Electric field distribution in AlGaN/GaN high electron mobility transistors investigated by electroluminescence

Electric field distributions in AlGaN/GaN high electron mobility transistors have been assessed by studying electroluminescence and its spatial intensity distribution. Three gate architectures were compared: (i) standard gate, (ii) slant gate, and (iii) recessed slant gate with fluorination. It was found that differences in peak electric field strengths between devices, determined using electroluminescence, agreed well with simulations. However, recessed slant gate devices with fluorination exhibited a spread of electroluminescence intensity and therefore electric field distribution toward the drain contact by 0.2–0.3 μm which was not predicted by simulation. Implication of the disagreement between measured and simulated electric field distribution are discussed.