Electrical properties of Si:Er/Si layers grown by sublimation molecular-beam epitaxy

Temperature dependences of the concentration and electron Hall mobility in Si:Er/Sr epitaxial layers grown at T = 600 deg. C and annealed at 700 or 900 deg. C have been investigated. The layers were grown by sublimation molecular-beam epitaxy in vacuum (∼10-5 Pa). The energy levels of Er-related donor centers are located 0.21-0.27 eV below the bottom of the conduction band of Si. In the range 80-300 K, the electron Hall mobility in unannealed Si:Er epitaxial layers was lower than that in Czochralski-grown single crystals by a factor of 3-10. After annealing the layers, the fraction of electron scattering from Er donor centers significantly decreases