By Dr Matt Smith, Researcher, Tyndall National Institute
In recent years the discovery of hundreds of extra-solar planets has led to the consideration of Jupiter as a gas-giant archetype, and the emerging field of astrobiology has refocused the search for extra-terrestrial life on its larger moons.
Proper investigation of the Jovian system is currently limited by the stability and reliability of the electrical components used to process experimental data aboard unmanned probes and transmit back to Earth. In this work I investigate InAlN/GaN high electron mobility transistors (HEMTs) as a candidate for future missions, such as the European Space Agency’s upcoming Jupiter Icy Moon Explorer, based on the recent successes of the established AlGaN/GaN HEMT technology. InAlN HEMTs showed good suitability for space applications through electrical characterization after exposure to high temperatures and gamma radiation and by extended bias stressing. A comparison between InAlN and AlGaN HEMTs, both in various stages of development, highlighted the great potential of the material system to provide space-ready electronics. The physics behind HEMT operation was explored, leading to optimisation of device performance and reliability and culminating in the realization of InAlN HEMTs manufactured in a typical AlGaN HEMT production environment. The success of the project sets the stage for wide-scale implementation of GaN-based electronics in the space industry, which is expected to occur in the years to come, and circumvents the major obstacle of electrical failure from mankind’s route to exploring and understanding the universe at large.