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Information × Registration Number 0217U000086, 0112U000895 , R & D reports Title Research heternyh properties of radiation defects in semiconductors popup.stage_title Head Litovchenko Piotr G., Registration Date 17-01-2017 Organization Institute for Nuclear Research of National Academy of Sciences of Ukraine popup.description2 Investigation of oxygen-silicon precipitates properties as gettering centers of impurities and point radiation defects in irradiated silicon Object of study - monocrystalline silicon doped isovalence impurity, whiskers Si1-xGex and binary semiconductors irradiated by nuclear particles. Purpose - Study of electro-physical changes and structural properties of semiconductors in the fields of nuclear radiation, the determination possibilities to use gettering properties of oxygen Si precipitates in neutron irradiated silicon. The study of the spatial distribution of radiation defects and effects at long range action in silicon irradiated by high-energy ions of helium, hydrogen and deuterium. Research results: Determined that the high-energy irradiated silicon are evident effect of radiation defects, especially in reducing the incubation period and time of oxygen precipitation at 600 - 1000 °C heat treatment. These centers may exhibit gettering properties for impurities and point defects. Irradiation of monocrystalline silicon by ions with energies of helium 27,2 MeV at fluence F> 1016 cm-2 leads to the formation of layer structures were formed in ion path of the Si and behind it at currents ~ 0,25 - 0,45 µA. At high-energy irradiation of silicon by ions hydrogen and helium in the case height fluence F > 1017 cm-2 defects passes through the ordering stage (in the form of "walls") as a result of self-organization. Distribution defects in silicon as a "wall" in behind ions path indicates the presence long-range effect. In Si, irradiated by fast neutrons, IR spectroscopy show the existence of two types of regions disorder: vacancies and interstitials. The model of modifications the main known levels of radiation defects in silicon and germanium were proposed. If the vacancy defect is located near interstitials oxygen atom, the energy negatively charged acceptor defect decreases by 0,06 eV and donor - increased by the same amount. Interstitial silicon or germanium atom changes the level of the defect by 0,03 eV. Interstitial carbon atoms changes energy of vacancy defect at 0,035 eV, but in the opposite direction. Modification of the vacancies defects does not change the energy level of the defect in the neutral state in band gap of silicon and germanium. It was shown that continuous change of the Fermi level at radiation dose of nuclear particles are determined by the ratio between divacancies concentrations in the first and second configurations. Experimentally, the Fermi level is constantly changing from EV + 0,476 to EV + 0,53 eV. At high doses, the Fermi level is at neutral levels divacancies in first configuration state EV + 0.53 eV. It was investigated the effect of proton irradiation at energy by 6,8 MeV at doses up to 1 * 1017 p+/ cm2 on conductivity Whiskers Si0,97Ge0,03 with impurity concentration near the metal-insulator range in the temperature range 4,2-300 K at magnetic fields with induction to 14 T. Established the mechanism of conductivity at low temperatures in samples irradiated dose at 5 *1015 p+ /cm2 through a series of annealing at 100 C and 280 C. Annealing samples will destroys these band, resulting decreased conductivity in the upper zone Habbard, which leads to increase magneto resistance and decrease of negative values of magneto resistivity in the temperature range 13-30 K. It was established that influence of neutron irradiation on magnetic susceptibility whiskers Si0,97Ge0,03 is significantly less (over 30%) than in the case of single-crystal silicon grown by the Czochralski method. It is shown that in GaP LED irradiation by a-particles fluence Ф=1012 cm-2 was observed-effect small doses, which evident itself in the form of "improvement" parameters: increase capacity p-n-junction, reduction of the potential barrier between the areas and the value of the differential resistance of the CVC. The features are the result of nuclear reactions a-particles with atoms of the crystal, giving rise of additional donor levels. At high levels excitation of electronic subsystems of crystal will significant contribution to the structural ordering of the transition region and can create the effect of radiation-stimulated gettering of defects. Product Description popup.authors Варніна Валентина Іванівна Васильківський Анатолій Степанович Воробйов Володимир Герасимович Гайдар Галина Петрівна Долголенко Олександр Петрович Конорева Оксана Володимирівна Кочкін Василь Іванович Ластовецький Володимир Францевич Макуха Олександр Миколайович Малий Євгеній Вікторович Марченко Лариса Сергіївна Пінковська Мирослава Богданівна Петренко Ігор Віталійович Старчик Маргарита Іванівна Тартачник Володимир Петрович Шматко Галина Григорівна popup.nrat_date 2020-04-02 Close