Heavy-Ion Testing Method and Results of Normally OFF GaN-Based High-Electron-Mobility Transistor

Gallium nitride (GaN) power switches are promising devices for power conversion applications because this new technology enables the design of power converters with higher efficiency and reduced size than those achievable with conventional silicon devices. For space applications, normally-OFF devices are mandatory to avoid potential current shoot through during startup or loss of power control. The use of these devices in space environment shall be carefully considered with respect to natural radiation and especially under heavy-ion impact that can induce the burnout of the device known as single-event effect (SEE) failure. Therefore, radiation hardness evaluation of GaN devices is of prime interest. Another important parameter affecting GaN power device reliability is the current collapse or dynamic
$R_{\mathrm{\scriptscriptstyle ON}}$
since in particular functioning condition, the device can generate extra losses that may lead to failure. Five commercial off-the-shelf (COTS) GaN high-electron-mobility transistor (HEMT) references were selected and tested under heavy ions. This article presents first the testing methodology and device preparation used for heavy-ion test campaign. Then observations from the irradiation run are presented and discussed. At last, a potential dynamic
$R_{\mathrm{\scriptscriptstyle ON}}$
issue with respect to heavy-ion safe operating area (SOA) of one reference is highlighted.