MMICs on Single Crystal AlN for Extreme RF Systems

Congestion of the radio frequency spectrum and increased bandwidth demands are pushing wireless systems to higher and higher frequencies. In order to maintain performance overmatch, high power RF transistors and diodes using extreme bandgap semiconductor (EBS) AlN and Al-rich AlGaN are being developed on single-crystal AlN substrates. For final deployment, however, microwave monolithic integrated circuits (MMICs) are needed. We thus propose to build on the development of discrete devices to demonstrate the first single-crystal AlN MMICs. Phase I will focus on the microwave and mmWave characterization of AlN substrates in order to enable transmission line demonstrations up to W-Band frequencies. In Phase II, AlN will be characterized up to 170 GHz to capture behavior through W- and D-Bands. Through substrate via technology (TSV) will be developed to enable low-loss substrate-integrated waveguides at these frequencies. Ultimately, an AlN MMIC phase shifter will be demonstrated via integration with an AlN-based diode.