Date of Award
Master of Science
Department of Engineering Physics
James C. Petrosky, PhD
In this research, the first ever neutron irradiation study of AlGaN/GaN MODFETs was conducted. Devices irradiated to a total 1 MeV Eq (Si) neutron fluence of 1.2x1016 n/sq cm demonstrated the temperature dependence of irradiation and annealing. Devices irradiated at 80 K exhibited significant persistent electrical degradation at only 5.4 rad (Si), whereas those irradiated at elevated temperatures exhibit transient increases in gate and drain current up to 400 krad (Si). I-V measurements indicate substantial radiation-induced increased gate and drain currents occur only at low-temperature irradiations. The introduction of a high-density of donor defects is hypothesized as the primary cause of both increased values. Irradiating at temperatures > 300 K effectively reduces total accumulated dose effects even at 400 krad(Si). Further analysis of the Schottky contacts has determined that the devices are field-emission and defect-assisted tunneling dominated at all temperatures. The Schottky diode parameters were extracted using a novel six-parameter fitting routine. To the authors knowledge this is the first application of such theory on AlGaN/GaN MODFETs.
DTIC Accession Number
Uhlman, Troy A., "Temperature Dependent Current-Voltage Measurements of Neutron Irradiated Al0.27Ga0.73N/GaN Modulation Doped Field Effect Transistors" (2005). Theses and Dissertations. 3745.