In this work sSi nMOSFETs with 13 run sSi thickness on 27% Ge virtual substrates (VS) are investigated and an increased LF noise level with a characteristic gate bias dependence is found. High off-state leakage of the MOSFETs indicates the presence of misfit dislocations in the channel region. A channel conductance based model is proposed to analyse the noise originating from a highly localized defect in the channel.