A.A. Golubeva - Post-graduate Student, Department «Physics», Yuri Gagarin State Technical University of Saratov. E-mail: annamoroz@mail.ru N.M. Ushakov - Dr. Sc. (Phys.-Math.),проф, Head of Laboratory of Submicron Electronics, Saratov branch of Kotel\'nikov IRE of RAS. E-mail: nmu@bk.ru