Targeted Germanium Ion Irradiation of Aluminum Gallium Nitride/Gallium Nitride High Electron Mobility Transistors
AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH WRIGHT-PATTERSON AFB United States
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Microscale beams of germanium ions were used to target different locations of aluminum gallium nitridegallium nitride AlGaNGaN high electron mobility transistors HEMTs to determine location dependent radiation effects. 1.7 MeV Ge ions were targeted at the gap between the gate and the drain to observe displacement damage effects while 47 MeV Ge ions were targeted at the gate to observe ionization damage effects. Electrical data was taken pre, during, and post irradiation. To separate transient from permanent degradation, the devices were characterized after a room temperature anneal for at least 30 days. Optical images were also analyzed pre and post irradiation. This is the first use of localized dynamic irradiation testing has been used to compare AlGaNGaN HEMT performance to the results of stress testing via in situ measurements of the gate and drain currents. The 6 MV Tandem Accelerator at Sandia National Laboratories using the Micro-ONE system was used to induce displacement and ionization damage. Displacement damage was caused by 1.7 MeV Ge ions targeting the gate-drain gap of ten HEMTs in the off, on, and semi-on bias states where a fluence dependent delayed response between ion deposition and gate current degradation in the semi-on and on bias state was observed. The delayed response was also observed in the drain current degradation when biased in the semi-on state, while occurring immediately in the on state. Ionization damage was induced by 47 MeV Ge ions targeting the gate region in the semi-on bias state where gate current degradation occurred during the initial irradiation of the gate active region. Drain current degradation occurred in both the initial and subsequent irradiations. Pre and post irradiation output and transfer performance characteristics indicate drain current and transconductance degradation for both experiments in all bias states.
- Electrical and Electronic Equipment