In this paper a Gallium Nitride MMIC technology for RF‐ and microwave and high power amplifiers based on 100 nm gate technology is presented. The MMIC technology includes alloyed ohmic contacts, T‐shaped 100 nm gates, air‐bridges, MIM capacitors, inductors, and a full through wafer viahole backside process. As a key element for a high MMIC yield, we'll present low ohmic contact resistances with a high yield on several wafers in different processing batches and low leakage currents for a reliable device performance, respectively. Single HEMT performance exhibits PAE values of up to 60% and power densities of 1.3 W/mm. For a single stage power amplifier with a WG = 4 × 45 µm dual‐gate HEMT configuration, a gain beyond 10 dB at 60 GHz is presented. By using only one transistor for the amplifier stage, a maximum output power of more than 21 dBm and a PAE of 9.3% is achieved. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)