E.A. Il-Iichev - Dr.Sc. (Phys.-Math.), Senior Research Scientist, National Research University of Electronic Technology. E-mail: edil44@mail.ru
S.A. Kostrjukov - Ph.D. (Phys.-Math.), Senior Research Scientist, Regional Center Probe Microscopy for Collective Use when Ryazan State Radio Engineering University. E-mail: me@rsreu.ru
G.P. Zhigal'skii - Dr.Sc. (Eng.), Professor, National Research University of Electronic Technology. E-mail: gp@zhigalskii.com
T.A. Kholomina - Dr.Sc. (Phys.-Math.), Professor, Head of Department «Biomedical and Semiconductor Electronics», Ryazan State Radio Engineering University. E-mail: me@rsreu.ru
V.G. Litvinov - Ph.D. (Phys.-Math.), Associate Professor, Department «Biomedical and Semiconductor Electronics», Ryazan State Radio Engineering University. E-mail: me@rsreu.ru

With the development of nuclear and medical technologies become increasingly important work on improving nuclear particle detector, x-ray and gamma-radiations on alternative silicon materials and, above all, on the basis of gallium arsenide (GaAs). Detectors based on GaAs can work in areas with high temperature and high background radiation (for example, in nuclear reactors). This can significantly reduce operating voltages (up to 20-30 for the detectors of -particles), which is important in signal processing peripheral circuits. When using GaAs detectors can significantly increase the thermal and radiation resistance sensors of charged particles and radiation. One of the important tasks for the improvement of detectors is the choice of a design and technology of detectors of nuclear radiation on the criterion of ensuring the lowest level of excess low-frequency noise. Results of experimental investigation of excess noise in the detectors with gettered regions by Yb are presented. Investigations were carried out with structures fabricated on base of epitaxial GaAs layers. Structures preparing on layers with lower doping concentration have the lowest excess noise level. Variations of excess noise level in different frequency ranges on structures with different active contacts areas were determined.