Excellent electrical performance has been achieved on Ge meta I-oxide-semiconductor (MOS) devices using molecular beam epitaxy (MBE)-deposited dielectrics of Al2O3/Y2O3 directly on Ge(1 0 0) without utilizing any interfacial layers, such as GeOxNy or Si. Slight Ge diffusion into Y2O3 was observed using in-situ X-ray photoelectron spectroscopy. The interface between Y2O3 and Ge is atomically smooth after a high-temperature anneal at 500 degrees C for 10 min as characterized using high-resolution transmission electron microscopy. A high kappa value of Y2O3 of similar to 17.3 and a low gate leakage current density of 7.6 x 10(-9) A/cm(2) have been obtained from the MOS capacitors with a total capacitance equivalent thickness (CET) of 2.41 nm. Furthermore, ring-type p-channel MOS field-effect transistors with the same gate oxides have exhibited a high drain current density of 98 mA/mm, a peak transconductance of 43 mS/mm, and a hole mobility of 241 cm(2)/V S with a gate length and a gate width of 4 and 400 mu m, respectively. (c) 2008 Elsevier B.V. All rights reserved.