A study was made of the electronic defects which were produced by the proton-bombardment of relaxed epitaxial p-type Si1-xGex layers that had been grown by means of molecular beam epitaxy. Specimens with x-values of between 0 and 0.25 were investigated by means of deep-level transient spectroscopy. Three predominant lines in the deep-level transient spectra were observed and were related to di-vacancies, interstitial C, and interstitial B plus substitutional C pairs. It was found that, for all 3 levels, the activation enthalpy relative to the valence band decreased with increasing Ge content. Further study demonstrated that the annealing of the defect level which was attributed to interstitial C was retarded with increasing Ge content. Meanwhile, the annealing temperatures of the other 2 defects were similar to those observed in Si. The behaviors of the activation enthalpies, with increasing Ge content, of the levels that were associated with Ci and BiCi were found to be almost identical even though the levels were quite different.

E.V.Monakhov, A.N.Larsen, P.Kringhøj: Journal of Applied Physics, 1997, 81[3], 1180-3