Molecular beam epitaxial samples, which contained multiple B δ-layers and a single Sb δ-layer, were sputter depth-profiled using O2+ ions with incident energy of 8.2 or 3.2keV. The leading and trailing edges of the B distributions exhibited an anomalous broadening which was caused by the sputtering. This appeared to increase with ion energy. The effect was not observed in the case of the Sb distribution. The incorporation of substitutional C, to concentrations of about 1019/cm3, almost completely suppressed the broadening. It was concluded that the broadening was due to the injection of Si self-interstitials from the region which was damaged by ion bombardment. Such interstitials could migrate far beyond the mixing depth, and interact with B, thus permitting the mixing of B atoms before the distribution was within the expected mixing depth.

Injection of self-interstitials during sputter depth-profiling of Si at room temperature J.Cardenas, B.G.Svensson, W.X.Ni, K.B.Joelsson, G.V.Hansson: Applied Physics Letters, 1998, 73[21], 3088-90