about 100 to 200 W. Also, the reaction time can be appropriately set according to the scale of the reactor and the discharge conditions, but in general, it is appropriate to set it to about several minutes.

  By performing plasma discharge and generating plasma in a mixed system of the compound B containing carbon element and the reaction solvent A, the compound B containing carbon element decomposes and reacts, and a diamond-like carbon film is formed on the electrodes 11 and 12. It is formed. In the present embodiment, the electrode 11 is a base material on which a diamond-like carbon film is formed.

  Furthermore, after completion of the reaction, the substance in the supercritical state is transferred again to a state below the critical point by reducing the pressure or lowering the temperature. In this process, the supercritical substance is rapidly vaporized or liquefied, so that a vigorous flow is generated in the system, and the impurities on the base material are blown away and washed. Therefore, washing with water or the like conventionally performed after the reaction is unnecessary, and waste liquid such as water used for washing does not occur.

  According to the above embodiment (1), since the reaction is performed in a mixed system of the reaction solvent A in a supercritical state and the compound B containing carbon element, a high concentration raw material can be supplied, and high density It is possible to form a diamond-like carbon film. In particular, since a reaction solvent in a supercritical state has high solubility, various compounds containing carbon element can be used as a raw material. In addition, since the material in the supercritical state has high diffusibility, it is possible to efficiently supply the raw material onto the base material. Further, since the mixed system of the reaction solvent A and the compound B containing the carbon element is brought into a supercritical state, the reaction system is maintained at a uniform concentration, so that the density of the produced diamond-like carbon film is improved.

  The method for producing a diamond-like carbon film according to the embodiment (1) includes forming a film on a sliding part of a mechanical part, forming an LSI interlayer insulating film, creating a PDP (Plasma Display Panel) electron-emitting device, and mold It can be used for coating on PET, coating on PET bottles, and the like.

  In the embodiment (1), the diamond-like carbon film is formed using the electrodes 11 and 12 as the base material. However, the base material to be formed is provided on the electrodes 11 and 12 and the film is formed on the base material. It is also possible to form.

  In the above-described example, the case where a high-frequency power source is used when performing plasma discharge has been described. However, a DC power source may be used instead. In the case of a high-frequency power source, the target diamond-like carbon film is formed on both electrodes or a substrate provided on both electrodes, but when a DC power source is used, one electrode (cathode) or one electrode side A diamond-like carbon film can be efficiently produced on the substrate.

  Next, the embodiment (2) will be described. The embodiment (2) is characterized in that a silicon film is formed using a compound containing a silicon atom instead of the compound B containing a carbon element in the embodiment (1).

Even when a silicon film is formed using a compound containing a silicon atom, a method of forming a diamond-like carbon film because a silicon atom is a substance having a structure in which atoms are arranged tetrahedrally in the same manner as a carbon element. Can be done as well. As the compound containing a silicon primary atom, a compound represented by the chemical formula Si _x H _y , where x is an integer of 1 to 10 and y is 2 to 2x + 2 is preferably used. Of these, SiH ₄ and Si ₂ H ₆ are particularly preferably used. Note that the reaction solvent, discharge conditions, and the like are the same as those in the embodiment (1).

  According to the above embodiment (2), the same effect as in the above embodiment (1) is obtained, and a high-density and uniform silicon film is formed on the substrate. The obtained silicon film is used for solar cell elements and thin film transistors by doping impurities.

  Next, the embodiment (3) will be described. The embodiment (3) is characterized in that a germanium film is formed using a compound containing a germanium element instead of the compound B containing a carbon element in the embodiment (1).

Even when a germanium film is formed using a compound containing a germanium element, a diamond-like carbon film is formed because the germanium element is a substance that adopts a structure in which atoms are arranged tetrahedrally like a carbon element. This can be done in the same way as The compound containing germanium is preferably represented by the chemical formula Ge _x H _y , where x is an integer of 1 to 10 and y is 2 to 2x + 2. Of these, GeH ₄ and Ge ₂ H ₆ are particularly preferably used. Note that the reaction solvent, discharge conditions, and the like are the same as those in the embodiment (1).

    According to the said Embodiment (3), there exists an effect similar to the said Embodiment (1), and a high-density and uniform germanium film | membrane is formed on a base material. The obtained germanium film is used for a semiconductor in a high-speed electronic device or the like by doping impurities.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these, The reaction solvent etc. can be suitably changed within the range described in the claim.

(Example)
The apparatus shown in FIG. 1 was used as a film manufacturing apparatus. As a pump and a pressure regulating valve, a carbon dioxide feeding pump, a fully automatic pressure regulating valve, and a fully automatic exhaust pressure regulating valve manufactured by JASCO were used. As the electrode material, platinum of 10 mm × 20 mm was used. The reactor used was a 6-well cell made of SUS316L that can be energized. PSG-1301 (AC generator), PA-150 (high frequency generator), PS-330 (DC converter), and HC-2000 (matching unit) manufactured by Tokyo High Power Co., Ltd. were used as the high frequency power source and the matching unit. The fluid source was liquefied carbon dioxide with a purity of 99.99%. And the apparatus using the pressure cell with a parallel plate electrode was assembled based on the plasma chemical vapor deposition method (plasma CVD), and the distance between electrodes was set to 0.5 mm.

  The atmospheric gas in the pressure cell (100 ml) was replaced with carbon dioxide. Thereafter, pressurization (7.5 MPa) and temperature rise (313 K) were performed. After leaving for about 60 minutes, 120 W of electric power was applied between the electrode plates for about 3 minutes using a high frequency power source (13.56 MHz) to perform plasma discharge. Then, it cooled with ice water for 60 minutes, and pressure reduction operation was performed at 0.1 MPa / min.

  The surface of the product on the electrode plate was observed using a reflection type optical microscope (Digital HF microscope VH-8000, manufactured by Keyence Corporation). The surface was observed using a scanning electron microscope (FE-SEM S-4500, manufactured by Hitachi, Ltd.). In preparing a sample for SEM observation, an electrode was coated with a platinum-palladium alloy using ion sputtering (Ion Sputter E-1030, manufactured by Hitachi, Ltd.). Note that the growth rate of the platinum-palladium alloy was set to 6.7 nm / min for 2 minutes.

Moreover, the crystal structure of the product deposited on the electrode plate was measured using a laser Raman spectrophotometer (NRS-1000 manufactured by JASCO Corporation). The measurement was performed at an excitation light wavelength of 647 nm. The resolution was 0.54 cm ⁻¹ .

  Traces due to discharge corrosion were observed on the electrode plate after the reaction, and it is thought that discharge occurred in the supercritical fluid. The discharge corrosion traces were formed by continuous overlapping of circles. Since the same discharge corrosion trace was observed on each electrode plate, it is assumed that cylindrical plasma was generated. Moreover, FIGS. 3-7 shows the photograph which observed the electrode surface with the scanning electron microscope. As shown in FIGS. 3 and 4, it can be seen that fine particles having different sizes are generated depending on the region. Each region is designated as region P and region Q, respectively. As shown in FIGS. 5 and 6, nanoscale fine particles of about 10 nm to 50 nm are generated in the region P, and fine particles of about 0.1 μm to 1.0 μm are generated in the region Q. . Further, as shown in FIG. 7, it can be seen that a diamond-like carbon thin film is formed on the electrode.

FIG. 8 shows a Raman spectrum in a region P where nanoscale fine particles of about 10 nm to 50 nm are generated. FIG. 9 shows a Raman spectrum in a region Q where fine particles of about 0.1 μm to 1.0 μm are generated. As shown in FIGS. 8 and 9, the vicinity of 1350 cm ^-1 peculiar to sp3 carbon of the diamond peak in the vicinity of ^-1 peculiar 1600cm to sp2 carbon graphite has appeared. This shows that the fine particles generated in the regions P and B are diamond-like carbon.

Furthermore, a comparison of the Raman spectra shown in FIGS. 8 and 9, the vicinity of 1350 cm ^-1 in the region P, the peak around 1600 cm ^-1 is the half width is less sharp. Therefore, it can be seen that fine particles of about 10 nm to 50 nm in the region P have high crystallinity of graphite and diamond. Further, there is a possibility that a desired diamond-like carbon film can be obtained by changing the plasma discharge conditions.

It is a figure which shows the manufacturing apparatus of the film | membrane used for the manufacturing method of the film | membrane of Embodiment (1) of this invention. It is a figure which shows an example of the vapor-liquid equilibrium curve of the reaction solvent A and the compound B containing a carbon element. It is a figure which shows the scanning electron micrograph on an electrode plate. It is a figure which shows the scanning electron micrograph on an electrode plate. FIG. 6 is a view showing a scanning electron micrograph in a region P. 3 is a view showing a scanning electron micrograph in a region Q. FIG. It is a figure which shows the scanning electron micrograph on an electrode plate. 3 is a diagram showing a Raman spectrum of a product in a region P. FIG. 2 is a diagram showing a Raman spectrum of a product in a region Q. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reactor 11, 12 Electrode 21 Constant temperature bath 22 Cylinder 23 Cooler 24 Liquid feed pump 25 Pressure adjustment valve 26 Exhaust pressure adjustment valve 27 High frequency power supply 28 Matching device

Claims (12)

  A method for producing a film, wherein a film is formed on a substrate by performing plasma discharge in a mixed system of a compound containing a group 14 element and a substance in a supercritical state.   A method for producing a film, in which a mixed system of a compound containing a group 14 element and a reaction solvent is put into a supercritical state, and a film is formed on the substrate by performing plasma discharge in the mixed system in the supercritical state.   3. The method for producing a film according to claim 1, wherein the group 14 element is carbon, and the formed film is a diamond-like carbon film.   The method for producing a film according to claim 3, wherein the compound containing carbon element is one or more selected from saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, and ethers. A method for producing a film, comprising:   4. The method for producing a film according to claim 3, wherein the compound containing carbon element is one or more selected from saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, and aromatic hydrocarbons. A method for producing a film.   6. The method for producing a film according to claim 5, wherein the saturated aliphatic hydrocarbon is one or more selected from compounds having 1 to 20 carbon atoms.   6. The method for producing a film according to claim 5, wherein the unsaturated aliphatic hydrocarbon is one or more selected from compounds having 1 to 20 carbon atoms.   3. The method of manufacturing a film according to claim 1, wherein the group 14 element is silicon and the formed film is a silicon film. 9. The method for manufacturing a film according to claim 8, wherein the compound containing silicon element is at least one selected from SiH ₄ and Si ₂ H ₆ .   3. The method for manufacturing a film according to claim 1, wherein the group 14 element is germanium, and the formed film is a germanium film. 11. The method for manufacturing a film according to claim 10, wherein the compound containing a germanium element is at least one selected from GeH ₄ and Ge ₂ H ₆ . 3. The method for producing a film according to claim 2, wherein the reaction solvent is carbon dioxide.