Silicon carbide: a material for radioisotope power sources

Abstract

Silicon carbide as a radioactive isotope energy source material, containing a single crystalline phase of a silicon carbide semiconductor structure in the form of a film, having n-type or p-type electrical conductivity for separating electron-hole pairs, comprising the elements: carbon isotope C 12 and additionally carbon isotope C 14 for converting its radiation energy into electrical energy, characterized in that the concentration of radioactive isotope C 14 in one of the n-type or p-type conductivity layers is from 5·10 17 to 10 20 cm ‑3 -3 14 , wherein the n-type or p-type conductivity silicon carbide layer is formed on the surface of a monocrystalline silicon substrate, the n-type or p-type conductivity silicon carbide layer with C 14 has a porous surface topography.

Description

TECHNICAL FIELD

[0001] The present invention relates to substances in the field of electronics, and in particular to a silicon carbide semiconductor structure, the molecular composition of which contains atoms of the radioactive isotope carbon-14, which functionally act as a source of radiochemical decay energy, the energy barrier of which is capable of directly converting this energy into the form of electrical energy. BACKGROUND

[0002] The known technical solution [1] uses a radioactive isotope substance (Si 14 C) as a tracer to study the self-diffusion coefficient of carbon in a single-crystal semiconductor silicon carbide. Silicon powder with a particle size of 325 microns and active carbon C-14 at a rate of 309.59 millicuries per gram at a ratio of 1:1.2 were used in the preparation. The use of radioactive labeled carbon made it possible to obtain a formula for the dependence of the activation energy and temperature of the self-diffusion coefficient of carbon in silicon carbide, i.e. to track the self-diffusion path of C-14 in the substance using the properties of the beta electrons emitted by C-14. This is a difference from the proposed technical solution and is related to the use of a structure of a substance (Si 14 C) with a high activity of the C-14 component.

[0003] The known other radioactive isotope substances that emit beta electrons and the proposed semiconductor ordered structure of the invention object, which makes it possible to directly convert the radioactive isotope conversion energy into electrical energy with high specific power and lifetime.

[0004] The known analogues of the proposed invention can be a technical solution [2] that uses a diamond film on a diamond substrate with Schottky model rectifying metallization properties as a charge of a structure semiconductor material diamond substrate. A series of radioactive isotopes that are combined with the material of the semiconductor structure substance through physical contact are proposed as ionizing radiation sources: tritium compounds, nickel-63, promethium-147. The specific energy per unit area of the semiconductor material combined with the radioactive isotope released upon its decay characterizes the efficiency of the conversion agent. The beta radiation of the radioactive isotope atoms propagates on a sphere, and in the analogue, only half of the sphere of radiation propagation is effectively used to direct the conversion energy to the semiconductor substance. Another part of the energy is lost - this is a drawback that affects the effective efficiency of the structure substance related to the generation of electron-hole pairs. If the inventors use carbon-14 introduced into the growth film by epitaxy as a radioactive isotope, the radiochemical decay energy conversion efficiency can be improved in relation to the method of selection / combination of the substance, in which case the center of radiation will be the radioactive isotope atom, and the radiation will propagate along the sphere, resulting in the generation of secondary electron-hole pairs of non-equilibrium carriers, which significantly changes the interaction and leads to the generation of electron-hole pairs separated by a Schottky barrier in the interaction region. Therefore, the drawback is the limited number of generated non-equilibrium carriers due to the small contact area of the combined elements.

[0005] The substances that make up the p-i-n structure of vanadium-doped silicon carbide composition layer nuclear batteries are known [3]. The structure or composition of the sequence of substance composition layers that make up the battery includes an n-type silicon carbide substrate with an impurity concentration of 1 • 10 18 cm -3 to 7 • 10 18 cm -3 , on one side of which an ohmic contact is applied, and on the other side, an n-type continuous intrinsic conductivity silicon carbide epitaxial layer with an impurity concentration of 1 10 13 cm -3 ~5 10 14 cm -3 thick, and a p-type silicon carbide epitaxial layer with an impurity concentration of 1 10 19 cm -3 ~5 10 19 cm -3 thick, which forms a silicon carbide layer with intrinsic conductivity by implanting vanadium ions with an energy of 2000-2500 keV at a dose of 5 10 13 cm -3 to 1 10 15 cm -2 . An ohmic contact is applied to a part of the surface of the p-type silicon carbide epitaxial layer; a radioactive isotope layer is applied to another part of the surface. This technical solution uses a structure with a small surface contact area, the contact and interaction between the radioactive isotope composition and the composition of the semiconductor substance structure. The semiconductor structure substance is combined with the radioactive isotope substance by physical phase conjugation, so the area of interaction is determined by the physical contact area of each layer of the structure with the radioactive isotope, which is effective, but not enough, because one of the layers with the sandwiched radioactive isotope works effectively only in one direction, so the energy loss of the radioactive isotope decay, converted into electrical energy.

[0006] The composition of the substances used in a Schottky model contact silicon carbide nuclear battery is known [4]. The composition of the substance in the form of a conductive n+-type silicon carbide single crystal substrate with an impurity concentration of 1 • 10 17 cm -3 to 1 • 10 18 cm -3 , on one side of which an n-type silicon carbide epitaxial layer with an impurity concentration of 1 • 10 14 cm -3 to 1 • 10 16 cm -3The other side is applied with ohmic contact metallization. On the layer of intrinsic conductive silicon carbide, a metal barrier layer of chromium or molybdenum or tungsten and a metal upper layer of gold or silver or aluminum or platinum of the same shape are coated. The surface of the metal barrier layer is coated with a radioisotope. The disadvantage of this technical solution is that the amount of expensive radioisotope used for coating the surface of the barrier layer is not reasonable. The radiation in the opposite direction is lost, which reduces the efficiency of the use of the specific energy of the radioisotope.

[0007] Another analogue of the substance used in technical solution [5] is a substance whose component composition forms a semiconductor structure, in which the matrix component has the form of a surface-textured semiconductor plate and has channels to increase the contact area with the radioisotope substance. The channel walls along the channel wall form a diode structure, and the channel walls and the surface are coated with a radioisotope substance containing 3 H or 63 Ni. The pitch of the channels in the honeycomb structure and the diameter of the channels are identical in value, 100 μm. This feature reflects the interrelation between the components. The disadvantage of this technical solution is that the use of the expensive Ni-63 isotope is technically inefficient due to the presence of self-absorption phenomena in the channel track area filled with the isotope. In addition, this technical solution uses a structure in which the contact area between the components of the substance structure is small. The semiconductor structure substance is combined with the radioisotope substance by physical phase conjugation, so the contact area determines the limited efficiency of the interaction of beta electrons with the semiconductor phase, and therefore the low efficiency of the conversion of the energy of the radioisotope decay into electrical energy.

[0008] In the known technical solution [6], the semiconductor material array is represented as a polytype 4H silicon carbide structure, which includes a p-conductivity region and an n-conductivity region with a hole rate of 3x10 15 cm -3 and a thickness of 4 μm; and an electron rate of 2x10 18 cm -3 and a thickness of 0.25 μm. To convert the energy of the radiochemical decay of the nickel-63 isotope with an activity of 1 microcurie, a nickel-63 coating with a thickness of 3 μm is used, and other contact metallization is performed using an Al / Ti coating. The paper gives the energy conversion characteristics of the structure material and the simulated equivalent electron flow irradiation in the electron microscope, but there is no physical experiment with a nickel-63 film. The obtained efficiency indicators are: efficiency 3.7%, short-circuit current 22 pA, open-circuit voltage 0.95 V. The disadvantage of this technical solution is that the combination of the radioisotope and the semiconductor components in the proposed structure limits the contact area, so the energy conversion efficiency is limited by this factor.

[0009] Known substance components can be used as prototypes depending on the number of similar significant features [7]. In the technical solution provided in this publication, two components of the substance are used as energy converters: the radioactive isotope carbon-14, which is undergoing a radiochemical transformation with the emission of beta electrons with an energy of 156 keV and a half-life of 5730 years; a silicon carbide semiconductor heterostructure (β-SiC / Si) on a monocrystalline silicon substrate, characterized by the fact that the silicon carbide film has a p-n junction. Silicon carbide is a material with high resistance to induced radiation defects in its physical and chemical properties, and the beta electron energy of carbon-14 is sufficient to create pairs of secondary electrons and holes. In the paper, it is proposed to use the radioactive isotope carbon-14 as a source of radiochemical energy in pairs of Si - SiC molecular structure layers, instead of carbon-12 atoms, and the p-n junction of the structure separates pairs of secondary electrons and holes through its internal electrostatic field, generating direct current in an external circuit. To increase the radiation resistance and significantly increase the activity, a solution is proposed to use a porous silicon carbide heterostructure on a monocrystalline silicon substrate.

[0010] The technical solution has the following drawbacks:

[0011] 1. The high content of a radioactive isotope in one of the p-n junction regions requires special production organization conditions to ensure radiation safety;

[0012] 2. The excessive consumption of carbon-14 is economically unfeasible.

[0013] 3. The source of information does not provide examples of specific components of the energy conversion substance, such as the concentration range of the radioactive isotope, the tactical and technical characteristics of the resulting substance that converts the energy of the radioactive isotope into electrical energy.

[0014] The advantage is the efficiency of the generation of pairs of secondary electrons and holes in the p-n junction region due to the internal radiation of the semiconductor silicon carbide itself, as well as the elimination of the typical self-absorption losses of the substance to beta radiation. SUMMARY

[0015] The purpose of the invention is to minimize the concentration of a radioactive isotope in a SiC semiconductor structure substance used to directly convert the radiochemical transformation energy of carbon-14 atoms into electrical energy.

[0016] The technical result of the invention is a semiconductor structure substance, silicon carbide, whose molecular structure contains carbon atoms. The non-obvious effect related to the generation of an electric current is manifested in the fact that the source of radioisotope energy within the molecule is its atomic component: the radioactive isotope carbon-14, combined with the stable radioactive isotope carbon-12, forms a monocrystalline structure of the semiconductor substance. The compound (Si 14C) does not exist in nature, is artificially synthesized, has different properties from SiC compounds with C-12 isotope, new properties resulting from the radioisotope can be used for practical purposes. In addition, the radioisotope carbon-14 can exist in the homogeneous phase of the semiconductor compound SiC in the form of superstoichiometric atoms, i.e. located interstitially, replacing silicon atoms or replacing part of the carbon-12 atoms, i.e. acting as a dopant. New properties include: the size of the electronic output work is unknown, the value of the lattice parameter is different, a new property appears, i.e. the release of energy from the material structure component with a known half-life of 5760 years that is undergoing a radiochemical transformation, the electron energy spectrum in silicon carbide is different. All new properties expand the methodological arsenal of semiconductor silicon carbide structure materials, directly converting the radiochemical transformation energy into another form - electrical energy. At the same time, the content or proportion of the radioisotope component in the substance has a wide range of concentrations, determining the technical and economic efficiency and radiation safety of the application of this substance in semiconductor energy conversion devices.

[0017] The technical result of the proposed invention is the relationship structure of its components at the molecular level. The molecular structure of the silicon carbide phase component is represented by:

[0018] 1. Silicon carbide in the form of a single-crystal film. The silicon carbide SiC film substance contains carbon in the form of a mixture of radioisotopes C-12 and C14, the concentration of C-14 carbon ranges from 5 10 17 cm -3 to 10 20 cm -3 , the component (Si 14 C) in the semiconductor structure is to release the radioisotope decay energy of C-14 atoms (β electromagnetic radiation form of electrons in the spherical configuration around the radioisotope atom) into the substance;

[0019] 2. Silicon carbide in the form of a single-crystal film containing a component (Si 14 C) that can be located in the SiC phase n- or p-type conduction region;

[0020] 3. Silicon carbide in the form of a single-crystal film combined with n- or p-type conduction silicon substrate (forming a SiC / Si heterostructure);

[0021] 4. The SiC / Si heterostructure can have different implementation options: n-p junction or heterojunction, the function of which is to separate the secondary electron-hole pair by the internal field of the space charge region of the n-p junction or heterojunction, the latter directly converts the radioisotope nuclear transformation energy into direct current through an external circuit;

[0022] The technical effect based on the new properties generated by the structure of the substance is represented as follows:

[0023] - Carbon-14 atoms emit beta electrons with energy sufficient to create pairs of secondary non-equilibrium carriers (electron-hole pairs) in a spherically symmetric space around the radioactive isotope atom;

[0024] - Secondary non-equilibrium carriers are separated by the internal field of the p-n junction, at which a direct current short-circuit current appears in the external circuit and a high specific power of the unit energy converter and a continuous operating life of the idle voltage;

[0025] - The energy conversion efficiency is determined by the direct conversion of the energy generated in the SiC phase molecular structure;

[0026] - The minimum concentration range of the radioactive isotope silicon carbide component (Si 14 C) in the p-n structure of SiC is 5·10 17 cm -3 - 10 20 cm -3 , which changes the entire structure of the electrical, physical and chemical and functional properties. At the level of substance doping, the concentration of the radioactive isotope C-14 does not require permission from the radiation supervision authorities;

[0027] - The p-n structure of SiC can be formed on a monocrystalline silicon substrate with (111), (110), (100) orientation, which increases the technical and economic efficiency by reducing the cost of the substrate material by 100 times, instead of using a substrate of silicon carbide as a component;

[0028] - The thickness of the silicon carbide film is 50 nm - 5 μm, the polytype structure is hexagonal on a silicon carbide substrate or cubic on a monocrystalline silicon substrate, and the quantitative composition of the compound is stoichiometric or hyperstoichiometric (excess of carbon-14 due to point defects in the monocrystalline silicon structure itself);

[0029] - In one of the options for the structure of the substance, non-equilibrium carriers are separated by the internal electric field of the heterojunction of the structure of the substance;

[0030] - One of the options for the substance can use the n-SiC* / p-SiC / p-Si or p-Si C* / n-SiC / n-Si structure, where SiC* is a silicon carbide phase containing C-14;

[0031] - The beta electron energy of C-14 decay is not sufficient to create radiation defects, and the porous morphology of the silicon carbide surface activated by the radioactive isotope increases its radiation stability by emitting defects to the developing surface;

[0032] - One of the options uses a mirror symmetry sequence of layers of semiconductor substance structures relative to the silicon substrate (with a double-sided working area).

[0033] Therefore, the semiconductor monocrystalline silicon carbide (with the properties of doped atoms of donor or acceptor components, forming n- and p-type electrically conductive layers) formed in the process of layering of the energy conversion substance during the decay of the radioactive isotope 15 transforms the energy of the decay of the radioactive isotope 15 directly into the form of electric energy, characterized in that the n- or p-conductive layer is used in the concentration range of 5 10 17 cm -3 to 10 20 cm -3 / 20: the radioactive isotope carbon-14 as an additional dopant. BRIEF DESCRIPTION OF DRAWINGS

[0034] The essence of the technical solution is illustrated in Figure 1 , where Figure 1 shows the energy converter heterostructure with dimensions of 10 x 10 mm, doped with the activity of beta electrons of the radioactive isotope carbon-14 in the concentration of 10 20 cm -3 . Figure 2 shows fragments of the SiC (111), (222), (333) reflection diffraction patterns. Figure 3 shows the diffraction pattern of the por-SiC / Si (111) energy converter structure. Figure 4 shows the diffraction pattern of the por-SiC / Si (001) structure, the red dashed line is the tabulated value of the reflection angle position of the third SiC synthesis. Figure 5 shows the 10 x 10 mm energy converter heterostructure, doped with the activity of beta electrons of the radioactive isotope carbon-14 in the concentration of 1.5 10 18 cm -3 . DETAILED DESCRIPTION

[0035] A specific embodiment of the invention of a semiconductor structure substance for the generation of low-power direct current by converting the energy of the nucleus of the unstable radioactive isotope carbon-14.

[0036] Example 1

[0037] The monocrystalline silicon carbide semiconductor structure for the energy source of the radioactive isotope has the following sequence of layers:

[0038] - KGB (КДБ) - 4,5 (100) oriented p-type conductive silicon substrate with a 0.5 μm thick silicon oxide layer on the non-working side;

[0039] - p-type conductive silicon carbide film, inheriting the orientation of the silicon substrate on the working side, doped with the concentration of 5 10 17 cm -3 and 2 10 18 cm -3 of impurities gallium and carbon-14, the ratio of carbon-14 atoms to carbon-12 atoms in the silicon carbide film is 1 atom to 10 5 atoms.

[0040] In the p-SiC* / p-Si / SiO2heterostructure layer, the interrelation between the components is that the atomic carbon-14 dopant in the semiconductor structure silicon carbide molecule (Si 14 C) emits energy sufficient to produce beta electrons of secondary electron-hole pairs in the SiC* / Si heterojunction region, which are separated by the electrostatic internal field of the heterojunction. The thick layer of SiC2on the non-working side is intended to prevent the diffusion of carbon-14 into silicon and the formation of silicon carbide on the non-working side.

[0041] The structural properties of the substance are manifested by structural probes prepared in planar and vertical versions. In the planar version, the measurement probe is installed in the open window area of the silicon carbide and silicon pre-carbide (on the side of the silicon carbide film). In the vertical version, the measurement probe is installed in the silicon carbide and silicon (on the side of the open window in the silicon pre-oxide). For vertical and planar structure chips with working side geometry of 2 mm x 2 mm and 2 mm x 5 mm, respectively, the average short-circuit current and open-circuit voltage are 15 nA and 0.1 mV, respectively (measuring instrument B7-21A, measuring accessories - camera, does not include electromagnetic interference and optical radiation in addition to natural thermal radiation).

[0042] Example 2

[0043] The monocrystalline silicon carbide semiconductor structure for a radioisotope energy source has layers in the following order:

[0044] - KEF (КЭФ)-20 (110) oriented n-type conductive silicon substrate with a thick 0.5 silicon oxide layer on the non-working side;

[0045] - n-type conductive silicon carbide film, which inherits the orientation of the silicon substrate on the working side, doped with impurities phosphorus and carbon-14 at a concentration of 5 10 18 cm -3 and 2 10 18 cm -3 , respectively, the ratio of carbon-14 atoms to carbon-12 atoms in the silicon carbide film is 1 atom to 10 5 atoms.

[0046] In the n-SiC* / n-Si / SiO2 heterostructure layer, the interrelationships between the components are such that the carbon-14 dopant atoms in the silicon carbide (Si 14 C) semiconductor structure emit sufficient energy to generate β electrons for secondary electron-hole carrier pairs in the SiC* / Si heterojunction region. These secondary electron-hole carriers are separated by the electrostatic internal field of the heterojunction. The thick SiC2 layer on the non-working side aims to prevent carbon-14 from diffusing into silicon and to prevent silicon carbide formation on the non-working side.

[0047] The structural properties of the material are measured using structural probes fabricated in planar and vertical configurations. In the planar configuration, the probe is installed in the open window area (on the silicon carbide film side) between the silicon carbide and silicon. In the vertical configuration, the probe is installed in the open window area (on the silicon oxide side) between the silicon carbide and silicon. For vertical and planar structure chips with working side geometries of 2mm × 2mm and 2mm × 5mm respectively, the average short-circuit current and open-circuit voltage are 17nA and 0.15mV respectively (measuring instrument B7-21A, measuring accessory—camera, excluding electromagnetic interference and light radiation, except for natural thermal radiation).

[0048] Example 3

[0049] The single-crystal silicon carbide semiconductor structure used as a radioactive isotope energy source has layers in the following order:

[0050] - KEF(КЭФ)-5 (111) oriented n-type conductive silicon substrate with a 0.5 μm thick silicon oxide layer on the non-working side;

[0051] - n-type conductive silicon carbide film, inheriting the orientation of the silicon substrate on the working side, and doped with a concentration of 8.10. 20 см -3 and 2.10 20 см -3 The impurities are phosphorus and carbon-14. The ratio of carbon-14 atoms to carbon-12 atoms in the silicon carbide film is 1 atom to 10 atom. 3 One atom.

[0052] In the n-SiC* / n-Si / SiO2 heterostructure layer, the interactions between the components are manifested as semiconductor-structured silicon carbide molecules (Si... 14 The carbon-14 dopant in C) emits energy sufficient to generate β electrons for secondary electron-hole carrier pairs in the SiC* / Si heterojunction region. These secondary electron-hole carriers are separated by the electrostatic internal field of the heterojunction. The thick SiC2 layer on the non-working side is designed to prevent carbon-14 from diffusing into silicon and to prevent the formation of silicon carbide on the non-working side.

[0053] The structural properties of the substance are manifested in the measurements of the structural probe prepared in the planar and vertical versions. In the planar version, the measuring probe is installed in the area of the window opened in silicon carbide and silicon (on the side of the silicon carbide film). In the vertical version, the measuring probe is installed in silicon carbide and silicon (on the side of the window opened in silicon oxide). For the vertical and planar structural chips with the working side geometry of 2 mm x 2 mm and 2 mm x 5 mm, respectively, the average short-circuit current and the open voltage are 17.5 nA and 0.1 mV, respectively (measuring instrument B7-21A, measuring accessories - camera, electromagnetic interference and optical radiation are not included in addition to natural thermal radiation).

[0054] Example 4

[0055] The single-crystal silicon carbide semiconductor structure for a radioisotope energy source has layers in the following order:

[0056] - KEF (КЭФ) -20 (110) oriented n-type conductive silicon substrate with a 0.5 μm thick silicon oxide layer on the non-working side;

[0057] - n-type conductive silicon carbide film, inheriting the orientation of the silicon substrate on the working side, doped with impurities phosphorus and carbon-14 at a concentration of 5.10 17 cm -3 and 10 20 cm -3 , respectively, with a ratio of carbon-14 atoms to carbon-12 atoms in the silicon carbide film of 1 atom to 10 3 atoms.

[0058] In the n-SiC* / n-Si / SiO2heterostructure layer, the interrelation between the components is manifested in that the atomic carbon-14 dopant in the semiconductor structure silicon carbide molecules (Si 14 C) emits beta electrons with energy sufficient to generate pairs of secondary electron-hole carriers in the SiC / Si heterojunction region, which are separated by the electrostatic internal field of the heterojunction. The 2 μm thick layer of SiC2on the non-working side is intended to prevent the diffusion of carbon-14 into silicon and the formation of silicon carbide on the non-working side.

[0059] The structural properties of the substance are manifested in the measurements of the structural probe prepared in the planar and vertical versions. In the planar version, the measuring probe is installed in the area of the window opened in silicon carbide and silicon (on the side of the silicon carbide film). In the vertical version, the measuring probe is installed in silicon carbide and silicon (on the side of the window opened in silicon oxide). For the vertical and planar structural chips with the working side geometry of 2 mm x 2 mm and 2 mm x 5 mm, respectively, the average short-circuit current and the open voltage are 22 nA and 0.35 mV, respectively (measuring instrument B7-21A, measuring accessories - camera, electromagnetic interference and optical radiation are not included in addition to natural thermal radiation).

[0060] Example 5

[0061] The monocrystalline silicon carbide semiconductor structure for a radioisotope energy source has layers in the following order:

[0062] - KEF (КЭФ) -20 (110) oriented n-conductivity silicon substrate;

[0063] - n-conductivity silicon carbide film, inheriting the orientation of the silicon substrate on both sides, doped with impurities phosphorus and carbon-14 with concentrations of 5.10 18 cm -3 and 10 20 cm -3 respectively, the ratio of carbon-14 atoms to carbon-12 atoms in the silicon carbide film is 1 atom to 103 atoms.

[0064] In the n-SiC* / n-Si / SiO2 heterostructure layer, the interrelation between the components is such that the atomic carbon-14 dopant in the semiconductor structure silicon carbide molecules (Si 14 C) emits energy sufficient to generate beta electrons of secondary electron-hole pairs in the SiC / Si heterojunction region, which are separated by the electrostatic internal field of the heterojunction. The structural properties of the substance are manifested in the measurement of the structure probe prepared in the planar version. In the planar version, the measurement probe is installed in the area of the open window (on the side of the silicon carbide film) of the silicon carbide and silicon. For a structure chip with working side geometry of 2x5 mm, the average short-circuit current and open-circuit voltage on both sides of the symmetric structure are 22 nA and 0.35 mV, respectively (measuring instrument B7-21A, measuring accessories - camera, does not include electromagnetic interference and optical radiation in addition to natural thermal radiation).

[0065] Example 6.

[0066] The monocrystalline silicon carbide semiconductor structure for a radioisotope energy source has layers in the following order:

[0067] - KEF (КЭФ) -4,5 (100) oriented n-conductivity silicon substrate, on the non-working side there is a 0.5 μm thick silicon oxide layer;

[0068] - along the inner surface of the pores, a layer sequence silicon carbide film is formed, forming an n-p junction structure, in addition, the n layer of the film extends to the surface doped with extraneous impurities phosphorus and carbon-14 (concentrations of 5.10 18 cm -3 and 10 20 cm -3 respectively), the ratio of carbon-14 atoms to carbon-12 atoms in the silicon carbide film is 1 atom to 10 3 atoms.

[0069] In the por-n-SiC* / p-SiC / p-Si / n-Si / SiO2 heterostructure layer, the interrelation between the components is represented by the fact that the atomic carbon-14 dopant in the semiconductor structure silicon carbide molecule (Si 14 C) emits energy sufficient to produce beta electrons of the secondary electron-hole pair at the p-n junction area of por-n-SiC* / p-SiC, which are separated by the junction electrostatic internal field. The thick layer of SiC2 on the non-working side is intended to prevent the diffusion of carbon-14 into silicon and the formation of silicon carbide on the non-working side. The developed surface area of the structure of the same geometric volume increases the specific activity of the radioisotope and at the same time is an effective sink for radiation-induced structural defects, increasing the radiation passivity without destroying the functional properties of the secondary electron-hole pair separation.

[0070] The structural properties of the substance are manifested by the structural probe measurements made in the planar version. In the planar version, the measurement probe is installed in the area of the window opened in front of the n-type silicon carbide and p-type silicon carbide. For planar structure chips with a working side geometry of 5x10 mm, the average short-circuit current and open-circuit voltage are 32 nA and 0.45 mV, respectively (measuring instrument B7-21A, measuring accessories - camera, does not include electromagnetic interference and optical radiation in addition to natural thermal radiation).

[0071] References

[0072] 1. Self-diffusion in alfa and beta silicon cardide. J.D. Hong, M.N.Hon, R.F. Davis / / Ctrammurgia international. Vol.5, n.4, 1979.C. 155-160.

[0073] 2. Blank V.D., Burmashov V.S., Golovanov A.V. Method of production of semiconductor converter of ionizing radiation energy into electric energy. Patent of the Russian Federation No. 2668229, patent owner: Federal State Budgetary Institution of Science "Institute of Technology of Superhard and New Carbon Materials" (Blank V.D., Burmashov V.S., Golovanov A.V. Method of production of semiconductor converter of ionizing radiation energy into electric energy. Patent of the Russian Federation No. 2668229, patent owner: Federal State Budgetary Institution of Science "Institute of Technology of Superhard and New Carbon Materials").

[0074] 3. Patent US No. 9728292 B2, International Classification G21H 1 / 06, H01L 21 / 04, H01L 29 / 868, H01L 29 / 167, H01L 29 / 66, H01L 29 / 36, H01L 29 / 861, H01L 29 / 16, H01L 21 / 02, priority date: 09.10.2011 (Patent US No. 9728292 B2, IPC G21H 1 / 06, H01L 21 / 04, H01L 29 / 868, H01L 29 / 167, H01L 29 / 66, H01L 29 / 36, H01L 29 / 861, H01L 29 / 16, H01L 21 / 02, date of priority 09.10.2011).

[0075] 4. Patent CN No. 101320601 B, International Classification G21H1 / 00, 21H 1 / 06, H01L 29 / 47, priority date: 18.06.2008 (Patent CN No. 101320601 B, IPC G21H1 / 00, 21H 1 / 06, H01L 29 / 47, date of priority 18.06.2008).

[0076] 5. Zadde V.V., Pustovalov A.A., Pustovalov S.A., Tsvetkov L.A., Tsvetkov S.L. Semiconductor converter of beta-radiation into electric energy. Patent RU N°2452060 C2, H01L 31 / 04, G01H 01 / 00 Published: 27.05.2012, Bull. No. 15.

[0077] 6. M.V.S. Chandrashekhar, Christopher I. Thomas. Demonstration of a 4H SiC Betavoltaic Cell / / Materials science forum vols. 527-529 (2006) pp. 1351-1354.

[0078] 7. 14 C beta-converter. Gurskaya A.V., Dolgopolov M.B., Chepurin V.I. / / Physics of Elementary Particles and Atomic Nuclei. 2017. Vol. 48. No. 6. P. 901-909. 14 C beta-converter. Gurskaya A.V., Dolgopolov M.B., Chepurin V.I. / / Physics of Elementary Particles and Atomic Nuclei. 2017. Vol. 48. No. 6. P. 901-909.

Claims

1. Silicon carbide: a material for a radioisotope energy source, the composition of which contains a single-crystal phase of a silicon carbide semiconductor structure in the form of a film, having n-type and p-type electrical conductivity for separating electron-hole pairs, including elements in the silicon carbide molecular structure: carbon isotope C 12 and additional carbon isotope C 14 for converting its radiation energy into electrical energy, characterized in that Radioisotope C in one of the n-type or p-type electrically conductive silicon carbide layers 14 with a concentration of 5 · 10 17 cm -3 to 10 20 cm -3 .

2. The silicon carbide of claim 1, wherein, The n-type or p-type electrically conductive silicon carbide layer is formed on the surface of a monocrystalline silicon substrate. The n-type or p-type electrically conductive silicon carbide layer is formed on the surface of a monocrystalline silicon substrate.

3. The silicon carbide of claim 1, wherein, C-containing 14 The n-type or p-type electrically conductive silicon carbide layer has a porous surface topography.

4. The silicon carbide of any one of claims 1 to 3, wherein, C 14 The n-type or p-type electrically conductive silicon carbide layer forms a heterojunction with the silicon substrate, and beta radiation energy is converted in the space charge region of the heterojunction.

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