Dose-Rate Dependence of the Total-Ionizing-Dose Response of GaN-Based HEMTs

Abstract

Significant threshold voltage Vth shifts are observed during 10-keV X-ray irradiation of AlGaN/GaN high-electron mobility transistors (HEMTs). Shifts are much smaller for lower dose-rate Cs-137 irradiation than that for higher dose-rate X-ray irradiation. This occurs because hydrogen transport and interactions with defects and impurities in these crystalline wide bandgap semiconductor materials differ fundamentally from those in amorphous SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . The electric field is also higher in GaN-based HEMTs than in bipolar base oxides. The absence of enhanced low-dose-rate sensitivity in these devices simplifies testing of GaN-based HEMTs for space applications. No significant X-ray-induced V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> shifts are observed in development stage InAlN/GaN HEMTs.