RU2769430C1 - Method for obtaining epitaxial calcium silicide film (variants) - Google Patents

Abstract

FIELD: semiconductor industry.

SUBSTANCE: invention relates to the technology of manufacturing semiconductor devices. In the method for obtaining an epitaxial calcium silicide film, CaF₂ is first deposited on a substrate with a silicon layer on its working surface, a CaF₂ layer is formed from 4 to 10 nm or from 20 to 40 nm. Then, at the same time, ionizing radiation particles are irradiated with energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF₂, and high-temperature treatment is carried out. The treatment is carried out by maintaining the heated state of the substrate to the temperature and the passage of time, providing, in relation to the irradiated sections of the CaF₂ layer, a layer of calcium silicide CaSi₂ of a characteristic

spatial group is obtained. In another variant of the method, CaF₂ is simultaneously deposited on the silicon layer, irradiated with ionizing radiation particles, and high-temperature treatment is carried out over time, providing for the irradiated deposition sites of CaF₂ to obtain a layer of calcium silicide CaSi₂ of a characteristic spatial group

, the deposition of CaF₂ is carried out with respect to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the layer of CaF₂ from 4 to 10 nm or from 20 to 100 nm during the time providing for the irradiated deposition sites of CaF₂ to obtain a layer of calcium silicide.

EFFECT: obtaining a strictly specified, single, polytype of the formed CaSi₂ film with the realization of obtaining both 6R and 3R polytype characteristic of the spatial group

.

8 cl, 5 dwg

Description

The technical solution relates to semiconductor devices, to the technology for producing epitaxial thin-film materials used in semiconductor devices, and can be used in the formation of elements of conductive structures, such as contacts and connections in integrated circuit components, as well as in the creation of sensors of various physical quantities, including photoelectric and thermoelectric converters, when creating systems with a reduced dimension, in technological processes of resistanceless formation of nanostructures.

и осаждают на его поверхность слой кальция, используя испарительный тигель из нитрида бора. Слой атомарного кальция осаждают до достижения толщины 200

поддерживая при осаждении кальция температуру подложки на уровне комнатной. Заключительную термообработку, обеспечивающую протекание реакции образования силицида и получение пленки, содержащей силицид кальция, осуществляют посредством отжига, в результате которого проводят реакцию между кальцием и кремнием буферного слоя и получают силицид кальция.A known method for producing an epitaxial film of calcium silicide (JF Morar, M. Wittmer, ((Metallic CaSi ₂ epitaxial films on Si(111)", Phys. Rev. B: Condens. Matter Mater. Phys., 1988, 37, pp 2618- 2621), which includes preliminary preparation of the surface of the Si (111) substrate, subsequent formation of layers - first, a silicon buffer layer, then a calcium layer - and final heat treatment, which ensures the reaction of silicide formation and the formation of a film containing calcium silicide. ) is carried out by carrying out thermal desorption of natural oxide at a temperature of 940 ° C for 20 s. After that, a buffer layer of undoped silicon with a thickness of 1000

and a calcium layer is deposited on its surface using a boron nitride evaporation crucible. A layer of atomic calcium is deposited until a thickness of 200

maintaining the temperature of the substrate at room temperature during calcium deposition. The final heat treatment to carry out the silicide formation reaction and obtain a film containing calcium silicide is carried out by annealing, as a result of which a reaction between calcium and silicon of the buffer layer is carried out and calcium silicide is obtained.

After calcium precipitation, prior to annealing, the Auger spectroscopy data shows only Ca, indicating that there is no reaction between Ca and Si. After annealing, Auger spectroscopy data show the presence of both Ca and Si. Rutherford backscattering data show a Ca:Si atomic ratio of 2:1 and a layer size including both Ca and Si of about 150

The method does not solve the technical problem of increasing the efficiency of the process of obtaining a CaSi ₂ film, in particular, with a decrease in its duration, with the possibility of expanding the scope of the obtained CaSi ₂ films for creating active elements of devices, the possibility of forming 2D CaSi ₂ structures, including those encapsulated with dielectric films , in one technological cycle.

The disadvantages of the known method include the impossibility of obtaining a strictly defined, single, polytype during the implementation of the actions of the method. The considered method is suitable for the formation of only passive elements, such as contacts and/or interconnects. The steps of the method are carried out sequentially.

A known method for producing an epitaxial film of calcium silicide (A. Schopke, R. Wurz, M. Schmidt, "Epitaxial growth of CaSi ₂ on Si(111)", Surf. Interface Anal., 2002, 4, pp 464-467), including preliminary preparation of the Si (111) substrate surface, then sequential formation of a calcium layer and final heat treatment, which ensures the reaction of silicide formation and the formation of a film containing calcium silicide. Preliminary preparation of the surface of the Si (111) substrate is carried out by etching the surface in NH ₄ F (40%) and passivating the silicon surface with hydrogen, after which the substrate is placed in a chamber with an ultrahigh vacuum and heated to 650 ° C, hydrogen is removed, obtaining in with respect to the silicon surface, the superstructure is 7×7. After that, a layer of calcium is formed by molecular beam epitaxy. A layer of atomic calcium is deposited until a thickness of 1 to 2 nm or 15 to 20 nm is reached, while maintaining the substrate temperature at room level during calcium deposition, and the deposition rate is 0.01 nm⋅s ^-1 . The final heat treatment, which ensures the reaction of the formation of silicide and the production of a film containing calcium silicide, is carried out by annealing at a temperature of more than 400°C for a duration of 15 to 75 minutes.

с определенным политипом (политип 6R) достигают при использовании осажденных слоев атомарного кальция толщиной от 15 до 20 нм и длительного отжига - 75 мин при температуре 400°С.Obtaining a film of calcium silicide CaSi ₂ characteristic space group

with a certain polytype (polytype 6R) is achieved using deposited layers of atomic calcium with a thickness of 15 to 20 nm and long-term annealing - 75 min at a temperature of 400°C.

The known method does not solve the technical problem of increasing the efficiency of the process of obtaining a CaSi ₂ film, with the possibility of expanding the scope of the obtained CaSi ₂ films for creating active elements of devices, the possibility of forming 2D CaSi ₂ structures, including those encapsulated by dielectric films, in one technological cycle.

The disadvantages of the known method include the implementation of the possibility of obtaining only 6R polytype. The possibility of obtaining a 3R polytype is not achieved; instead of obtaining a single polytype, a mixture of phases is formed. The steps of the method are carried out sequentially.

A known method for producing an epitaxial film of calcium silicide (US patent No. 5248633, published 28.09.1993), which is taken as the closest analogue.

This method includes the sequential implementation of three stages. At the first stage, epitaxial deposition is carried out on a substrate with a layer of silicon on its working surface, CaF ₂ , forming a dielectric layer. As said substrate, in particular, a Si (111) substrate is used. At the second stage, ionizing radiation particles are irradiated with an energy that provides decomposition and formation of an atomic layer of Ca on the silicon layer on its working surface of the substrate in relation to CaF ₂ . In this case, as irradiation with ionizing radiation particles, electron beam irradiation with an energy of 1 to 100 keV, or X-ray irradiation with an energy of 1 to 100 keV, or irradiation with As ⁺ ions with an energy of 50 keV, B ⁺ ions, or Ga ⁺ , or Sb ⁺ . At the third stage, high-temperature treatment is carried out at a given temperature, which ensures the production of a conductive film of calcium silicide CaSi ₂ in the areas of the CaF ₂ dielectric layer that were irradiated with particles of ionizing radiation with an energy that ensures the decomposition of CaF ₂ and the formation of an atomic Ca layer on the silicon layer located on the surface of the substrate . When this is carried out the specified processing at a given temperature, providing a conductive film of calcium silicide CaSi ₂ , namely, at a temperature of 300°C or higher.

The given closest analogue does not solve the technical problem of increasing the efficiency of the process of obtaining a CaSi ₂ film, in particular, with a decrease in the duration of the silicide formation process, with the possibility of expanding the scope of application of the obtained CaSi ₂ films for creating active elements of devices, the possibility of forming 2D CaSi ₂ structures, including including those encapsulated with dielectric films, in one technological cycle.

The considered method is suitable for the formation of only passive elements, such as contacts and/or interconnects. This method does not ensure the production of calcium silicide, in respect of which its polytype is a given, single, polytype. The irradiated initial layer is made of arbitrary thickness. The steps of the method are carried out sequentially.

The development of the proposed method for obtaining an epitaxial film of calcium silicide is aimed at solving the technical problem of increasing the efficiency of the process of obtaining a CaSi ₂ film with a decrease in the duration of the formation of calcium disilicide, with the possibility of expanding the scope of the resulting CaSi ₂ films for creating active elements of devices, the possibility of forming 2D CaSi ₂ structures, including those encapsulated with dielectric films, in one technological cycle, due to the achieved technical result.

The technical result is:

- achievement of obtaining a strictly specified, single, polytype of the formed film CaSi ₂ ;

- realization of the possibility of obtaining both 6R and 3R polytypes characteristic of the space group

The technical result is achieved by implementing a method for producing an epitaxial calcium silicide film, which consists in first depositing CaF ₂ on a substrate with a silicon layer on its working surface and forming a CaF ₂ layer on the silicon layer, then the latter is irradiated with particles of ionizing radiation, high-temperature processing is carried out, at the same time, a layer of CaF ₂ is formed from 4 to 10 nm or from 20 to 40 nm, including the indicated values of the intervals, after the formation of the CaF ₂ layer, irradiation and high-temperature processing are carried out simultaneously, irradiated with particles of ionizing radiation with energy that provides excitation, decomposition in relation to CaF ₂ and the formation of atomic Ca, and the high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and time that provides, in relation to the irradiated sections of the CaF ₂ layer, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

In the method, particles of ionizing radiation are irradiated with an energy that, in relation to CaF ₂ , excites, decomposes and forms atomic Ca, using electron beam irradiation with an energy of 20 keV at a current density of 50 μA/cm ² .

- от 350 до 550°С, включая значения указанного интервала, в течение 4 минут.In the method, high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a period of time providing, in relation to the irradiated sections of the CaF ₂ layer, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

- from 350 to 550°C, including the values of the specified interval, for 4 minutes.

In the method, a CaF ₂ layer is formed by molecular beam epitaxy.

при этом осаждение CaF₂ осуществляют в отношении количества дифторида кальция, которое эквивалентно в пересчете на формируемую толщину слоя CaF₂ от 4 до 10 нм или от 20 до 100 нм в течение времени, обеспечивающего в отношении облучаемых участков осаждения CaF₂ получение слоя силицида кальция, включая указанные значения интервалов.The technical result is achieved by implementing a method for producing an epitaxial film of calcium silicide, which consists in the fact that CaF ₂ is deposited on a substrate with a layer of silicon on its working surface, irradiated with particles of ionizing radiation, high-temperature processing is carried out, while CaF ₂ is deposited on silicon layer, irradiation with particles of ionizing radiation, carrying out high-temperature processing, irradiation is carried out with particles of ionizing radiation with an energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF ₂ , high-temperature processing is implemented by maintaining the heated state of the substrate to a temperature and for a time, providing in in relation to the irradiated areas of CaF ₂ deposition obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

wherein the deposition of CaF ₂ is carried out in relation to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the CaF ₂ layer from 4 to 10 nm or from 20 to 100 nm for a time providing, in relation to the irradiated areas of CaF ₂ deposition, obtaining a layer of calcium silicide, including the specified interval values.

In the method, ionizing radiation particles are irradiated with an energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF ₂ using irradiation with an electron beam with an energy of 20 keV, at a current density of 50 μA/cm ² .

- от 350 до 550°С, включая значения указанного интервала, в течение времени осаждения CaF₂, осаждение CaF₂ осуществляют в отношении количества дифторида кальция, которое эквивалентно в пересчете на формируемую толщину слоя CaF₂ от 4 до 10 нм или от 20 до 100 нм, включая указанные значения интервалов, в течение времени, обеспечивающего в отношении облучаемых участков осаждения CaF₂ получение слоя силицида кальция, которое задают выбирая скорость осаждения 0,3

In the method, high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time that provides, in relation to the irradiated areas of CaF ₂ deposition, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

- from 350 to 550°C, including the values of the specified interval, during the time of deposition of CaF ₂ , the deposition of CaF ₂ is carried out in relation to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the CaF ₂ layer from 4 to 10 nm or from 20 to 100 nm, including the indicated values of the intervals, during the time providing, in relation to the irradiated sites of CaF ₂ deposition, obtaining a layer of calcium silicide, which is set by choosing a deposition rate of 0.3

In the method, the deposition of CaF ₂ is carried out by molecular beam epitaxy.

The essence of the technical solution is illustrated by the following description and the attached figures.

On FIG. Figure 1 shows the Raman spectra measured after CaF ₂ deposition on the substrate silicon layer, before simultaneous irradiation and high-temperature treatment, and after CaF ₂ deposition on the substrate silicon layer and subsequent simultaneous irradiation with 20 keV electrons and high-temperature treatment at 550°C for 4 min for cases of different thicknesses of the initial layer and the resulting CaSi ₂ - from 4 to 40 nm, where: 1 - Raman spectrum before simultaneous irradiation and high-temperature treatment of the CaF ₂ layer 10 nm thick; 2 - Raman spectrum after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 4 nm thick; 3 - Raman spectrum after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 10 nm thick; 4 - Raman spectrum after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 20 nm thick; 5 - Raman spectrum after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 40 nm thick.

On FIG. Figure 2 shows the Raman spectra measured with respect to a CaF ₂ layer 10 nm thick deposited on a silicon substrate layer, subjected to simultaneous irradiation with electrons with an energy of 20 keV and high-temperature treatment at various substrate temperatures from 150 to 550°C for 4 min, where: 6 - Raman spectrum of the layer subjected to treatment at 550°C; 7 - Raman spectrum of the layer subjected to treatment at 400°C; 8 - Raman spectrum of the layer subjected to treatment at 300°C; 9 - Raman spectrum of the layer subjected to treatment at 150°C.

On FIG. Figure 3 shows the Raman spectra measured with respect to a CaF ₂ layer 40 nm thick deposited on the silicon layer of the substrate, subjected to simultaneous irradiation with electrons with an energy of 20 keV and high-temperature treatment at various substrate temperatures from 150 to 550°C for 4 min, where: 10 - Raman spectrum of the layer subjected to treatment at 550°C; 11 - Raman spectrum of the layer subjected to treatment at 400°C; 12 - Raman spectrum of the layer subjected to treatment at 300°C; 13 - Raman spectrum of the layer subjected to treatment at 150°C.

On FIG. Figure 4 shows the Raman spectra measured with respect to the layer obtained by depositing a CaF ₂ layer 10 nm thick on a silicon substrate layer, followed by simultaneous irradiation with electrons with an energy of 20 keV and high-temperature treatment at 550°C for 4 min, and also with respect to the layer obtained as a result of simultaneous deposition of CaF ₂ in an amount taken in terms of the formed thickness of 10 nm of the initial layer, irradiation with electrons with an energy of 20 keV and high-temperature treatment at 550°C for 4 min, where: 14 is the Raman spectrum of the substrate; 15 - Raman spectrum of the layer obtained by high-temperature treatment with simultaneous irradiation after deposition of the initial layer of CaF ₂ with a thickness of 10 nm; 16 - Raman spectrum of the layer obtained by simultaneous deposition, high-temperature processing and irradiation, with the deposition of CaF ₂ in an amount taken in terms of a thickness of 10 nm of the original layer.

On FIG. Figure 5 shows the Raman spectra measured with respect to the layer obtained by depositing a CaF ₂ layer 40 nm thick on a silicon substrate layer, followed by simultaneous irradiation with electrons with an energy of 20 keV and high-temperature treatment at 550°C for 4 min, and also with respect to the layer obtained as a result of simultaneous deposition of CaF ₂ in an amount taken in terms of the formed thickness of 100 nm of the initial layer, irradiation with electrons with an energy of 20 keV and high-temperature treatment at 550°C for 4 min, where: 14 is the Raman spectrum of the substrate; 17 - Raman spectrum of the layer obtained by simultaneous deposition, high-temperature processing and irradiation, during the deposition of CaF ₂ in an amount taken in terms of the thickness of 100 nm of the original layer; 18 - Raman spectrum of the layer obtained by high-temperature treatment with simultaneous irradiation after deposition of the initial layer of CaF ₂ with a thickness of 40 nm.

Calcium silicides have a wide range of properties - from those characteristic of semiconductors to those characteristic of metals and semimetals. The specified variety of properties is associated with the possibility of fine tuning the electronic structure of calcium silicides by varying the concentration of silicon and, as a consequence, varying the proportion of covalent and ionic bonds in silicides, due to the participation of Ca d-electrons in varying degrees in the formation of a bond with Si. This circumstance provides an expansion of the scope of possible applications, in particular, in electronics when creating semiconductor devices. However, calcium silicide in practice has found application for the manufacture of only passive elements.

The volume of publications concerning the processes of epitaxial formation of calcium silicide films on silicon substrates shows that, to date, the corresponding processes have not been studied in detail. This fact is explained as follows. First, in relation to the Ca-Si system, up to six types of calcium silicide can be isolated, differing in composition, with an insignificant difference in their formation energies. Secondly, during the formation of layers of calcium silicide, the influence of the mismatch of crystal lattices affects. These factors cause a mixture of phases during growth, complicating epitaxial formation, and, as a result, difficulty in practical application.

для обоих соединений)).Related phases of CaSi ₂ in particular are: single-layer (the so-called E _u Ge2 structure, space group P3m1), two-layer (space group P63mc, which exists only under pressure and has superconductivity below 14 K), and structures with a three-layer and six-layer translational period of silicon substructures in the unit cell (3R and 6R respectively (space group

for both connections.

The formation of an epitaxial layer of calcium silicide is possible using the deposition of atomic Ca on a substrate with a layer of silicon on its working surface, with silicon of which, during subsequent heat treatment, calcium reacts to form silicide. In addition, the formation of an epitaxial layer of calcium silicide can be carried out using CaF ₂ as a substance deposited on the silicon layer of the substrate. The layer of calcium difluoride, being deposited on the silicon layer of the substrate on its working surface, is exposed to radiation in order to form a layer of atomic Ca, which, during subsequent heat treatment, reacts with silicon to form silicide. The function of radiation exposure in the specified sequence of actions is the formation of atomic Ca, for which irradiation with particles of ionizing radiation is carried out, causing decomposition of calcium difluoride, using irradiation with electrons or ions, X-ray irradiation. The role of this radiation exposure directly in the formation of silicon silicide is not considered in the prior art.

Achieving a technical result and solving a technical problem is based on the use of radiation-stimulated formation of CaSi ₂ during heat treatment, which ensures the reaction of calcium with silicon with the formation of silicide. In the proposed solution, radiation exposure directly affects the process of silicon silicide formation.

The proposed method in one embodiment of its implementation includes the simultaneous implementation of two actions, which is its distinctive feature. The specified feature is the simultaneous conduction of ionizing radiation with an energy during irradiation with particles that provides, in relation to CaF ₂ , the excitation of the electronic subsystem throughout the thickness of the deposited layer, decomposition and formation of atomic Ca, high-temperature treatment involving atomic calcium in the reaction of formation of silicide. Said treatment consists in heating the substrate to a temperature sufficient to initiate the calcium silicide formation reaction and maintaining it for the time necessary for the formation of calcium silicide. Carrying out irradiation in combination with high-temperature treatment ensures more efficient formation of silicide, having formed, atomic calcium is immediately exposed to temperature and is involved in the reaction.

When the temperature is not maintained at the level at which the silicide formation reaction is initiated and proceeds, the process stops, even if the irradiation is not completed. Thus, high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time that ensures that, in relation to the irradiated sections of the CaF ₂ layer, a layer of calcium silicide CaSi _{2 of} a characteristic space group is obtained.

In addition, in another embodiment, the proposed method includes the simultaneous implementation of three actions, which is its distinctive feature. This feature is the simultaneous deposition of calcium difluoride on the silicon layer of the substrate on its working surface, irradiation with particles of ionizing radiation with an energy that provides excitation of the electronic subsystem in relation to the deposited CaF ₂ , decomposition and formation of atomic Ca, and high-temperature treatment involving atomic calcium in the formation reaction silicide. These three actions are carried out by heating the substrate to a temperature sufficient to initiate the reaction of formation of calcium silicide. The high-temperature treatment consists in heating the substrate to a temperature sufficient to initiate the calcium silicide formation reaction and maintaining it for the time necessary for the formation of calcium silicide. Carrying out simultaneous deposition, irradiation and high-temperature treatment provides even more efficient formation of silicide, having formed without the formation of the initial layer of calcium difluoride, atomic calcium is immediately exposed to temperature and is involved in the reaction.

When the temperature is stopped at the level at which the silicide formation reaction is initiated and proceeds, the process stops even if the deposition and irradiation are prolonged. Thus, high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time that provides, in relation to the irradiated areas of CaF ₂ deposition, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

It is known that, in relation to solids, irradiation with particles of ionizing radiation, such as quanta of electromagnetic radiation (ultraviolet, x-ray, gamma) or high-energy particles (electrons, ions, neutrons), leads to the appearance of defects in their crystal structure. Moreover, radiation damage can occur in solids as a result of the interaction of particles with both nuclear and electronic subsystems of the crystal lattice. In this regard, the mechanisms of radiation defect formation in solids are differentiated into shock and electronic mechanisms.

The implementation of impact mechanisms for the formation of radiation defects requires the minimum amount of energy required to displace an atom (ion) from its normal position at a site of the crystal lattice. Impact mechanisms are typical for semiconductors and metals (“Physical processes in irradiated semiconductors”, edited by L.S. Smirnov, Novosibirsk, “Nauka”, 1977, 254 pp.; “Issues of radiation technology of semiconductors”, edited by L.S. Smirnova, Novosibirsk, "Nauka", 1980, 296 p.).

Ideas about the mechanism of formation of radiation defects in ionic crystals are reduced to a non-impact mechanism (Ch.B. Lushchik, I.K. Vitol, M.A. Elango, “The decay of electronic excitations into radiation defects in ionic crystals”, Uspekhi fizicheskikh nauk, 1977, vol. 122, issue 2, pp. 223-251). In the process of interaction of these particles of ionizing radiation with solids, a significant fraction of their energy is spent on excitation of the electronic subsystem of crystals. Various electronic excitations that arise in this case determine the electronic mechanisms of radiation defect formation. In this case, much lower energies are required for the formation of radiation defects than with impact mechanisms. In ionic crystals, especially in alkali halide and alkaline earth metal fluorides, this mechanism of formation of radiation defects is dominant.

In the proposed variants of the method, electron beam irradiation with an energy of 20 keV is used, which is sufficient in relation to the initial layer of calcium difluoride of the selected thickness, with which it is grown by molecular beam epitaxy, to obtain atomic Ca in the required amount for the formation of calcium silicide or in relation to the deposited amount calcium difluoride in terms of the formed thickness of the initial layer during the heat treatment. In the proposed variants of the method, the current density is 50 μA/cm ² .

В случае получения в качестве требуемого политипа 6R пространственной группы

слой CaF₂ формируют толщиной от 20 до 40 нм (или от 20 до 100 нм в случае реализации способа с осуществлением одновременно трех действий), включая указанные значения интервала. В диапазоне значений толщины исходного слоя дифторида кальция от 10 до 20 нм, как установлено экспериментально, происходит формирование смешанной фазы.The formation of the initial layer of calcium difluoride is carried out with a thickness of 4 to 10 nm, including the values of the specified interval, in the case of obtaining the required space group 3R polytype

In the case of obtaining the space group 6R as the required polytype

the CaF ₂ layer is formed with a thickness of 20 to 40 nm (or 20 to 100 nm in the case of implementing the method with the implementation of three actions simultaneously), including the specified values of the interval. In the range of thicknesses of the initial layer of calcium difluoride from 10 to 20 nm, as established experimentally, the formation of a mixed phase occurs.

а затем - в этой же ростовой камере установки МЛЭ проводят реакцию силицидообразования, одновременно осуществляя облучение и высокотемпературную обработку. Значение скорости осаждения может быть как больше, так и меньшее относительно указанного значения, поскольку не влияет на протекание реакции образования силицида.The formation of the initial layer of calcium difluoride is carried out in the installation of molecular beam epitaxy (MBE) "Katun-100", equipped with an effusion source of CaF ₂ with a graphite crucible. As a substrate with a silicon layer on its working surface, a (111) orientation silicon substrate is used. A silicon-on-insulator silicon substrate provided on its planar side or a silicon-on-sapphire substrate may be used. After the standard chemical preparation of the substrate for MBE growth, it is subjected to a preliminary high-temperature treatment in a working chamber at a temperature of 400°C in order to clean it. Then, at a temperature of 720°C and a weak flow of Si, the protective oxide is removed, after which, at a temperature of 550°C, a buffer Si layer 100 nm thick is grown on the planar side. The substrate has no contact with the heater, heating is carried out by means of thermal radiation. After completion of the pregrowth preparation of the planar surface of the substrate with a layer of silicon on its working surface, the initial layer of calcium difluoride of the required thickness is first formed with a deposition rate of 0.3

and then - in the same growth chamber of the MBE installation, the reaction of silicide formation is carried out, simultaneously irradiating and high-temperature processing. The value of the deposition rate can be either higher or lower relative to the specified value, since it does not affect the course of the silicide formation reaction.

осаждают количество дифторида кальция, которое эквивалентно в пересчете толщине исходного слоя от 4 до 10 нм, включая значения указанного интервала. В случае получения в качестве требуемого политипа 6R пространственной группы

осаждают количество дифторида кальция, которое эквивалентно в пересчете толщине исходного слоя от 20 до 100 нм, включая указанные значения интервала. Осаждение указанного количества осуществляют в течение временного интервала, величина которого равна времени высокотемпературной обработки и необходима при используемой скорости осаждения для достижения осаждения требуемого количества дифторида кальция, являющегося эквивалентным в пересчете на заданную толщину исходного слоя с целью получения желаемого политипа. Скорость осаждения составляет 0,3

In the case of implementing the proposed method with the simultaneous implementation of three actions - the deposition of calcium difluoride, irradiation and high-temperature treatment, these actions are carried out in the above installation, using the above substrates, with their preliminary preparation in the above way, with growing the same buffer layer. After completion of the pregrowth preparation of the clanar surface of the substrate with a layer of silicon on its working surface, calcium difluoride is deposited in the growth chamber of the MBE installation, with a deposited amount of calcium difluoride, which is equivalent in terms of the thickness of the initial layer, during the time necessary for the formation of calcium silicide from the deposited material , at which the specified actions performed simultaneously achieve the required, strictly specified, calcium disilicide polytype. So, in the case of obtaining the space group 3R as the required polytype

precipitate the amount of calcium difluoride, which is equivalent in terms of the thickness of the original layer from 4 to 10 nm, including the values of the specified range. In the case of obtaining the space group 6R as the required polytype

depositing an amount of calcium difluoride, which is equivalent in terms of the thickness of the original layer from 20 to 100 nm, including the indicated values of the interval. The deposition of the specified amount is carried out for a time interval, the value of which is equal to the high-temperature treatment time and is necessary at the deposition rate used to achieve deposition of the required amount of calcium difluoride, which is equivalent in terms of the given initial layer thickness in order to obtain the desired polytype. The settling rate is 0.3

Another value of the speed can be chosen, both greater and lesser relative to the specified value, taking into account the characteristics of the course of the chemical reaction of the formation of silicide.

Any heterogeneous processes are associated with the transfer of matter, and in them, in particular, three stages can be distinguished (R.T. Marchenko "Physical and colloidal chemistry", M .: "Higher school", 1965, 374 p., p. 203 ): supply of the reactant to the surface; chemical reaction on the surface; removal of the reaction product from the surface. The first and last stage is carried out by diffusion. In many cases, a chemical reaction could proceed very quickly if the supply of the reactant to the surface was fast enough. Such processes are called diffusion-controlled, since the rate is determined by the rate of substance transfer (diffusion). If the chemical reaction (second stage) has a high activation energy, then this stage turns out to be the slowest one, and the process is not accelerated by a sufficiently fast supply of the reactant to the surface. Such heterogeneous reactions are called kinetically controlled. To speed them up, you need to increase the temperature.

The rate of a heterogeneous reaction is defined as the amount of a substance entering into a reaction or formed during a reaction per unit of time per unit of phase surface. Obviously, the rate of a chemical reaction depends on the concentration of reagents on the surface (I.I. Ioffe, L.M. Pismen "Engineering chemistry of heterogeneous catalysis", L.: "Chemistry", 1972, 464 p., pp. 79-80 ).

The time required for the formation of calcium disilicide, both in the case of simultaneous implementation of two actions for the purpose of silicide formation - irradiation and high-temperature treatment, and in the case of simultaneous implementation of three actions for the purpose of silicide formation - precipitation, irradiation and high-temperature treatment, determined by the time of high-temperature treatment, is chosen deliberately maximum for the specified values of the thickness of calcium difluoride, with a guarantee of the onset of the end of the process of silicide formation relative to the specified values of the thickness. In particular, when implementing the method according to the first variant, the time is chosen to be 4 minutes, which is obviously the maximum for the specified values of the thickness of the deposited layer of calcium difluoride, with a guarantee of the onset of the end of the process of silicide formation relative to the specified values of the thickness of the initial layer. When implementing the method according to the second variant, the time is chosen to be 1 minute or more, depending on the deposited amount of calcium difluoride, which is equivalent in terms of the given thickness of the initial layer in order to obtain the desired polytype, which is obviously the maximum for the given values of the thickness of the deposited layer of calcium difluoride and guaranteeing the end of the process of silicide formation.

Simultaneous implementation of irradiation and high-temperature treatment stimulates the reaction of formation of calcium disilicide, and the time required for the formation of calcium silicide, in contrast to analogues of the prior art, is reduced several times, reaching a value of 4 minutes or even less.

High-temperature treatment consists in heating the substrate to a temperature sufficient to initiate the reaction of formation of calcium silicide, and maintaining the temperature for the time necessary for the formation of calcium disilicide, while using temperatures whose values are set in the range from 300 to 550 ° C , including the specified values. The above range of temperature values is comparable to the range known from the prior art.

Experimental data - Raman spectra (see Fig. 1-5) confirm the possibility of obtaining a strictly specified, single, polytype of the formed CaSi ₂ film, the implementation of obtaining both 6R and 3R polytypes characteristic of the space group

а для исходного слоя CaF₂ толщиной от 20 до 40 нм, включая указанные значения интервалов, - формирование дисилицида кремния 6R политипа пространственной группы

в сравнении с со спектром КРС 1 до одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 10 нм (спектр КРС исходного слоя).In the case of implementing the method in a variant of its implementation, including the simultaneous implementation of two actions - irradiation with particles of ionizing radiation and high-temperature treatment, leading to the formation of calcium disilicide, from the Raman spectra (see Fig. 1) obtained for different thicknesses of the initial layer of calcium difluoride and at fixed parameters of irradiation and high-temperature treatment (electrons with an energy of 20 keV, temperature 550°C, time 4 min), it can be seen that for the initial CaF ₂ layer with a thickness of 4 to 10 nm, including the indicated values of the intervals, silicon disilicide 3R of the 3R polytype is formed. groups

and for the initial layer of CaF ₂ with a thickness of 20 to 40 nm, including the indicated values of the intervals, the formation of silicon disilicide 6R space group polytype

in comparison with the Raman spectrum 1 before simultaneous irradiation and high-temperature treatment of the CaF ₂ layer 10 nm thick (Raman spectrum of the original layer).

The Raman spectrum of the initial layer is characterized by a large peak due to single-phonon scattering by long-wavelength optical phonons (520.6 cm ^-1 ). Also, this spectrum is characterized by features associated with two-phonon scattering - a wide band from 200 to 450 cm ^-1 with a maximum at 305 cm ^-1 associated with scattering by two acoustic phonons, and a band with a maximum at 650 cm ^-1 associated with scattering on optical and acoustic phonons. The Raman spectrum of the initial CaF ₂ layer completely repeats the Raman spectrum from the silicon substrate, which indicates that this initial CaF ₂ layer is transparent, its presence on the silicon layer of the substrate does not introduce any changes into the spectrum from the surface silicon of the substrate.

Simultaneous irradiation with electrons with an energy of 20 keV and high-temperature treatment - heating the substrate to 550°C and maintaining this temperature for 4 min - lead, as can be seen from the spectra (see Fig. 1), regardless of the thickness of the initial calcium difluoride layer, to the appearance of peaks in the region of 414 cm ^-1 , 385 cm ^-1 and 345 cm ^-1 , which are characteristic for the formation of calcium disilicide 3R polytype. On the other hand, simultaneous irradiation with electrons with an energy of 20 keV and high-temperature treatment - heating the substrate to 550°C and maintaining this temperature for 4 min - lead, as can be seen from the spectra (see Fig. 1), with the thickness of the initial layer of calcium difluoride , equal to 20 nm or 40 nm, to the appearance of other peaks in the range from 150 to 250 cm ^-1 with a pronounced peak in the region of 203 cm ^-1 (Respectively, the Raman spectrum 4 after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer with a thickness of 20 nm or Raman spectrum 5 after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 40 nm thick).

Одна фаза характеризуется трехслойным трансляционным периодом кремниевых подструктур в элементарной ячейке (3R). Вторая фаза характеризуется шестислойным трансляционным периодом кремниевых подструктур в элементарной ячейке (6R). Наблюдаемые на спектрах КРС (см. Фиг. 1) пики находятся в полном согласии с известными как теоретическими, так и экспериментальными данными для объемного CaSi₂ пространственной группы

Ключевым отличием структурной модификации 6R от структурной модификации 3R является наличие на КРС спектрах (Спектр КРС 4 после одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 20 нм и спектр КРС 5 после одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 40 нм) пиков, связанных с фононными модами колебания атомов Са, таких как E_u(Са) 113 см^-1, A_2u (Са) 152 см^-1 и A_lg(Ca) 205 см^-1, а также сдвигов пиков модовых симметрий, связанных с колебанием атомов Si, в область более низких частот для фазы 6R (спектр КРС 4 после одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 20 нм и спектр КРС 5 после одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 40 нм) по сравнении с 3R (спектр КРС 2 после одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 4 нм и спектр КРС 3 после одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 10 нм). Наличие или отсутствие указанных пиков и их положение на КРС спектрах свидетельствует о той или иной фазе CaSi₂ пространственной группы

В рассматриваемом случае это наличие (спектр КРС 4 после одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 20 нм и спектр КРС 5 после одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 40 нм) или отсутствие (спектр КРС 2 после одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 4 нм и спектр КРС 3 после одновременных облучения и высокотемпературной обработки слоя CaF₂ толщиной 10 нм) пика A_lg(Ca) 205 см^-1 и смещение пиков, связанных с колебанием атомов Si.It is known from publications that there are two phases of CaSi ₂ space group

One phase is characterized by a three-layer translational period of silicon substructures in the unit cell (3R). The second phase is characterized by a six-layer translational period of silicon substructures in the unit cell (6R). The peaks observed in the Raman spectra (see Fig. 1) are in full agreement with the known both theoretical and experimental data for bulk CaSi ₂ space group

The key difference between structural modification 6R and structural modification 3R is the presence in the Raman spectra (Raman spectrum 4 after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 20 nm thick and Raman spectrum 5 after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 40 nm thick) of peaks associated with phonon vibration modes of Ca atoms, such as E _u (Ca) 113 cm ^-1 , A _2u (Ca) 152 cm ^-1 and A _lg (Ca) 205 cm ^-1 , as well as shifts of peaks of mode symmetries associated with the vibration of atoms Si, to lower frequencies for the 6R phase (Raman spectrum 4 after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 20 nm thick and Raman spectrum 5 after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 40 nm thick) compared with 3R (Raman spectrum 2 after simultaneous irradiation and high temperature treatment of a 4 nm thick CaF ₂ layer and Raman spectrum 3 after simultaneous irradiation and high temperature treatment of a 10 nm thick CaF ₂ layer). The presence or absence of these peaks and their position in the Raman spectra indicates one or another phase of the CaSi ₂ space group

In the case under consideration, this is the presence (Raman spectrum 4 after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 20 nm thick and Raman spectrum 5 after simultaneous irradiation and high-temperature treatment of a CaF ₂ layer 40 nm thick) or absence (Raman spectrum 2 after simultaneous irradiation and high-temperature treatment CaF ₂ layer 4 nm thick and Raman spectrum 3 after simultaneous irradiation and high-temperature treatment of the CaF ₂ layer 10 nm thick) peak A _lg (Ca) 205 cm ^-1 and the shift of peaks associated with the vibration of Si atoms.

Experimental data - Raman spectra (Fig. 2 and 3) reflect the effect of temperature (with variation from 150 to 550°C) high-temperature treatment on the formation of 6R or 3R polytype, characteristic of the space group

In the case of obtaining a 3R polytype, which is obviously determined by the thickness of the initial layer of calcium difluoride, in particular, 10 nm, which is subjected to simultaneous irradiation with electrons with an energy of 10 keV and high-temperature treatment for 4 min, it was found that at a substrate temperature of 400 - 550 ° C, the formation of CaSi ₂ is precisely the 3R polytype (see Fig. 2), since the positions of the corresponding peaks of the Raman spectrum of the 6th layer treated at 550°C and the Raman spectrum of the 7th layer treated at 400°C coincide with the positions of the peaks of the Raman spectrum 2 after simultaneous irradiation and high temperature treatment of a 4 nm thick CaF ₂ layer and Raman spectrum 3 after simultaneous irradiation and high temperature treatment of a 10 nm thick CaF ₂ layer in FIG. 1. Differences in the intensity of the peaks are due to the dependence of the mode symmetries of atomic vibrations in CaSi ₂ on the angle of rotation of the incident and scattered light.

An analysis of the Raman spectra of the layer irradiated with electrons at a substrate temperature of 300°C, with an initial layer thickness of 10 nm (Raman spectrum of the 8th layer treated at 300°C, see Fig. 2) shows that peaks appear in the range of 150 - 250 cm ^-1 and there is also a shift of the main peaks to lower frequencies. This indicates that, as the temperature decreases below 400°С, CaSi _{2 of} the 6R polytype is formed. In the Raman spectra at a substrate temperature of 150°C, in particular, in relation to the Raman spectrum of layer 9 treated at 150°C, with an initial layer 10 nm thick, no peaks characteristic of CaSi ₂ are observed. Thus, at a temperature of 150°C CaSi ₂ is not formed.

In the case of obtaining the 6R polytype, which is obviously determined by the thickness of the initial layer of calcium difluoride, in particular 40 nm, which is subjected to simultaneous irradiation with electrons with an energy of 20 keV and high-temperature treatment for 4 min, at temperatures from 150 to 550°C, the following data were experimentally obtained .

At a substrate temperature of 400 - 550°C, the CaSi ₂ 6R polytype is formed (see Fig. 3), as evidenced by the Raman spectrum of the 10th layer treated at 550°C, and the Raman spectrum of the 11th layer treated at 400°C. These spectra have a range of 150-250 cm ^-1 (Raman spectrum of layer 10 treated at 550°C, Raman spectrum of layer 11 treated at 400°C, see Fig. 3), for a temperature of 550°C (spectrum CRS 10 layer treated at 550°C) there is a peak in the region of 203 cm ^-1 . For a temperature of 300°C (Raman spectrum of 12 layer treated at 300°C, see Fig. 3) peaks characteristic of the CaSi ₂ 6R polytype in the range of 345 - 415 cm ^-1 are absent, but there is a range of 150-250 cm ^-1 . This fact testifies in favor of the fact that the temperature of 300°C, at which simultaneous irradiation and high-temperature treatment take place, is critical for the formation of the CaSi ₂ 6R polytype. In the Raman spectra at a substrate temperature of 150°C, in particular in relation to the Raman spectrum of the 13th layer treated at 150°C (see Fig. 3), peaks characteristic of CaSi ₂ are not observed. Thus, at a temperature of 150°C CaSi ₂ is not formed.

In the case of the implementation of the method in its embodiment, including the simultaneous implementation of three actions - the deposition of calcium difluoride, irradiation with particles of ionizing radiation and high-temperature treatment, leading to the formation of calcium disilicide, the Raman spectra (see Fig. 4 and 5) show the following.

Comparison of the Raman spectra (see Fig. 4), one of which was measured in relation to the layer obtained by depositing a CaF ₂ layer 10 nm thick on a substrate, followed by simultaneous irradiation with electrons with an energy of 20 keV and high-temperature treatment at 550°C for 4 min ( the Raman spectrum of the 15th layer obtained by high-temperature treatment with simultaneous irradiation after the deposition of the initial layer of CaF ₂ with a thickness of 10 nm), and the second - in relation to the layer obtained as a result of the simultaneous deposition of CaF ₂ in an amount taken in terms of the formed thickness of 10 nm of the initial layer, irradiation with electrons with an energy of 20 keV and high-temperature treatment at 550°C for 4 min, (Raman spectrum of layer 16 obtained by simultaneous deposition, high-temperature treatment and irradiation, with the deposition of CaF ₂ in an amount taken in terms of the thickness of 10 nm of the initial layer) , shows that both in one case and in the other case, peaks are visible in the regions of 414 cm ^-1 , 385 cm ^-1 and 345 cm ^-1 , characteristic for films of the CaSi ₂ 3R polytype and the substrates absent for the Raman spectrum 14.

Comparison of the Raman spectra (see Fig. 5), one of which was measured in relation to the layer obtained as a result of simultaneous deposition of CaF ₂ in an amount taken in terms of the formed thickness of 100 nm of the initial layer, irradiation with electrons with an energy of 20 keV and high-temperature treatment at 550°C during the specified simultaneous processes of deposition and irradiation (Raman spectrum of the 17th layer obtained by simultaneous deposition, high-temperature processing and irradiation, with the deposition of CaF ₂ in an amount taken in terms of the thickness of 100 nm of the original layer, 17), and the second - in ratio of the layer obtained by deposition of a CaF ₂ layer 40 nm thick on the substrate, followed by simultaneous irradiation with electrons with an energy of 20 keV and high-temperature treatment at 550°C for 4 min (Raman spectrum of 18 layer obtained by high-temperature treatment with simultaneous irradiation after deposition of the initial CaF layer ₂ with a thickness _of 40 nm) shows that both spectra contain n iki in the areas of 414 cm ^-1 , 385 cm ^-1 and 345 cm ^-1 . Peaks are also observed in the range of 150-250 cm ^-1 with a pronounced peak in the region of 203 cm ^-1 , the intensity of which is higher for a thickness of 100 nm compared to a thickness of 40 nm. Thus, both in one case and in another case, these characteristic features are attributes for CaSi ₂ 6R polytype films.

As information confirming the possibility of implementing the method, we present the following examples of its implementation.

Example 1

To obtain an epitaxial layer of calcium silicide, CaF ₂ is first deposited on a substrate with a layer of silicon on its working surface and a CaF ₂ layer 4 nm thick is formed.

, а именно, при 350°С в течение 4 минут. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 3R политип.Then the original CaF ₂ layer is irradiated with particles of ionizing radiation, high-temperature processing is carried out. Irradiation and high temperature treatment are carried out simultaneously. Irradiated with particles of ionizing radiation with an energy that provides for CaF ₂ excitation, decomposition and formation of atomic Ca, namely, using electron beam irradiation with an energy of 20 keV at a current density of 50 μA/cm ² . High-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and time that ensures, in relation to the irradiated sections of the CaF ₂ layer, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

, namely, at 350°C for 4 minutes. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 3R polytype is obtained.

Example 2

To obtain an epitaxial layer of calcium silicide, CaF ₂ is first deposited on a substrate with a silicon layer on its working surface and a CaF ₂ layer 5 nm thick is formed.

а именно, при 360°С в течение 4 минут. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 3R политип.Then the original CaF ₂ layer is irradiated with particles of ionizing radiation, high-temperature processing is carried out. Irradiation and high temperature treatment are carried out simultaneously. Irradiated with particles of ionizing radiation with an energy that provides for CaF ₂ excitation, decomposition and formation of atomic Ca, namely, using electron beam irradiation with an energy of 20 keV at a current density of 50 μA/cm ² . High-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and time that ensures, in relation to the irradiated sections of the CaF ₂ layer, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 360°C for 4 minutes. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 3R polytype is obtained.

Example 3

To obtain an epitaxial layer of calcium silicide, CaF ₂ is first deposited on a substrate with a layer of silicon on its working surface and a CaF ₂ layer 10 nm thick is formed.

а именно, при 550°С в течение 4 минут. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 3R политип.Then the original CaF ₂ layer is irradiated with particles of ionizing radiation, high-temperature processing is carried out. Irradiation and high temperature treatment are carried out simultaneously. Irradiated with particles of ionizing radiation with an energy that provides for CaF ₂ excitation, decomposition and formation of atomic Ca, namely, using electron beam irradiation with an energy of 20 keV at a current density of 50 μA/cm ² . High-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and time that ensures, in relation to the irradiated sections of the CaF ₂ layer, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 550°C for 4 minutes. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 3R polytype is obtained.

Example 4

To obtain an epitaxial layer of calcium silicide, CaF ₂ is first deposited on a substrate with a layer of silicon on its working surface and a CaF ₂ layer 20 nm thick is formed.

а именно, при 550°С в течение 4 минут. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 6R политип.Then the original CaF ₂ layer is irradiated with particles of ionizing radiation, high-temperature processing is carried out. Irradiation and high temperature treatment are carried out simultaneously. Irradiated with particles of ionizing radiation with an energy that provides for CaF ₂ excitation, decomposition and formation of atomic Ca, namely, using electron beam irradiation with an energy of 20 keV at a current density of 50 μA/cm ² . High-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and time that ensures, in relation to the irradiated sections of the CaF ₂ layer, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 550°C for 4 minutes. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 6R polytype is obtained.

Example 5

To obtain an epitaxial layer of calcium silicide, CaF ₂ is first deposited on a substrate with a layer of silicon on its working surface and a CaF ₂ layer 38 nm thick is formed.

а именно, при 500°С в течение 4 минут. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 6R политип.Then the original CaF ₂ layer is irradiated with particles of ionizing radiation, high-temperature processing is carried out. Irradiation and high temperature treatment are carried out simultaneously. Irradiated with particles of ionizing radiation with an energy that provides for CaF ₂ excitation, decomposition and formation of atomic Ca, namely, using electron beam irradiation with an energy of 20 keV at a current density of 50 μA/cm ² . High-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and time that ensures, in relation to the irradiated sections of the CaF ₂ layer, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 500° C. for 4 minutes. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 6R polytype is obtained.

Example 6

To obtain an epitaxial layer of calcium silicide, CaF ₂ is first deposited on a substrate with a layer of silicon on its working surface and a CaF ₂ layer 40 nm thick is formed.

а именно, при 400°С в течение 4 минут. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 6R политип.Then the original CaF ₂ layer is irradiated with particles of ionizing radiation, high-temperature processing is carried out. Irradiation and high temperature treatment are carried out simultaneously. Irradiated with particles of ionizing radiation with an energy that provides for CaF ₂ excitation, decomposition and formation of atomic Ca, namely, using electron beam irradiation with an energy of 20 keV at a current density of 50 μA/cm ² . High-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and time that ensures, in relation to the irradiated sections of the CaF ₂ layer, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 400° C. for 4 minutes. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 6R polytype is obtained.

Example 7

To obtain an epitaxial layer of calcium silicide on a substrate with a layer of silicon on its working surface, CaF ₂ is deposited, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. At the same time, CaF ₂ is deposited on a substrate with a layer of silicon on its working surface, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. Precipitate calcium difluoride by molecular beam epitaxy at a rate of 0.3

The deposition of CaF ₂ is carried out in relation to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the CaF ₂ layer of 4 nm for a time providing for the irradiated areas of deposition of CaF ₂ with the indicated rate of obtaining a layer of calcium silicide.

The irradiation is carried out with particles of ionizing radiation with an energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF ₂ , namely, using irradiation with an electron beam with an energy of 20 keV at a current density of 50 μA/cm ² .

а именно, при 350°С. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 3R политип.The high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time that provides, in relation to the irradiated areas of CaF ₂ deposition at a specified rate, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 350°C. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 3R polytype is obtained.

Example 8

To obtain an epitaxial layer of calcium silicide on a substrate with a layer of silicon on its working surface, CaF ₂ is deposited, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. When this is carried out simultaneously the deposition of CaF ₂ on the silicon layer of the substrate, irradiation with particles of ionizing radiation, high-temperature processing. Precipitate calcium difluoride by molecular beam epitaxy at a rate of 0.3

The deposition of CaF ₂ is carried out in relation to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the CaF ₂ layer of 5 nm over a period of time providing for the irradiated areas of deposition of CaF ₂ with the indicated rate of obtaining a layer of calcium silicide.

The irradiation is carried out with particles of ionizing radiation with an energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF ₂ , namely, using irradiation with an electron beam with an energy of 20 keV at a current density of 50 μA/cm ² .

а именно, при 350°С. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 3R политип.The high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time that provides, in relation to the irradiated areas of CaF ₂ deposition at a specified rate, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 350°C. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 3R polytype is obtained.

Example 9

To obtain an epitaxial layer of calcium silicide on a substrate with a layer of silicon on its working surface, CaF ₂ is deposited, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. At the same time, CaF ₂ is deposited on a substrate with a layer of silicon on its working surface, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. Precipitate calcium difluoride by molecular beam epitaxy at a rate of 0.3

The deposition of CaF ₂ is carried out in relation to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the CaF ₂ layer of 10 nm for a time providing for the irradiated areas of deposition of CaF ₂ with the indicated rate of obtaining a layer of calcium silicide.

The irradiation is carried out with particles of ionizing radiation with an energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF ₂ , namely, using irradiation with an electron beam with an energy of 20 keV at a current density of 50 μA/cm ² .

а именно, при 550°С. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 3R политип.The high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time that provides, in relation to the irradiated areas of CaF ₂ deposition at a specified rate, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 550°C. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 3R polytype is obtained.

Example 10

To obtain an epitaxial layer of calcium silicide on a substrate with a layer of silicon on its working surface, CaF ₂ is deposited, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. At the same time, CaF ₂ is deposited on a substrate with a layer of silicon on its working surface, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. Precipitate calcium difluoride by molecular beam epitaxy at a rate of 0.3

The deposition of CaF ₂ is carried out in relation to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the CaF ₂ layer of 20 nm over a period of time providing for the irradiated areas of deposition of CaF ₂ with the indicated rate of obtaining a layer of calcium silicide.

The irradiation is carried out with particles of ionizing radiation with an energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF ₂ , namely, using irradiation with an electron beam with an energy of 20 keV at a current density of 50 μA/cm ² .

а именно, при 550°С. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 6R политип.The high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time that provides, in relation to the irradiated areas of CaF ₂ deposition at a specified rate, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 550°C. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 6R polytype is obtained.

Example 11.

To obtain an epitaxial layer of calcium silicide on a substrate with a layer of silicon on its working surface, CaF ₂ is deposited, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. At the same time, CaF ₂ is deposited on a substrate with a layer of silicon on its working surface, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. Precipitate calcium difluoride by molecular beam epitaxy at a rate of 0.3

The deposition of CaF ₂ is carried out in relation to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the CaF ₂ layer of 40 nm for a time providing for the irradiated areas of deposition of CaF ₂ with the indicated rate of obtaining a layer of calcium silicide.

The irradiation is carried out with particles of ionizing radiation with an energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF ₂ , namely, using irradiation with an electron beam with an energy of 20 keV at a current density of 50 μA/cm ² .

а именно, при 400°С. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 6R политип.The high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time that provides, in relation to the irradiated areas of CaF ₂ deposition at a specified rate, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 400°C. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 6R polytype is obtained.

Example 12.

To obtain an epitaxial layer of calcium silicide on a substrate with a layer of silicon on its working surface, CaF ₂ is deposited, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. At the same time, CaF ₂ is deposited on a substrate with a layer of silicon on its working surface, irradiated with particles of ionizing radiation, and high-temperature processing is carried out. Precipitate calcium difluoride by molecular beam epitaxy at a rate of 0.3

The deposition of CaF ₂ is carried out in relation to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the CaF ₂ layer of 100 nm for a time providing for the irradiated areas of deposition of CaF ₂ with the indicated rate of obtaining a layer of calcium silicide.

The irradiation is carried out with particles of ionizing radiation with an energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF ₂ , namely, using irradiation with an electron beam with an energy of 20 keV at a current density of 50 μA/cm ² .

а именно, при 450°С. В результате получают строго заданный, единый, политип формируемой пленки CaSi₂ - 6R политип.The high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time that provides, in relation to the irradiated areas of CaF ₂ deposition at a specified rate, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

namely, at 450°C. As a result, a strictly specified, single, polytype of the formed CaSi ₂ - 6R polytype is obtained.

Claims (8)

1. A method for producing an epitaxial layer of calcium silicide, which consists in the fact that CaF ₂ is first deposited on a substrate with a layer of silicon on its working surface and a layer of CaF ₂ is formed on the silicon layer, then the latter is irradiated with particles of ionizing radiation, high-temperature processing is carried out, characterized in that that form a layer of CaF ₂ from 4 to 10 nm or from 20 to 40 nm, including the indicated values of the intervals, after the formation of the CaF ₂ layer, irradiation and high-temperature treatment are carried out simultaneously, irradiated with particles of ionizing radiation with an energy that provides for CaF ₂ excitation, decomposition and the formation of atomic Ca, and high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time providing, in relation to the irradiated sections of the CaF ₂ layer, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

. 2. The method according to claim 1, characterized in that it is irradiated with particles of ionizing radiation with an energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF ₂ , using irradiation with an electron beam with an energy of 20 keV at a current density of 50 μA/cm ² . 3. The method according to claim 1, characterized in that the high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time providing, in relation to the irradiated sections of the CaF ₂ layer, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

, - from 350 to 550°C, including the values of the specified interval, for 4 minutes. 4. The method according to p. 1, characterized in that the CaF ₂ layer is formed by molecular beam epitaxy. 5. A method for producing an epitaxial layer of calcium silicide, which consists in the fact that CaF ₂ is deposited on a silicon layer on a substrate with a layer of silicon on its working surface, irradiated with particles of ionizing radiation, high-temperature processing is carried out, characterized in that CaF ₂ is deposited on the layer simultaneously silicon, irradiation with particles of ionizing radiation, carrying out high-temperature processing, irradiation is carried out with particles of ionizing radiation with an energy that provides, in relation to CaF ₂ , excitation, decomposition and formation of atomic Ca, high-temperature processing is implemented by maintaining the heated state of the substrate to a temperature and for a time providing, in relation to irradiated areas of CaF ₂ deposition Obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

, while the deposition of CaF ₂ is carried out in relation to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the CaF ₂ layer from 4 to 10 nm or from 20 to 100 nm for a time providing, in relation to the irradiated sites of CaF ₂ deposition, obtaining a layer of calcium silicide , including the specified interval values. 6. The method according to claim 5, characterized in that it is irradiated with particles of ionizing radiation with an energy that provides excitation, decomposition and formation of atomic Ca in relation to CaF ₂ , using irradiation with an electron beam with an energy of 20 keV at a current density of 50 μA / cm ² . 7. The method according to claim 5, characterized in that the high-temperature treatment is implemented by maintaining the heated state of the substrate to a temperature and for a time that provides, in relation to the irradiated areas of CaF ₂ deposition, obtaining a layer of calcium silicide CaSi _{2 of} a characteristic space group

, - from 350 to 550°C, including the values of the specified interval, during the deposition of CaF ₂ , the deposition of CaF ₂ is carried out in relation to the amount of calcium difluoride, which is equivalent in terms of the formed thickness of the CaF ₂ layer from 4 to 10 nm or from 20 to 100 nm, including the indicated values of the intervals, for a time providing, in relation to the irradiated CaF ₂ deposition sites, a layer of calcium silicide is obtained, which is set by choosing a deposition rate of 0.3

. 8. The method according to p. 5, characterized in that the deposition of CaF ₂ is carried out by molecular beam epitaxy.

Images