Correlation of the Spatial Variation of Single-Event Transient Sensitivity With Thermoreflectance Thermography in ${\text {Al}}_{x} {\text {Ga}}_{1-x}$ N/GaN HEMTs

Spatial variations of single-event transient (SET) sensitivity in Al
_0.25
Ga
_0.75
N/GaN HEMTs are revealed using focused, pulsed UV laser light. SETs in regions of enhanced sensitivity have larger amplitudes and are termed “hot spots.” They are the same regions where large temperature changes are observed with thermoreflectance thermography. Both effects are attributed to the presence of material defects: SETs with enhanced amplitudes have reduced decay times due to thermally assisted detrapping; increased temperature is due to carrier scattering by the same defects.