The present report submitted to the Anniversary Conference of the A. F. Iof
fe Physicotechnical Institute, "Physics at the Turn of the 21st Century," d
eals with recent EPR studies of main impurities in the wide-gap semiconduct
ors SiC and GaN, which appear to be the most promising materials for microe
lectronics and quantum semiconductor electronics at the start of the 21st c
entury. (C) 1999 American Institute of Physics. [S1063-7834(99)00905-3].