Local compressive stress generation in electron irradiated boron-doped Si0.75Ge0.25/Si devices



We have investigated the stress behavior in 2-MeV electron irradiated boron-doped Si0.75Ge0.25/Si-substrate heterojunctions by using Raman spectroscopy. For a high fluence (∼1x1018 e/cm2), the Raman peak of the Si-Si bonds in the boron-doped Si0.75Ge0.25 layer has a tendency to move toward the high wave number side. The tendency increases with increasing electron fluence. This could be explained by local compressive stress variations in the Si0.75Ge0.25 layer during irradiation with varying fluence, due to the difference in the generation probability of the knock-on atoms for silicon, germanium and boron. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)