Gallium Nitride Devices on Semi-insulating Gallium Nitride Substrates for Advanced T/R Modules

Existing T/R modules are based on gallium arsenide (GaAs) transistors and power amplifiers. Current and future XBRs would benefit from improved resolution, enhanced discrimination, and increased power. Significant XBR performance enhancement can beachieved by developing T/R modules that incorporate gallium nitride (GaN) -based power amplifiers. High-performance GaN-based devices, such as HEMTs, have been demonstrated on sapphire and silicon carbide substrates; however, their device performance hasbeen limited due to growth on non-native substrates. The limiting factors in many high performance microelectronic applications based on GaN and GaN-related materials can be attributed directly to material defects in heteroepitaxially grown layers onnon-nitride substrates. This program will utilize semi-insulating gallium nitride wafers to produce high-performance GaN microelectronic devices for X-band radar applications. Kyma will develop and demonstrate novel device designs based on semiinsulating GaN substrates. Growth on a native GaN substrate will yield lower defects resulting from, improved device design, including features such as gate recess and passivation layers, and device cooling. The main goals of the Phase I program includeproof of concept epitaxial growth, device fabrication, and testing. Phase II work will focus on the further development of devices and integrated power amplifier modules. GaN-based FET technology with high device efficiency, stability, and reliabilitywill benefit commercial electronic applications throughout several industries, including wireless communications infrastructure and mobile phones, commercial radar, and satellites. Demonstration of the applicability of GaN substrates in these applicationswill expand their implementation in other technological areas, such as improving the performance of GaN-based optoelectronic devices.