Germanium is an attractive candidate for ultra fast CMOS technology due to its potential for doubling electron mobility and quadrupling hole mobility in comparison to silicon. To maintain the requirements of the International Technology Roadmap for Semiconductors (ITRS), high-kappa insulators and metal gates will be required in conjunction with Ge technology. Key issues which will have to be addressed in achieving Ge technology are: trap free insulators, assessment of appropriate crystallographic orientations and the selection of gate metals for the best mobility. In this work mobilities are evaluated for Ge-nMOSFET with two metal gates (Al and TiN) and high-kappa (HfO(2)) insulator. Scattering with bulk phonons, surface roughness and high-kappa phonons are taken into account. It is predicted that Al as the gate material on Ge {100} substrate performs 50% better than Ge {111} orientation at a sheet concentration of 1 x 10(13) cm(-2). Surface roughness is likely to be the most damaging mobility degradation mechanism at high fields for Ge {111}. (C) 2008 Elsevier B.V. All rights reserved.