  The effect of doping of cubic boron nitride with beryllium, silicon, sulfur
and magnesium on the lattice parameters, electrical conductivity and EPR
spectra has been studied. It is established that the degree of doping increases
significantly in the case of crystallization of cubic boron nitride from BN
solutions in supercritical ammonia at 3.9-4.2 GPa and 1100{\deg}C in comparison
with the conventional synthesis from melts of the Mg-B-N system at 4.2 GPa and
1400{\deg}C. Doping with silicon and beryllium results in semiconductor
properties of cubic boron nitride.
