High power solid state amplifiers on non-polar AlN substrates for ground-based missile defense system radars

Research efforts will focus on design, simulation and fabrication of X-band transistors for use in power amplifiers and T/R modules for missile defense radar systems. Innovative, next generation nitride based power transistors will be fabricated on non-polar native AlN substrates. This will enable new device designs without the strong polarization fields associated with typical nitride growth along the c-direction. Gate and channel breakdown along with RF-to-dc dispersion will be reduced or eliminated in the proposed devices. Novel device structures will not require Fe doping in the buffer layers or field plate extensions on the gate which will increase the gain and frequency response of the devices. New physical modeling will be developed to better understand the non-polar device performance and fed back to aid the epitaxial material development on non-polar nitride crystals. Epitaxial growth optimization on non-polar substrates will be extensively investigated to produce device quality films and heterostructures required for high performance, long lifetime devices for next generation X-band radar system. Nucleation strategies and growth parameters have proven to be quite different for the non-polar face substrates. In addition, transport properties of the 2DEG will be monitored on transistor structures to assess improvements in the material quality.