Single Event Burnout Hardening of Enhancement Mode HEMTs With Double Field Plates

Single event burnout (SEB) of enhancement mode GaN high-electron mobility transistors (HEMTs) under heavy ion irradiation is systematically studied based on simulations in this work. Susceptibility to SEB of different particle incidence environments is investigated to determine the device's sensitive position. Under these conditions, the mechanism of SEB in enhancement mode HEMTs is mainly associated with the charge congestion and subsequent continuous impact ionization. A hardened HEMT structure with the gate and drain double field plates is proposed correspondingly. Apart from better output characteristics and almost 25% improvement of breakdown voltage, the hardened structure also demonstrates better tolerance of SEB. This hardened structure can modify the electric field in the high field region so that charge accumulation is reduced significantly, thus effectively decreasing the possibility of SEB's occurrence. With a vertical heavy ion strike of 63.8 MeV ·cm
²
/mg linear energy transfer (LET), SEB threshold voltage of the conventional structure HEMT is 160 V, while that of the hardened structure HEMT is much higher, reaching 249 V. Besides, the hardened device exhibits better SEB tolerance than the conventional device even at different higher LET conditions. Furthermore, the contribution to SEB tolerance of each field plate is also discussed.