WO2006051641A1 - Procédé pour former un film semi-conducteur poreux, dispositif électroluminescent et capteur optique - Google Patents

Procédé pour former un film semi-conducteur poreux, dispositif électroluminescent et capteur optique Download PDF

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Publication number
WO2006051641A1
WO2006051641A1 PCT/JP2005/015752 JP2005015752W WO2006051641A1 WO 2006051641 A1 WO2006051641 A1 WO 2006051641A1 JP 2005015752 W JP2005015752 W JP 2005015752W WO 2006051641 A1 WO2006051641 A1 WO 2006051641A1
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light
porous
semiconductor film
film
substrate
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PCT/JP2005/015752
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English (en)
Japanese (ja)
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Sadao Adachi
Katsuhiro Tomioka
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National University Corporation Gunma University
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    • 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
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
    • H01L21/30604—Chemical etching
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H01L33/34—Materials of the light emitting region containing only elements of Group IV of the Periodic Table
    • H01L33/346—Materials of the light emitting region containing only elements of Group IV of the Periodic Table containing porous silicon

Definitions

  • the present invention relates to a method for forming a porous semiconductor film, a light emitting element, and an optical sensor, and more specifically, to form a porous film for forming a porous film capable of emitting light in the visible ultraviolet region on a semiconductor substrate.
  • the present invention relates to a method for forming a semiconductor film, and a light-emitting element and an optical sensor having a porous semiconductor film formed by the method.
  • an aqueous solution of hydrogen fluoride (hydrofluoric acid) is usually used as the electrolyte solution.
  • a porous film is formed on a substrate made of a compound semiconductor such as GaAs or GaP, hydrochloric acid, nitric acid, or a mixture thereof is often used as the electrolyte solution.
  • an alcohol solvent such as methanol or ethanol may be added to the electrolyte solution.
  • the current density flowing through the semiconductor substrate is an important factor for controlling the porous film forming process. For this reason, a technique for increasing the current density and controlling the thickness of the porous film and the degree of porosity by irradiating with ultraviolet light or visible light is known.
  • a p-type silicon substrate is irradiated with ultraviolet light or visible light from the side of the substrate immersed in the electrolyte solution.
  • Non-patent Document 2 a porous film formed on the surface of a silicon substrate emitted red light
  • the porous film emits red light with a wavelength of 630 nm and an emission energy of 2 eV.
  • a porous film produced by a light-assisted etching method also shows red light emission.
  • the conventional porous film forming method can only obtain a porous film that emits red light and cannot directly form a porous film that emits light in the ultraviolet.
  • Oxidizing the porous silicon film shifts the emission wavelength to the short wavelength side.
  • oxidation methods (a) thermal oxidation (Non-patent document 3), (b) natural oxidation by standing in air (Non-patent document 4), (c) hydrogen fluoride and alcohol are mixed during anodization.
  • Non-patent Document 5 There is a method of efficiently oxidizing a porous silicon film by dissolving metallic zinc in the electrolytic solution.
  • Non-Patent Document 9 It changes to the other two-color emission (Non-Patent Document 9). However, the origin of ultraviolet light emission is unknown, and there is a possibility of light emission that is not essential from MnO power, not light emission from a porous silicon film.
  • a silicon substrate is made porous by anodizing with a mixed solution of aqueous hydrogen fluoride and alcohol, and then the porous surface is repeatedly oxidized with chemicals and the oxide film removed with hydrogen fluoride. As a result, changes in the emission spectrum were measured while progressively miniaturizing the porous portion.
  • (a) is an emission spectrum of the porous silicon film immediately after anode formation.
  • (B) to (g) are emission spectra of the porous silicon film refined by oxidation and removal of the oxide film. In particular, (g) is refined by repeating the most frequent oxidation and removal of the oxide film. It is the emission spectrum of the porous silicon film. From FIG. 9, it can be seen that the peak wavelength of the emission spectrum is shifted from red to green by miniaturization of the porous portion, and the wavelength is shortened. As in this example, if miniaturization progresses ideally, the wavelength can be shortened, and the emission wavelength can be controlled over a wide range from red to green with a shorter wavelength than just green.
  • Patent Document 1 Japanese Patent Laid-Open No. 2002-93775
  • Non-Patent Document 1 N. Noguchi and I. Suemune, Appl. Phys. Lett. Vol. 62, p. 1429, 1993
  • Non-Patent Document 2 T. Canham, Appl. Phys. Lett. Vol. 57, p. 1046, 1990
  • Non-Patent Document 3 H. Mimura et al, Jpn. J. Appl. Phys. Vol. 33, p. 586, 1994
  • Non-Patent Document 4 T. Maruyama and S. Ohtani, Appl. Phys. Lett. Vol. 65, p. 1346, 1994
  • Non-Patent Document 5 KY Suh et al., J. Electrochem. Soc. Vol. 148, p. C439, 2001
  • Non-Patent Document 6 T. Moriguchi et al., J. Electrochem. Soc. Vol. 147, p .602, 2000
  • Non-Patent Document 7 MV Wolkin et al., Phys. Rev. Lett. Vol. 82, p. 197, 1999
  • Non-Patent Document 8 QW Chen et al., Appl. Phys. Lett. Vol. 82, p. 1018, 2003
  • Non-Patent Document 9 Q. Chen et al, Appl. Phys. Lett. Vol. 77, p. 854, 2000
  • the conventional method for controlling the emission wavelength is carried out after producing a porous semiconductor film by anodization, and in order to obtain a porous film that can emit light in the ultraviolet as well, There was a problem that the manufacturing process was complicated by necessity because two-stage treatment was required, namely anodization and subsequent treatment of the porous membrane.
  • the porous semiconductor film produced by the above-described anodic deposition method is processed by methods such as oxidation, miniaturization, and coating with different substances, there is a limit to shortening the emission wavelength.
  • the wavelength can only be shortened to blue (emission wavelength: about 400 nm) at most, and ultraviolet emission below 400 nm is extremely difficult.
  • a fatal defect is that subtle differences in the porous part from lot to lot have a subtle effect on the reproducibility of the subsequent refinement process.
  • the present invention has been made in view of the above, and provides a method for forming a porous semiconductor film that can easily and reproducibly form a porous semiconductor film capable of emitting light from visible to ultraviolet. .
  • the present invention also provides a light emitting element and a sensor capable of emitting light from visible to ultraviolet using a semiconductor substrate on which a porous semiconductor film is formed by the method of the present invention.
  • the method for forming a porous semiconductor film of the present invention comprises irradiating a substrate surface of a semiconductor substrate immersed in an aqueous solution of a fluorine-containing salt (fluoride salt) with light, and exposing the porous semiconductor film to the substrate surface. Is formed.
  • a fluorine-containing salt fluoride salt
  • a porous semiconductor film capable of emitting light from visible to ultraviolet can be simply formed by forming a porous semiconductor film on the substrate surface by simply irradiating the substrate surface with light. Can be formed with good reproducibility.
  • an alkali metal salt, an ammonium salt, or a hydrazine salt is used.
  • the light is preferably light having a wavelength equal to or shorter than the wavelength of light absorbed by the semiconductor substrate.
  • the light-emitting element of the present invention includes a semiconductor substrate in which a porous semiconductor film is formed by irradiating light onto a substrate surface in a state of being immersed in an aqueous solution of a fluoride salt, and a porous semiconductor of the semiconductor substrate. And a transparent electrode formed on the side on which the body film is formed.
  • This light emitting device uses a semiconductor substrate on which a porous semiconductor film is formed by the method of the present invention.
  • the visible light can be emitted in the ultraviolet.
  • the sensor of the present invention is characterized by having a semiconductor substrate on which a porous semiconductor film is formed by the method of the present invention.
  • this sensor uses a semiconductor substrate on which a porous semiconductor film is formed by the method of the present invention, light emission in the visible power ultraviolet region is possible.
  • a porous semiconductor film capable of emitting light from visible to ultraviolet can be easily and reproducibly formed. There is an effect. In addition, there is an effect that it is possible to provide a light emitting element and a sensor capable of emitting light in the visible power ultraviolet region using the semiconductor substrate on which the porous semiconductor film is formed by the method of the present invention.
  • FIG. 1 is a schematic cross-sectional view for explaining a method for forming a porous semiconductor film of the present invention.
  • FIG. 2 is a partial cross-sectional view showing a layer structure of a semiconductor substrate on which a porous semiconductor film is formed by the forming method of the present invention.
  • FIG. 3 is a partial cross-sectional view showing a layer structure of a light emitting device including a semiconductor substrate on which a porous semiconductor film is formed.
  • FIG. 4A is a diagram showing an emission spectrum of a light-emitting element according to an example of the present invention.
  • FIG. 4B is a diagram showing an emission spectrum of a light emitting device of a comparative example manufactured by a conventional technique.
  • FIG. 5A is an AFM image of a porous silicon film formed in an example of the present invention.
  • FIG. 5B is an AFM image of a comparative porous silicon film produced by a conventional technique.
  • FIG. 6 is a diagram showing infrared absorption spectra of a porous silicon film formed in an example of the present invention and a porous silicon film of a comparative example manufactured by a conventional technique.
  • FIG. 7 is a diagram showing an emission spectrum of a light emitting device according to another example of the present invention.
  • FIG. 8 is a diagram showing an emission spectrum of a light emitting device according to another example of the present invention.
  • FIG. 9 is a diagram for explaining a conventional method for controlling an emission wavelength.
  • FIG. 1 is a schematic cross-sectional view for explaining a method for forming a porous semiconductor film of the present invention.
  • FIG. 2 is a partial cross-sectional view showing a layer structure of a semiconductor substrate on which a porous semiconductor film is formed by the forming method of the present invention.
  • an apparatus for carrying out the method of the present invention includes a container 12 that contains an aqueous solution 10 of a fluoride salt and a substrate surface 14 a of a semiconductor substrate 14 that is immersed in the aqueous solution 10. And a light source 16 for irradiating 18.
  • the container 12 opens upward and has a flat bottom.
  • the light source 16 is disposed above the opening of the container 12.
  • the semiconductor substrate 14 is placed on the bottom of the container 12 containing the fluoride aqueous solution 10 with the substrate surface 14a facing upward, and the semiconductor substrate 14 is half-filled in the fluoride salt aqueous solution 10.
  • the conductor substrate 14 is immersed.
  • the substrate surface 14 a of the semiconductor substrate 14 is irradiated with excitation light 18 from the light source 16.
  • the semiconductor substrate 14 is etched from the substrate surface 14a, and the porous semiconductor film 20 is formed on the substrate surface 14a side of the semiconductor substrate 14 as shown in FIG.
  • the substrate surface 14a of the semiconductor substrate 14 is irradiated with the excitation light 18
  • the container 12 may be made of a material transparent to the excitation light 18, and the excitation light 18 may be irradiated from the side surface of the container 12.
  • the substrate surface 14a is sufficient if it can be irradiated with the excitation light 18 on the substrate surface 14a of the semiconductor substrate 14.
  • Semiconductor substrate so that it is perpendicular or diagonal to A plate 14 may be arranged.
  • the aqueous solution 10 is an aqueous solution of a fluoride salt.
  • the “salt” means that dissociable hydrogen ions contained in the acid are cations such as metal ions (Na +, K +, etc.) and ammonia ions (NH +).
  • a substituted compound wherein conventional optically assisted chemical etching methods use acids such as HF, HC1, and HNO, the formation method of the present invention immerses the semiconductor substrate 14
  • the aqueous solution 10 is characterized in that an aqueous solution of fluoride is used.
  • An aqueous salt solution exhibits properties completely different from those of acids. Further, as is well known, an aqueous solution of hydrogen fluoride is the most commonly used chemical in semiconductor processes, but there are few examples in which an aqueous salt solution is used in semiconductor processes.
  • Fluoride salts include alkali metal salts such as lithium fluoride (LiF), sodium fluoride (NaF), potassium fluoride (KF), rubidium fluoride (RbF), cesium fluoride (CsF), ammonia -Umu salt (NH F), hydrazimuum salt (NHF) can be used.
  • LiF lithium fluoride
  • NaF sodium fluoride
  • KF potassium fluoride
  • RbF rubidium fluoride
  • CsF cesium fluoride
  • NH F ammonia -Umu salt
  • hydrazimuum salt NHS
  • fluoride salts LiF, NaF, and KF are more preferred from the viewpoint of ease of handling and economy, and KF is particularly preferred.
  • a plurality of types of salts can be used in appropriate combination.
  • the molar concentration of the fluoride salt can be in the range of the molar concentration or less depending on the saturation solubility of the salt.
  • the molar concentration of aqueous KF solution with saturated solubility of KF is about 16M
  • the molar concentration of aqueous NaF solution with saturated solubility of NaF is about 1M.
  • the concentration of hydrogen fluoride (HF) and hydroxide ions (OH-) involved in the formation of the porous membrane also increases, and the porous membrane is formed efficiently.
  • the mole concentration of the fluoride salt is preferably about 0.05M or more.
  • the molar concentration of the fluoride salt also affects the formation of the microstructure of the porous semiconductor film, such as the porosity (porosity) and the porous size.
  • the molar concentration of the fluoride salt has the most influence on the formation rate of the porous. Is formed. Therefore, it is preferable to increase the molar concentration of the aqueous solution when the intensity of the excitation light is small, and decrease the molar concentration of the aqueous solution when the intensity of the excitation light is large.
  • the pH of the aqueous solution is closely related to the molarity.
  • alkali metal salts such as KF
  • the temperature of the aqueous solution increases as the pH increases, and the rate of formation of the porous membrane increases. Therefore, it is preferable that the reaction temperature is room temperature (20 ° C) or higher for the viewpoint of promoting the formation of porous membranes!
  • other chemicals can be added to the aqueous solution 10.
  • other chemicals include water-soluble solvents such as alcohol and acidic liquids such as hydrochloric acid.
  • alcohol solvent such as methanol or ethanol, a finer porous structure can be obtained.
  • the semiconductor substrate 14 in addition to a silicon substrate, a germanium (Ge) substrate of the same elemental semiconductor, a GaAs substrate of a compound semiconductor, a GaP substrate, an InP substrate, or the like can be used. That is, the formation method of the present invention can be applied to these semiconductor substrates.
  • silicon substrates are particularly preferred because they are available at low cost and have accumulated processing technology.
  • the price per unit deposition of silicon which is a material of a silicon substrate, is several thousand to several tens of thousands times cheaper than the price per unit deposition of gallium (Ga), which is one of GaN semiconductor materials. It is. Another great attraction is that advanced silicon manufacturing technology cultivated in image sensors for VLSI and digital cameras can be used as is.
  • the excitation light 18 may be any light having a wavelength that can generate a free electron / hole pair in a semiconductor.
  • the excitation light 18 is appropriately selected according to the band gap of the semiconductor.
  • the bandgap of silicon crystal is about 1. leV, and in principle light energy of 1. leV or more should be applied. That is, the wavelength of the excitation light may be shorter than 1130 nm.
  • the excitation light 18 is preferably light having a wavelength equal to or less than the wavelength of light absorbed by the semiconductor substrate.
  • a silicon crystal is irradiated with He—Ne laser light having a wavelength of 633 nm and a light energy of 1.96 eV as excitation light.
  • the excitation light 18 is coherent light (laser light) or non-coherent light (non-laser light). Therefore, as the light source 16, a xenon lamp, a mercury lamp, a light-emitting diode, etc. that can be used only with a laser light source can be used. As a laser light source, for example, A He—Ne gas laser can be used. As the light emitting diode, a surface array type GaN light emitting diode can be used.
  • the intensity of the excitation light can be in the range of several mW to several tens of W.
  • the stronger the intensity of the irradiated light the higher the concentration of free electron / hole pairs generated by photoexcitation, and the porous film is efficiently formed.
  • the intensity of the excitation light is too weak, it takes a long time to form the porous film, which is not practical. Conversely, if the intensity of the excitation light is too strong, the porous film is not formed and the semiconductor substrate is simply etched flat.
  • the light penetration depth into the semiconductor crystal also changes, and this affects the formation of the microstructure of the porous semiconductor film, such as the degree of porosity and the porous size.
  • the light penetration depth into the semiconductor crystal becomes shallower.
  • the penetration depth of each wavelength of light into a silicon crystal is about 2 ⁇ for a He-Ne laser with a wavelength of 632.8 nm, about 0.5 m for a 488.
  • the wavelength of the excitation light is 250 ⁇ !
  • the range of ⁇ 1 OOOnm is preferred
  • the range of 400nm to 800nm is more preferred.
  • the wavelength of the excitation light is preferably in the range of 400 nm to 800 nm, more preferably in the range of 250 nm to 1000 nm.
  • the irradiation time of the excitation light is preferably in the range of 10 minutes to 10 hours as appropriate depending on the molar concentration of the fluoride salt, the intensity of the excitation light, and the wavelength of the excitation light.
  • KF potassium fluoride
  • an aqueous HF solution dissolves a glass substance (Si oxide). Therefore, in the photo-assisted etching method, when the porous silicon film is formed, holes generated by light irradiation slightly acidify the surface of the silicon crystal, and this acid film is etched away with an HF aqueous solution. As a result, it can be considered that a porous film is formed on the surface of the silicon crystal as a result.
  • an aqueous solution of an alkali halide such as potassium fluoride (KF) is a neutral force, and it is unlikely that the glass material is etched away by a neutral aqueous solution.
  • Salt is also an alkali halide, like KF. If an aqueous solution of salt, ie, salt solution, dissolves the glass material, it will not be possible to pour the salt solution into a glass cup. Such a thing should be impossible in reality.
  • this reagent causes hydrolysis in the aqueous solution.
  • Typical alkaline aqueous solution power such as KOH aqueous solution and NaOH aqueous solution
  • the aqueous HF solution which is an acidic aqueous solution, dissolves only the oxide film (glass material). Therefore, in the KF aqueous solution, as shown in the above formula (1), HF and OH-ions coexist, and therefore HF efficiently etched the glass material and OH-ions etched the silicon crystal itself. It is thought that a high-quality porous silicon film was formed on the surface of the silicon crystal.
  • FIG. 3 is a partial cross-sectional view showing a layer structure of a light emitting device including a semiconductor substrate on which a porous semiconductor film is formed.
  • the porous semiconductor film 20 is formed on the substrate surface 14a of the semiconductor substrate 14 by the method described above, and the transparent electrode 22 is formed on the surface of the porous semiconductor film 20.
  • the transparent electrode 22 is an electrode formed of a substance that transmits emitted light.
  • the transparent electrode 22 includes an indium oxide (InO) thin film, a tin oxide (SnO) thin film, an oxide It can be composed of Ngum tin (ITO) thin film. Examples of the method for forming the transparent electrode 22 include sputtering and chemical vapor deposition.
  • the porous semiconductor film 20 When a voltage is applied between the transparent electrode 22 and the semiconductor substrate 14 described above and a current is passed through the porous semiconductor film 20, the porous semiconductor film 20 emits ultraviolet light.
  • the emission wavelength of the light-emitting element is controlled by appropriately immersing the semiconductor substrate 14 on which the porous semiconductor film 20 is formed in an acidic or alkaline chemical before forming the transparent electrode 22, so that the porous semiconductor film 20 This is done by modifying the surface structure.
  • the acidic or alkaline chemical a chemical that removes the porous semiconductor or the oxide film formed on the semiconductor surface by etching can be used.
  • examples of such chemicals include an aqueous solution of hydrogen fluoride, ammonium fluoride (NH 2 F), and the like.
  • the aqueous solution of hydrogen fluoride is applicable to a porous GaAs film, a porous GaP film, a porous InP film, and the like that are formed only by a porous silicon film, and is formed on the surface of a porous semiconductor.
  • the emission wavelength can be lengthened.
  • the emission wavelength is controlled after the formation of the porous semiconductor film.
  • the concentration of fluoride, the intensity of the excitation light, and the excitation light By changing the wavelength in various ways, the emission wavelength can be controlled by changing the fine structure of the porous semiconductor film.
  • the porous semiconductor film formed by the forming method of the present invention can be applied to a light source device such as a light emitting element that emits light from visible to ultraviolet.
  • a light source device such as a light emitting element that emits light from visible to ultraviolet.
  • Luminescent elements that emit light from visible to ultraviolet have overlapping fields with GaN-based light emitting diodes that have been attracting attention in recent years, and the field scale is large.
  • a GaN-based light emitting diode is essentially a point light source, whereas a porous semiconductor film
  • the light source provided with is a surface emitting light source, and superiority in this respect can be expected.
  • Surface light sources that emit ultraviolet light are promising as excitation light sources for ultraviolet Z-visible conversion light sources.
  • surface light sources that emit visible light are expected as backlights for liquid crystal panel displays and next-generation mobile phone displays, for example.
  • various devices having a porous semiconductor film such as sensors for detecting humidity, gas, etc., optical resonators, optical waveguides, surface emission cold cathodes, etc. can do. Since the porous semiconductor film has a large surface area, detection accuracy can be improved by applying it to a sensor.
  • a semiconductor can be produced with a very simple apparatus, as long as there is a container containing an aqueous solution of fluoride and an excitation light source.
  • a porous semiconductor film can be formed on the substrate surface of the substrate. In other words, the electrodes and power supply devices necessary for anodization are unnecessary.
  • the porous semiconductor film obtained by the forming method of the present invention is (1) the crystal diameter of the porous film is finely and uniformly distributed, (2) ultraviolet light emission of 375 nm is obtained, etc. It has the characteristics that it can emit light at a short wavelength, and (3) it is easy to control the emission wavelength by immersion in chemicals.
  • An n-type silicon crystal substrate was prepared as a semiconductor substrate. This silicon crystal substrate was degreased and washed in turn with trichloroethylene (tricrene), acetone, and alcohol, and then immersed in an aqueous solution of 1M potassium fluoride (KF) so that the substrate surface was facing up.
  • An aqueous solution is qualitatively weakly alkaline. Its pH is about 7 (almost neutral).
  • a He—Ne laser with an oscillation wavelength of 632.8 nm was used as a light source for irradiating excitation light, and the silicon crystal substrate was immersed in a KF aqueous solution at room temperature of 20 ° C. The entire surface was irradiated with a laser beam having a wavelength of 632.8 nm with an intensity of 5 mW.
  • the KF aqueous solution power silicon crystal substrate was pulled up.
  • the silicon crystal substrate was also etched due to the surface force of the substrate and was discolored by being porous. This discolored portion is a porous silicon film.
  • a porous silicon film is formed on the silicon crystal substrate in the same manner as in Example 1 except that the aqueous solution in which the n-type silicon crystal substrate is immersed is an aqueous solution of 25% hydrogen fluoride (HF).
  • HF hydrogen fluoride
  • a transparent electrode was formed on the film to obtain a light emitting device of Comparative Example 1.
  • Example 1 For each of the light-emitting elements obtained in Example 1 and Comparative Example 1, a predetermined voltage was applied between the transparent electrode and the silicon crystal substrate, and the light emission spectrum from the porous semiconductor film was measured.
  • Example 1 For each of the porous silicon films formed in Example 1 and Comparative Example 1, the film surface was observed using an atomic force microscope (AFM). AFM observation of the film surface was performed before forming the transparent electrode on the porous silicon film.
  • 5A is an AFM image of the porous silicon film formed in Example 1
  • FIG. 5B is an AFM image of the porous silicon film formed in Comparative Example 1. is there.
  • the porous film formed in Example 1 has a finer and more uniform distribution of crystal grain size than the porous film formed in Comparative Example 1. I understand that. The difference in the emission spectrum observed from the light emitting element is also assumed to reflect such a structural difference in the porous film.
  • infrared absorption spectra on the film surface were measured by Fourier transform infrared spectroscopy (FT-IR).
  • Figure 6 shows the measurement results.
  • the measurement result of Example 1 is indicated by a thick solid line
  • the measurement result of Comparative Example 1 is indicated by a dotted line.
  • the measurement result of the infrared absorption spectrum of a silicon crystal substrate that has only been degreased and cleaned is shown by a thin solid line.
  • the absorption at wave numbers 600 cm ⁇ 1 to 700 cm ⁇ 1 is due to the Si—H strain mode, and the absorption near 1100 cm ⁇ 1 is due to the Si—O Si stretch mode.
  • the large difference between the infrared absorption spectrum of the porous film of Example 1 and the infrared absorption spectrum of the porous film of Comparative Example 1 is that Si—O Si ⁇ near 1100 cm 1 It is in the absorption peak due to the trech mode.
  • the absorption peak due to the Si-O-Si ⁇ -tretches mode near 1100cm- 1 was observed as a doublet peak, as in the case of natural standing when the porous film was formed.
  • the emission wavelength is 375 nm, which is an extremely short wavelength (ultraviolet light). This suggests that the surface of the porous membrane of Example 1 was initially covered with an acidic membrane and was in a chemically stable state as compared to the porous membrane of Comparative Example 1. Yes.
  • a porous silicon film was formed on the silicon crystal substrate in the same manner as in Example 1 except that the aqueous solution in which the n-type silicon crystal substrate was immersed was an aqueous solution of 5M potassium fluoride (KF).
  • KF 5M potassium fluoride
  • a transparent electrode was formed on the porous silicon film to obtain a light emitting device of Example 2.
  • the pH of the aqueous solution is 7.6.
  • the obtained light-emitting device For the obtained light-emitting device, a predetermined voltage was applied between the transparent electrode and the silicon crystal substrate, and the emission spectrum from the porous semiconductor film was measured. As in the light-emitting device of Example 1, A strong! ⁇ ultraviolet emission and a weak! ⁇ ⁇ green emission were observed.
  • a porous silicon film was formed on the silicon crystal substrate in the same manner as in Example 1 except that the aqueous solution in which the n-type silicon crystal substrate was immersed was an aqueous solution of 1M sodium fluoride (NaF).
  • a transparent electrode was formed on the porous silicon film to obtain a light emitting device of Example 3.
  • Example 4 as in Example 1, the silicon crystal substrate on which the porous silicon film was formed was immersed in an acidic HF aqueous solution to control the emission wavelength. That is, similarly to Example 1, an n-type silicon crystal substrate was prepared as a semiconductor substrate. This silicon crystal substrate is degreased and washed in turn with trichlorethylene (tricrene), acetone, and alcohol, and then immersed in an aqueous solution of 1M potassium fluoride (KF) so that the substrate surface faces up.
  • tricrene trichlorethylene
  • KF 1M potassium fluoride
  • a He—Ne laser with an oscillation wavelength of 632.8 nm was used as a light source for irradiating excitation light, and the silicon crystal substrate was immersed in a KF aqueous solution at room temperature of 20 ° C. The entire surface was irradiated with a laser beam having a wavelength of 632.8 nm at an intensity of 5 mW for 3 hours. As a result, a silicon crystal substrate having a porous silicon film formed on the substrate surface was obtained.
  • the obtained silicon crystal substrate was immersed in a 46% HF aqueous solution for 10 seconds.
  • HF aqueous solution Liquid crystal After pulling up the silicon crystal substrate, cleaning the surface, and drying, an indium oxide (In 2 O 3) thin film is formed as a transparent electrode on the porous silicon film, and the light-emitting device of Example 4
  • Example 4 With respect to the light emitting device obtained in Example 4, a predetermined voltage was applied between the transparent electrode and the silicon crystal substrate, and the emission spectrum from the porous semiconductor film was measured. As shown, only red emission was obtained. For comparison, the emission spectrum of the light-emitting element of Example 1 is also shown in FIG.
  • the emission wavelength can be controlled very easily from ultraviolet light emission and green light emission to red light emission.
  • the porous semiconductor film formed by the forming method of the present invention can be applied to a light source device such as a light emitting element that emits light from visible to ultraviolet.
  • a light source device such as a light emitting element that emits light from visible to ultraviolet.
  • the present invention can also be applied to devices having a porous semiconductor film, such as sensors for detecting humidity and gas, optical resonators, optical waveguides, surface emission type cold force swords, and the like.
  • a porous semiconductor film capable of emitting light outside can be easily and reproducibly formed. Further, it is possible to provide a light emitting element and a sensor capable of emitting light from visible to ultraviolet using a semiconductor substrate on which a porous semiconductor film is formed by the method of the present invention.

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  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Chemical & Material Sciences (AREA)
  • Electromagnetism (AREA)
  • Weting (AREA)
  • Led Devices (AREA)

Abstract

La présente invention concerne un procédé de formation d’un film semi-conducteur poreux qui permet de former un film semi-conducteur poreux pouvant émettre de la lumière dans la plage du visible à l’ultraviolet grâce à un procédé simple ayant une bonne reproductibilité. En irradiant la surface d’un substrat semi-conducteur (14) immergé dans une solution aqueuse (10) d’un sel contenant du fluor (sel de fluorure) avec une lumière d’excitation (18) provenant d’une source lumineuse (16), un film semi-conducteur poreux pouvant émettre une lumière ultraviolette se forme sur la surface du substrat.
PCT/JP2005/015752 2004-11-15 2005-08-30 Procédé pour former un film semi-conducteur poreux, dispositif électroluminescent et capteur optique WO2006051641A1 (fr)

Applications Claiming Priority (2)

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JP2004-331166 2004-11-15
JP2004331166A JP4257431B2 (ja) 2004-11-15 2004-11-15 多孔質半導体膜の形成方法

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WO2006051641A1 true WO2006051641A1 (fr) 2006-05-18

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JP (1) JP4257431B2 (fr)
WO (1) WO2006051641A1 (fr)

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US11289322B2 (en) 2018-10-18 2022-03-29 Sciocs Company Limited Structure manufacturing method including surface photoelectrochemical etching and structure manufacturing device

Families Citing this family (4)

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Publication number Priority date Publication date Assignee Title
JP5703780B2 (ja) * 2011-01-26 2015-04-22 株式会社Sumco 太陽電池用ウェーハの製造方法、太陽電池セルの製造方法、および太陽電池モジュールの製造方法
US9276153B2 (en) 2011-01-26 2016-03-01 Sumco Corporation Solar cell wafer and method of producing the same
JP2013012705A (ja) * 2011-06-01 2013-01-17 Sumco Corp 太陽電池用ウェーハ、太陽電池セルおよび太陽電池モジュール
JP5591763B2 (ja) * 2011-06-23 2014-09-17 株式会社トクヤマ 多孔質シリコンの製造方法

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JPS5080090A (fr) * 1973-11-13 1975-06-28
JPH04356977A (ja) * 1991-03-28 1992-12-10 Res Dev Corp Of Japan 多孔質シリコン
JP2002093775A (ja) * 2000-03-10 2002-03-29 Interuniv Micro Electronica Centrum Vzw 多孔質シリコン層の形成方法およびリフトオフ方法
JP2002252202A (ja) * 2001-02-27 2002-09-06 Takashi Matsuura 半導体基材表面への微細構造形成方法およびその方法により微細構造を形成した半導体基材ならびにそれを用いたデバイス

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JPS5080090A (fr) * 1973-11-13 1975-06-28
JPH04356977A (ja) * 1991-03-28 1992-12-10 Res Dev Corp Of Japan 多孔質シリコン
JP2002093775A (ja) * 2000-03-10 2002-03-29 Interuniv Micro Electronica Centrum Vzw 多孔質シリコン層の形成方法およびリフトオフ方法
JP2002252202A (ja) * 2001-02-27 2002-09-06 Takashi Matsuura 半導体基材表面への微細構造形成方法およびその方法により微細構造を形成した半導体基材ならびにそれを用いたデバイス

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TOMIOKA K.: "Porous Si kara no Ryokushoku Sigai Hakko (1p-ZL-4)", THE 65TH EXTENDED ABSTRACTS; THE JAPAN SOCIETY OF APPLIED PHYSICS, no. 3, 1 September 2004 (2004-09-01), pages 1272, XP003006474 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11289322B2 (en) 2018-10-18 2022-03-29 Sciocs Company Limited Structure manufacturing method including surface photoelectrochemical etching and structure manufacturing device
US11791151B2 (en) 2018-10-18 2023-10-17 Sumitomo Chemical Company, Limited Structure production wet etch method and structure production apparatus

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JP2006140426A (ja) 2006-06-01

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