Radiation-Tolerant High-Voltage GaN Devices for Space Power Applications

Power electronic components with high operating voltages are desirable in NASA Power Management and Distribution (PMAD) systems as they result in reduced mass and higher efficiency at the system level. Gallium nitride (GaN) offers significant advantages over state-of-the-art silicon (Si) technologies for power electronic applications including higher breakdown voltage and power density, faster switching, and lower switching losses. High-voltage (HV) enhancement mode GaN-on-Sapphire multi-channel lateral Schottky barrier diode (SBD) technology has recently been demonstrated up to 10 kV breakdown voltage (BV), the highest in GaN devices till date. This GaN device technology is scalable for voltage.nbsp; Other commercial GaN power device technologies are known to show heavy-ion induced radiation susceptibility with leakage and catastrophic damage seen well below their rated voltages. A thorough investigation of the heavy-ion response of this emerging, HV GaN SBDs and underlying mechanisms is essential to developing radiation tolerant devices for space applications. We propose to use an integrated experimental and physics-based modeling approach to address this challenge. In Phase I, we will perform heavy-ion testing of the HV GaN SBDs to generate radiation response data. Detailed TCAD modeling of heavy-ion induced single-event effects (SEEs) will be performed for the SBD structures to investigate physical mechanisms driving the observed radiation response. In Phase II, we will perform additional heavy-ion and total dose testing as a function of temperature and bias. Extensive TCAD-based modeling will be performed to determine radiation and temperature-dependent physical mechanisms, and to investigate device design changes for improved radiation tolerance. Promising solutions will be prototyped and characterized via electrical and radiation testing. Participation by a commercial vendor of GaN devices in Phase II and beyond will ensure space qualified GaN power diodes.