WO2013018292A1 - Film formation method - Google Patents

Film formation method Download PDF

Info

Publication number
WO2013018292A1
WO2013018292A1 PCT/JP2012/004522 JP2012004522W WO2013018292A1 WO 2013018292 A1 WO2013018292 A1 WO 2013018292A1 JP 2012004522 W JP2012004522 W JP 2012004522W WO 2013018292 A1 WO2013018292 A1 WO 2013018292A1
Authority
WO
WIPO (PCT)
Prior art keywords
gas
sih
plasma
gas supply
film
Prior art date
Application number
PCT/JP2012/004522
Other languages
French (fr)
Japanese (ja)
Inventor
雅人 森嶋
Original Assignee
東京エレクトロン株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 東京エレクトロン株式会社 filed Critical 東京エレクトロン株式会社
Publication of WO2013018292A1 publication Critical patent/WO2013018292A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/1804—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic Table
    • H01L31/182—Special manufacturing methods for polycrystalline Si, e.g. Si ribbon, poly Si ingots, thin films of polycrystalline Si
    • H01L31/1824—Special manufacturing methods for microcrystalline Si, uc-Si
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/24—Deposition of silicon only
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/455—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/50—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges
    • C23C16/511—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges using microwave discharges
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
    • H01L21/0237—Materials
    • H01L21/02422—Non-crystalline insulating materials, e.g. glass, polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02524—Group 14 semiconducting materials
    • H01L21/02532—Silicon, silicon germanium, germanium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/0262—Reduction or decomposition of gaseous compounds, e.g. CVD
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/545—Microcrystalline silicon PV cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a technique for forming a silicon film by converting silane gas into plasma.
  • Thin-film silicon solar cells have been actively studied in recent years because they consume less silicon than bulk type crystalline silicon solar cells, are relatively easy to increase in area, and are low in manufacturing costs.
  • a tandem thin-film silicon solar cell (hereinafter simply referred to as a solar cell) has an amorphous silicon film laminated on the top surface of a microcrystalline silicon film, and each layer absorbs light in different wavelength regions, thereby converting light energy conversion efficiency. It is a thing that raised.
  • a plasma CVD (Chemical Vapor Deposition) method is used.
  • a plasma source in this case, generally capacitively coupled plasma (CCP) using a high frequency power source (RF power source) is used. Coupled Plasma) is used.
  • various active species derived from SiH 4 or H 2 are generated.
  • the dominant active species for growing the ⁇ c-Si film is SiH 3 .
  • active species other than SiH 3 such as Si, SiH, and SiH 2 are taken into the film while having dangling bonds (dangling bonds), thereby increasing the defect density of the ⁇ c-Si film.
  • VHF Ultra high frequency
  • Patent Document 1 H 2 gas is activated to generate the plasma, and SiH 4 gas is supplied to the substrate side from the plasma generation space while suppressing decomposition of SiH 4 due to contact with the plasma.
  • a technique for improving the film quality by forming a film by increasing the proportion of SiH 3 in the active species by reacting with the active species of H 2 is different from the present invention.
  • the present invention has been made under such a background, and an object of the present invention is to provide a film forming method capable of obtaining a silicon film having high crystallinity and low defect density and having a high film forming speed in the plasma CVD method. It is to provide.
  • the film forming method of the present invention comprises: A method of forming a film with plasma on a substrate placed in a processing container, Supplying a silane-based gas and a helium gas as a dilution gas into the processing vessel; Generating inductively coupled plasma or microwave plasma in the processing vessel and activating a silane-based gas; Forming a silicon film on the substrate with a silane-based gas that has been converted to plasma, and Hydrogen gas is not supplied into the processing container.
  • helium (He) gas is used as a dilution gas without supplying a normally used hydrogen gas, and inductively coupled plasma or microwave plasma is used.
  • the gas is turned into plasma. For this reason, the effect is estimated as described later, and a silicon film having a high crystallinity and a low defect density can be quickly formed as supported by experimental examples.
  • reference numeral 1 denotes a processing container (vacuum chamber) that is configured in a cylindrical shape as a whole, for example, and a substrate S that is a glass substrate for a flat panel display, for example, is placed in the approximate center of the processing container 1.
  • a mounting table 2 for this purpose is provided via an insulating material 21.
  • the mounting table 2 is made of, for example, aluminum nitride (AlN) or Al 2 O 3 , and a cooling jacket 22 through which a cooling medium flows is provided.
  • a heater 23 is provided as a heating unit that constitutes a temperature control mechanism together with the cooling jacket 22.
  • the mounting surface of the mounting table 2 is provided with an electrostatic chuck (not shown) so that the substrate S can be held.
  • a first gas supply unit 3 for supplying helium gas into the processing container 1 is provided on the upper side wall of the processing container 1.
  • the first gas supply unit 3 is provided over the entire circumference in the side wall of the processing container 1 and a plurality of gas supply holes 31 that are bored substantially evenly in the side wall of the processing container 1 over the entire circumference.
  • the buffer chamber 32 is connected to the gas supply hole 31.
  • the buffer chamber 32 is connected by a gas flow path 33 to a first gas supply source 36 for supplying helium gas via a valve 34 and a flow rate adjustment unit (MFC) 35.
  • MFC flow rate adjustment unit
  • a second planar shape is formed in a substantially circular shape, for example, below the upper space and between the mounting table 2 and the height level of the first gas supply unit 3.
  • a gas supply unit 4 is provided.
  • the second gas supply unit 4 is made of a dielectric material.
  • a gas channel network 41 is formed in a lattice shape inside the second gas supply unit 4, and a large number of gas supply holes 42 are formed from the gas channel network 41. 2 is drilled toward the upper surface of the gas supply unit 4 (surface opposite to the mounting table 2).
  • the gas supply passage 43 to the gas flow passage network 41, via a valve 44 and a flow rate adjuster (MFC) 45, silane gas, such as monosilane (SiH 4) of the second gas supply source for supplying a gas 46 is connected.
  • the second gas supply unit 4 is formed with a large number of openings 47 penetrating vertically through the second gas supply unit 4 so as to sew the gaps of the reaction gas channel network 41.
  • the opening 47 is for allowing gas to pass from the upper region to the lower region of the second gas supply unit 4.
  • the ceiling of the processing vessel 1 is open, and a plasma generation mechanism 5 serving as an activating means is provided at this portion via a seal member (not shown) such as an O-ring.
  • the plasma generation mechanism 5 includes a cover plate 51 made of a dielectric provided so as to face the second gas supply unit 4, and above the cover plate 51 (outside the processing container 1).
  • An antenna 52 that is a conductor, for example, a spiral coil, and a high-frequency (for example, RF) power supply 53 are provided.
  • the high frequency power supply 53 is connected between both ends of the antenna 52, and includes a high frequency (for example, RF) power supply 53 that generates a high frequency of 13.56 Hz, for example.
  • the plasma generation mechanism 5 generates a high-frequency magnetic field by flowing a high-frequency current through the antenna 52 from a high-frequency power source 53, and causes high-frequency discharge in the space above the processing container 1 by an induction electric field generated by electromagnetic induction by the high-frequency magnetic field. To generate plasma.
  • An exhaust port 11 is provided at the bottom of the processing container 1, and an exhaust pipe 12 is connected to the exhaust port 11.
  • the exhaust pipe 12 is connected to a vacuum pump 14 via a pressure adjusting unit 13 so that the inside of the processing container 1 can be evacuated to a predetermined pressure.
  • the plasma film forming apparatus in this embodiment is provided with a control unit 6, which starts and stops the high-frequency power supply 53, opens and closes the valves 34 and 44, and adjusts the gas flow rate by the flow rate adjustment units 35 and 45.
  • the pressure adjustment in the processing container 1 by the adjustment and pressure adjustment unit 13 is controlled.
  • the operation of the present embodiment will be described with an example in which a microcrystalline silicon thin film ( ⁇ c-Si film) is formed on the substrate S.
  • the substrate S is carried into the processing container 1 by a transport mechanism (not shown), placed on the mounting table 2 by a cooperative action of a lifting pin (not shown) and the transport mechanism, and held by an electrostatic chuck (not shown) of the mounting table 2. Is done.
  • the temperature of the mounting table 2 is adjusted by the cooling jacket 22 and the heater 23 so that the substrate S is heated to 200 ° C., for example.
  • the processing container 1 is decompressed by the vacuum pump 14 and the pressure is adjusted to, for example, 0.6 Pa to 20 Pa by the pressure adjusting unit 13.
  • helium gas is supplied from the first gas supply unit 3 to the upper space in the processing container 1 at a flow rate of 200 sccm, for example, and monosilane gas is adjusted from the second gas supply unit 4 at a flow rate of 20 sccm, for example.
  • high frequency power 13.56 MHz and 2000 W is applied to the antenna 52 by the high frequency power source 53.
  • the gas supplied into the processing container 1 is turned into plasma and a silicon film is formed on the substrate S. The situation is shown schematically.
  • the helium gas supplied to the upper space of the processing container 1 is turned into plasma by the high-frequency electric field induced in the upper space of the processing container 1 based on the high-frequency power applied to the antenna 52 to generate active helium species. Is done. Since the atmosphere in the processing container 1 is evacuated at the lower part of the processing container 1, the activated helium gas flows downward. On the other hand, the monosilane gas discharged upward from the second gas supply unit 4 is partially activated by the high-frequency electric field, but most is activated (plasmaized) in contact with the activated species of helium gas. It is thought. In this case, it can be said that the monosilane gas is activated by the inductively coupled plasma as a result.
  • the monosilane gas is mixed with plasma helium gas and supplied to the substrate S through the opening 47 of the second gas supply unit 4 while being activated.
  • the estimation mechanism of the activation of the monosilane gas is described in the following a to c.
  • the generated active species of hydrogen react with SiH 4 to produce SiH 3 as an active species as follows, and further, the active species of hydrogen generated during this reaction react with SiH 3. Te SiH 2 is generated, the chain reactions as described below takes place and so on.
  • the concentration of active species SiH 3 is increased, and the concentration of active species (for example, SiH 2 , SiH, Si, etc.) further decomposed from SiH 3 is increased. It is known that it is necessary to suppress this.
  • the active species obtained by further decomposing SiH 3 is taken into the film while having dangling bonds (dangling bonds), thereby increasing the defect density of the microcrystalline silicon film.
  • helium gas is used as a dilution gas without using hydrogen gas.
  • the monosilane gas is converted into plasma mainly by helium gas converted into plasma, so that helium gas can also be referred to as plasma generation gas.
  • hydrogen gas is supplied to the substrate at a flow rate of, for example, several tens of times that of monosilane gas in order to improve crystallinity.
  • Such a method is a film forming method with high production efficiency because it can promote hydrogenation of silicon dangling bonds while maintaining high crystallinity in a plasma CVD process using capacitively coupled plasma, for example.
  • FIG. 5 shows an image in which SiH 3 is deposited on the substrate S, and the active species indicated by oblique lines in the figure are those generated by further decomposition of SiH 3 . Then, after a preset time has elapsed, the application of high-frequency power is stopped, and then the gas supply is stopped.
  • silane-based gas monosilane gas is used as the silane-based gas, but other silane-based gases such as disilane (Si 2 H 6 ) gas and trichlorosilane (SiHCl 3 ) gas may be used.
  • inductively coupled plasma is generated.
  • an antenna in which a cross-shaped opening is formed in a spiral shape on a circular conductor plate may be used.
  • a waveguide is joined to the central portion of the antenna, microwaves are radiated from the waveguide through the antenna, and gas is turned into plasma by the microwaves.
  • the present invention requires that no hydrogen gas is used, and the adverse effect of promoting the decomposition of the monosilane gas by adding the hydrogen gas appears.
  • the influence of hydrogen gas becomes a problem when supplying many times the amount of monosilane gas, and hardly affects when supplying the same amount of hydrogen gas as monosilane gas.
  • the addition of such a small amount of hydrogen gas has no technical meaning in the first place, and this approach is an unreasonable practice that seeks to dive into the limitations of the expression of the claims while carrying out the present invention. Therefore, the term “do not use hydrogen gas” in the claims does not exclude the addition of a small amount of hydrogen gas which has no technical meaning.
  • the process pressure is set to 0.4 Pa to 1.0 Pa so that substantially the same film forming conditions are obtained in each embodiment.
  • the SiH 4 gas supply amount is fixed in the range of 5 sccm to 6 sccm, and a microcrystalline silicon ( ⁇ c-Si) film is formed by ICP-CVD while adding various dilution gases about 10 times the monosilane (SiH 4 ) gas. Was deposited.
  • the microcrystalline silicon film was measured by Raman spectroscopy and the deposition rate.
  • the dilution gas described below is a gas added to the reaction gas during the film forming process.
  • Example 1 High frequency power: 2000W Reaction gas species and reaction gas supply amount: SiH 4 , 5 sccm Dilution gas type and dilution gas supply amount: Helium (He), 49 sccm Process pressure: 0.6Pa (Reference Example 1) High frequency power: 2000W Reaction gas species and reaction gas supply amount: SiH 4 , 5 sccm Dilution gas type and dilution gas supply amount: Ar, 50 sccm Process pressure: 0.9Pa (Comparative Example 1-1) High frequency power: 2000W Reaction gas species and reaction gas supply amount: SiH 4 , 6 sccm Dilution gas type and dilution gas supply: No dilution gas is supplied.
  • Process pressure 1.0 Pa (Comparative Example 1-2) High frequency power: 2000W Reaction gas species and reaction gas supply amount: SiH 4 , 5 sccm Dilution gas type and dilution gas supply amount: H 2 , 50 sccm Process pressure: 0.4 Pa
  • the Raman spectroscopic measurement result in this experiment is shown in FIG. 6, and the calculated value of the intensity ratio Xc and the film formation rate calculated from the Raman spectroscopic measurement result are shown in Table 1.
  • the intensity patterns a, b, c, and d in FIG. 6 correspond to Example 1, Reference Example 1, Comparative Example 1-1, and Comparative Example 1-2, respectively.
  • the intensity Ia at a wave number of 480 cm ⁇ 1 in Raman spectroscopy corresponds to the amount of material of amorphous silicon (a-Si), and the intensity Ic at 520 cm ⁇ 1 corresponds to the amount of material of microcrystalline silicon ( ⁇ c-Si). .
  • Example 1 the wave number at the peak position of the intensity pattern is quite close to 520 cm ⁇ 1 (ideal wave number) corresponding to ⁇ c-Si, but in Reference Example 1, the wave number at the peak position. Is about 515 cm ⁇ 1, which is slightly shifted from the ideal wave number.
  • the wave number at the peak position in Comparative Example 1-1 is further shifted from the ideal wave number, and in Comparative Example 1-2, the wave number at the peak position is below 510 cm ⁇ 1 .
  • Example 1 is slower than Comparative Example 1-1 and Comparative Example 1-2, but as can be seen from the results of the following Experiment 2, film formation is performed by increasing the flow rates of monosilane gas and helium gas. Speed can be improved.
  • the strength ratio Xc is 80% or more, and it can be seen that the crystallinity is good.
  • Example 2 High frequency power: 2000W Reaction gas species and reaction gas supply amount: SiH 4 , 5, 10, 15, 20 sccm Dilution gas type and dilution gas supply amount: He, 10 times the reaction gas supply amount Process pressure: 0.6 Pa to 1.9 Pa (Comparative Example 2) High frequency power: 2000W Reactive gas species and reactive gas supply amount: SiH 4 , 6, 8, 12 sccm Dilution gas type and dilution gas supply: No dilution gas is supplied. Process pressure: 1.0 Pa
  • FIG. 7 shows the experimental results when no He gas is added.
  • SiH 4 gas supply amount was 6 sccm
  • Xc 60% or more
  • the SiH 4 gas supply amount was 8 sccm or more
  • the deposition rate increased in proportion to the SiH 4 gas supply amount.
  • Xc was significantly reduced.
  • H 2 gas was added.
  • He gas is added, as shown in FIG. 8, as the SiH 4 gas supply amount is increased, the deposition rate increases almost in proportion to this, and when Xc is not added with He gas (comparison).
  • the high value of about 80% was maintained without decreasing as in Example 2).
  • the deposition rate of the silicon film is 0.55 nm / sec or more and the peak intensity ratio (crystallinity) Xc is 70% or more, it is a preferable manufacturing method in terms of productivity and crystallinity of the silicon film. Can do.
  • Example 3 As described in the above-described embodiment, the present inventor has activated SiH 4 under a condition in which the radical density is suppressed by the He radical having a high electron temperature. Therefore, the active species SiH 3 is further decomposed. It is considered that film formation can be performed in a state where the above is suppressed. Therefore, in this experiment, the degree of decomposition from SiH 3 to SiH 2 was investigated for each of the case using helium gas (Example 3) and the case using hydrogen gas (Comparative Example 3). Specifically, the concentration of SiH, which is a further active product of decomposition of SiH 2 , and the concentration of Si in the processing atmosphere were identified by emission spectroscopy (OES).
  • OES emission spectroscopy
  • SiH 4 gas flow rate ratio is the ratio of the SiH 4 gas supply amount to the total gas supply amount of the SiH 4 gas and the dilution gas.
  • the SiH 4 gas flow rate ratio of 100% indicates a case where only SiH 4 gas is supplied without adding a dilution gas.
  • the diluent gas is hydrogen gas
  • the emission intensity ratio SiH / Si tends to decrease. That is, as the ratio of the supply amount of hydrogen gas in the mixed gas is increased, the degree to which SiH 3 is decomposed into SiH 2 tends to increase.
  • the dilution gas is helium gas
  • the emission intensity ratio SiH / Si increases as the SiH 4 gas flow rate ratio is increased from 5% (the flow rate ratio of helium gas is decreased from 95%).
  • the emission intensity ratio SiH / Si is presumed to decrease, but hydrogen gas is used by adjusting the supply amount of helium gas. It can be seen that a considerably high value is obtained for the emission intensity ratio SiH / Si as compared to the case.
  • Plasma source ICP, high frequency power 2000W Reaction gas species and reaction gas supply amount: SiH 4 , 5 sccm Dilution gas type and dilution gas supply ratio: He, 10/1 Process pressure: 0.6Pa (Comparative Example 4-1) Plasma source: ICP, high frequency power 2000W Reaction gas species and reaction gas supply amount: SiH 4 , 6 sccm Dilution gas type and dilution gas supply ratio: No dilution gas is supplied.
  • Example 4 Comparative Example 4-1, and Comparative Example 4-2, which are examples of ICP-CVD, are performed in order of increasing peak intensity ratio I (220) / I (111).
  • the results were 4, Comparative Example 4-1, and Comparative Example 4-2. That is, the crystal orientation was good in the order of He dilution, SiH 4 supply, and H 2 dilution.
  • Example 4 when Example 4 is compared with Reference Example 4-1 and Reference Example 4-2, which are CCP-CVD examples, Example 4 does not reach Reference Example 4-1 in terms of crystal orientation. However, it was better than Reference Example 4-2.
  • Plasma source ICP, high frequency power 2000W Reaction gas species and reaction gas supply amount: SiH 4 , 15 sccm Dilution gas type and dilution gas supply ratio: He, 6/1 Process pressure: 1.0 Pa (Comparative Example 5-1) Plasma source: ICP, high frequency power 2000W Reaction gas species and reaction gas supply amount: SiH 4 , 6 sccm Dilution gas type and dilution gas supply ratio: No dilution gas is supplied.
  • Process pressure 1.0 Pa (Comparative Example 5-2)
  • Plasma source ICP, high frequency power 1600W Reaction gas species and reaction gas supply amount: SiH 4 , 2 sccm Dilution gas type and dilution gas supply ratio: H 2 , 7/1
  • Process pressure 1.0 Pa (Reference Example 5)
  • Plasma source CCP, high frequency power 100-700W Reaction gas species and reaction gas supply amount: SiH 4 , 5 to 40 sccm Dilution gas type and dilution gas supply ratio: H 2 , 50/1 to 100/1
  • Process pressure 800-1200Pa
  • Example 5 shows the measurement results in this experiment. As shown in Table 2, the detection value of ESR analysis in Example 5 is smaller than that in Comparative Example 5-1 and Comparative Example 5-2, so that dangling bonds are reduced by adding He gas. It is presumed that defects in the formed silicon film are reduced. As for the degree of crystallinity Xc and the film formation rate, Example 5 was better than Comparative Example 5-1 and Comparative Example 5-2. Example 5 resulted in more dangling bonds compared to Reference Example 5, which is a silicon film formed by CCP-CVD.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Materials Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Manufacturing & Machinery (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Metallurgy (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Plasma & Fusion (AREA)
  • Electromagnetism (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Vapour Deposition (AREA)
  • Photovoltaic Devices (AREA)

Abstract

[Problem] The present invention relates to a film formation method which provides a high film formation speed enabling a silicon film having high crystallinity and a low defect density to be obtained with a plasma CVD technique. [Solution] A coil-shaped antenna (52) is disposed at the upper surface of a processing container (1) and high-frequency AC power is applied to the antenna (52) so that a plasma generation space is formed at an upper section in the processing container (1). An active species of helium is created by supplying helium gas from a first gas supply unit to the plasma generation space. At a section lower than the first gas supply unit, monosilane gas is discharged upwards from a second gas supply unit (4). The active species of helium is mixed with the monosilane gas, and monosilane is turned into plasma. Mixed gas containing the monosilane that has turned into the plasma is supplied to a substrate (S) for film formation treatment. Hydrogen gas is not used in the film formation treatment.

Description

成膜方法Deposition method
　本発明は、シランガスをプラズマ化して、シリコン膜を成膜する技術に関する。 The present invention relates to a technique for forming a silicon film by converting silane gas into plasma.
　薄膜シリコン太陽電池は、バルク型の結晶シリコン太陽電池と比較してシリコンの消費量が少なく、大面積化が比較的容易であり、また製造コストも低いため近年盛んに研究がなされている。例えばタンデム型の薄膜シリコン太陽電池（以下、単に太陽電池という）は、微結晶シリコン膜の上面にアモルファスシリコン膜を積層して、各層で異なる波長域の光を吸収することにより光エネルギーの変換効率を高めたものである。 Thin-film silicon solar cells have been actively studied in recent years because they consume less silicon than bulk type crystalline silicon solar cells, are relatively easy to increase in area, and are low in manufacturing costs. For example, a tandem thin-film silicon solar cell (hereinafter simply referred to as a solar cell) has an amorphous silicon film laminated on the top surface of a microcrystalline silicon film, and each layer absorbs light in different wavelength regions, thereby converting light energy conversion efficiency. It is a thing that raised.
　薄膜シリコン太陽電池における発電層となる微結晶シリコン薄膜（μｃ－Ｓｉ膜）の成膜方法としては、例えばモノシラン（ＳＨ４）ガスと水素（Ｈ２）ガスとを用いて基板上にシリコンを堆積させるプラズマＣＶＤ（Chemical Vapor Deposition）法などが採用されている。この場合のプラズマ源としては、一般的に高周波電源（ＲＦ電源）を用いた容量結合プラズマ（ＣＣＰ；Capacitively
Coupled Plasma）が使用されている。 Depositing silicon on the substrate as a method of forming a microcrystalline silicon thin film ([mu] c-Si film) serving as a power generation layer of the thin-film silicon solar cells, for example, monosilane (SH 4) gas and hydrogen (H 2) with a gas A plasma CVD (Chemical Vapor Deposition) method is used. As a plasma source in this case, generally capacitively coupled plasma (CCP) using a high frequency power source (RF power source) is used.
Coupled Plasma) is used.
　このプラズマＣＶＤ法において、ＳｉＨ４やＨ２由来の多様な活性種が生成されるが、その中でμｃ－Ｓｉ膜を成長させる支配的な活性種はＳｉＨ３である。一方で、例えばＳｉやＳｉＨ、ＳｉＨ２といったＳｉＨ３以外の活性種は、未結合手（ダングリングボンド）を持ったまま膜中に取り込まれて、μｃ－Ｓｉ膜の欠陥密度の増加を引き起こす。またこれらの活性種が重合してＳｉｎＨ２ｎ＋２（ｎ＝２，３，４・・・）といった高次シランを生成し、これらが膜中へと取り込まれたり、またこの高次シランがさらに成長して微粒子化した状態で取り込まれたりした場合にもμｃ－Ｓｉ膜の欠陥密度の増加の要因となる。このためプラズマＣＶＤ法において成膜速度を上げていくと、プラズマ中における上述のＳｉＨ３以外の活性種の割合が増加し、μｃ－Ｓｉ膜の結晶性が低下すると共に、欠陥密度が増加するという問題があった。 In this plasma CVD method, various active species derived from SiH 4 or H 2 are generated. Among them, the dominant active species for growing the μc-Si film is SiH 3 . On the other hand, for example, active species other than SiH 3 such as Si, SiH, and SiH 2 are taken into the film while having dangling bonds (dangling bonds), thereby increasing the defect density of the μc-Si film. In addition, these active species are polymerized to produce higher order silanes such as Si n H 2n + 2 (n = 2, 3, 4...), And these are taken into the film. Even if it grows and is taken in the form of fine particles, it also causes an increase in the defect density of the μc-Si film. For this reason, when the film formation rate is increased in the plasma CVD method, the proportion of active species other than the above-mentioned SiH 3 in the plasma increases, the crystallinity of the μc-Si film decreases, and the defect density increases. There was a problem.
　このようにＲＦ電源を用いるプラズマＣＶＤ法では、要求されているμｃ－Ｓｉ膜の結晶性及び低い欠陥密度を維持したまま成膜速度を上げることが困難であるため、その対策としてＣＣＰ電源周波数の超短波（ＶＨＦ；Very High Frequency）化が提案されているが、大面積基板に対応するためには更なる検討が必要である。 As described above, in the plasma CVD method using the RF power source, it is difficult to increase the deposition rate while maintaining the required crystallinity and low defect density of the μc-Si film. Ultra high frequency (VHF) has been proposed, but further studies are required to deal with large-area substrates.
　特許文献１には、Ｈ２ガスを活性化させてそのプラズマを生成させると共に、ＳｉＨ４ガスをそのプラズマ生成空間よりも基板側に供給して、プラズマとの接触によるＳｉＨ４の分解を抑えながらＨ２の活性種と反応させることで、活性種中のＳｉＨ３の割合を高めて成膜することで膜質を向上させる技術が記載されているが、本発明とは異なる。 In Patent Document 1, H 2 gas is activated to generate the plasma, and SiH 4 gas is supplied to the substrate side from the plasma generation space while suppressing decomposition of SiH 4 due to contact with the plasma. A technique for improving the film quality by forming a film by increasing the proportion of SiH 3 in the active species by reacting with the active species of H 2 is different from the present invention.
特開２０１１－８６９１２号公報JP 2011-86912 A
　本発明はこのような背景の下になされたものであり、その目的はプラズマＣＶＤ法において、結晶性が高く欠陥密度が低いシリコン膜を得ることができ、また成膜速度が高い成膜方法を提供することにある。 The present invention has been made under such a background, and an object of the present invention is to provide a film forming method capable of obtaining a silicon film having high crystallinity and low defect density and having a high film forming speed in the plasma CVD method. It is to provide.
　本発明の成膜方法は、
　処理容器内に載置された基板に対してプラズマにより成膜を行う方法であって、
　前記処理容器内にシラン系のガス及び希釈ガスであるヘリウムガスを供給する工程と、
　前記処理容器内に誘導結合プラズマまたはマイクロ波プラズマを生成し、シラン系のガスを活性化させる工程と、
　プラズマ化されたシラン系のガスにより前記基板上にシリコン膜を成膜する工程と、を含み、
　前記処理容器内には水素ガスが供給されないことを特徴とする。 The film forming method of the present invention comprises:
A method of forming a film with plasma on a substrate placed in a processing container,
Supplying a silane-based gas and a helium gas as a dilution gas into the processing vessel;
Generating inductively coupled plasma or microwave plasma in the processing vessel and activating a silane-based gas;
Forming a silicon film on the substrate with a silane-based gas that has been converted to plasma, and
Hydrogen gas is not supplied into the processing container.
　本発明は、シラン系のガスを分解してシリコン膜を成膜するにあたり、通常使用されている水素ガスを供給せずにヘリウム（Ｈｅ）ガスを希釈ガスとして用い、誘導結合プラズマまたはマイクロ波プラズマによりガスをプラズマ化している。このため後述のようにその作用を推測し、実験例にて裏づけられているように、結晶性が高く欠陥密度が低いシリコン膜を速やかに成膜することができる。 In the present invention, when a silicon film is formed by decomposing a silane-based gas, helium (He) gas is used as a dilution gas without supplying a normally used hydrogen gas, and inductively coupled plasma or microwave plasma is used. The gas is turned into plasma. For this reason, the effect is estimated as described later, and a silicon film having a high crystallinity and a low defect density can be quickly formed as supported by experimental examples.
実施形態に係る成膜装置の縦断側面図である。It is a vertical side view of the film-forming apparatus which concerns on embodiment. 前記成膜装置に設けられた第２のガス供給部を示す平面図である。It is a top view which shows the 2nd gas supply part provided in the said film-forming apparatus. 前記成膜装置に設けられたプラズマ生成機構を模式的に示す平面図である。It is a top view which shows typically the plasma production mechanism provided in the said film-forming apparatus. 前記実施形態に係わる作用を模式的に説明する縦断側面図である。It is a vertical side view explaining typically the operation concerning the embodiment. 前記実施形態に係わる作用を模式的に説明する縦断側面図である。It is a vertical side view explaining typically the operation concerning the embodiment. 本発明の実施例に係わる実験結果を示すグラフである。It is a graph which shows the experimental result concerning the Example of this invention. 本発明の実施例に係わる実験結果を示すグラフである。It is a graph which shows the experimental result concerning the Example of this invention. 本発明の実施例に係わる実験結果を示すグラフである。It is a graph which shows the experimental result concerning the Example of this invention. 本発明の実施例に係わる実験結果を示すグラフである。It is a graph which shows the experimental result concerning the Example of this invention. 本発明の実施例に係わる実験結果を示すグラフである。It is a graph which shows the experimental result concerning the Example of this invention.
　本発明の実施形態について誘導結合プラズマ（ＩＣＰ；Inductively Coupled Plasma）成膜装置を例に説明する。図１中１は、例えば全体が筒状体に構成された処理容器（真空チャンバ）であり、処理容器１のほぼ中央には、例えばフラットパネルディスプレイ用のガラス基板である基板Ｓを載置するための載置台２が絶縁材２１を介して設けられている。この載置台２は、例えば窒化アルミニウム（ＡｌＮ）もしくはＡｌ２Ｏ３により構成され、内部には冷却媒体を通流させる冷却ジャケット２２が設けられている。また、この載置台２内には、冷却ジャケット２２と共に温調機構を構成する加熱手段であるヒータ２３が設けられている。載置台２の載置面には図示しない静電チャックが設けられており、基板Ｓを保持することができるように構成されている。 An embodiment of the present invention will be described by taking an inductively coupled plasma (ICP) film forming apparatus as an example. In FIG. 1, reference numeral 1 denotes a processing container (vacuum chamber) that is configured in a cylindrical shape as a whole, for example, and a substrate S that is a glass substrate for a flat panel display, for example, is placed in the approximate center of the processing container 1. A mounting table 2 for this purpose is provided via an insulating material 21. The mounting table 2 is made of, for example, aluminum nitride (AlN) or Al 2 O 3 , and a cooling jacket 22 through which a cooling medium flows is provided. In addition, in the mounting table 2, a heater 23 is provided as a heating unit that constitutes a temperature control mechanism together with the cooling jacket 22. The mounting surface of the mounting table 2 is provided with an electrostatic chuck (not shown) so that the substrate S can be held.
　処理容器１の上部の側壁には、ヘリウムガスを処理容器１内に供給するための第１のガス供給部３が設けられている。この第１のガス供給部３は、処理容器１の側壁に全周に亘って略均等に穿設された複数のガス供給孔３１と、処理容器１の側壁内に全周に亘って設けられ、ガス供給孔３１と接続されているバッファ室３２とからなる。このバッファ室３２は、ガス流路３３により、バルブ３４及び流量調整部（ＭＦＣ）３５を介して、ヘリウムガスを供給するための第１のガス供給源３６に接続されている。 A first gas supply unit 3 for supplying helium gas into the processing container 1 is provided on the upper side wall of the processing container 1. The first gas supply unit 3 is provided over the entire circumference in the side wall of the processing container 1 and a plurality of gas supply holes 31 that are bored substantially evenly in the side wall of the processing container 1 over the entire circumference. The buffer chamber 32 is connected to the gas supply hole 31. The buffer chamber 32 is connected by a gas flow path 33 to a first gas supply source 36 for supplying helium gas via a valve 34 and a flow rate adjustment unit (MFC) 35.
　処理容器１内には、前記上部空間よりも下方で、かつ載置台２と第１のガス供給部３の高さレベルとの間に、例えば平面形状が略円形状に構成された第２のガス供給部４が設けられている。この第２のガス供給部４は、誘電体により構成されている。この第２のガス供給部４の内部には、図２に示すように、ガス流路網４１が格子状に形成されており、そのガス流路網４１からは多数のガス供給孔４２が第２のガス供給部４の上面（載置台２と反対側の面）に向けて穿設されている。このガス流路網４１にはガス供給路４３により、バルブ４４及び流量調整部（ＭＦＣ）４５を介して、シラン系のガス例えばモノシラン（ＳｉＨ４）ガスを供給するための第２のガス供給源４６が接続されている。 In the processing container 1, a second planar shape is formed in a substantially circular shape, for example, below the upper space and between the mounting table 2 and the height level of the first gas supply unit 3. A gas supply unit 4 is provided. The second gas supply unit 4 is made of a dielectric material. As shown in FIG. 2, a gas channel network 41 is formed in a lattice shape inside the second gas supply unit 4, and a large number of gas supply holes 42 are formed from the gas channel network 41. 2 is drilled toward the upper surface of the gas supply unit 4 (surface opposite to the mounting table 2). The gas supply passage 43 to the gas flow passage network 41, via a valve 44 and a flow rate adjuster (MFC) 45, silane gas, such as monosilane (SiH 4) of the second gas supply source for supplying a gas 46 is connected.
　また第２のガス供給部４には、多数の開口部４７が反応ガス流路網４１の間隙を縫うように当該第２のガス供給部４を上下に貫通して形成されている。この開口部４７は、第２のガス供給部４の上方側領域から下方側領域にガスを通過させるためのものである。 Further, the second gas supply unit 4 is formed with a large number of openings 47 penetrating vertically through the second gas supply unit 4 so as to sew the gaps of the reaction gas channel network 41. The opening 47 is for allowing gas to pass from the upper region to the lower region of the second gas supply unit 4.
　処理容器１の天井部は解放されており、この部分にはＯリング等のシール部材（図示せず）を介して、活性化手段であるプラズマ生成機構５が設けられている。プラズマ生成機構５は、図１に示すように、第２のガス供給部４に対向するように設けられた誘電体からなるカバープレート５１と、カバープレート５１の上方（処理容器１の外側）に設けられた導電体例えば渦巻き状のコイルであるアンテナ５２と高周波（例えばＲＦ）電源５３とを備えている。高周波電源５３は、アンテナ５２の両端間に接続されており、例えば１３．５６Ｈｚの高周波を発生させる高周波（例えばＲＦ）電源５３などからなる。このプラズマ発生機構５は、高周波電源５３によりアンテナ５２に高周波電流を流すことで高周波磁界を発生させ、その高周波磁界による電磁誘導で発生する誘導電界により、処理容器１の上方空間において高周波放電を起こしてプラズマを生成させる。 The ceiling of the processing vessel 1 is open, and a plasma generation mechanism 5 serving as an activating means is provided at this portion via a seal member (not shown) such as an O-ring. As shown in FIG. 1, the plasma generation mechanism 5 includes a cover plate 51 made of a dielectric provided so as to face the second gas supply unit 4, and above the cover plate 51 (outside the processing container 1). An antenna 52 that is a conductor, for example, a spiral coil, and a high-frequency (for example, RF) power supply 53 are provided. The high frequency power supply 53 is connected between both ends of the antenna 52, and includes a high frequency (for example, RF) power supply 53 that generates a high frequency of 13.56 Hz, for example. The plasma generation mechanism 5 generates a high-frequency magnetic field by flowing a high-frequency current through the antenna 52 from a high-frequency power source 53, and causes high-frequency discharge in the space above the processing container 1 by an induction electric field generated by electromagnetic induction by the high-frequency magnetic field. To generate plasma.
　処理容器１の底部には、排気ポート１１が設けられており、この排気ポート１１に排気管１２が接続されている。この排気管１２は、圧力調整部１３を介して真空ポンプ１４に接続され、処理容器１内を所定の圧力まで真空引きできるようになっている。　
　処理容器１の下部の側壁には、成膜処理の対象である基板Ｓの搬入出用の開口部である搬入出口１５が設けられており、この搬入出口１５はシャッター１６により開閉自在に構成されている。 An exhaust port 11 is provided at the bottom of the processing container 1, and an exhaust pipe 12 is connected to the exhaust port 11. The exhaust pipe 12 is connected to a vacuum pump 14 via a pressure adjusting unit 13 so that the inside of the processing container 1 can be evacuated to a predetermined pressure.
A loading / unloading port 15, which is an opening for loading / unloading the substrate S that is the target of the film forming process, is provided on the lower side wall of the processing container 1. ing.
　本実施形態におけるプラズマ成膜装置には制御部６が設けられており、この制御部６は、高周波電源５３の起動及び停止、バルブ３４、４４の開閉、流量調整部３５、４５によるガス流量の調整、圧力調整部１３による処理容器１内の圧力調整をコントロールする。 The plasma film forming apparatus in this embodiment is provided with a control unit 6, which starts and stops the high-frequency power supply 53, opens and closes the valves 34 and 44, and adjusts the gas flow rate by the flow rate adjustment units 35 and 45. The pressure adjustment in the processing container 1 by the adjustment and pressure adjustment unit 13 is controlled.
　続いて本実施形態の作用について、基板Ｓ上に微結晶シリコン薄膜（μｃ－Ｓｉ膜）を成膜する例を挙げて説明する。先ず基板Ｓが図示しない搬送機構により処理容器１内に搬入され、図示しない昇降ピンと搬送機構との協働作用により、載置台２上に載置され、載置台２の図示しない静電チャックにより保持される。このとき載置台２は、基板Ｓが例えば２００℃に加熱されるように、冷却ジャケット２２及びヒータ２３により温度調整されている。シャッター１６により搬入出口１５が閉じられた後、処理容器１は、真空ポンプ１４により減圧され、圧力調節部１３により例えば０．６Ｐａ～２０Ｐａに圧力調整される。 Subsequently, the operation of the present embodiment will be described with an example in which a microcrystalline silicon thin film (μc-Si film) is formed on the substrate S. First, the substrate S is carried into the processing container 1 by a transport mechanism (not shown), placed on the mounting table 2 by a cooperative action of a lifting pin (not shown) and the transport mechanism, and held by an electrostatic chuck (not shown) of the mounting table 2. Is done. At this time, the temperature of the mounting table 2 is adjusted by the cooling jacket 22 and the heater 23 so that the substrate S is heated to 200 ° C., for example. After the loading / unloading port 15 is closed by the shutter 16, the processing container 1 is decompressed by the vacuum pump 14 and the pressure is adjusted to, for example, 0.6 Pa to 20 Pa by the pressure adjusting unit 13.
　そして処理容器１内の上部空間に第１のガス供給部３からヘリウムガスが例えば２００ｓｃｃｍの流量で供給されると共に、第２のガス供給部４からモノシランガスが例えば２０ｓｃｃｍの流量で調整される。更に高周波電源５３によりアンテナ５２に例えば１３．５６ＭＨｚ、２０００Ｗの高周波電力が印加される
　図４には、処理容器１内に供給されたガスがプラズマ化されて基板Ｓ上にシリコン膜が成膜される様子が模式的に示されている。即ち処理容器１の上部空間に供給されたヘリウムガスは、アンテナ５２に印加された高周波電力に基づいて処理容器１の上部空間に誘導された高周波電界により、プラズマ化されてヘリウムの活性種が生成される。処理容器１内の雰囲気は処理容器１の下部にて真空排気されていることから、活性化されたヘリウムガスは下方側に向かって流れる。一方第２のガス供給部４から上向きに吐出されたモノシランガスについては、前記高周波電界により一部が活性化されるが、大部分はヘリウムガスの活性種と接触して活性化（プラズマ化）されると考えられる。なおこの場合、モノシランガスは結果として誘導結合プラズマにより活性化されたと言うことができる。 Then, helium gas is supplied from the first gas supply unit 3 to the upper space in the processing container 1 at a flow rate of 200 sccm, for example, and monosilane gas is adjusted from the second gas supply unit 4 at a flow rate of 20 sccm, for example. Further, for example, high frequency power of 13.56 MHz and 2000 W is applied to the antenna 52 by the high frequency power source 53. In FIG. 4, the gas supplied into the processing container 1 is turned into plasma and a silicon film is formed on the substrate S. The situation is shown schematically. That is, the helium gas supplied to the upper space of the processing container 1 is turned into plasma by the high-frequency electric field induced in the upper space of the processing container 1 based on the high-frequency power applied to the antenna 52 to generate active helium species. Is done. Since the atmosphere in the processing container 1 is evacuated at the lower part of the processing container 1, the activated helium gas flows downward. On the other hand, the monosilane gas discharged upward from the second gas supply unit 4 is partially activated by the high-frequency electric field, but most is activated (plasmaized) in contact with the activated species of helium gas. It is thought. In this case, it can be said that the monosilane gas is activated by the inductively coupled plasma as a result.
　そしてモノシランガスはプラズマ化されたヘリウムガスと混合され、活性化されながら第２のガス供給部４の開口部４７を通って基板Ｓ上に供給される。ここでモノシランガスの活性化の推定メカニズムを下記のａ～ｃに記載する。　
　ａ．　ＳｉＨ４が高周波電界により直接プラズマ化されて活性種であるＳｉＨｘ（ｘ＝０，１，２，３）が生成される。　
　ｂ．　このとき生成された水素の活性種とＳｉＨ４とが反応して以下のように活性種であるＳｉＨ３が生成され、更にこの反応時に生成された水素の活性種ととＳｉＨ３とが反応してＳｉＨ２が生成され、といった具合に下記のように連鎖的な反応が起こる。　
　ｃ．　ＳｉＨ４とヘリウムの活性種とが反応してＳｉＨｘ（ｘ＝０，１，２，３）が生成される。 Then, the monosilane gas is mixed with plasma helium gas and supplied to the substrate S through the opening 47 of the second gas supply unit 4 while being activated. Here, the estimation mechanism of the activation of the monosilane gas is described in the following a to c.
a. SiH 4 is directly converted into plasma by a high-frequency electric field to generate SiH x (x = 0, 1, 2, 3) which is an active species.
b. At this time, the generated active species of hydrogen react with SiH 4 to produce SiH 3 as an active species as follows, and further, the active species of hydrogen generated during this reaction react with SiH 3. Te SiH 2 is generated, the chain reactions as described below takes place and so on.
c. SiH 4 reacts with the active species of helium to produce SiH x (x = 0, 1, 2, 3).
　微結晶シリコン膜の結晶性を高めるためには、活性種であるＳｉＨｘに対して十分大量な水素ラジカルが必要であることが知られている。同時に微結晶シリコン膜中の欠陥密度を減らすためには、活性種であるＳｉＨ３の濃度を高くし、ＳｉＨ３から更に分解が進んだ活性種（例えば、ＳｉＨ２、ＳｉＨ、Ｓｉなど）の濃度を抑えることが必要であることが知られている。ＳｉＨ３が更に分解した活性種は、未結合手（ダングリングボンド）を持ったまま膜中に取り込まれて微結晶シリコン膜の欠陥密度の増加を引き起こす。またこれらの活性種が重合してＳｉｎＨ２ｎ＋２（ｎ＝２，３，４・・・）といった高次シランを生成し、これらが膜中へと取り込まれたり、またこの高次シランがさらに成長して微粒子化した状態で取り込まれたりした場合にも微結晶シリコン膜の欠陥密度増加の要因となる。 In order to increase the crystallinity of the microcrystalline silicon film, it is known that a sufficiently large amount of hydrogen radicals are required for the active species SiH x . At the same time, in order to reduce the defect density in the microcrystalline silicon film, the concentration of active species SiH 3 is increased, and the concentration of active species (for example, SiH 2 , SiH, Si, etc.) further decomposed from SiH 3 is increased. It is known that it is necessary to suppress this. The active species obtained by further decomposing SiH 3 is taken into the film while having dangling bonds (dangling bonds), thereby increasing the defect density of the microcrystalline silicon film. In addition, these active species are polymerized to produce higher order silanes such as Si n H 2n + 2 (n = 2, 3, 4...), And these are taken into the film. Even when it grows and is taken in the form of fine particles, it becomes a factor in increasing the defect density of the microcrystalline silicon film.
　従ってプラズマ中の水素ラジカルの量を維持したままＳｉＨ３の濃度を高めることが重要であり、このため本発明では水素ガスを用いずにヘリウムガスを希釈ガスとして用いている。記述のようにモノシランガスのプラズマ化は、主としてプラズマ化されたヘリウムガスによりプラズマ化されることからヘリウムガスはプラズマ生成用のガスということもできる。一般にモノシランガスを成膜ガスとして用いてシリコン膜を成膜する場合には、結晶性を高めるために水素ガスをモノシランガスに対して例えば数十倍以上の流量で基板に供給している。このような手法は、たとえば容量結合プラズマを用いたプラズマＣＶＤプロセスにおいて高い結晶性を維持しつつ、シリコンダングリングボンドの水素化を促進できるため、生産効率の高い成膜方法である。 Therefore, it is important to increase the concentration of SiH 3 while maintaining the amount of hydrogen radicals in the plasma. Therefore, in the present invention, helium gas is used as a dilution gas without using hydrogen gas. As described, the monosilane gas is converted into plasma mainly by helium gas converted into plasma, so that helium gas can also be referred to as plasma generation gas. In general, when a silicon film is formed using monosilane gas as a film forming gas, hydrogen gas is supplied to the substrate at a flow rate of, for example, several tens of times that of monosilane gas in order to improve crystallinity. Such a method is a film forming method with high production efficiency because it can promote hydrogenation of silicon dangling bonds while maintaining high crystallinity in a plasma CVD process using capacitively coupled plasma, for example.
　しかしながら、誘導結合プラズマまたはマイクロ波プラズマに同様の水素ガス添加を用いると、水素ラジカルが過剰に発生してしまい、そうすると水素ラジカルとＳｉＨ３との接触確率が高まるので、ＳｉＨ３から更に分解が進んだ活性種が多く生成されてしまう。これに対して、ヘリウムガスを用いる場合には、ヘリウムラジカルは、水素ラジカルに比べて電子温度が高いため、ラジカル密度を低く抑えてもＳｉＨ４をＳｉＨ３に素早く活性化させることができ成膜速度を上げることができる。 However, when the same hydrogen gas addition is used for inductively coupled plasma or microwave plasma, hydrogen radicals are excessively generated, so that the contact probability between the hydrogen radicals and SiH 3 is increased, so that further decomposition proceeds from SiH 3. Many active species are generated. On the other hand, when helium gas is used, the helium radical has a higher electron temperature than the hydrogen radical, so that SiH 4 can be rapidly activated to SiH 3 even if the radical density is kept low. You can increase the speed.
　そしてラジカル密度を低く抑えることによりヘリウムラジカルとＳｉＨ３との接触確率を少なくすることができるため、ＳｉＨ３の分解が抑制されて、成膜する微結晶シリコン膜中の欠陥密度を減少させることができると考えられる。また、シリコン薄膜の結晶化に必要な水素ラジカルはＳｉＨ４からＳｉＨ３への分解の過程において十分に生成されるため、高い結晶性と低い欠陥密度を維持したまま成膜速度を増加させることができると考えられる。 Since the probability of contact between the helium radical and SiH 3 can be reduced by keeping the radical density low, decomposition of SiH 3 is suppressed, and the defect density in the microcrystalline silicon film to be formed can be reduced. It is considered possible. Further, since hydrogen radicals necessary for crystallization of the silicon thin film are sufficiently generated in the process of decomposition from SiH 4 to SiH 3 , it is possible to increase the deposition rate while maintaining high crystallinity and low defect density. It is considered possible.
　こうして高濃度のＳｉＨ３を含み、ＳｉＨ３の分解が抑えられた活性種群が基板Ｓに供給され、結晶性が高く欠陥密度の低い微結晶シリコン膜が基板Ｓの表面に成膜される。図５はＳｉＨ３が基板Ｓ上に降り積もるイメージを示しており、図中において斜線で示す活性種はＳｉＨ３が更に分解して生成されたものである。そして予め設定した時間が経過した後、高周波電力の印加を停止し、次いでガスの供給を停止する。 Thus, an active species group containing a high concentration of SiH 3 and in which decomposition of SiH 3 is suppressed is supplied to the substrate S, and a microcrystalline silicon film with high crystallinity and low defect density is formed on the surface of the substrate S. FIG. 5 shows an image in which SiH 3 is deposited on the substrate S, and the active species indicated by oblique lines in the figure are those generated by further decomposition of SiH 3 . Then, after a preset time has elapsed, the application of high-frequency power is stopped, and then the gas supply is stopped.
　本実施形態によれば、水素ガスを用いずにモノシランガスとヘリウムガスとの混合ガスを高周波電力の印加により誘導される高周波電界によりプラズマ化しているため、すでに詳述したように高濃度のＳｉＨ３を含み、ＳｉＨ３の分解が抑えられた活性種群が基板Ｓ上に供給される。このため、速い成膜速度で、結晶性が高く欠陥密度が低い微結晶シリコンを得ることができる。 According to this embodiment, since a mixed gas of monosilane gas and helium gas is converted into a plasma by a high-frequency electric field induced by application of high-frequency power without using hydrogen gas, high-concentration SiH 3 as already described in detail. The active species group in which decomposition of SiH 3 is suppressed is supplied onto the substrate S. Therefore, microcrystalline silicon with high crystallinity and low defect density can be obtained at a high film formation rate.
　上述の実施形態では、シラン系のガスとしてモノシランガスを用いているが、例えばジシラン（Ｓｉ２Ｈ６）ガスやトリクロロシラン（ＳｉＨＣｌ３）ガスなどの他のシラン系ガスでもよい。この場合においてもヘリウムの活性種を生成することにより、シラン系ガスの分子がいわば細切れになるのが抑えられ、同様の効果が得られる。ここで言うシラン系ガスとは、ＳｉＨ４ガス、ポリシラン（ＳｉｎＨ２ｎ＋２（ｎ＝２，３，４・・・））のガス、シラン化合物のガスなどのことを言う。また上述の実施形態では、誘導結合プラズマを生成しているが、アンテナ５２に代えて例えば円形状の導体板に十字型の開口を渦巻き状に形成したアンテナを用いてもよい。この場合、このアンテナの中心部に導波管を接合してこの導波管から前記アンテナを介してマイクロ波を放射し、このマイクロ波によりガスをプラズマ化する。 In the above-described embodiment, monosilane gas is used as the silane-based gas, but other silane-based gases such as disilane (Si 2 H 6 ) gas and trichlorosilane (SiHCl 3 ) gas may be used. In this case as well, by generating helium active species, it is possible to suppress the silane-based gas molecules from being shredded, and the same effect can be obtained. Here, the silane-based gas means SiH 4 gas, polysilane (Si n H 2n + 2 (n = 2, 3, 4...)) Gas, silane compound gas, and the like. In the above-described embodiment, inductively coupled plasma is generated. However, instead of the antenna 52, for example, an antenna in which a cross-shaped opening is formed in a spiral shape on a circular conductor plate may be used. In this case, a waveguide is joined to the central portion of the antenna, microwaves are radiated from the waveguide through the antenna, and gas is turned into plasma by the microwaves.
　ここで本発明は、水素ガスを用いないことを要件としており、水素ガスを加えることによりモノシランガスの分解を促進させるという悪影響が現れる。しかし水素ガスの影響は、モノシランガスの何倍もの量を供給した場合に問題となり、モノシランガスと同量程度の水素ガスを供給した場合にはほとんどその影響は出てこない。このような少量の水素ガスの添加はそもそも技術的意味がなく、このした手法は、本発明を実施しながら、特許請求の範囲の記載の表現の限界を潜ろうとする不当な実施である。従って特許請求の範囲でいう「水素ガスを用いない」とは、このような技術的意味のない少量の水素ガスの添加までをも排除するものではない。 Here, the present invention requires that no hydrogen gas is used, and the adverse effect of promoting the decomposition of the monosilane gas by adding the hydrogen gas appears. However, the influence of hydrogen gas becomes a problem when supplying many times the amount of monosilane gas, and hardly affects when supplying the same amount of hydrogen gas as monosilane gas. The addition of such a small amount of hydrogen gas has no technical meaning in the first place, and this approach is an unreasonable practice that seeks to dive into the limitations of the expression of the claims while carrying out the present invention. Therefore, the term “do not use hydrogen gas” in the claims does not exclude the addition of a small amount of hydrogen gas which has no technical meaning.
　本発明における実施例について説明する。　
　［実験１］
　以下で述べるように各実施例においてほぼ同様の成膜条件となるように、プロセス圧力を０．４Ｐａ～１．０Ｐａに設定する。更にＳｉＨ４ガス供給量を５ｓｃｃｍ～６ｓｃｃｍの範囲で夫々固定し、モノシラン（ＳｉＨ４）ガスに対して約１０倍の各種希釈ガスを添加しながらＩＣＰ－ＣＶＤにより微結晶シリコン（μｃ－Ｓｉ）膜を成膜した。そして前記微結晶シリコン膜に対してラマン分光による測定及び成膜速度の測定を行った。なお、以下で述べる希釈ガスとは、成膜処理時において反応ガスに添加するガスのことである。　 Examples of the present invention will be described.
[Experiment 1]
As described below, the process pressure is set to 0.4 Pa to 1.0 Pa so that substantially the same film forming conditions are obtained in each embodiment. Further, the SiH 4 gas supply amount is fixed in the range of 5 sccm to 6 sccm, and a microcrystalline silicon (μc-Si) film is formed by ICP-CVD while adding various dilution gases about 10 times the monosilane (SiH 4 ) gas. Was deposited. The microcrystalline silicon film was measured by Raman spectroscopy and the deposition rate. Note that the dilution gas described below is a gas added to the reaction gas during the film forming process.
　（実施例１）
　高周波電力：　２０００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、５ｓｃｃｍ
　希釈ガス種及び希釈ガス供給量：　ヘリウム（Ｈｅ）、４９ｓｃｃｍ
　プロセス圧力：　０．６Ｐａ
　（参考例１）
　高周波電力：　２０００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、５ｓｃｃｍ
　希釈ガス種及び希釈ガス供給量：　Ａｒ、５０ｓｃｃｍ
　プロセス圧力：　０．９Ｐａ
　（比較例１－１）
　高周波電力：　２０００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、６ｓｃｃｍ
　希釈ガス種及び希釈ガス供給量：　希釈ガスは供給しない。　
　プロセス圧力：　１．０Ｐａ
　（比較例１－２）
　高周波電力：　２０００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、５ｓｃｃｍ
　希釈ガス種及び希釈ガス供給量：　Ｈ２、５０ｓｃｃｍ
　プロセス圧力：　０．４Ｐａ Example 1
High frequency power: 2000W
Reaction gas species and reaction gas supply amount: SiH 4 , 5 sccm
Dilution gas type and dilution gas supply amount: Helium (He), 49 sccm
Process pressure: 0.6Pa
(Reference Example 1)
High frequency power: 2000W
Reaction gas species and reaction gas supply amount: SiH 4 , 5 sccm
Dilution gas type and dilution gas supply amount: Ar, 50 sccm
Process pressure: 0.9Pa
(Comparative Example 1-1)
High frequency power: 2000W
Reaction gas species and reaction gas supply amount: SiH 4 , 6 sccm
Dilution gas type and dilution gas supply: No dilution gas is supplied.
Process pressure: 1.0 Pa
(Comparative Example 1-2)
High frequency power: 2000W
Reaction gas species and reaction gas supply amount: SiH 4 , 5 sccm
Dilution gas type and dilution gas supply amount: H 2 , 50 sccm
Process pressure: 0.4 Pa
　本実験におけるラマン分光測定結果を図６に示し、またラマン分光測定結果から算出した後述の強度比Ｘｃの算出値及び成膜速度を表１に示す。 The Raman spectroscopic measurement result in this experiment is shown in FIG. 6, and the calculated value of the intensity ratio Xc and the film formation rate calculated from the Raman spectroscopic measurement result are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　図６の強度パターンａ、ｂ、ｃ、ｄは夫々、実施例１、参考例１、比較例１－１、比較例１－２に対応する。　
　ラマン分光における波数が４８０ｃｍ－１における強度Ｉａはアモルファスシリコン（ａ－Ｓｉ）の物質量に対応し、同じく５２０ｃｍ－１における強度Ｉｃは微結晶シリコン（μｃ－Ｓｉ）の物質量に対応している。そしてこれらの強度比Ｘｃ（Ｘｃ＝Ｉｃ／（Ｉａ＋Ｉｃ））は、測定したシリコン膜の結晶性を表す指標として知られている。本実施例では、この結晶化度に相当する強度比Ｘｃを用いてシリコン膜の結晶性を評価した。 The intensity patterns a, b, c, and d in FIG. 6 correspond to Example 1, Reference Example 1, Comparative Example 1-1, and Comparative Example 1-2, respectively.
The intensity Ia at a wave number of 480 cm −1 in Raman spectroscopy corresponds to the amount of material of amorphous silicon (a-Si), and the intensity Ic at 520 cm −1 corresponds to the amount of material of microcrystalline silicon (μc-Si). . The intensity ratio Xc (Xc = Ic / (Ia + Ic)) is known as an index representing the crystallinity of the measured silicon film. In this example, the crystallinity of the silicon film was evaluated using the intensity ratio Xc corresponding to this crystallinity.
　図６から分かるように、実施例１では強度パターンのピーク位置の波数がμｃ－Ｓｉに対応する波数である５２０ｃｍ－１（理想波数）にかなり近づいているが、参考例１ではピーク位置の波数が約５１５ｃｍ－１であり、理想波数から少しシフトしている。そして比較例１－１のピーク位置の波数は理想波数から更にシフトし、比較例１－２ではピーク位置の波数が５１０ｃｍ－１を下回っている。一方成膜速度については、実施例１は比較例１－１及び比較例１－２よりも遅いが、次の実験２の結果から分かるように、モノシランガス及びヘリウムガスの流量を増やすことにより成膜速度を向上させることができる。
　実施例１及び参考例１は、強度比Ｘｃが８０％以上であり、結晶性が良好であることが分かる。 As can be seen from FIG. 6, in Example 1, the wave number at the peak position of the intensity pattern is quite close to 520 cm −1 (ideal wave number) corresponding to μc-Si, but in Reference Example 1, the wave number at the peak position. Is about 515 cm −1, which is slightly shifted from the ideal wave number. The wave number at the peak position in Comparative Example 1-1 is further shifted from the ideal wave number, and in Comparative Example 1-2, the wave number at the peak position is below 510 cm −1 . On the other hand, with respect to the film formation rate, Example 1 is slower than Comparative Example 1-1 and Comparative Example 1-2, but as can be seen from the results of the following Experiment 2, film formation is performed by increasing the flow rates of monosilane gas and helium gas. Speed can be improved.
In Example 1 and Reference Example 1, the strength ratio Xc is 80% or more, and it can be seen that the crystallinity is good.
　［実験２］
　上述の実験１の結果を受けて、Ｈｅガスを添加して成膜する場合にＳｉＨ４ガス供給量を増やすことで成膜速度の向上を図った場合に、シリコン膜の結晶性がどのような挙動を示すかを検証した。即ちＨｅガスを添加した場合（実施例２）としない場合（比較例２）夫々について、ＳｉＨ４ガス供給量とＸｃ及び成膜速度との関係を実験にて調べた。本実験における成膜条件を以下に示す。 [Experiment 2]
In response to the result of Experiment 1 described above, when the deposition rate is increased by increasing the supply amount of SiH 4 gas when forming a film by adding He gas, what is the crystallinity of the silicon film? It was verified whether it behaved. That is, for each of the cases where He gas was added (Example 2) and not (Comparative Example 2), the relationship between the SiH 4 gas supply amount, Xc, and the film formation rate was examined experimentally. The film forming conditions in this experiment are shown below.
　（実施例２）
　高周波電力：　２０００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、５、１０、１５、２０ｓｃｃｍ
　希釈ガス種及び希釈ガス供給量：　Ｈｅ、反応ガス供給量の１０倍
　プロセス圧力：　０．６Ｐａ～１．９Ｐａ
　（比較例２）
　高周波電力：　２０００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、６、８、１２ｓｃｃｍ
　希釈ガス種及び希釈ガス供給量：　希釈ガスは供給しない。　
　プロセス圧力：　１．０Ｐａ (Example 2)
High frequency power: 2000W
Reaction gas species and reaction gas supply amount: SiH 4 , 5, 10, 15, 20 sccm
Dilution gas type and dilution gas supply amount: He, 10 times the reaction gas supply amount Process pressure: 0.6 Pa to 1.9 Pa
(Comparative Example 2)
High frequency power: 2000W
Reactive gas species and reactive gas supply amount: SiH 4 , 6, 8, 12 sccm
Dilution gas type and dilution gas supply: No dilution gas is supplied.
Process pressure: 1.0 Pa
　本実験における結果を図７及び図８に示す。　
　先ず図７は、Ｈｅガスを添加していない場合の実験結果である。ＳｉＨ４ガス供給量が６ｓｃｃｍの場合には６０％以上のＸｃを得ることができたが、ＳｉＨ４ガス供給量を８ｓｃｃｍ以上とすると、成膜速度がＳｉＨ４ガス供給量に比例して上昇するのに対して、Ｘｃは著しく減少した。図示していないが、Ｈ２ガスを添加した場合についても同様の傾向が見られた。　
　一方Ｈｅガスを添加した場合には、図８に示すように、ＳｉＨ４ガス供給量を増やしていくと、それにほぼ比例して成膜速度は上昇し、ＸｃはＨｅガス無添加の場合（比較例２）のように低下することなくほぼ８０％付近という高い値を維持し続けた。例えばシリコン膜の成膜速度が０．５５ｎｍ／ｓｅｃ以上であり、前記ピーク強度比（結晶化度）Ｘｃが７０％以上であれば、生産性及びシリコン膜の結晶性の点で好ましい製法ということができる。 The results of this experiment are shown in FIGS.
First, FIG. 7 shows the experimental results when no He gas is added. When the SiH 4 gas supply amount was 6 sccm, Xc of 60% or more could be obtained. However, when the SiH 4 gas supply amount was 8 sccm or more, the deposition rate increased in proportion to the SiH 4 gas supply amount. In contrast, Xc was significantly reduced. Although not shown, the same tendency was observed when H 2 gas was added.
On the other hand, when He gas is added, as shown in FIG. 8, as the SiH 4 gas supply amount is increased, the deposition rate increases almost in proportion to this, and when Xc is not added with He gas (comparison). The high value of about 80% was maintained without decreasing as in Example 2). For example, if the deposition rate of the silicon film is 0.55 nm / sec or more and the peak intensity ratio (crystallinity) Xc is 70% or more, it is a preferable manufacturing method in terms of productivity and crystallinity of the silicon film. Can do.
　［実験３］
　本発明者は、上述の実施形態において述べたように、電子温度の高いＨｅラジカルにより、ラジカル密度を抑えた条件でＳｉＨ４を活性化しているため、その活性種であるＳｉＨ３について更なる分解が抑えられた状態で成膜を行うことができると考えている。そこで本実験では、ＳｉＨ３からＳｉＨ２へと分解される度合を、ヘリウムガスを用いた場合（実施例３）と水素ガスを用いた場合（比較例３）との各々について調査した。具体的にはＳｉＨ２の更なる分解生成活性種であるＳｉＨ及びＳｉ夫々の処理雰囲気中の濃度を発光分光法（ＯＥＳ）により同定した。そしてそれらの濃度比即ちそれらのピーク強度比ＳｉＨ／ＳｉがＳｉＨ３とＳｉＨ２との濃度比と等しいと仮定することで、ＳｉＨ３からＳｉＨ２へと分解される度合を評価した。なお、以下に記載する「ＳｉＨ４ガス流量比」とは、ＳｉＨ４ガス及び希釈ガスの合計ガス供給量に対するＳｉＨ４ガス供給量の割合のことである。 [Experiment 3]
As described in the above-described embodiment, the present inventor has activated SiH 4 under a condition in which the radical density is suppressed by the He radical having a high electron temperature. Therefore, the active species SiH 3 is further decomposed. It is considered that film formation can be performed in a state where the above is suppressed. Therefore, in this experiment, the degree of decomposition from SiH 3 to SiH 2 was investigated for each of the case using helium gas (Example 3) and the case using hydrogen gas (Comparative Example 3). Specifically, the concentration of SiH, which is a further active product of decomposition of SiH 2 , and the concentration of Si in the processing atmosphere were identified by emission spectroscopy (OES). Then, the degree of decomposition from SiH 3 to SiH 2 was evaluated by assuming that the concentration ratio thereof, that is, the peak intensity ratio SiH / Si was equal to the concentration ratio of SiH 3 and SiH 2 . The “SiH 4 gas flow rate ratio” described below is the ratio of the SiH 4 gas supply amount to the total gas supply amount of the SiH 4 gas and the dilution gas.
　（実施例３）
　高周波電力：　２０００Ｗ
　ＳｉＨ４ガス及び希釈ガスの合計ガス供給量：　１００ｓｃｃｍ
　希釈ガス種：　Ｈｅ
　ＳｉＨ４ガス流量比：　５、１０、１５、２０、２５、３０％
　プロセス圧力：　１．０Ｐａ
　（比較例３）
　高周波電力：　２０００Ｗ
　ＳｉＨ４ガス及び希釈ガスの合計ガス供給量：　１０ｓｃｃｍ
　希釈ガス種：　Ｈ２
　ＳｉＨ４ガス流量比：　１５、４０、５０、６０、８０、１００％
　プロセス圧力：　１．０Ｐａ (Example 3)
High frequency power: 2000W
Total gas supply amount of SiH 4 gas and dilution gas: 100 sccm
Dilution gas type: He
SiH 4 gas flow ratio: 5, 10, 15, 20, 25, 30%
Process pressure: 1.0 Pa
(Comparative Example 3)
High frequency power: 2000W
Total gas supply amount of SiH 4 gas and dilution gas: 10 sccm
Dilution gas type: H 2
SiH 4 gas flow ratio: 15, 40, 50, 60, 80, 100%
Process pressure: 1.0 Pa
　本実験の結果を図９に示す。ＳｉＨ４ガス流量比が１００％とは、希釈ガスを添加せずＳｉＨ４ガスのみ供給した場合を示している。図９に示すように、希釈ガスが水素ガスの場合、ＳｉＨ４ガス流量比を低下させるに従って、発光強度比ＳｉＨ／Ｓｉが低下する傾向にある。即ち混合ガス中の水素ガス供給量の割合を増やすに従って、ＳｉＨ３がＳｉＨ２に分解される度合いが増していく傾向にある。これに対して希釈ガスがヘリウムガスの場合には、ＳｉＨ４ガス流量比を５％から増やす（ヘリウムガスの流量比を９５％から減らす）につれて発光強度比ＳｉＨ／Ｓｉが上昇している。更にＳｉＨ４ガス流量比を増やす（ヘリウムガスの流量比を減らす）と発光強度比ＳｉＨ／Ｓｉが低下していくと推測されるが、ヘリウムガスの供給量を調整することにより、水素ガスを用いる場合に比べて発光強度比ＳｉＨ／Ｓｉについてかなり高い値が得られることが分かる。 The result of this experiment is shown in FIG. The SiH 4 gas flow rate ratio of 100% indicates a case where only SiH 4 gas is supplied without adding a dilution gas. As shown in FIG. 9, when the diluent gas is hydrogen gas, according to lower the SiH 4 gas flow rate ratio, the emission intensity ratio SiH / Si tends to decrease. That is, as the ratio of the supply amount of hydrogen gas in the mixed gas is increased, the degree to which SiH 3 is decomposed into SiH 2 tends to increase. On the other hand, when the dilution gas is helium gas, the emission intensity ratio SiH / Si increases as the SiH 4 gas flow rate ratio is increased from 5% (the flow rate ratio of helium gas is decreased from 95%). If the SiH 4 gas flow rate ratio is further increased (the helium gas flow rate ratio is decreased), the emission intensity ratio SiH / Si is presumed to decrease, but hydrogen gas is used by adjusting the supply amount of helium gas. It can be seen that a considerably high value is obtained for the emission intensity ratio SiH / Si as compared to the case.
　［実験４］
　本実験では、成膜したシリコン膜の結晶配向性についてＸ線回折（ＸＲＤ）により検証した。測定試料の膜厚は１０００ｎｍとし、Ｓｉ（２２０）に対応するピーク強度Ｉ（２２０）とＳｉ（１１１）に対応するピーク強度Ｉ（１１１）との比Ｉ（２２０）／Ｉ（１１１）を結晶配向性の指標とした。一般的にピーク強度比Ｉ（２２０）／Ｉ（１１１）が大きいほど、太陽電池として望ましい特性を示すとされている。また本実験では、参考例としてＨ２ガスを添加してＣＣＰ－ＣＶＤにより成膜したシリコン膜についてもＸ線回折による測定を行った。なお、以下に記載の希釈ガス供給比とは、ＳｉＨ４ガス供給量に対する希釈ガス供給量の比である。 [Experiment 4]
In this experiment, the crystal orientation of the deposited silicon film was verified by X-ray diffraction (XRD). The film thickness of the measurement sample is 1000 nm, and the ratio I (220) / I (111) between the peak intensity I (220) corresponding to Si (220) and the peak intensity I (111) corresponding to Si (111) is crystallized. It was used as an index of orientation. Generally, it is said that the larger the peak intensity ratio I (220) / I (111), the more desirable characteristics as a solar cell. In this experiment, as a reference example, measurement by X-ray diffraction was also performed on a silicon film formed by CCP-CVD with addition of H 2 gas. The dilution gas supply ratio described below is the ratio of the dilution gas supply amount to the SiH 4 gas supply amount.
　（実施例４）
　プラズマ源：　ＩＣＰ、高周波電力２０００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、５ｓｃｃｍ
　希釈ガス種及び希釈ガス供給比：　Ｈｅ、１０／１
　プロセス圧力：　０．６Ｐａ
　（比較例４－１）
　プラズマ源：　ＩＣＰ、高周波電力２０００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、６ｓｃｃｍ
　希釈ガス種及び希釈ガス供給比：　希釈ガスは供給しない。　
　プロセス圧力：　０．９Ｐａ
　（比較例４－２）
　プラズマ源：　ＩＣＰ、高周波電力１６００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、２ｓｃｃｍ
　希釈ガス種及び希釈ガス供給比：　Ｈ２、７／１
　プロセス圧力：　１．０Ｐａ
　（参考例４－１）
　プラズマ源：　ＣＣＰ、高周波電力１００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、１０ｓｃｃｍ
　希釈ガス種及び希釈ガス供給比：　Ｈ２、５０／１
　プロセス圧力：　８００Ｐａ
　（参考例４－２）
　プラズマ源：　ＣＣＰ、高周波電力１００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、５ｓｃｃｍ
　希釈ガス種及び希釈ガス供給比：　Ｈ２、１００／１
　プロセス圧力：　８００Ｐａ (Example 4)
Plasma source: ICP, high frequency power 2000W
Reaction gas species and reaction gas supply amount: SiH 4 , 5 sccm
Dilution gas type and dilution gas supply ratio: He, 10/1
Process pressure: 0.6Pa
(Comparative Example 4-1)
Plasma source: ICP, high frequency power 2000W
Reaction gas species and reaction gas supply amount: SiH 4 , 6 sccm
Dilution gas type and dilution gas supply ratio: No dilution gas is supplied.
Process pressure: 0.9Pa
(Comparative Example 4-2)
Plasma source: ICP, high frequency power 1600W
Reaction gas species and reaction gas supply amount: SiH 4 , 2 sccm
Dilution gas type and dilution gas supply ratio: H 2 , 7/1
Process pressure: 1.0 Pa
(Reference Example 4-1)
Plasma source: CCP, high frequency power 100W
Reaction gas species and reaction gas supply amount: SiH 4 , 10 sccm
Dilution gas type and dilution gas supply ratio: H 2 , 50/1
Process pressure: 800Pa
(Reference Example 4-2)
Plasma source: CCP, high frequency power 100W
Reaction gas species and reaction gas supply amount: SiH 4 , 5 sccm
Dilution gas type and dilution gas supply ratio: H 2 , 100/1
Process pressure: 800Pa
　本実験における測定結果を図１０に示す。　
　先ずＩＣＰ－ＣＶＤによる実施例である実施例４、比較例４－１及び比較例４－２の３つの比較を行うと、ピーク強度比Ｉ（２２０）／Ｉ（１１１）の大きい順に、実施例４、比較例４－１、比較例４－２という結果となった。即ち、Ｈｅ希釈、ＳｉＨ４のみ供給、Ｈ２希釈の順に結晶配向性が良好であった。次に実施例４とＣＣＰ－ＣＶＤによる実施例である参考例４－１及び参考例４－２との比較を行うと、実施例４は、結晶配向性において参考例４－１には及ばなかったが、参考例４－２よりは良好であった。 The measurement results in this experiment are shown in FIG.
First, three comparisons of Example 4, Comparative Example 4-1, and Comparative Example 4-2, which are examples of ICP-CVD, are performed in order of increasing peak intensity ratio I (220) / I (111). The results were 4, Comparative Example 4-1, and Comparative Example 4-2. That is, the crystal orientation was good in the order of He dilution, SiH 4 supply, and H 2 dilution. Next, when Example 4 is compared with Reference Example 4-1 and Reference Example 4-2, which are CCP-CVD examples, Example 4 does not reach Reference Example 4-1 in terms of crystal orientation. However, it was better than Reference Example 4-2.
　［実験５］
　本実験では、電子スピン共鳴（ＥＳＲ）分析により成膜したシリコン膜のスピン密度を測定して、そのシリコン膜における未結合手（ダングリングボンド）の密度について測定を行った。またそのとき、結晶化度Ｘｃ及び成膜速度についても測定したのでその結果も後述の表２に併記する。 [Experiment 5]
In this experiment, the spin density of a silicon film formed by electron spin resonance (ESR) analysis was measured, and the density of dangling bonds in the silicon film was measured. At that time, the crystallinity Xc and the film formation rate were also measured, and the results are also shown in Table 2 described later.
　（実施例５）
　プラズマ源：　ＩＣＰ、高周波電力２０００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、１５ｓｃｃｍ
　希釈ガス種及び希釈ガス供給比：　Ｈｅ、６／１
　プロセス圧力：　１．０Ｐａ
　（比較例５－１）
　プラズマ源：　ＩＣＰ、高周波電力２０００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、６ｓｃｃｍ
　希釈ガス種及び希釈ガス供給比：　希釈ガスは供給しない。　
　プロセス圧力：　１．０Ｐａ
　（比較例５－２）
　プラズマ源：　ＩＣＰ、高周波電力１６００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、２ｓｃｃｍ
　希釈ガス種及び希釈ガス供給比：　Ｈ２、７／１
　プロセス圧力：　１．０Ｐａ
　（参考例５）
　プラズマ源：　ＣＣＰ、高周波電力１００～７００Ｗ
　反応ガス種及び反応ガス供給量：　ＳｉＨ４、５～４０ｓｃｃｍ
　希釈ガス種及び希釈ガス供給比：　Ｈ２、５０／１～１００／１
　プロセス圧力：　８００～１２００Ｐａ (Example 5)
Plasma source: ICP, high frequency power 2000W
Reaction gas species and reaction gas supply amount: SiH 4 , 15 sccm
Dilution gas type and dilution gas supply ratio: He, 6/1
Process pressure: 1.0 Pa
(Comparative Example 5-1)
Plasma source: ICP, high frequency power 2000W
Reaction gas species and reaction gas supply amount: SiH 4 , 6 sccm
Dilution gas type and dilution gas supply ratio: No dilution gas is supplied.
Process pressure: 1.0 Pa
(Comparative Example 5-2)
Plasma source: ICP, high frequency power 1600W
Reaction gas species and reaction gas supply amount: SiH 4 , 2 sccm
Dilution gas type and dilution gas supply ratio: H 2 , 7/1
Process pressure: 1.0 Pa
(Reference Example 5)
Plasma source: CCP, high frequency power 100-700W
Reaction gas species and reaction gas supply amount: SiH 4 , 5 to 40 sccm
Dilution gas type and dilution gas supply ratio: H 2 , 50/1 to 100/1
Process pressure: 800-1200Pa
　表２に本実験における測定結果を示す。　
　実施例５は、表２に示すように、比較例５－１及び比較例５－２に比べてＥＳＲ分析の検出値が小さいことから、Ｈｅガスを添加することによりダングリングボンドが少なくなり成膜したシリコン膜の欠陥が少なくなることが推測される。結晶化度Ｘｃ及び成膜速度についても、実施例５は比較例５－１及び比較例５－２に比較して良好な結果であった。実施例５は、ＣＣＰ－ＣＶＤによるシリコン膜である参考例５と比較するとダングリングボンドが多い結果であった。 Table 2 shows the measurement results in this experiment.
As shown in Table 2, the detection value of ESR analysis in Example 5 is smaller than that in Comparative Example 5-1 and Comparative Example 5-2, so that dangling bonds are reduced by adding He gas. It is presumed that defects in the formed silicon film are reduced. As for the degree of crystallinity Xc and the film formation rate, Example 5 was better than Comparative Example 5-1 and Comparative Example 5-2. Example 5 resulted in more dangling bonds compared to Reference Example 5, which is a silicon film formed by CCP-CVD.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Ｓ　　　ガラス基板
１　　　処理容器
１３　　圧力調整部
１４　　真空ポンプ
２　　　載置台
３　　　第１のガス供給部
４　　　第２のガス供給部
５　　　プラズマ発生機構
５２　　アンテナ
５３　　高周波電源
６　　　制御部 S glass substrate 1 processing vessel 13 pressure adjusting unit 14 vacuum pump 2 mounting table 3 first gas supply unit 4 second gas supply unit 5 plasma generation mechanism 52 antenna 53 high frequency power supply 6 control unit

Claims (3)

  1. 　処理容器内に載置された基板に対してプラズマにより成膜を行う方法であって、
    　前記処理容器内にシラン系のガス及び希釈ガスであるヘリウムガスを供給する工程と、
    　前記処理容器内に誘導結合プラズマまたはマイクロ波プラズマを生成し、シラン系のガスを活性化させる工程と、
    　プラズマ化されたシラン系のガスにより前記基板上にシリコン膜を成膜する工程と、を含み、
    　前記処理容器内には水素ガスが供給されないことを特徴とする成膜方法。     A method of forming a film with plasma on a substrate placed in a processing container,
    Supplying a silane-based gas and a helium gas as a dilution gas into the processing vessel;
    Generating inductively coupled plasma or microwave plasma in the processing vessel and activating a silane-based gas;
    Forming a silicon film on the substrate with a silane-based gas that has been converted to plasma, and
    A film forming method, wherein hydrogen gas is not supplied into the processing container.
  2. 　シリコン膜を成膜する速度が０．５５ｎｍ／ｓｅｃ以上であり、
    　シリコン膜についてラマン分光による結晶シリコンのピーク強度及びアモルファスシリコンのピーク強度を夫々Ｉｃ及びＩａとすると、Ｉｃ／（Ｉａ＋Ｉｃ）が７０％以上であることを特徴とする請求項１記載の成膜方法。     The rate of forming the silicon film is 0.55 nm / sec or more,
    2. The film forming method according to claim 1, wherein Ic / (Ia + Ic) is 70% or more when the peak intensity of crystalline silicon and the peak intensity of amorphous silicon by Raman spectroscopy are Ic and Ia, respectively.
  3. 　基板、シラン系のガスの供給口、ヘリウムガスの供給口及びプラズマ生成部が下からこの順に配置され、
    　ヘリウムガスがプラズマ化され、プラズマ化されたヘリウムガスによりシラン系のガスがプラズマ化されることを特徴とする請求項１記載の成膜方法。
     
          A substrate, a silane-based gas supply port, a helium gas supply port, and a plasma generation unit are arranged in this order from the bottom,
    2. The film forming method according to claim 1, wherein the helium gas is turned into plasma, and the silane-based gas is turned into plasma by the turned helium gas.

PCT/JP2012/004522 2011-08-01 2012-07-12 Film formation method WO2013018292A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011-168766 2011-08-01
JP2011168766A JP2013033828A (en) 2011-08-01 2011-08-01 Method for forming film

Publications (1)

Publication Number Publication Date
WO2013018292A1 true WO2013018292A1 (en) 2013-02-07

Family

ID=47628844

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/004522 WO2013018292A1 (en) 2011-08-01 2012-07-12 Film formation method

Country Status (3)

Country Link
JP (1) JP2013033828A (en)
TW (1) TW201318036A (en)
WO (1) WO2013018292A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107408497A (en) * 2015-03-13 2017-11-28 新南创新私人有限公司 Method for handling silicon materials

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6861479B2 (en) * 2016-06-24 2021-04-21 東京エレクトロン株式会社 Plasma deposition method and plasma deposition equipment
JP6914149B2 (en) * 2017-09-07 2021-08-04 東京エレクトロン株式会社 Plasma processing equipment

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02202018A (en) * 1989-01-31 1990-08-10 Tonen Corp Manufacture of polycrystalline silicon thin film
JPH05275354A (en) * 1992-03-27 1993-10-22 Tokuyama Soda Co Ltd Manufacture of silicon film
JP2007165717A (en) * 2005-12-15 2007-06-28 Tokyo Electron Ltd Filming method and filming device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02202018A (en) * 1989-01-31 1990-08-10 Tonen Corp Manufacture of polycrystalline silicon thin film
JPH05275354A (en) * 1992-03-27 1993-10-22 Tokuyama Soda Co Ltd Manufacture of silicon film
JP2007165717A (en) * 2005-12-15 2007-06-28 Tokyo Electron Ltd Filming method and filming device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107408497A (en) * 2015-03-13 2017-11-28 新南创新私人有限公司 Method for handling silicon materials

Also Published As

Publication number Publication date
TW201318036A (en) 2013-05-01
JP2013033828A (en) 2013-02-14

Similar Documents

Publication Publication Date Title
CN1082569C (en) Microwave plasma processing apparatus and method therefor
JP3514186B2 (en) Thin film forming method and apparatus
JP3812232B2 (en) Polycrystalline silicon thin film forming method and thin film forming apparatus
JP5920453B2 (en) Deposition equipment
US8474403B2 (en) Apparatus for forming thin film and method of manufacturing semiconductor film
JP4497068B2 (en) Silicon dot forming method and silicon dot forming apparatus
WO2008056557A1 (en) Method for forming silicon based thin film by plasma cvd method
KR100325500B1 (en) Method of producing thin semiconductor film and apparatus therefor
US20050048796A1 (en) Forming method and a forming apparatus of nanocrystalline silicon structure
WO2013018292A1 (en) Film formation method
JP2000096239A (en) Induction coupling type plasma cvd method and induction coupling type plasma cvd device therefor
JP2002008982A (en) Plasma cvd system
JP2002164290A (en) Method of manufacturing polycrystalline silicone film
JPH11150283A (en) Manufacture of polycrystalline silicon thin film
Li et al. Structural analysis of polycrystalline silicon thin films produced by two different ICPCVD approaches
WO2013031142A1 (en) Film forming method and storage medium
JP3547158B2 (en) Method for manufacturing multilayer silicon film
JP5039120B2 (en) Alumina member for plasma processing apparatus and method for manufacturing alumina member for plasma processing apparatus
JPH1174204A (en) Method and device for manufacturing semiconductor thin film
Wang et al. Effects of the distance between the inductance coil and substrates on the microstructure and optical properties of silicon films deposited by ICP-CVD
JPH11150284A (en) Manufacture of polycrystalline silicon thin film
JP2011021256A (en) Method for depositing nanocrystal silicon thin film, nanocrystal silicon thin film and film deposition system depositing the thin film
JPH06326043A (en) Amorphous silicon film and manufacture thereof
Tung et al. Control of crystalline volume fraction of μC-Si thin film using 40.68 MHz PECVD system for solar cell application
JPH09208389A (en) Crystalline silicon membrane, forming of the same and device therefor

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12819257

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12819257

Country of ref document: EP

Kind code of ref document: A1