  We report the results of theoretical investigations of tunneling current
noise spectra in a wide range of applied bias voltage. Localized states of
individual impurity atoms play an important role in tunneling current noise
formation. It was found that switching "on" and "off" of Coulomb interaction of
conduction electrons with two charged localized states results in power law
singularity of low-frequency tunneling current noise spectrum ($1/f^{\alpha}$)
and also results on high frequency component of tunneling current spectra
(singular peaks appear).
