▎ 摘　　要

We report that the deposition of graphene as a heat spreading layer on AlGaN/GaN/sapphire high electron mobility transistors (HEMT) can lower the temperature of localized hot spots, which can reach as high as 300 degrees C. As the number of gate fingers increased, the peak channel temperature also increased. From our simulation, graphene was shown to be extremely effective in distributing the localized heat in both SiC and sapphire substrates. The reliability of AlGaN/GaN HEMT can be remarkably improved by using a graphene layer because it can act as a heat-spreading layer and lower the temperature of localized hot spots, which are known to limit device performance and activate the formation of defects.