The used methods: irradiation by protons and electrons in accelerators, X-ray diffraction, electron microscopy, the method of high-field tunnel injection of electrons, methods of both analytical diagram expansions and difficult computer calculations of contour integrals for the solution of the integrated equation of Bethe-Salpeter in the Cooper channel and the equation Gor’kov for a superconducting energy gap in a hexagonal lattice with use of crystal group of symmetry.
Empirical base of research: The original technique for ion irradiation of materials developed during implementation of the project (this technique allows to carry out the irradiation of specimens at simultaneous action on a crystal of both an intensive beam of photons for its heating and a proton beam for creating of the radiation defects in material), the complex of X-ray techniques developed within this project for research of the surface layers of material subjected to action of the concentrated energy flows, the developed method for calculation of difficult integrals with not spread out electronic spectrum at presence of the integrated features on noncircular contours for effective interaction at actual electronic concentration in an interval between the Dirak’s point and two points of Van Hove, experimental data about both synergetic action of proton radiation and temperature on electrophysical properties and structure of silicon monocrystals and influence of high-field action, an alloying, electronic irradiation and post-radiation annealing on kinetics of a negative charge accumulation in a volume of dielectric, its charging state and a value of breakdown voltage.
Results of research:
- the technique for irradiation of silicon crystals by protons at the increased temperatures consisting in simultaneous irradiation of a sample with both an intensive photon beam for its heating and a beam of protons for creating of the radiation defects in material was developed;
- the technique for combined use of both X-ray diffractometry and reflectometry allowing to analyze the various areas of diffraction volume for research of the lateral limited layers subjected to action of the concentrated energy flows was developed;
- on the basis of the experimental data obtained by the high-resolved X-ray methods the integrated characteristics of the imperfect layers created at various temperatures were calculated;
- it has been established that unlike an usual post-implantation annealing the synergetic effect of formation of interstitial defects of various types was observed at simultaneous irradiation of a silicon sample by both a proton beam and an intensive photon beam with the heating of crystals to temperatures of 440 and 730K;
- within the scope of the Shubin-Vonsovsky model and in Born approach of weak bond at the accounting of inra-atomic, interatomic, and also interlayer Coulomb interactions of electrons the physical model and the phase diagram of a superconducting state in layered semi-metal defining borders of realization of areas of superconductivity with various types of symmetry of parameter of an order have been constructed;
- it has been shown that both the Kohn-Luttinger polarization contributions up to the second order of perturbation theory in the Coulomb interaction inclusively and an account for the long-range interplane Coulomb interactions significantly affected the competition between the superconducting phases with the f-, p+ ip-, and d+ id-wave symmetries of the order parameter. It has been demonstrated that the account for the interlayer Coulomb interaction led to an increase of realization for the enhances of the critical temperature of the transition to the superconducting phase in a graphene bilayer;
- the models describing change of a charging state of MIS-structures both in the capacity charge mode, and in the mode of injection of charge carriers were developed. Use of these models allows to choose optimum algorithm of current influence and to increase the accuracy of measurements;
- it has been established that the negative charge accumulated in the thin film of thephosphorus silicon glass (PSG) inphosphorus-doped structures with two-layer gate dielectric SiO2-PSG during both the high-field tunnel injection of electrons and the electron irradiation can be used for modification of the MIS devices. It has been shown that the application of the high-field injection of electrons to modify of the MIS structures charge state was more preferable than the usage of electron irradiation because the possibility of an individual correction of the characteristics for each device takes place, besides in the selected mode of the high-field injection it was possible to reduce significantly the related degradation processes;
- it has been established that both the densities of the accumulated negative charge and its thermostable component increased with the growth of degree of alloying for SiO2 by phosphorus leading to an increase of the PSG film thickness. However, increasing of the PSG film thickness is not applicable for thin gate dielectrics. Therefore, we came to the conclusion that to realize the increasing of the correction range of the parameters of MIS devices more preferable by changing of the ratio between the thickness of silicon dioxide and PSG, shifting the centroid of the negative charge to the Si-SiO2 interface;
- it has been shown thatthe post-irradiation annealing at temperatures not lower than 200°С after modificating by the high-field electron injection or electron irradiation was necessary to produce the devices on the base of MIS-structures with high temperature stability.
Recommendations on implementation or outcomes of the implementation of the results: recommendations for the implementation of research results include conditions of increase of critical temperature of superconducting transition of a bilayer graphene in comparison with a monolayer grapheme, increase of range of correction for electrophysical parameters of MIP-devices by using of their radiation modifying, execution of post-irradiation annealing of MIS-structures at temperatures not lower than 200°С after modificating by the high-field electron injection or electron irradiation for production of the devices on its base with high temperature stability, dose and temperature regimes for irradiation of silicon crystals by protons for creation of the imperfect layers with the controlled parameters.
Application field: the results obtained can be used in theformation of the deeply-lying p-n junctions in the power devices, production of both devices on the base of MIS-structures and silicon fotovoltaic devices.