JP2004210635A - Amorphous optical semiconductor, manufacturing method of the same and optical semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an amorphous optical semiconductor having excellent photoconductive characteristic, high speed response, environment resistant characteristic and high temperature resistance, a method of manufacturing the same and an optical semiconductor device using the amorphous optical conductor. <P>SOLUTION: The amorphous semiconductor which contains hydrogen and in which the ratio of the total number of group III element atom to the number of nitrogen atom is (1:0.5)-(1:2). The amorphous optical semiconductor containing 1 to 50 atom% hydrogen, at least one or more elements of Al, Ga and In, nitrogen and ≤15 atom% each of oxygen and carbon is suitably used. The amorphous optical semiconductor contains further one or more element selected from C, Si, Ge and Sn or one or more elements selected from Be, Mg, Ca, Zn and Sr. The amorphous optical semiconductor is obtained by activating a compound containing nitrogen to be a required energy state or to form excited species and reacting the activated species with an organic metallic compound containing a group III element. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an amorphous optical semiconductor, a method for manufacturing the same, and an optical semiconductor device using the amorphous optical semiconductor.

  Conventionally, as an amorphous optical semiconductor, an amorphous chalcogenide compound such as selenium or tellurium has been widely used as a photoelectric conversion member in an image pickup tube, a light receiving element, an electrophotographic photosensitive member, and the like (the basics of Ohm's amorphous semiconductor). . In recent years, hydrogenated amorphous silicon has been used for solar cells, image sensors, thin film transistors, electrophotographic photosensitive members, and the like.

  However, amorphous chalcogenide compounds are unstable with respect to heat, are easily crystallized, and have limited conditions under which they can be used. In addition, hydrogenated amorphous silicon can control valence electrons, realize an electric field effect at a pn junction or an interface, and has heat resistance up to about 250 ° C. However, strong light deteriorates photoconductivity (Staebller). , Wronski effect: Applied physics handbook) There is a problem that the efficiency of the solar cell is reduced during use. Also, the band gap of hydrogenated amorphous silicon is about 1.7 eV, and it is possible to reduce or widen the band gap by adding Ge or C to effectively use sunlight, but about 0.3 eV. Even with the change, the photoconductive characteristics deteriorate, and there is a problem that light in a wide range cannot be used effectively. In addition, semiconductors including these elements are indirect transition types including crystals, and cannot be used for light-emitting elements, and their applications are limited.

Conventionally, an amorphous material of a group III-V compound semiconductor is formed by vapor deposition or sputtering of a group III-V crystal, or by a reaction between an atomized group III metal and a molecule containing a group V element or an active molecule. A film or the like has been performed (for example, see Non-Patent Document 1).
In addition, a group III-V compound crystal film is formed on a substrate heated using an organic metal compound containing a group III metal and a compound containing a group V element (organic metal CVD: MOCVD). A non-crystalline group III-V compound is obtained by using these methods and setting the substrate temperature to a temperature lower than that for producing crystals (600 to 1000 ° C.).

  However, in this case, there was no amorphous III-V compound that could function as a photoelectric material due to problems such as carbon from the organic metal remaining in the film and a large number of defect levels in the film. On the other hand, it is known that hydrogenation of amorphous amorphous silicon lowers the density of defect states between bands and enables valence electron control.

  Many studies have been made on the role of hydrogen on defects in crystalline Group III-V compound semiconductors. (1) Improvement of crystal dislocation defects (for example, see Non-Patent Document 2), and (2) Improvement of interface defects (for example, see Non-Patent Document 3), (3) Improvement of n + -p junction surface (for example, see Non-Patent Document 4), and (4) Improvement of defects due to lattice mismatch (For example, see Non-Patent Document 5), and (5) passivation of coupling defects. Due to the role of hydrogen, the same relationship between crystalline silicon and amorphous silicon can be expected for III-V group compound semiconductors due to the problem of changing from crystalline to amorphous.

  On the other hand, in a group III-V crystal semiconductor, it is known that a pn control dopant is simultaneously passivated and inactivated (for example, see Non-Patent Document 6). Further, it has been found that the passivation of the dopant by passivation is activated by annealing. As described above, hydrogen passivates a dangling bond of a defect, but at the same time, inactivates a pn control dopant. Therefore, in the case of an amorphous film, the hydrogen is combined with the constituent elements and composition of the film and the hydrogen content in the film. The site is important.

  In a conventional method for producing an amorphous group III-V compound semiconductor, a method is employed in which a crystal is used as a raw material and sputtering is performed, and there is no hydrogen in the system (for example, see Non-Patent Document 7).

In addition, regarding an amorphous III-V compound semiconductor containing hydrogen, the photoconductivity of hydrogenated a-GaP was reported by reactive evaporation with H ₂ (for example, see Non-Patent Document 8). And the photoconductivity of hydrogenated a-GaAs is reported (for example, see Non-Patent Document 9). However, in these semiconductors, the light-dark resistance ratio is as small as about two digits, and pn control required for practical use as a semiconductor material cannot be performed.

  As a low-temperature film formation method, GaP or amorphous GaN containing amorphous hydrogen is obtained by plasma CVD using an organometallic compound as a group III material, but does not show photoconductivity or is insulated. (For example, see Non-Patent Document 10). The hydrogenated amorphous GaAs produced by the plasma CVD method has only a very small photoconductivity of about 10%, which is far from practical use. In a low temperature region for removing carbon, removal of carbon from the film has been a problem (for example, see Non-Patent Document 11).

Further, an amorphous III-V compound semiconductor formed by a sputtering method, a CVD method, a molecular beam epitaxy method, a plasma CVD method, or the like has been proposed as a material having a lower melting point than Si as an antifuse memory material. 1), GaN and AlN are not suitable. No mention is made of the properties as an optical semiconductor.
H. Reuter, H .; Schmitt, M .; Boffgen, Thin Solid Films 254, 94 (1995). Y. Okada, S.M. Ohta, H .; Shimomura, A .; Kawabata and M.S. Kawabe, J .; J. Appl. Phys. , 32, L1556 (1993) Y. Chang, W.C. Widra, S .; I. Yi, J. et al. Merz, W.C. E. FIG. Weinberg and E Hu, J. et al. Vac. Sci. Tech. B12.2605 (1994) S. Min, W.M. C. Choi, H .; Y. Cho, M .; Yamaguchi, Appl. Phys. Lett 64, 1280 (1994) B. Chatterjee, S .; A. Ringel, R.A. Sieg, R .; Hoffman and I. Weinberg, Appl. Phys. Lett 65, 58 (1994) S. J. Pearton, Material Sci. Forum, 148-149, (1994) 113-139. H. Reuter, H .; Schmitt, M .; Boffgen, Thin Solid Films 254, 94 (1995) M. Onuki, T .; Fujii and H.S. Kubota, J .; non-Cryst, Solids, 114, 792 (1989). V. Coscia, R .; Murri, N .; Pinto, L .; Trojani, J .; Non. Cryst. Solid, 194 (1996) 103 J, Knight, and R.J. A. Lujan, J, Appl. Phys. , 42.1291 (1978). Y. Segui, F .; Carrere and A. Bui, Thin Solid Films, 92, 303, (1982). JP-A-6-295991

A first object of the present invention is to improve the disadvantages of such an amorphous group III-V compound semiconductor, make use of the role of hydrogen in amorphous semiconductors and crystals, freely select a wide range of optical gaps, and achieve high resolution. An object of the present invention is to provide an amorphous optical semiconductor which has excellent photoconductive characteristics, high-speed response, environmental resistance characteristics and high temperature resistance, and can be used as an optically active large-area, inexpensive new optoelectronic material.
A second object of the present invention is to provide a method for manufacturing an amorphous optical semiconductor that can safely manufacture an amorphous optical semiconductor having the above-described characteristics and can be manufactured at low cost.
A third object of the present invention is to provide an optical semiconductor device having the above-mentioned amorphous optical semiconductor.

  The present invention provides an amorphous III-V compound semiconductor containing hydrogen as a III-V nitride, and a disadvantage of the conventional amorphous III-V compound as an optoelectronic material. It was completed by using improved materials and deposition techniques to compensate for the defects therein with hydrogen and to include the dopants in an activated state.

That is, the present invention
Activating a compound containing at least nitrogen to an energy state or an excited species, decomposing and / or activating an organic metal compound containing Ga or Ga and In by reacting with the active species, and converting these active species containing active hydrogen The reaction was performed to produce a group III-V compound film. In this way, even at a low temperature at which an amorphous film can be grown, the organic group is separated from the organic metal as a stable molecule at a low temperature, and is taken into the film. The inventors have found that active hydrogen or active hydrogen generated by hydrogen and a hydrogen compound added separately can reduce impurities to a trace amount by removing carbon on the film surface during film growth, and have completed the present invention. In addition, a stoichiometric state can be easily maintained even in the case of an amorphous material in which the composition ratio can be freely determined by selecting nitrogen present as a gas as a group V material.

The amorphous optical semiconductor of the present invention contains hydrogen, and the ratio of the total number of Ga atoms or the total number of Ga and In atoms to the number of nitrogen atoms is 1: 0.5 to 1: 2. An amorphous optical semiconductor.
Further, the method for producing an amorphous optical semiconductor of the present invention activates a compound containing nitrogen to a required energy state or an excited species, and reacts these active species with an organometallic compound containing Ga or Ga and In. And a method of manufacturing an amorphous optical semiconductor.
The amorphous optical semiconductor of the present invention preferably contains 1 to 50 atomic% of hydrogen, Ga or Ga and In, and a nitrogen element, and each of oxygen and carbon is preferably 15 at% or less. More preferably, the n-type control element includes at least one element selected from C, Si, Ge, and Sn, or the p-type control element includes Be, Mg, Ca, Zn. And at least one element selected from Sr.

In this method for manufacturing an amorphous optical semiconductor, the activating means for activating the compound containing nitrogen to a required energy state or an excited species includes discharge energy, for example, high-frequency discharge and / or microwave discharge energy. Can be used. A gaseous raw material containing Ga or Ga and In or an element for controlling pn is introduced from the downstream side of each activating means.
The optical semiconductor element uses the above-described amorphous optical semiconductor as a photoconductive member, or includes at least one of a p-type amorphous optical semiconductor and an n-type amorphous optical semiconductor.

  As described above, according to the amorphous optical semiconductor of the present invention, high light transmittance, low dark conductivity, and high light sensitivity enable effective use of a wide range of light from visible to ultraviolet light, and light resistance, It is excellent in heat resistance and oxidation resistance and has high-speed response. By utilizing these properties, it can be used for various optical semiconductor devices.

Hereinafter, the present invention will be described in more detail.
The amorphous optical semiconductor of the present invention contains hydrogen, and the ratio of the total number of Ga atoms or the total number of Ga and In atoms to the number of nitrogen atoms is 1: 0.5 to 1: 2. is there. Generally, the term “amorphous” refers to a solid state in which a crystal lattice is hardly recognized, but in many cases, there is no clear boundary between amorphous and crystalline. The amorphous in the present invention is a so-called amorphous having only short-range order with adjacent atoms, and a case where the amorphous has microcrystals, or a case where the whole is a collection of microcrystals. Include. However, in this case, the size of the microcrystal is less than 50 °, and it can be considered that no structural order is recognized as a whole.
In the present invention, the ratio of the total number of Ga atoms or the total number of Ga and In atoms to the number of nitrogen atoms is 1: 0.5 to 1: 2. When the ratio of the number of atoms is less than 1: 0.5 or more than 1: 2, a portion of the zinc-blende (Zincblend) type formed by bonding of Ga or Ga and In with a nitrogen element is small. Therefore, the number of defects increases, and the semiconductor does not function as a good optical semiconductor.

  The amorphous optical semiconductor of the present invention contains hydrogen, and its amount is preferably 1 atomic% or more and 50 atomic% or less. In an amorphous optical semiconductor, when the film contains less than 1 atomic% of hydrogen, Ga, In as a group III element and nitrogen as a group V element become amorphous while maintaining a three-dimensional structure. The generated dangling bonds are eliminated by bonding with hydrogen, which is insufficient to inactivate the defect level formed in the band, and cannot function as a practical amorphous optical semiconductor.

  On the other hand, if the hydrogen content exceeds 50 atomic% in the film, the probability that hydrogen bonds to two or more of Ga, In as a group III element and nitrogen as a group V element increases, and as a result, these elements become Instead of maintaining a three-dimensional structure, a chain-like network is formed, a new level is formed in the band, and electrical characteristics are deteriorated and mechanical properties such as hardness are lowered. Further, the film is liable to be oxidized, and as a result, a large amount of impurity defects are generated in the film, so that good photoelectric characteristics cannot be obtained. On the other hand, if the hydrogen content in the film exceeds 50 atomic%, the dopant to be doped for controlling the electrical characteristics is activated by hydrogen, so that an electrically active amorphous semiconductor cannot be obtained as a result. .

  Further, it is desirable that oxygen and carbon are each 15 atomic% or less in the amorphous optical semiconductor. When oxygen in the film exceeds 15 atomic%, the oxygen atom forms a stable bond with Ga and In as a group III element, and Ga, In and a nitrogen atom as a group V element To partially form the three-dimensional structure into a two-dimensional flexible structure, thereby preventing the substitutional dopant for electrical control from taking an electrically active bonding arrangement in the three-dimensional rigid structure, As a result, pn control cannot be performed.

Further, when carbon in the film exceeds 15 atomic%, the bond between carbon and hydrogen (81 kcal / mol) becomes the bond between Ga and In and hydrogen as a group III atom (Ga-H: 66 kcal / mol, an in-H: for 59kcal / mol) than stable, the hydrogen is to couple a number and carbon atoms, and more carbon -CH ₂ -, - CH ₃ - by the occurrence of likely chain structure and voids take bond, The pn control cannot be performed due to structural flexibility when a dopant is doped because the defect level increases as the whole film. Further, in the case of a transparent film having a wide band gap, the film is colored and changes from yellow to brown, so that the optical characteristics are deteriorated. The concentration of oxygen and carbon may increase in oxygen and carbon near the surface of the film due to surface adsorption or contamination on the film or oxidation of the surface. Refers to the part where there is no.

In order to realize an amorphous structure while maintaining a three-dimensional structure, dangling bonds are generated in both the group III element and the group V element. For this reason, it is desirable that hydrogen be bonded to the group III element and the group V element equally. When hydrogen is bonded to the dopant, substitutional impurity doping cannot be performed. Therefore, it is preferable that hydrogen is not bonded to the dopant. These hydrogen bonding states can be easily measured by an infrared absorption spectrum.
Each composition in the film can be measured by a method such as X-ray photoelectron spectroscopy (XPS), electron microprobe, or hydrogenford backscattering (HFS). The absolute amount of hydrogen can be measured by Rutherford back scattering (RBS). The amount of hydrogen can also be estimated by measuring the amount of hydrogen released by heating or measuring the IR spectrum.

Next, the amorphous optical semiconductor of the present invention can be manufactured as follows.
Hereinafter, description will be made with reference to the drawings. The method shown in FIG. 1 is a method using plasma as an activating means. 1 is a container which can be evacuated to a vacuum, 2 is an exhaust port, 3 is a substrate holder, 4 is a heater for heating the substrate, and 5 and 6 are quartz tubes connected to the container 1. Communicating. The quartz tube 5 is connected to a gas introduction tube 11, and the quartz tube 6 is connected to a gas introduction tube 12.

In this apparatus, for example, N ₂ is used as a nitrogen source and introduced into the quartz tube 5 from the gas introduction tube 9. A microwave of 2.45 GHz is supplied to a microwave waveguide 8 connected to a microwave oscillator (not shown) using a magnetron to generate a discharge in the quartz tube 5. From another gas inlet 10, for example, H ₂ is introduced into the quartz tube 6. A high frequency of 13.56 MHz is supplied from a high frequency oscillator (not shown) to the high frequency coil 7 to generate a discharge in the quartz tube 6. Amorphous gallium nitride can be obtained on the substrate by introducing trimethyl gallium from the gas introduction pipe 12 from the downstream side of the discharge space.
The amorphous state can be changed by the substrate temperature and the gas flow pressure. When the substrate temperature is high or the flow rate of the group III source gas is small, it is likely to become amorphous having microcrystal nuclei of less than 50 °.
Instead of trimethylgallium, an organometallic compound containing indium can be used, or can be mixed. Further, these organometallic compounds may be introduced from the gas introduction pipe 11.

  Further, a gas containing at least one or more elements selected from C, Si, Ge, and Sn, or a gas containing at least one or more elements selected from Be, Mg, Ca, Zn, and Sr is supplied to the discharge space. By introducing the gas from the downstream side (gas introduction pipe 11 or gas introduction pipe 12), an amorphous nitride semiconductor of any conductivity type such as n-type or p-type can be obtained. In the case of C, carbon may be used as the organometallic compound depending on conditions.

The substrate temperature is between 20C and 600C. In the above-described apparatus, active nitrogen or active hydrogen formed by discharge energy may be controlled independently, or a gas such as NH ₃ containing both nitrogen and hydrogen atoms may be used. Further, H ₂ may be added. Further, a condition under which active hydrogen is liberated from the organometallic compound may be used. In this manner, activated Ga or Ga and In atoms and nitrogen atoms are present on the substrate in a controlled state, and hydrogen atoms convert methyl and ethyl groups to non-functional groups such as methane and ethane. Despite the low temperature, an amorphous film containing almost no carbon and having reduced film defects can be formed.

In the above-described apparatus, the activating means may be a high-frequency oscillator, a micro-oscillator, an electrocyclotron resonance method, a helicon plasma method, one of these may be used, or two or more may be used. Further, both may be microwave oscillators, and both may be high frequency oscillators. In the case of high-frequency discharge, it may be of induction type or capacitance type. Further, an electron cyclotron resonance method may be used. When different activating means (exciting means) are used, it is necessary to generate a discharge at the same pressure at the same time, and a pressure difference may be provided between the discharge and the film forming unit (in the container 1). When the same pressure is used, different activating means (exciting means), for example, microwave and high-frequency discharge can be used to greatly change the excitation energy of excited species, which is effective for controlling film quality.
The amorphous optical semiconductor of the present invention can be formed in an atmosphere in which at least hydrogen is activated, such as a reactive vapor deposition method, ion plating, or reactive sputtering.

The substrate used in the present invention may be conductive or insulating, and may be crystalline or non-quality. Examples of the conductive substrate include metals such as aluminum, stainless steel, nickel, and chromium, and semiconductors such as alloy crystals of Si, GaAs, and SiC.
Alternatively, an insulating substrate having a substrate surface subjected to a conductive treatment can be used. Examples of the insulating substrate include a polymer film, glass, and ceramic. The conductive treatment is performed by forming a film of the above metal, gold, silver, copper, or the like by an evaporation method, a sputtering method, an ion plating method, or the like.
Further, as a light-transmitting support of a transparent conductive substrate for light input / output, a transparent inorganic material such as glass, quartz, and sapphire, or a fluororesin, polyester, polycarbonate, polyethylene, polyethylene terephthalate, epoxy, or the like. A transparent organic resin film or plate, an optical fiber, a selfoc optical plate, or the like can be used.

  As the light-transmitting electrode provided on the light-transmitting support, a transparent conductive material such as ITO, zinc oxide, tin oxide, lead oxide, indium oxide, or copper iodide is used. Or a metal such as Al, Ni, Au or the like formed thin enough to be translucent by vapor deposition or sputtering.

As a raw material of the amorphous optical semiconductor of the present invention, Ga or an organic metal compound containing Ga and In can be used. As these organometallic compounds, liquids and solids such as trimethylgallium, triethylgallium, tertiary butylgallium, trimethylindium, triethylindium, and tertiary butylindium are vaporized alone or in a mixed state by bubbling with a carrier gas. Can be used. As the carrier gas, hydrocarbons such as hydrogen, N ₂ , methane and ethane, and halogenated carbons such as CF ₄ and C ₂ F ₆ can be used.

As a nitrogen raw material, a gas or liquid such as N ₂ , NH ₃ , NF ₃ , N ₂ H ₄ , and methylhydrazine can be used by vaporizing or bubbling with a carrier gas.
Further, in the amorphous optical semiconductor of the present invention, an element can be doped into the film for controlling p and n.
Examples of the n-type element include Ia group Li, Ib group Cu, Ag, Au, IIa group Mg, IIb group Zn, IVa group Si, Ge, Sn, Pb, VIa group S, Se, Te. Can be used.
Examples of p-type elements are Li, Na, K, Ib group Cu, Ag, Au, IIa group Be, Mg, Ca, Sr, Ba, Ra, IIb group Zn, Cd, Hg, and IVa. Group C, Si, Ge, Sn, Pb, Group VIa S, Se, Te, Group VIb Cr, Mo, W, Group VIIIa Fe, Co, Ni and the like can be used.

  It is known that hydrogen in a film binds and inactivates a dopant in the case of a crystal, and in order for a doping element to function as a dopant in an amorphous network, passivation of a defect level occurs. Must be bonded to the group III element and the group V element more selectively than the dopant, and the bond energy is [group 3 element] -H, [group 5 element] -H> dopant atom-H It is desirable. From this point, Si, Ge, and Sn are particularly preferable as the n-type element, and Be, Mg, Ca, Zn, and Sr are particularly preferable as the p-type element.

Doping methods include SiH ₄ , Si ₂ H ₆ , GeH ₄ , GeF ₄ , and SnH ₄ for n-type, and BeH ₂ , BeCl ₂ , BeCl ₄ , cyclopentadienyl magnesium, and dimethyl calcium for p-type. , Dimethyl strontium, dimethyl zinc, diethyl zinc, and the like. In addition, a known method such as a thermal diffusion method or an ion implantation method can be used for doping the film with an element.

  In order to obtain an optical semiconductor device using the amorphous optical semiconductor of the present invention, only an undoped film, p-type or i-type may be provided on the substrate, or p-type and n-type films may be formed and pn A junction may be formed, or an i-type film may be provided between the p-type and n-type films. Further, a film p + or n + layer doped at a higher concentration than p-type and n-type may be inserted between the electrodes for contact with the electrodes. Further, a multilayer structure having a pn or pin structure unit can be formed. Further, these p-type, i-type, and n-type layers may have different Ga, In, and N compositions for the sake of transparency and formation of a barrier. The film may be composed of a plurality of compositions.

  Such an amorphous optical semiconductor containing Ga or Ga and In and nitrogen has a variable band gap in the entire region from red to ultraviolet. Due to high light transmittance, low dark conductivity, and high light sensitivity, the amorphous optical semiconductor can be used alone. Of course, if a tandem type is formed by sequentially combining layers having different absorption regions, a wide range of light from the visible to the ultraviolet region can be effectively used. Furthermore, this optical semiconductor element has excellent light resistance, heat resistance, and oxidation resistance, can respond at high speed, and has a light-emitting function that is not available in conventional amorphous semiconductors in the entire wavelength range. It can also be used for hybrid devices that combine light emitting devices. Specific examples include a high-efficiency solar cell, a high-speed TFT, an electrophotographic photosensitive member, a high-sensitivity sensor, a high-sensitivity avalanche light sensor, a large-area LED, a full-color display, a light modulator, and an element for an optical interconnect.

Example 1
The washed Al substrate, quartz substrate, and Si wafer were placed on the substrate holder 3, and the inside of the container 1 was evacuated through the exhaust port 2, and then the substrate was heated to 250 ° C. by the heater 4. 500 sccm of N ₂ gas was introduced into the quartz tube 5 having a diameter of 25 mm from the gas introduction tube 9, a microwave of 2.45 GHz was set to 200 W through the microwave waveguide 8, matching was performed with a tuner, and discharge was performed. . The reflected wave at this time was 0W. H ₂ gas was introduced from the gas introduction tube 10 into the quartz tube 6 having a diameter of 30 mm at 200 sccm. The microwave output was set to 200W. The reflected wave was 0W. In this state, a vapor of trimethylgallium (TMGa) kept at room temperature was introduced at a flow rate of 2 sccm from the gas introduction tube 12 directly through a mass flow controller. At this time, the reaction pressure measured by a Baratron vacuum gauge was 0.2 Torr.

The film was formed for 1 hour, and the film thickness was measured by a step measurement to be 3 μm. When the film composition was measured by XPS and RBS (Rutherford Backscattering), it was found that the stoichiometry was almost equivalent to that of Ga / N ratio of 1.1. At this time, carbon (C) was 8 atomic%, and oxygen (O) could not be detected. The optical gap was 3.5 eV. Hydrogen was contained in this GaN film as Ga-H, NH as a result of IR spectrum measurement. The amount of hydrogen measured from the hydrogen heated and released in vacuum was 20 atomic%. The X-ray diffraction spectrum did not show a clear peak, indicating that it was amorphous. When the resistance of this amorphous GaN film was measured, it was 2.0 × 10 ⁺¹⁴ Ωcm, and when irradiated with Xe lamp light, it was 1.5 × 10 ¹⁰ Ωcm. It turned out to show.

Example 2
A film was formed under the same conditions as in Example 1 except that the H ₂ gas was discharged at a high frequency of 13.56 MHz and an output of 100 W through the high frequency coil 7.
The film composition was almost stoichiometric with a Ga / N ratio of 0.99 and carbon was 3 atomic%. No oxygen was detected. The amount of hydrogen was 30 atomic%. The dark resistance was 1 × 10 ⁺¹⁴ Ωcm, and the light-dark resistance ratio was four digits or more.
The infrared absorption spectrum of the film composition was as shown in FIG. In FIG. 2, 2900 cm ^-1 is the stretching vibration of C-H, around 3200 cm ^-1 is the stretching vibration of N-H, 2100cm ^-1 is the stretching vibration of Ga-H. The absorption intensity ratio of NH / GaH was 0.23.

Comparative Example 5 g of GaN powder having a purity of 5N was placed in a crucible using a commercially available electron beam evaporation apparatus, and the same substrate as in Example 1 was placed on the upper portion of 15 cm. The evaporator was carefully evacuated to 10 ^-4 Pa. The substrate was heated to 200 ° C. with an infrared lamp heater. The electron beam current was gradually increased, kept constant at 100 mA, and the shutter was opened to perform vapor deposition on the substrate for 5 minutes. The substrate temperature was increased by 50 ° C. during the deposition. It was cooled immediately after the completion of the vapor deposition, taken out into the air after cooling, and evaluated for characteristics. This film was amorphous and its composition was almost stoichiometric. This film did not contain hydrogen. The same light irradiation as in Example 1 was performed on this amorphous GaN film, but the conductivity did not change.

Example 3
Using the same apparatus and the same substrate as in Example 1, 500 sccm of N ₂ gas was introduced from the gas introduction pipe 9, and discharge was performed at a microwave output of 2.45 GHz and 200 W. At this time, the reflected wave was 0W. 200 sccm of H ₂ gas was introduced from the gas introduction tube 10, and discharge was performed at a high frequency of 13.56 MHz and an output of 100 W. At this time, the reflected wave was 0W. The temperature of the substrate holder was set to 250 ° C. by the heater 4. In this state, trimethylgallium (2 sccm) and trimethylindium heated to 50 ° C. and mixed at 1 sccm together with N ₂ gas were introduced from the gas inlet tube 12. Further, SiH ₄ diluted to 1% with N ₂ was introduced from the gas introduction pipe 11 to form an n-type a-Ga _X In _Y N _Z film. The pressure was set to 0.2 Torr. After forming the film for 10 minutes, the valves of the gas introduction pipe 12 and the gas introduction pipe 11 were closed. At this time, the discharge was continued. In this state, a mixed gas of 2 sccm of trimethylgallium and 1 sccm of trimethylindium was again introduced from the gas introduction tube 12, and bispentadienyl magnesium was introduced again at 10 sccm from the gas introduction tube 11 using N ₂ as a carrier gas to form a p-type. a-Ga _X In _Y and the N _Z was 5 minutes film.

  The obtained film thickness was 1 μm. As a result of measuring the composition of this film by RBS, Ga / In / N was 0.7 / 0.3 / 1, oxygen was 5 atomic%, and carbon was 7 atomic%. The amount of hydrogen measured by HFS was 18 atomic%. The overall optical gap of this film was 2.9 eV. A 100 A Au electrode capable of transmitting light to the film on the Al substrate and an Au electrode on and under the Si wafer were vapor-deposited and irradiated with a Xe lamp. As a result, a photovoltaic power of 0.9 V was obtained at an open voltage.

Example 4
Using the same apparatus and the same substrate as in Example 2, 500 sccm of N ₂ gas was introduced from the gas introduction pipe 9, and discharge was performed at a microwave output of 2.45 GHz and 250 W. At this time, the reflected wave was 0W. 100 sccm of H ₂ gas was introduced from the gas introduction tube 10 and discharge was performed at a high frequency of 13.56 MHz and an output of 100 W. At this time, the reflected wave was 0W. The temperature of the substrate holder was set to 100 ° C. by the heater 4. In this state, 1 sccm of trimethylgallium was introduced from the gas introduction tube 12. It was found that the film composition was almost equal to stoichiometric at a Ga / N ratio of 1.05. At this time, carbon (C) and oxygen (O) were 0 atomic%. Also, the hydrogen content by HFS measurement was 35 atomic%. However, the surface was oxidized, and the hydrogen concentration was low while the oxygen concentration exceeded 20 atomic%. The optical gap was 3.5 eV. An electron diffraction spectrum and an X-ray diffraction spectrum did not show a clear peak, indicating that they were amorphous. Further, the infrared absorption spectrum of the obtained film composition was as shown in FIG. In FIG. 3, the absorption intensity ratio between NH and GaH was 0.4, and CH was hardly absorbed. When the amorphous GaN film was irradiated with Xe lamp light and the light-dark resistance ratio was measured, it was found that the amorphous GaN film exhibited photoconductivity of three digits or more.

Example 5
A film was produced under the same conditions as in Example 4 except that the temperature of the substrate was set to 200 ° C. It was found that the film composition was almost equal to stoichiometric at a Ga / N ratio of 0.95. At this time, carbon (C) was not detected, but oxygen (O) was 10 atomic%. The cause of this oxygen was unknown. In addition, hydrogen by RBS measurement was 27 atomic%. No oxidation of the surface was observed. An electron diffraction spectrum and an X-ray diffraction spectrum did not show a clear peak, indicating that they were amorphous. Further, the infrared absorption spectrum of the obtained film composition was as shown in FIG. In FIG. 4, the absorption intensity ratio between NH and GaH was 0.25, and there was no absorption of CH. The amorphous GaN film was irradiated with Xe lamp light and the light-dark resistance ratio was measured. As a result, it was found that the amorphous GaN film exhibited photoconductivity of four digits or more.

Example 6
A film was produced under the same conditions as in Example 4 except that the temperature of the substrate was set to 300 ° C.
It was found that the film composition was almost equal to stoichiometric at a Ga / N ratio of 0.98. At this time, carbon (C) and oxygen (O) were not detected. In addition, hydrogen was 18 atomic% by RBS measurement. No oxidation of the surface was observed. In the electron beam diffraction spectrum, bright spots were observed in the blurred pattern, and it was found that the film was amorphous having microcrystals of less than about 50 °. Further, the infrared absorption spectrum of the obtained film composition was as shown in FIG. In FIG. 5, the absorption intensity ratio between NH and GaH was 0.46, and there was no absorption of CH. In addition, it was found that the peak absorption intensity of GaN near 570 cm ^-1 increased, and the line width became narrower, which included a microcrystalline state. The amorphous GaN film was irradiated with Xe lamp light and the light-dark resistance ratio was measured. As a result, it was found that the amorphous GaN film exhibited photoconductivity of four digits or more. The dark resistance was lower than in Example 5.

Example 7
Using the same apparatus and the same substrate as in Example 2, N ₂ gas was introduced at 900 sccm from the gas introduction pipe 9, and discharge was performed at a microwave output of 2.45 GHz and 250 W. At this time, the reflected wave was 0W. 300 sccm of H ₂ gas was introduced from the gas introduction tube 10 and no discharge was performed. The temperature of the substrate holder was set to 250 ° C. by the heater 4. In this state, trimethylgallium 3seem was introduced from the gas introduction tube 12. It was found that the film composition was almost equal to stoichiometric at a Ga / N ratio of 0.97. At this time, carbon (C) was 12 atomic%. Oxygen (O) was 0 atomic%. In addition, hydrogen was 22 atomic% by RBS measurement. The optical gap was 3.4 eV. An electron diffraction spectrum and an X-ray diffraction spectrum did not show a clear peak, indicating that they were amorphous.
Further, the infrared absorption spectrum of the obtained film composition was as shown in FIG. In FIG. 6, the absorption intensity ratio between NH and GaH was 0.2. The amorphous GaN film was irradiated with Xe lamp light and the light-dark resistance ratio was measured. As a result, it was found that the amorphous GaN film exhibited photoconductivity of four digits or more.

1 is a schematic configuration diagram showing a preferred embodiment of an apparatus for manufacturing an amorphous optical semiconductor of the present invention. 5 is a graph showing an infrared absorption spectrum of a film composition obtained in Example 2. 9 is a graph showing an infrared absorption spectrum of the film composition obtained in Example 4. 9 is a graph showing an infrared absorption spectrum of the film composition obtained in Example 5. 9 is a graph showing an infrared absorption spectrum of the film composition obtained in Example 6. 9 is a graph showing an infrared absorption spectrum of the film composition obtained in Example 7.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Exhaust port 3 Substrate holder 4 Heater 5, 6 Quartz tube 7 High frequency coil 8 Micro waveguide 9-12 Gas introduction tube

Claims (15)

  An amorphous semiconductor containing hydrogen, Ga or Ga and In, and a nitrogen element, wherein the total number of Ga atoms or the total number of Ga and In atoms and the number of nitrogen atoms Is an amorphous optical semiconductor having a ratio of 1: 0.5 to 1: 2.   2. The amorphous optical semiconductor according to claim 1, wherein the amorphous optical semiconductor contains 1 atomic% or more and 50 atomic% or less of hydrogen.   3. The non-metal oxide film according to claim 1, wherein the non-metallic compound is formed using an organic metal compound containing at least Ga or Ga and In as a raw material, contains hydrogen, and is made of Ga or Ga and In and a nitrogen element. Crystalline optical semiconductor.   An amorphous optical semiconductor comprising 1 to 50 atomic% of hydrogen, Ga or Ga and In, and a nitrogen element, wherein oxygen and carbon are each 15 atomic% or less.   The amorphous optical semiconductor according to any one of claims 1 to 4, further comprising at least one element selected from the group consisting of C, Si, Ge, and Sn.   The amorphous optical semiconductor according to claim 1, further comprising at least one element selected from Be, Mg, Ca, Zn, and Sr.   A method for producing an amorphous optical semiconductor, comprising activating a compound containing nitrogen to a required energy state or excited species and reacting these active species with an organometallic compound containing Ga or Ga and In.   By activating the Ga or the organometallic compound containing Ga and In to a required energy state or an excited species, it contains hydrogen and contains the total number of Ga atoms or the total number of Ga and In atoms and nitrogen. The method according to claim 7, wherein an amorphous optical semiconductor having a ratio of the number of atoms to the number of atoms of 1: 0.5 to 1: 2 is obtained.   7. The method according to claim 7, further comprising one or more activating means for activating the compound containing nitrogen to a required energy state or an excited species, wherein the activating means is discharge energy. 9. The method for producing an amorphous optical semiconductor according to item 8.   The method according to claim 7, wherein a high-frequency discharge and / or a microwave discharge is used as the activating means.   11. The method according to claim 7, wherein Ga or a compound containing Ga and In is introduced downstream of the activating means.   12. The method according to claim 7, wherein hydrogen, nitrogen, ammonia, and an inert gas are used for the high-frequency discharge and / or the microwave discharge.   13. The method according to claim 7, wherein a gaseous raw material containing at least one element selected from Be, Mg, Ca, Zn, and Sr is introduced from a downstream side of the activating means. A method for manufacturing an amorphous optical semiconductor.   14. The amorphous material according to claim 7, wherein a gaseous raw material containing at least one element selected from C, Si, Ge, and Sn is introduced from a downstream side of the activating means. Method for manufacturing optical semiconductors.   An optical semiconductor device comprising the amorphous optical semiconductor according to claim 1.

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