High-energy proton irradiation effects on GaN hybrid-drain-embedded gate injection transistors

The characterization of commercial-grade power transistors upon high levels of particle irradiation is required to enable radiation tolerant LED power supplies for the new luminaires of CERN accelerator tunnels, which represent a harsh environment for semiconductor devices. This work describes the effects of 24 GeV/c proton irradiation on commercial GaN hybrid-drain-embedded gate injection transistors (HD-GITs) after a fluence of $5.9 × 10^{14}$ p/cm$^2$. Measurements of drain leakage current, threshold voltage and $I_{\textrm{ds}} − V_{\textrm{ds}}$ curves show that only a minor variation occurs in the electrical properties of GaN HD-GITs after the considered fluence; for example, an average increase of ≈11–13 mV is found in the threshold voltage upon irradiation. We also put forward a physical explanation of the observed degradation caused by proton irradiation; in particular, the electron drift velocity in the 2DEG channel at high electric fields appears to decrease due to a radiation-induced increase in phonon relaxation rate. Finally, an AC/DC LED power supply with current control using GaN HD-GITs is proposed for the new luminaires of CERN tunnels, meeting the requirements in terms of radiation hardness and light quality.