Schottky contacts offer the possibility of an implantless fabrication process for p-channel germanium MOSFETs. Nickel germanide Schottky contacts, formed by rapid thermal annealing of thin nickel films, have been characterized on n-type germanium wafers for a range of RTA temperatures. The highest Schottky barrier heights for electrons (phi(Bn) = 0.6-0.7 eV) were obtained for RTA temperatures of approximately 300 C. For this RTA schedule, the corresponding barrier height for holes is close to zero, ideal for Schottky contacted p-channel germanium MOSFETs. When the RTA temperature was increased to 400 degrees C, a dramatic reduction in electron barrier height (phi(Bn) < 0.1 eV) was observed. This RTA schedule, therefore, appears ideal for ohmic source/drain contacts to n-channel germanium MOSFETs. From sheet resistance measurements and XRD characterization, nickel germanide formation was found to occur at 300 degrees C and above. The NiGe phase was dominant for RTA temperatures up to at least 435 degrees C.