Positron annihilation spectroscopy was applied to study relaxed P-doped n-type Si1-xGex layers with Ge concentrations up to 30%. As-grown SiGe layers were defect-free and annihilations were superpositions from bulk Si and Ge. Proton irradiation at 2MeV energy with a 1.6 x 1015/cm2 fluence was used to produce saturated positron trapping in monovacancy related defects. The defects were identified as V–P pairs, the E-center. The distribution of Si and Ge atoms surrounding the E-center was the same as in the host lattice. The vacancy migration process leading to the formation of V–P pairs therefore did not seem to have a preference for either Si or Ge atoms.

Vacancy-Impurity Pairs in n-Type Si1-xGex Studied by Positron Spectroscopy. M.Rummukainen, J.Slotte, K.Saarinen, H.H.Radamson, J.Hållstedt, A.Y.Kuznetsov: Physica B, 2006, 376-377, 208-11