The nature of interaction of point and linear defects in semiconductor boron doped with zirconium (∼ 1.5% at.) has been studied using electron microscope and internal friction methods. It was shown that doping with zirconium promoted the multiplication of polysynthetic twins and stacking faults. A computer simulated analysis of diffraction patterns was performed in terms of trigonal presentation. At the frequency of free torsional vibrations of ∼ 1Hz a high level of internal friction with maxima at 250, 300–320 and 380–420°C was revealed. It is supposed that the maxima are respectively due to: the twin-boundary motion accompanied by breaking of intericosahedral bonds (a); the process of ordering-disordering of atoms in the impurity atmospheres under the continuous change of the temperature and elastic fields of moving twinning dislocations in the {100} system (b); the impurity controlled twin-boundary motion in the {511} system.

Amorphous powders of boron isotopes have been studied in the temperature range 100–450 K using EPR method. It was shown that paramagnetic centers with g=2.0029 ± 0.0001 are the holes captured on trapping levels. The centers represent volume defects. On the basis of temperature dependent measurements of the concentration of paramagnetic centers and their linewidth an energetical parameter of trapping level equal to 0.11eV over valence band was defined. An observed strong narrowing of the EPR line is connected with the increase of the frequency of delocalization of electrons with temperature. The structure of powders was studied by electron microscope method. Experimental results confirm the existence of icosahedral arrangement in amorphous boron.