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The electrical properties of GeO1-xNx/HfO2 stack deposited by atomic beam on Ge are reported. The incorporation of N in the GeOx layer is found to be quite beneficial in reducing the gate leakage current, improving the uniformity of the device characteristics and reducing the equivalent oxide thickness of the gate stack down to about 0.8 nm. On the other hand, N incorporation also leads to a large density of fixed positive charges and slow states, which can be reduced by post- deposition anneals in O2 or N2. These gate stacks were successfully integrated into a simple transistor flow with TiN gates. Both n and p-channel transistors show promising electrical characteristics, with Ion/Ioff ratios of about 4 to 5 orders of magnitude. However, the mobility of the n-channel devices is found to be extremely low, which is most likely due to a large density of acceptor-like interface states in the upper-part of the Ge band-gap.