The deep hole traps which were introduced into relaxed epitaxial Si0.70Ge0.30 on Si, by dislocations and other relaxation-induced defects, were compared to the hole traps that were introduced by the plastic deformation of bulk Si. The deep-level transient spectra for these samples were shown to be almost identical in every respect. The key difference was a translation in temperature which resulted from a change in valence-band energy with SiGe composition. A one-to-one correlation was found between each hole trap that was detected in p-type Si0.70Ge0.30, and a given level in p-type plastically deformed bulk Si. The difference in deep-level transient spectroscopic activation energy between each correlated level was approximately equal to the difference in valence-band energy (about 0.12eV) between relaxed Si0.70Ge0.30 and bulk Si. It was concluded that these hole traps were characteristic of the defects which were introduced into Si0.70Ge0.30 by plastic strain; regardless of the composition and deformation method. This implied the existence of invariant defect configurations. The comparison also revealed a hole trap at H(0.60), in Si0.70Ge0.30, which had not previously been reported in plastically deformed Si. It was tentatively attributed to hole capture at dislocation kink sites.

P.N.Grillot, S.A.Ringel: Applied Physics Letters, 1996, 69[14], 2110-2