Resolving Lateral Heat Transport in GaN-on-SiC HEMT Structures via Transient Thermometry

Understanding lateral heat transport in GaN high-electron-mobility transistors (HEMTs) is essential for the thermal management of high-power and high-frequency electronics. Here, lateral thermal transport in GaN HEMTs on 4H-SiC is investigated using electrical thermometry. Nonlocal temperature transients are measured using a pulse I–V technique combined with on-chip resistance thermometry, enabling high temporal and temperature resolution at lateral separations up to 424 𝜇⁢m from the heated channel. The employed technique resolves diffusion-controlled transient lateral heat transport, enabled by Joule-heating pulses that are approximately one order of magnitude shorter than the characteristic thermal diffusion time.