Comprehensive Analysis of DC, Pulsed, and RF Performance of Submicron GaN-on-Si MIS-HEMTs Under Gamma Radiation

This study comprehensively investigates the impact of gamma radiation on the DC, pulse, and RF performance of GaN-on-Si MIS-HEMTs exposed to a total dose of 100 kGy. The DC performance reveals an enhancement in drain current and transconductance along with reduced contact and sheet resistance, as confirmed through input, output and TLM measurements. Breakdown analysis further supports these improvements, revealing decreased leakage currents across the gate, drain, and buffer, which lead to reduced leakage paths and higher breakdown voltages. Furthermore, the pulse I-V measurements show minimal threshold voltage shift and reduced current collapse, providing evidence of diminished trapping sites in the gate-drain access region post-gamma radiation. The study also explores improvements in small-signal (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f$</tex><inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</inf> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f$</tex><inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MAX</inf>) and large-signal (η) RF figures of merit, as evidenced by S-parameter and load-pull measurements. These experimental findings highlight the exceptional robustness of GaN-on-Si MIS-HEMTs under gamma radiation, enhancing their suitability for harsh and space applications.