Impact of Channel Effects on Radiation-Hardened InAlGaN HEMTs for Low-Earth-Orbit Applications

This study investigates the impact of channel thickness effects on the radiation hardness of InAlGaN HEMTs under 90 MeV proton irradiation for low-earth-orbit (LEO) applications. Devices with varying channel thicknesses (50, 100, and 150 nm) were exposed to proton fluences ranging from 2 × 10¹⁰ to 2 × 10¹³ protons/cm². Results show that the 100 nm channel thickness exhibits superior radiation hardness, maintaining higher mobility, lower sheet resistance, and superior DC and RF performance compared to other thicknesses, even at high proton fluences. Ionizing energy loss is identified as the dominant contributor to degradation, although both ionization and displacement damage mechanisms are observed. Gate leakage current remains relatively stable across all proton fluences and thicknesses due to the counteracting effects of irradiation-induced knock-on atoms. These findings highlight the importance of channel thickness optimization for enhancing the radiation tolerance of InAlGaN HEMTs in demanding applications.