We have experimentally fabricated Ge-nanocrystals (ncs) metal-oxide-semiconductor field-effect transistors (MOSFETs) with significant capacitance-voltage hysteresis window, threshold voltage shift and good retention. The Ge-ncs/SiO2 system has a good charge storage capability with a charge loss of 12.5% after 10 years retention. This work shows that the heart of the nonvolatile memory transistors, Ge-ncs, is formed by thermal oxidation of polycrystalline Si0.88Ge0.12, which is a simple method and can be easily adapted in the fabrication of embedded circuits.