No abstract available

No abstract available

[en] By secondary ion mass-spectrometry (SIMS) measurements of heavily doped (∼1x10²⁰ cm^-3) with boron silicon we have found, that the evolution of boron profiles from monotonous ones to the oscillated structures took place during annealing in the range 900-1075 deg. C, if silicon had been implanted with boron ions with the energy in the range 180-400 keV. The structures with five peaks seem quasi-periodic ones, and the mean period of these modulated distributions equal to 95 nm with the spread from 88 nm to 109 nm. The processes of the formation of these structures are localized at the flat parts of background boron profile, namely, in the region, which had been disturbed by ion implantation. The total amount of boron involved in these processes is conserved within experimental accuracy 10 % during annealing. At the same time the more deep parts of boron background distribution remained static, the front region of the background diffusive profile, especially. The temperature near 900 deg. C is high enough to exhaust both as vacancies, as interstitial atoms from all existing defect-impurity associations produced by room temperature implantation. Therefore, the phenomenon of spatial structures formation in boron distributions is discussed in terms of well-adopted suggestions about the interactions of point defects and impurity atoms. Scheme of quasi chemical reactions is proposed for most probable participants: free vacancies V and self interstitial atoms I, boron atoms at substitution positions B_S and mobile boron atoms at non-regular sites B_m. Three widely recognized micro processes have been included into it: the 'kick-out' reaction B_S+I→B_m, the reaction of the recovery of solubility limit B_m+I→B_S, and the chain of the reactions of impurity clustering B_m+B_n-1→B_n. On this base it became possible to match experimental findings very close to the theory of coalescence stage in supersaturated solid solution and to suggest the mechanism of self localization of boron atoms in the region, the boundaries of which was produced due to defect impurity interaction, as follows. At the very beginning of annealing the spread of vacancies from damaged region is limited by the reaction of mounting of impurity atoms into substitution positions, because the initial concentrations of B_m is high and B_s is low. Therefore, the vacancies are preferably locked in a damaged region. At the same time, the spread of self-interstitial atoms is limited by 'kick-out' reaction, but the rate of the letter is small in damage region due to the concentration Bs is near zero. Going out from damaged region, self interstitial atoms meet high concentration of substitution boron at the non-disturbed by implantation flat parts of background profile and produce the excess of boron atoms B_m at both sides of damaged region. By this way the initial and boundary conditions for further boron redistribution are quickly established as far as the relaxation of non - equilibrium concentration of elementary defects goes to completeness. First of all, three superior positions for spontaneous precipitation of boron are introduced. One of them is situated at the maximum of implanted ion distribution and two positions are situated near the approximate borders of damaged region. Than, micro gradients of B_m developed around these positions sustain the growth of boron clusters at these places and diffusive flow to them. The estimations of boron diffusivity through non-regular positions in a lattice were made, and these values surprisingly well coincide with boron diffusivity through a regular lattice sites under intrinsic conditions. The differences between resulted profiles after implantation and annealing of low and high-doped silicon are discussed

No abstract available

[en] The redistribution of nitrogen atoms implanted in synthetic diamond crystals was investigated by secondary ion mass-spectrometry in course of an isothermal annealing program at 1400 deg. C during 1, 5 and 20 h. It was shown that the nitrogen profiles spread at a macroscopic scale, and the broadening is well described in terms of the diffusion movement of impurity atoms. The preliminary estimates of diffusion coefficients were obtained: 2.3x10^-15 cm²/s for 1 h annealing, 8.5x10^-16 cm²/s for 5 h annealing and 3.7x10^-16 cm²/s for 20 h annealing

[en] Short communication

[en] Low-temperature photoluminescence (PL) of silicon irradiated by 1.5 MeV protons and 400 KeV H₂⁺ ions is investigated. At annealing temperatures over 300 deg C a number of new lines appears in PL spectra. New lines connected with hydrogen-containing complexes are discriminated by comparing the spectra of samples irradiated by protons and H₂⁺ with those irradiated by He₂⁺(800 KeV). The range of the annealing temperatures when the lines are observed is determined. The maximum number of lines appears when the annealing temperature reaches 550 deg C. The complete annealing of impurity radiation and restoration of exciton lines caused by doping impurity depend on the type of irradiation and dose and take place in the range of 550 - 700 deg C

[en] The main aim of the experiment has been the study of secondary radiative defects arising in conditions of radiation-enhanced diffusion (RED) in Si and in Ge as well, by means of electron microscopy. It has been stated that bar-like defects (BD) along <110> are the main type of defects in Si at Tsub(irrad.)=400-600 deg C and in Ge at 400 deg C. The electronmicroscopic analysis has shown that BD are of interstitial character and represent narrow plates with the habitus of (113). BD should be presented as deposits containing impurity atoms of oxygen and carbon along with the matrix interstitial atoms. The great diffusion mobility of the interstitial atoms causes the BD formation in the surface layer of Si crystal with the width up to approximately 5μm, which considerably exceeds Rsub(p) of protons approximately 2,5 μm. The temperature and radiation doze increases provide BD transfer into full dislocation loops. The active interaction of dislocation loops with vacancies at Tsub(irrad.) > or approximately 600 deg for Si is found which leads to sharp decrease of the BD and dislocation loop density in the irradiated crystals. High temperature irradiation (Tsub(irrad.)=400-800 deg C) with 500 keV H₂⁺ ions is used for radiation-enhanced diffusion (RED) of boron introduced into Si through implantation. The correlation between the BD existence and worsening of the p-n-junction properties obtained through RED, is observed. The BD presence is accompanied by leakage of charge carriers through p-n-junction

[en] The dependence of the boron distribution on the initial boron concentration in (1-9) x 10¹⁹ cm^-3 range have been studied by SIMS after a heat treatment at 900 deg C of a silicon implanted with boron ions. It as established that when the initial boron concentration exceeded the solid solubility limits in substitutional sites at the annealing temperature, there were two additional peaks on the boron concentration profiles which arise at both borders of the region disturbed by ion implantation. It was suggested, that its appearance in these regions at high doping level was due to clustering the interstitial boron atom excess

[en] Formed on n-Si layers of p-type conductivity with 0.7 μm thickness and boron concentration to 10¹⁹ cm^-3 were irradiated by Ar⁺ at 135 keV and doses of 10¹⁵ - 10¹⁷ cm^-2 at 900 deg C. Together with appearance of radiation-stimulated diffusion redistribution of boron was found a process of increased with dose accumulation of boron near the surface. The accumulation was accompanied by electric neutralization of acceptors. Boron neutralization effects was kept at annealings to 1100 deg C, moreover thermal stability of the effect was grown with the ion dose. Mechanism of the phenomenon is proposed. 12 refs., 3 figs