Experimental Insights into the Role of Inter-valley and Defect Transitions of Hot Electrons in Determining Self-heating in AlGaN/GaN HEMTs

In this work, we reveal the presence of unique phonon-assisted hot electron transitions during semi-ON state operation of AlGaN/GaN HEMTs resulting in distinct self-heating behavior of the device. This establishes the importance of considering hot electron-triggered transitions, in addition to conventionally considered self-heating sources, while estimating heating effects in these devices. The phenomena are probed through detailed experimentation involving devices with different field plate lengths, electroluminescence microscopy and spectroscopy, and thermal imaging analysis.