Ge-on-insulator (GOI) layer by the Ge-condensation technique is characterized from the viewpoint of the carrier transport. We fabricate GOI channel metal-oxide-semiconductor field-effect transistors (MOSFETs) featuring ultra-low Schottky barrier metal source/drain for holes using Pt germanide where a buried oxide and a silicon substrate are used as a gate dielectric and a bottom gate electrode, respectively. P-type and N-type channel MOSFET operations in the accumulation and inversion mode, respectively, are demonstrated successfully, according to Schottky barrier heights for each carrier. Hall measurement for the GOI layers indicates the existence of relatively high carrier density of holes, 1.3 x 10(17) cm(-1), which is not attributable to doped impurities. (c) 2005 Elsevier B.V. All rights reserved.