Normally-off AlGaN/GaN Low-Density-Drain HEMTs (LDD-HEMT) with Enhanced Breakdown Voltage and Suppressed Current Collapse

We report a low-density drain HEMT (LDD-HEMT) that exhibits enhanced breakdown voltage and reduced current collapse. The LDD region is created by introducing negatively charged fluorine ions in the region between the gate and drain electrodes, effectively modifying the surface field distribution on the drain side of the HEMT without using field plate electrodes. Without changing the device physical dimensions, the breakdown voltage can be improved by 50% in LDD-HEMT and the current collapse can be reduced. No degradation of current cutoff frequency (f_t) and slight improvement in power gain cutoff frequency (f_max) are achieved in the LDD-HEMT, owing to the absence of any additional field plate electrode.